A large tear-drop shaped balloon towers above surrounding work trucks on a flat expanse of snow.

Get to know GUSTO and learn how to bring the science and engineering behind this unique balloon-based mission into the classroom.


A NASA balloon mission designed to study the interstellar medium – the space between stars – will take to the skies above Antarctica in December 2023.

Read on to learn how the GUSTO mission's unique design and science goals can serve as real-life examples of STEM concepts. Then, explore lessons and resources you can use to get students learning more.

What the GUSTO Mission Will Do

Though many people think of space as empty except for things like stars, planets, moons, asteroids, meteors, and comets, it’s anything but. Typically, there is one molecule of matter in every cubic centimeter of the space between stars known as the interstellar medium. In more dense clouds of interstellar gas, there could be as many as 1,000,000 molecules per cubic centimeter. It might not seem like much compared with the 10,000,000,000,000,000,000 molecules in every cubic centimeter of air we breathe, but the interstellar medium can tell us a lot about how stars and planets form and what role gases and dust play in our galaxy and others.

Star-forming nebulas birth Sun-like stars, which turn into red giants, then planetary nebulae, then white dwarfs. Massive stars are also born from star-forming nebulas and become red supergiants, then supernova, then either black holes or neutron stars.

This diagram shows the life cycles of Sun-like and massive stars. Credit: NASA, Night Sky Network | › Learn more about star life cycles

Like plants and animals, stars have a life cycle that scientists want to better understand. Gases and dust grains that make up a dense interstellar cloud, known as a nebula, can become disturbed, and under the pull of their own gravity, begin collapsing in on themselves. Eventually stars form from the gas and planets form from the dust. As a star goes through its life, it eventually runs out of sources of energy. When this happens, the star dies, expelling gases – sometimes violently, as in a supernova – into a new gas cloud. From here, the cycle can start again. Scientists want to know more about the many factors at play in this cycle. This is where GUSTO comes in.

GUSTO – short for Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory – is a balloon-based telescope that will study the interstellar medium, the small amount of gas and dust between the stars. From its vantage point high above almost all of the Earth’s atmosphere, GUSTO will measure carbon, nitrogen, and oxygen emissions in the far-infrared portion of the electromagnetic spectrum, focusing its sights on the Milky Way galaxy and the nearby galaxy known as the Large Magellanic Cloud.

A speckled field of bluish stars is intersected by a diagonal strip of purple and brown clouds covering a glowing yellow band beyond.

Our galaxy, the Milky Way, has hundreds of billions of stars and enough gas and dust to make billions more stars. Credit: NASA | › Full image and caption

The mission is designed to provide scientists with data that will help them understand the complete lifecycle of the gas and dust that forms planets and stars. To achieve its goals, GUSTO will study:

  • The composition and formation of molecular clouds in these regions.
  • The formation, birth, and evolution of stars from molecular clouds.
  • The formation of gas clouds following the deaths of stars. And the re-start of this cycle.
Thick clouds of purple and pastel pink cover a speckled field of stars with clusters of large and especially bright blue and yellow stars glowing through the clouds.

Nearly 200,000 light-years from Earth, the Large Magellanic Cloud is a satellite galaxy of the Milky Way. Vast clouds of gas within it slowly collapse to form new stars. In turn, these light up the gas clouds in a riot of colors, visible in this image from the Hubble Space Telescope. Credit: NASA | › Full image and caption

Scientists hope to use the information collected by GUSTO to develop models of the Milky Way and Large Magellanic Cloud. Studying these two galaxies allows scientists to observe more details and make more accurate models. Those models can then be used for comparing and studying more distant galaxies that are harder to observe.

Why Fly on a Balloon?

Unlike most NASA missions, GUSTO won’t launch on a rocket. It will be carried to approximately 120,000 feet (36.5 kilometers) above Antarctica using what’s known as a Long Duration Balloon, or LDB.

Balloon missions provide a number of advantages to scientists conducting research. They are more affordable than missions that go to space and require less time to develop. They also offer a way to test new scientific instruments and technologies before they are used in space. For these reasons, balloons have become a popular way for university students to gain experience building and testing science instruments.

Explore how balloons are being used for Earth and space science in this video from the Johns Hopkins Applied Physics Laboratory, which is providing the mission operations for GUSTO and the balloon gondola where the mission's instruments will be mounted. | Watch on YouTube

GUSTO's use of the Long Duration Balloon provided by NASA’s Balloon Science Program offers several advantages over other types of scientific balloons. Conventional scientific balloons stay aloft for a few hours or a few days and rely on the balloon maintaining a line-of-sight to send and receive data. Long Duration Balloons use satellites for sending data and receiving commands and can stay afloat for a few weeks to a couple of months.

Made with a thin, strong, plastic film called polyethylene, LDBs are partially inflated with helium. As the balloon rises, the surrounding air pressure decreases, allowing the gas inside the balloon to expand, increasing the volume and pressure of the balloon. When fully expanded, the balloon has a volume of around 40 million cubic feet (1.1 million cubic meters). That’s big enough to fit an entire football stadium inside.

An A-frame support structure with two sets of wing-like solar panels extending from its sides floats above Earth holding a telescope at its center.

GUSTO will be attached to a balloon gondola like the one depicted in this artist's rendering. | + Expand image

The telescope itself will be attached to a platform known as a gondola, which is home to several components that make the mission possible. The multi-axis control system will keep the platform stable during flight, allowing for precisely pointing GUSTO’s 35-inch (90-centimeter) diameter telescope in the right direction. Cryocoolers and liquid helium will keep the telescope’s scientific instruments at the necessary low temperature of -452°F (4° Kelvin). And the gondola will house a radio system that allows operators on the surface to control the balloon and telescope. All these systems will be powered by lithium-ion batteries charged during flight by a set of solar arrays.

Location is Everything

GUSTO is designed to measure terahertz wavelengths (in the far-infrared portion of the electromagnetic spectrum), a range of energy that is easily absorbed by water vapor. However, the observatory's altitude will put it in the upper half of the stratosphere and above 99% of the water vapor in the atmosphere. This makes it an ideal location for the mission to make its measurements and avoid factors that might otherwise obstruct its view.

GUSTO will make its observations from the upper half of the stratosphere, which offers several benefits over observing from lower in the atmosphere or from the ground. Credit: NASA | › Explore the interactive graphic

The stratosphere offers another advantage for GUSTO. This layer of the atmosphere warms as altitude increases, making the top of the stratosphere warmer than the bottom. The colder air at the bottom and warmer air at the top prevents mixing and air turbulence, making the air very stable and providing a great place to observe space. You may have noticed this stability if you’ve seen a flat-topped anvil-shaped storm cloud. That flat top is the cloud reaching the bottom of the stratosphere, where the stable air prevents the cloud from mixing upward.

But why fly GUSTO above Antarctica? Even though balloons can be launched from all over the planet, the 24 hours of sunlight per day provided by the Antarctic summer make the south polar region an ideal launch location for a solar-powered mission like GUSTO. But more important is a weather phenomenon known as an anticyclone. This weather system is an upper-atmosphere counter-clockwise wind flow that circles the South Pole about every two weeks. The Antarctic anticyclone allows for long balloon flights of missions that can be recovered and potentially reflown.

Preparing for Liftoff

To launch a balloon mission in Antarctica, weather conditions have to be just right. The anticyclone typically forms in mid-December but can arrive a little earlier or a little later. Even with the anticyclone started, winds on the ground and in the first few hundred feet of the atmosphere need to be under six knots (seven miles per hour) for GUSTO to launch. A NASA meteorologist provides daily updates on the cyclone and the ground.

Once weather conditions are good and the balloon is launched, it will circle Antarctica about once every 14 days with the wind. The anticyclone typically lasts one to two months. Because GUSTO may be in the air for more than two months, it’s possible that the mission will continue after the anticyclone ends, causing the balloon to drift northward as winter progresses.

Bring GUSTO Into the Classroom

The GUSTO mission is a great opportunity to engage students with hands-on learning opportunities. Students can build a planetary exploration balloon and model how interstellar dust forms into planets. Explore these lessons and resources to get students excited about the STEM involved in the mission.

Resources for Educators

Resources for Students


NASA's Universe of Learning materials are based upon work supported by NASA under award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and the Jet Propulsion Laboratory.

TAGS: GUSTO, Astronomy, Astrophysics, Science, Teaching, Learning, K-12, Classroom, Teachable Moments, Universe of Learning, Balloon Mission, Missions

  • Lyle Tavernier
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A long boom extends from a cylindrical telescope floating above Earth. At the end of the spacecraft's boom are three converging circular mirrors, like petals on a flower.

A NASA space telescope mission is giving astronomers a whole new way to peer into the universe, allowing us to uncover long-standing mysteries surrounding objects such as black holes. Find out how it works and how to engage students in the science behind the mission.


Some of the wildest, most exciting features of our universe – from black holes to neutron stars – remain mysteries to us. What we do know is that because of their extreme environments, some of these emit highly energetic X-ray light, which we can detect despite the vast distances between us and the source.

Now, a NASA space telescope mission is using new techniques to not only scout out these distant phenomena, but also provide new information about their origins. Read on to learn how scientists are getting exciting new perspectives on our universe and what the future of X-ray astronomy holds.

How They Did It

In 2021, NASA launched the Imaging X-Ray Polarimeter Explorer, or IXPE, through a collaboration with Ball Aerospace and the Italian Space Agency. The space telescope is designed to operate for two years, detecting X-rays emitted from highly energetic objects in space, such as black holes, different types of neutron stars (e.g., pulsars and magnetars) and active galactic nuclei. In its first year, the telescope is focusing on roughly a dozen previously studied X-ray sources, spending hours or even days observing each target to reveal new data made possible by spacecraft's scientific instruments.

IXPE isn't the first telescope to observe the universe in X-ray light. NASA's Chandra X-ray Observatory, launched in 1999, has famously spent more than 20 years photographing our universe at a wavelength of light exclusively found in high-energy environments, such as where cosmic materials are heated to millions of degrees as a result of intense magnetic fields or extreme gravity.

Using Chandra, scientists can assign colors to the different energy levels, or wavelengths, produced by these environments. This allows us to get a picture of the highly energetic light ejected by black holes and tiny neutron stars – small, but extremely dense stars with masses 10-25 times that of our Sun. These beautiful images, such as from Chandra’s first target, Cassiopeia A (Cas A for short), show the violent beauty of stars exploding.

A blue halo of squiggly lines surrounds an explosion of colors extending out from the center of the supernova. Closest to the center is a circular splatter of orange surrounded by green and yellow and finally a hazy purple.

This image of the supernova Cassiopeia A from NASA’s Chandra X-ray Observatory shows the location of different elements in the remains of the explosion: silicon (red), sulfur (yellow), calcium (green) and iron (purple). Each of these elements produces X-rays within narrow energy ranges, allowing maps of their location to be created. Image credit: NASA/CXC/SAO | › Full image and caption

While Chandra has earned its name as one of “The Great Observatories,” astronomers have long desired to peer further into highly energetic environments in space by capturing them in even more detail.

IXPE expands upon Chandra’s work with the introduction of a tool called a polarimeter, an instrument used to understand the shape and direction of the light that reaches the space telescope's detectors. The polarimeter on IXPE allows scientists to gain insight into the finer details of black holes, supernovas, and magnetars, like which direction they are spinning and their three-dimensional shape.

A blue halo of squiggly lines surrounds a fuzzy donut-shaped haze of magenta with splatters of blue and white throughout.

This image of Cassiopeia A was created using some of the first X-ray data collected by IXPE, shown in magenta, combined with high-energy X-ray data from Chandra, in blue. Image credit: NASA/CXC/SAO/IXPE | › Full image and caption

While scientists have just begun putting IXPE's capabilities to use, they're already starting to reveal new details about the inner workings of these objects – such as the magnetic field environment around Cas A, shown in a newly released image.

The supernova remnant is shown as a blob of blue with swirls of brighter blues and large splatters of white. Dashed lines on top of the image flow from the center outward. Dividing the supernova and lines into quarter sections of a circle, the top right section has lines that flow directly northeast. The section at the bottom right has lines that flow nearly southeast but curve northwards slightly The section at the bottom left has lines that flow straight up from the bottom edge of the supernova, curve around the center and then flow back down. And the section at the top left has lines that flow from the center directly west, others that curve around the center and flow diagonally northwest and others that flow from the center to the north. Small sections of the lines are highlighted in green at the 1 o'clock, 2 o'clock, 4 o'clock, 7 o'clock and 11 o'clock portions of the supernova.

The lines in this newly released image come from IXPE measurements that show the direction of the magnetic field across regions of Cassiopeia A. Green lines indicate regions where the measurements are most highly significant. These results indicate that the magnetic field lines near the outskirts of the supernova remnant are largely oriented radially, i.e., in a direction from the center of the remnant outwards. The IXPE observations also reveal that the magnetic field over small regions is highly tangled, without a dominant preferred direction. Observations such as this one can help scientists learn how particles shooting out from supernovae interact with the magnetic field created by the explosion. Image credits: X-ray: Chandra: NASA/CXC/SAO; IXPE: NASA/MSFC/J. Vink et al. | + Expand image | › Full image and caption

“For the first time, we will use every collected photon of light to tell us about the nature and shapes of objects in the sky that would be dots of light otherwise,” says Roger Romani, a Stanford professor and the co-investigator on IXPE.

How It Works

Generally, when light is produced, it is what we call unpolarized, meaning that it oscillates in every direction. For example, our Sun produces unpolarized light. But sometimes, light is produced in a highly organized fashion, oscillating only in one direction. In astronomy, this arises when magnetic fields force particles to incredibly high speeds, creating highly organized, or polarized, light.

This is what makes objects like the supernova Cas A such enticing targets for IXPE. Exploded stars like Cas A generate massive energetic waves when they go supernova, giving scientists a view of how particles shooting out at immense speeds interact with the magnetic fields from such an event. In the case of Cas A, IXPE was able to determine that the x-rays are not very polarized, meaning the explosion created very turbulent regions with multiple field directions.

While the idea of polarized or organized light may sound abstract, you may have noticed it the last time you were outside on a sunny day. If you’ve tried on a pair of polarized sunglasses, you may have noticed that the glare was greatly reduced. That’s because as light scatters, it bounces off of reflective surfaces in all directions. However, polarized lenses have tiny filters that only allow light coming from a narrow band of directions to pass through.

The polarimeter on IXPE works in a similar way. Astronomers can determine the strength of an object's magnetic field by using the polarimeter to measure how much of the light detected by the telescope is polarized. Typically, the more polarized the light the stronger the magnetic field at the source.

Astronomers can even go a step further to measure the direction this light is oscillating by measuring the angle of the light that reaches the telescope. Because the polarized light leaves the source in a predictable fashion – namely perpendicular from its magnetic field – knowing the angle of the oscillating light provides information about the axis of rotation and potentially even the surface structure of objects such as neutron stars and nebulae.

Side by side animations showing a rope moving from side to side through an open window and a rope moving up and down through an open window. As the window closes, fewer of the waves in the rope moving up and down make it through the window whereas the rope moving from side to side is undisturbed.

In this demonstration, the rope represents light waves and the open window represents a polarimeter. Depending on the angle of the light waves (rope), more or less information makes it through the polarimeter (window) the narrower it is. By measuring the amount of light received through the polarimeter, IXPE can determine the angle and the polarization of the light. Image credit: NASA/JPL-Caltech | + Expand image

Imagine, for example, that you were holding one end of a piece of rope secured to an object at the other end. If you swung the rope side to side to make horizontal waves, those waves would be able to make it through a narrow target like a window. If you started to shut the window from the top, narrowing the opening, the waves could conceivably still make it through the opening. However, if you made veritcal waves by waving the rope up and down, as the window closed, fewer and fewer waves would make it through the opening. Likewise, by measuring the light that makes it through the polarimeter to the detector on the other side, IXPE can determine the angle of the light received.

To collect this light, IXPE uses three identical mirrors at the end of a four meter (13 foot) boom. The light received by IXPE is carefully focused on the spacecraft’s polarimeter at the other end of the boom, allowing scientists to collect those crucial measurements.

During the IXPE launch broadcast, commentators discuss the components of the spacecraft and how it measures polarization. | Watch on YouTube

Why It's Important

Building on Chandra's observations from the past two decades, IXPE's novel approach to X-ray science is pulling the curtain back even farther on some of the most fascinating objects in the universe, providing first looks at how and where radiation is being produced in some of the most extreme environments in the universe. IXPE's measurements of Cas A are just the beginning, with even more mysterious targets ready to be explored.

Take it from Martin Weisskopf, the principal scientist on IXPE and project scientist for Chandra, who has spent his 50-year career working in X-ray astronomy, who says, “IXPE will open up the field in ways we’ve been stuck only theorizing about."

Teach It

Explore more on how NASA uses light to map our universe, and dig deeper into some of the celestial features it allows to study, such as blackholes and neutron stars.

Activities

Educator Resources

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NASA's Universe of Learning materials are based upon work supported by NASA under award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and the Jet Propulsion Laboratory.

TAGS: Universe, Stars and Galaxies, Space Telescope, IXPE, Astronomy, Science, Electromagnetic Spectrum, Universe of Learning

  • Brandon Rodriguez
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In the cleanroom at Northrop Grumman, a technician inspects the bellows between the hexagonal sections that make up the large honeycomb-shaped mirror on the Webb telescope.

Get a look into the science and engineering behind the largest and most powerful space telescope ever built while exploring ways to engage learners in the mission.


NASA is launching the largest, most powerful space telescope ever. The James Webb Space Telescope will look back at some of the earliest stages of the universe, gather views of early star and galaxy formation, and provide insights into the formation of planetary systems, including our own solar system.

Read on to learn more about what the space-based observatory will do, how it works, and how to engage learners in the science and engineering behind the mission.

What It Will Do

The James Webb Space Telescope, or JWST, was developed through a partnership between NASA and the European and Canadian space agencies. It will build upon and extend the discoveries made by the Hubble Space Telescope to help unravel mysteries of the universe. First, let's delve into what scientists hope to learn with the Webb telescope.

A look at the James Webb Space Telescope, its mission and the incredible technological challenge this mission presents. | Watch on YouTube

How Galaxies Evolve

What the first galaxies looked like and when they formed is not known, and the Webb telescope is designed to help scientists learn more about that early period of the universe. To better understand what the Webb telescope will study, it’s helpful to know what happened in the early universe, before the first stars formed.

The universe, time, and space all began about 13.8 billion years ago with the Big Bang. For the first few hundred-thousand years, the universe was a hot, dense flood of protons, electrons, and neutrons, the tiny particles that make up atoms. As the universe cooled, protons and neutrons combined into ionized hydrogen and helium, which had a positive charge, and eventually attracted all those negatively charged electrons. This process, known as recombination, occurred about 240,000 to 300,000 years after the Big Bang.

An ellipse is filled with speckled dark blue, green, and small yellow and red splotches.

This image shows the temperature fluctuations (shown as color differences) in the cosmic microwave background from a time when the universe was less than 400,000 years old. The image was captured by the Wilkinson Microwave Anisotropy Probe, or WMAP, which spent nine years, from 2001 to 2010, collecting data on the early universe. Credit: NASA | › Full image and caption | + Expand image

Light that previously couldn’t travel without being scattered by the dense ionized plasma of early particles could now travel freely. The very first form of light we can look back and see comes from this time and is known as the cosmic microwave background radiation. It is essentially a map of temperature fluctuations across the universe left behind from the Big Bang. The fluxuations give clues about the origin of galaxies and the large-scale structure of galaxies. There were still no stars in the universe at this time, so the next several hundred million years are known as the cosmic dark ages.

Current theory predicts that the earliest stars were big – 30 to 300 times the size of our Sun – and burned quickly, ending in supernova explosions after just a few million years. (For comparison, our Sun has a lifespan of about 10 billion years and will not go supernova.) Observing these luminous supernovae is one of the few ways scientists could study the earliest stars. That is vital to understanding the formation of objects such as the first galaxies.

By using the Webb telescope to compare the earliest galaxies with those of today, scientists hope to understand how they form, what gives them their shape, how chemical elements are distributed across galaxies, how central black holes influence their galaxies, and what happens when galaxies collide.

Learn how the James Webb Space Telescope's ability to look farther into space than ever before will bring newborn galaxies into view. | Watch on YouTube

How Stars and Planetary Systems Form

Stars and their planetary systems form within massive clouds of dust and gas. It's impossible to see into these clouds with visible light, so the Webb telescope is equipped with science instruments that use infrared light to peer into the hearts of stellar nurseries. When viewing these nurseries in the mid-infrared – as the Webb telescope is designed to do – the dust outside the dense star forming regions glows and can be studied directly. This will allow astronomers to observe the details of how stars are born and investigate why most stars form in groups as well as how planetary systems begin and evolve.

Plumes of red stellar dust shoot out from the top and bottom of a bright central disk.

This mosaic image is the sharpest wide-angle view ever obtained of the starburst galaxy, Messier 82 (M82). The galaxy is remarkable for its bright blue disk, webs of shredded clouds and fiery-looking plumes of glowing hydrogen blasting out of its central regions.Throughout the galaxy's center, young stars are being born 10 times faster than they are inside our entire Milky Way Galaxy. Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA); Acknowledgment: J. Gallagher (University of Wisconsin), M. Mountain (STScI), and P. Puxley (National Science Foundation) | › Full image and caption | + Expand image

How Exoplanets and Our Solar System Evolve

Collage of futuristic posters depicting explorers on various exoplanets.

As we make more discoveries about exoplanets, artists at NASA are imagining what future explorers might encounter on these faraway worlds as part of the Exoplanet Travel Bureau poster series. Credit: NASA | › View and download the posters | + Expand image

The first planet outside our solar system, or exoplanet, was discovered in 1992. Since then, scientists have found thousands more exoplanets and estimate that there are hundreds of billions in the Milky Way galaxy alone. There are many waiting to be discovered and there is more to learn about the exoplanets themselves, such as what makes up their atmospheres and what their weather and seasons may be like. The Webb telescope will help scientists do just that.

In our own solar system, the Webb telescope will study planets and other objects to help us learn more about our solar neighborhood. It will be able to complement studies of Mars being carried out by orbiters, landers, and rovers by searching for molecules that may be signs of past or present life. It is powerful enough to identify and characterize icy comets in the far reaches of our solar system. And it can be used to study places like Saturn, Uranus, and Neptune while there are no active missions at those planets.

How It Works

The Webb telescope has unique capabilities enabled by the way it views the universe, its size, and the new technologies aboard. Here's how it works.

Peering Into the Infrared

To see ancient, distant galaxies, the Webb telescope was built with instruments sensitive to light in the near- and mid-infrared wavelengths.

Light leaving these galaxies can take billions of years to reach Earth, so when we see these objects, we’re actually seeing what they looked like in the past. The farther something is from Earth, the farther back in time it is when we observe it. So when we look at light that left objects 13.5 billion years ago, we're seeing what happened in the early universe.

A sideways funnel that fans out at one end encapsulates an illustration of the history of the universe starting with the Big Bang 13.7 billion years ago through the first stars, the development of galaxies, and accelerated expansion.

An illustrated timeline of the universe. Credit: WMAP | + Expand image

As light from distant objects travels to Earth, the universe continues to expand, something it’s been doing since the Big Bang. The waves that make up the light get stretched as the universe expands. You can see this effect in action by making an ink mark on a rubber band and observing how the mark stretches out when you pull on the rubber band.

https://www.jpl.nasa.gov/edu/images/redshift_demo.gif

Light waves get stretched as the universe expands similar to how this ink mark stretches out as the elastic is pulled. Get students modeling and exploring this effect with this standards-aligned math lesson. Credit: NASA/JPL-Caltech | + Expand image

What this means for light coming from distant galaxies is that the visible lightwaves you would be able to see with your eyes get stretched out so far that the longer wavelengths shift from visible light into infrared. Scientists refer to this phenomenon as redshift – and the farther away an object is, the more redshift it undergoes.

Webb telescope’s infrared sensing equipment will give scientists the chance to study some of the earliest stars that exploded in supernova events, creating the elements necessary to build planets and form life.

Gathering Light

The first stars were massive, their life cycles ending in supernova explosions. The light from these explosions has traveled so far that it is incredibly dim. This is due to the inverse square law. You experience this effect when a room appears to get darker as you move away from a light source.

To see such dim light, the Webb telescope needs to be extremely sensitive. A telescope’s sensitivity, or its ability to detect faint signals, is related to the size of the mirror it uses to gather light. On the Webb telescope, 18 hexagonal mirrors combine to form a massive primary mirror that is 21 feet (6.5 meters) across.

A technician in a white smock stands up in a gap between several large hexagonal mirrors forming a honeycomb shape.

A technician inspects the Webb telescope's honeycomb-shaped mirror. The telescope's primary mirror is 21 feet (6.5 meters) across and is made up of 18 smaller hexagonal mirrors that must fold for launch and unfurl after the telescope reaches its orbit in space. Credit: NASA/MSFC/David Higginbotham/Emmett Given | › Full image and caption | + Expand image

Compared with the Hubble Space Telescope’s eight-foot (2.4 meter) diameter mirror, this gives the Webb telescope more than six times the surface area to collect those distant particles of light known as photons. Hubble’s famous Ultra Deep Field observation captured images of incredibly faint, distant galaxies by pointing at a seemingly empty spot in space for 16 days, but the Webb telescope will be able to make a similar observation in just seven hours.

Colorful spirals, disks, and stars of various sizes and shapes appear against the blackness of space like sprinkles on a cake.

This image, called the Hubble Ultra Deep Field, shows 28 of the more than 500 young galaxies that existed when the universe was less than 1 billion years old. Credit: NASA, ESA, R. Bouwens and G. Illingworth (University of California, Santa Cruz) | › Full image and caption | + Expand image

Keeping Cool

The Webb Telescope gathers its scientific data as infrared light. To detect the faint signals of objects billions of light years away, the instruments inside the telescope have to be kept very cold, otherwise those infrared signals could get lost in the heat of the telescope. Engineers accounted for this with a couple of systems designed to get the instruments cold and keep them cold.

The Webb telescope's orbit around the Sun – sitting about 1 million miles (1.5 million kilometers) from Earth at Lagrange point 2 – keeps the spacecraft pretty far from our planet's heat, but even that’s not enough. To further reduce the temperature on the instruments, the spacecraft will unfurl a tennis-court-size sunshield that will block light and heat from the Sun, Earth, and Moon using five layers of specially coated material. Each layer blocks incoming heat, and the heat that does make it through is redirected out of the sides of the sunshield. Additionally, the vacuum between each layer provides insulation.

Technicians in white smocks stand on lifts looking at JWST's fully deployed sunshield in the cleanroom at Northrup Gruman. The five layers of the kite-shaped sunshield extend out around JWST's folded honeycomb-shaped mirror.

The sunshield is made up of five layers of specially coated material designed to block the Webb telescope's sensitive instruments from incoming heat from the Sun, Earth, and Moon. This photo, taken in the cleanroom at Northrop Grumman in Southern California in December 2020, shows the sunshield fully deployed and tensioned as it will be in space. Credit: NASA/Chris Gunn | › Full image and caption | + Expand image

The sunshield is so effective that the temperatures on the Sun-facing side of the telescope could be hot enough to boil water, while on the side closest to the instruments, the temperature could be as low as -394 F (-237 C, 36 K).

That’s cold enough for the near-infrared instruments to operate, but the Mid-Infrared Instrument, or MIRI, needs to be even colder. To bring down the temperature of MIRI, the Webb telescope is equipped with a special cryocooler that pumps chilled helium to the instrument to reduce its operating temperature to about -448 F (-267 C, 6 K).

Spotting Exoplanets

The Webb telescope will search for exoplanets using two different methods.

Using the transit method, the Webb telescope will look for the regular pattern of dimming that occurs when an exoplanet transits its star, or passes between the star and the telescope. The amount of dimming can tell scientists a lot about the passing exoplanet, such as the size of the planet and its distance from the star.

This animation shows how the transit method is used to hunt for planets outside our solar system. When exoplanets transit their parent star, the Webb telescope (like the Kepler space telescope, depicted here) will be able to detect the dip in the star’s brightness, providing scientists with key information about the transiting exoplanet. Students can see this technique in action with this transit math problem. Credit: NASA/JPL-Caltech | + Expand image

The second method the Webb telescope will use to search for exoplanets is direct imaging – capturing actual images of planets beyond our solar system. To enable direct imaging of exoplanets, the Webb telescope is equipped with a coronagraph. Just like you might use your hand to block a bright light, a coronagraph blocks starlight from reaching a telescope’s instruments, allowing a dim exoplanet orbiting a star to be seen.

Wispy solar flares from the Sun can be seen jutting out from a solid central circle.

This “coronagraph” image taken by the Solar and Heliospheric Observatory, or SOHO, shows dim features around our Sun. Similarly, direct images of exoplanets captured by the Webb telescope will reveal details normally washed out by the brightness of stars. Credit: ESA&NASA/SOHO | + Expand image

The Webb telescope can uncover even more using spectroscopy. Light from a star produces a spectrum, which displays the intensity of light at different wavelengths. When a planet transits its star, some of the light from the star will pass through the planet's atmosphere before reaching the Webb telescope. Since all elements and molecules, such as methane and water, absorb energy at specific wavelengths, spectra from light that has passed through a planet’s atmosphere may contain dark lines known as absorption lines that tell scientists if there are certain elements present.

This infographic shows the electromagnetic spectrum and how various wavelengths are used for different applications, such as infrared for remote controls.

By looking at the unique spectrum produced when the light from a star shines through the atmosphere of a transiting exoplanet, scientists can learn whether certain elements are present on that planet. Credit: NASA | + Expand image

Using direct imaging and spectroscopy, scientists can learn even more about an exoplanet, including its color, seasons, rotation, weather, and vegetation if it exists.

All this could lead scientists to the ultimate exoplanet discovery: an Earth-size planet with an atmosphere like ours in its star’s habitable zone – a place where liquid water could exist.

Setting Up in Space

The Webb telescope will launch from French Guiana on top of an Ariane 5 rocket, a massive rocket capable of lifting the telescope, which weighs nearly 14,000 pounds (6,200 kilograms), to its destination.

The telescope's large mirror and giant sunshield are too big to fit inside the 18-foot (5.4-meter) wide rocket fairing, which protects the spacecraft during launch. To overcome this challenge, engineers designed the telescope's mirror and sunshield to fold for launch.

Two sides of the mirror assembly fold back for launch, allowing them to fit inside the fairing. The sunshield, which is 69.5 feet (21 meters) long and 46.5 feet (14 meters) wide, is carefully folded 12 times like origami so that it's narrow enough for launch. These are just two examples of several folding mechanisms needed to fit the massive telescope in its rocket for launch.

It will take about a month for the Webb telescope to reach its destination and unfurl its mirrors and sunshield. Scientists need another five months to cool down the instruments to their operating temperatures and align the mirrors correctly.

Approximately six months after launch, checkouts should be complete, and the telescope will begin its first science campaign and science operations.

Learn more and follow along with the mission from launch and unfolding to science observations and discovery announcements on the James Webb Space Telescope website.

Teach It

Check out these resources to bring the real-life STEM behind the mission into your teaching with lesson guides for educators, projects and slideshows for students, and more.

Educator Guides

Student Activities

Articles for Students

Videos for Students

Resources for Educators and Parents

Events

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NASA's Universe of Learning materials are based upon work supported by NASA under award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and the Jet Propulsion Laboratory.

TAGS: JWST, James Webb Space Telescope, electromagnetic spectrum, exoplanets, universe, solar system, big bang, cosmology, astronomy, star formation, galaxy, galaxies, telescope, life, technology, MIRI, Mars, Engineering, Teaching, Education, Classroom, Science, Universe of Learning

  • Lyle Tavernier
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In the News

On Jan. 30, 2020, the venerable Spitzer Space Telescope mission will officially come to an end as NASA makes way for a next-generation observatory. For more than 16 years, Spitzer has served as one of NASA’s four Great Observatories, surveying the sky in infrared. During its lifetime, Spitzer detected planets and signs of habitability beyond our solar system, returned stunning images of regions where stars are born, spied light from distant galaxies formed when the universe was young, and discovered a huge, previously-unseen ring around Saturn. Read on to learn more about this amazing mission and gather tools to teach your students that there truly is more than meets the eye in the infrared universe!

How It Worked

Human eyes can see only the portion of the electromagnetic spectrum known as visible light. This is because the human retina can detect only certain wavelengths of light through special photoreceptors called rods and cones. Everything we see with our eyes either emits or reflects visible light. But visible light is just a small portion of the electromagnetic spectrum. To "see" things that emit or reflect other wavelengths of light, we must rely on technology designed to sense those portions of the electromagnetic spectrum. Using this specialized technology allows us to peer into space and observe objects and processes we wouldn’t otherwise be able to see.

Infographic showing the electromagnetic spectrum and applications for various wavelengths.

This diagram shows wavelengths of light on the electromagnetic spectrum and how they're used for various applications. Image credit: NASA | + Expand image

Infrared is one of the wavelengths of light that cannot be seen by human eyes. (It can sometimes be felt by our skin as heat if we are close enough to a strong source.) All objects that have temperature emit many wavelengths of light. The warmer they are, the more light they emit. Most things in the universe are warm enough to emit infrared radiation, and that light can be seen by an infrared-detecting telescope. Because Earth’s atmosphere absorbs most infrared radiation, infrared observations of space are best conducted from outside the planet's atmosphere.

Learn more about the infrared portion of the electromagnetic spectrum and how NASA uses it to explore space. Credit: NASA/JPL-Caltech | Watch on YouTube

So, to get a look at space objects that were otherwise hidden from view, NASA launched the Spitzer Space Telescope in 2003. Cooled by liquid helium and capable of viewing the sky in infrared, Spitzer launched into an Earth-trailing orbit around the Sun, where it became part of the agency's Great Observatory program along with the visible-light and near-infrared-detecting Hubble Space Telescope, Compton Gamma-Ray Observatory and Chandra X-ray Observatory. (Keeping the telescope cold reduces the chances of heat, or infrared light, from the spacecraft interfering with its astronomical observations.)

Over its lifetime, Spitzer has been used to detect light from objects and regions in space where the human eye and optical, or visible-light-sensing, telescopes may see nothing.

Why It's Important

NASA's Spitzer Space Telescope has returned volumes of data, yielding numerous scientific discoveries.

Vast, dense clouds of dust and gas block our view of many regions of the universe. Infrared light can penetrate these clouds, enabling Spitzer to peer into otherwise hidden regions of star formation, newly forming planetary systems and the centers of galaxies.

A whisp of orange and green dust bows out beside a large blue star among a field of smaller blue stars.

The bow shock, or shock wave, in front of the giant star Zeta Ophiuchi shown in this image from Spitzer is visible only in infrared light. The bow shock is created by winds that flow from the star, making ripples in the surrounding dust. Image credit: NASA/JPL-Caltech | › Full image and caption

Infrared astronomy also reveals information about cooler objects in space, such as smaller stars too dim to be detected by their visible light, planets beyond our solar system (called exoplanets) and giant molecular clouds where new stars are born. Additionally, many molecules in space, including organic molecules thought to be key to life's formation, have unique spectral signatures in the infrared. Spitzer has been able to detect those molecules when other instruments have not.

Bursts of reds, oranges, greens, blues and violets spread out in all directions from a bright center source. Reds and oranges dominate the left side of the image.

Both NASA's Spitzer and Hubble space telescopes contributed to this vibrant image of the Orion nebula. Spitzer's infrared view exposed carbon-rich molecules, shown in this image as wisps of red and orange. Image credit: NASA/JPL-Caltech/T. Megeath (University of Toledo) & M. Robberto (STScI) | › Full image and caption

Stars are born from condensing clouds of dust and gas. These newly formed stars are optically visible only once they have blown away the cocoon of dust and gas in which they were born. But Spitzer has been able to see infant stars as they form within their gas and dust clouds, helping us learn more about the life cycles of stars and the formation of solar systems.

A blanket of green- and orange-colored stellar dust surrounds a grouping of purple, blue and red stars.

Newborn stars peek out from beneath their natal blanket of dust in this dynamic image of the Rho Ophiuchi dark cloud from Spitzer. The colors in this image reflect the relative temperatures and evolutionary states of the various stars. The youngest stars are shown as red while more evolved stars are shown as blue. Image credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA | › Full image and caption

Infrared emissions from most galaxies come primarily from stars as well as interstellar gas and dust. With Spitzer, astronomers have been able to see which galaxies are furiously forming stars, locate the regions within them where stars are born and pinpoint the cause of the stellar baby boom. Spitzer has given astronomers valuable insights into the structure of our own Milky Way galaxy by revealing where all the new stars are forming.

A bright band of crimson-colored dust stretches across the center of this image covered in tiny specs of light from hundreds of thousands of stars.

This Spitzer image, which covers a horizontal span of 890 light-years, shows hundreds of thousands of stars crowded into the swirling core of our spiral Milky Way galaxy. In visible-light pictures, this region cannot be seen at all because dust lying between Earth and the galactic center blocks our view. Image credit: NASA/JPL-Caltech | › Full image and caption

Spitzer marked a new age in the study of planets outside our solar system by being the first telescope to directly detect light emitted by these so-called exoplanets. This has made it possible for us to directly study and compare these exoplanets. Using Spitzer, astronomers have been able to measure temperatures, winds and the atmospheric composition of exoplanets – and to better understand their potential habitability. The discoveries have even inspired artists at NASA to envision what it might be like to visit these planets.

Collage of exoplanet posters from NASA

Thanks to Spitzer, scientists are learning more and more about planets beyond our solar system. These discoveries have even inspired a series of posters created by artists at NASA, who imagined what future explorers might encounter on these faraway worlds. Image credit: NASA/JPL-Caltech | › Download posters

Data collected by Spitzer will continue to be analyzed for decades to come and is sure to yield even more scientific findings. It's certainly not the end of NASA's quest to get an infrared window into our stellar surroundings. In the coming years, the agency plans to launch its James Webb Space Telescope, with a mirror more than seven times the diameter of Spitzer's, to see the universe in even more detail. And NASA's Wide Field Infrared Survey Telescope, or WFIRST, will continue infrared observations in space with improved technology. Stay tuned for even more exciting infrared imagery, discoveries and learning!

Teach It

Use these lessons, videos and online interactive features to teach students how we use various wavelengths of light, including infrared, to learn about our universe:


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Also, check out these related resources for kids from NASA’s Space Place:

TAGS: Teachable Moments, science, astronomy, K-12 education, teachers, educators, parents, STEM, lessons, activities, Spitzer, Space Telescope, Missions, Spacecraft, Stars, Galaxies, Universe, Infrared, Wavelengths, Spectrum, Light

  • Ota Lutz
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Animated image of Mercury passing in front of the Sun during the 2019 transit of Mercury

In the News

It only happens about 13 times a century and won’t happen again until 2032, so don’t miss the transit of Mercury on Monday, Nov. 11! A transit happens when a planet crosses in front of a star. From our perspective on Earth, we only ever see two planets transit the Sun: Mercury and Venus. This is because these are the only planets between us and the Sun. (Transits of Venus are especially rare. The next one won’t happen until 2117.) During the upcoming transit of Mercury, viewers around Earth (using the proper safety equipment) will be able to see a tiny dark spot moving slowly across the disk of the Sun.

Read on to learn how transits contributed to past scientific discoveries and for a look at how scientists use them today. Plus, find resources for engaging students in this rare celestial event!

Why It's Important

Then and Now

In the early 1600s, Johannes Kepler discovered that both Mercury and Venus would transit the Sun in 1631. It was fortunate timing: The telescope had been invented just 23 years earlier, and the transits of both planets wouldn’t happen in the same year again until 13425. Kepler didn’t survive to see the transits, but French astronomer Pierre Gassendi became the first person to see the transit of Mercury. Poor weather kept other astronomers in Europe from seeing it. (Gassendi attempted to view the transit of Venus the following month, but inaccurate astronomical data led him to mistakenly believe it would be visible from his location.) It was soon understood that transits could be used as an opportunity to measure apparent diameter – how large a planet appears from Earth – with great accuracy.

After observing the transit of Mercury in 1677, Edmond Halley predicted that transits could be used to accurately measure the distance between the Sun and Earth, which wasn’t known at the time. This could be done by having observers at distant points on Earth look at the variation in a planet’s apparent position against the disk of the Sun – a phenomenon known as parallax shift. This phenomenon is what makes nearby objects appear to shift more than distant objects when you look out the window of a car, for example.

Today, radar is used to measure the distance between Earth and the Sun with greater precision than transit observations. But the transits of Mercury and Venus still provide scientists with opportunities for scientific investigation in two important areas: exospheres and exoplanets.

Exosphere Science

Some objects, like the Moon and Mercury, were originally thought to have no atmosphere. But scientists have discovered that these bodies are actually surrounded by an ultrathin atmosphere of gases called an exosphere. Scientists want to better understand the composition and density of the gases in Mercury’s exosphere, and transits make that possible.

“When Mercury is in front of the Sun, we can study the exosphere close to the planet,” said NASA scientist Rosemary Killen. “Sodium in the exosphere absorbs and re-emits a yellow-orange color from sunlight, and by measuring that absorption, we can learn about the density of gas there.”

Exoplanet Discoveries

When Mercury transits the Sun, it causes a slight dip in the Sun’s brightness as it blocks a tiny portion of the Sun’s light. Scientists discovered they could use that phenomenon to search for planets orbiting distant stars. These planets, called exoplanets, are otherwise obscured from view by the light of their star. When measuring the brightness of far-off stars, a slight recurring dip in the light curve (a graph of light intensity) could indicate an exoplanet orbiting and transiting its star. NASA’s Kepler space telescope found more than 2,700 exoplanets by looking for this telltale drop in brightness. NASA’s TESS mission is surveying 200,000 of the brightest stars near our solar system and is expected to potentially discover more than 10,000 transiting exoplanets.

Animated cartoon image of a planet crossing in front of a star and an inset that shows a graph dipping as the planet does so

This animation shows one method scientists use to hunt for planets outside our solar system. When exoplanets transit their parent star, we can detect the dip in the star’s brightness using space telescopes. Credit: NASA/JPL-Caltech | + Expand image

Additionally, scientists have been exploring the atmospheres of exoplanets. Similarly to how we study Mercury’s exosphere, scientists can observe the spectra – a measure of light intensity and wavelength – that passes through an exoplanet’s atmosphere. As a result, they’re beginning to understand the evolution and composition of exoplanet atmospheres, as well as the influence of stellar wind and magnetic fields.

Collage of exoplanet posters from NASA

Using the transit method and other techniques, scientists are learning more and more about planets beyond our solar system. These discoveries have even inspired a series of posters created by artists at NASA, who imagine what future explorers might encounter on these faraway worlds. Credit: NASA | › Download posters

Watch It

During the transit of Mercury, the planet will appear as a tiny dot on the Sun’s surface. To see it, you’ll need a telescope or binoculars outfitted with a special solar filter.

WARNING! Looking at the Sun directly or through a telescope without proper protection can lead to serious and permanent vision damage. Do not look directly at the Sun without a certified solar filter.

The transit of Mercury will be partly or fully visible across much of the globe. However, it won’t be visible from Australia or most of Asia and Alaska.

Graphic showing Mercury's path across the Sun on Nov. 11, 2019 and the times that it will be at each location

The transit of Mercury on Nov. 11, 2019, begins at 4:35 a.m. PST (7:35 a.m. EST), but it won’t be visible to West Coast viewers until after sunrise. Luckily, viewers will have several more hours to take in the stellar show, which lasts until 10:04 a.m. PST (1:04 p.m. EST). Credit: NASA/JPL-Caltech | + Expand image

Mercury’s trek across the Sun begins at 4:35 a.m. PST (7:35 a.m. EST), meaning viewers on the East Coast of the U.S. can experience the entire event, as the Sun will have already risen before the transit begins. By the time the Sun rises on the West Coast, Mercury will have been transiting the Sun for nearly two hours. Fortunately, the planet will take almost 5.5 hours to completely cross the face of the Sun, so there will be plenty of time for West Coast viewers to witness this event. See the transit map below to learn when and where the transit will be visible.

Graphic showing a flat map of the world with areas where the transit of Mercury on Nov. 11, 2019 will be partially to fully visible indicated along with transit start and end times

This map shows where and when the transit will be visible on November 11. Image credit: NASA/JPL-Caltech | + Expand image

Don’t have access to a telescope or binoculars with a solar filter? Visit the Night Sky Network website to find events near you where amateur astronomers will have viewing opportunities available.

During the transit, NASA will share near-real-time images of the Sun directly from the Solar Dynamics Observatory. Beginning at 4:41 a.m. PST (7:41 a.m. EST) you can see images of Mercury passing in front of the Sun at NASA’s 2019 Mercury Transit page, with updates through the end of the transit at 10:04 a.m. PST (1:04 p.m. EST).

If you’re in the U.S., don’t miss the show, as this is the last time a transit will be visible from the continental United States until 2049!

Watch this month's installment of "What's Up" to learn more about how to watch the Nov. 11 transit of Mercury. Credit: NASA/JPL-Caltech | Watch on YouTube

Teach It

Use these lessons and activities to engage students in the transit of Mercury and the hunt for planets beyond our solar system:

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Transit Resources:

Exoplanet Resources:

Check out these related resources for kids from NASA’s Space Place:

TAGS: K-12 Education, Teachers, Students, Educators, Mercury, Transit, Transit of Mercury, What's Up, Astronomy, Resources for Educators, Exoplanets, Kepler, TESS

  • Lyle Tavernier
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The supermoon lunar eclipse captured as it moved over NASA’s Glenn Research Center on September 27, 2015.

In the News

Looking up at the Moon can create a sense of awe at any time, but those who do so on the evening of January 20 will be treated to the only total lunar eclipse of 2019. Visible for its entirety in North and South America, this eclipse is being referred to by some as a super blood moon – “super” because the Moon will be closest to Earth in its orbit during the full moon (more on supermoons here) and “blood" because the total lunar eclipse will turn the Moon a reddish hue (more on that below). This is a great opportunity for students to observe the Moon – and for teachers to make connections to in-class science content.

How It Works

Eclipses can occur when the Sun, the Moon and Earth align. Lunar eclipses can happen only during a full moon, when the Moon and the Sun are on opposite sides of Earth. At that point, the Moon can move into the shadow cast by Earth, resulting in a lunar eclipse. However, most of the time, the Moon’s slightly tilted orbit brings it above or below Earth’s shadow.

Watch on YouTube

The time period when the Moon, Earth and the Sun are lined up and on the same plane – allowing for the Moon to pass through Earth’s shadow – is called an eclipse season. Eclipse seasons last about 34 days and occur just shy of every six months. When a full moon occurs during an eclipse season, the Moon travels through Earth’s shadow, creating a lunar eclipse.

Graphic showing the alignment of the Sun, Earth and Moon when a full moon occurs during an eclipse season versus a non-eclipse season

When a full moon occurs during an eclipse season, the Moon travels through Earth's shadow, creating a lunar eclipse. Credit: NASA/JPL-Caltech | + Enlarge image

Unlike solar eclipses, which require special glasses to view and can be seen only for a few short minutes in a very limited area, a total lunar eclipse can be seen for about an hour by anyone on the nighttime side of Earth – as long as skies are clear.

What to Expect

The Moon passes through two distinct parts of Earth’s shadow during a lunar eclipse. The outer part of the cone-shaped shadow is called the penumbra. The penumbra is less dark than the inner part of the shadow because it’s penetrated by some sunlight. (You have probably noticed that some shadows on the ground are darker than others, depending on how much outside light enters the shadow; the same is true for the outer part of Earth’s shadow.) The inner part of the shadow, known as the umbra, is much darker because Earth blocks additional sunlight from entering the umbra.

At 6:36 p.m. PST (9:36 p.m. EST) on January 20, the edge of the Moon will begin entering the penumbra. The Moon will dim very slightly for the next 57 minutes as it moves deeper into the penumbra. Because this part of Earth’s shadow is not fully dark, you may notice only some dim shading (if anything at all) on the Moon near the end of this part of the eclipse.

Graphic showing the positions of the Moon, Earth and Sun during a partial lunar eclipse

During a total lunar eclipse, the Moon first enters into the penumbra, or the outer part of Earth's shadow, where the shadow is still penetrated by some sunlight. Credit: NASA | + Enlarge image

At 7:33 p.m. PST (10:33 p.m. EST), the edge of the Moon will begin entering the umbra. As the Moon moves into the darker shadow, significant darkening of the Moon will be noticeable. Some say that during this part of the eclipse, the Moon looks as if it has had a bite taken out of it. That “bite” gets bigger and bigger as the Moon moves deeper into the shadow.

The Moon as seen during a partial lunar eclipse

As the Moon starts to enter into the umbra, the inner and darker part of Earth's shadow, it appears as if a bite has been taken out of the Moon. This "bite" will grow until the Moon has entered fully into the umbra. Credit: NASA | + Enlarge image

At 8:41 p.m. PST (11:41 p.m. EST), the Moon will be completely inside the umbra, marking the beginning of the total lunar eclipse. The moment of greatest eclipse, when the Moon is halfway through the umbra, occurs at 9:12 p.m. PST (12:12 a.m. EST).

Graphic showing the Moon inside the umbra

The total lunar eclipse starts once the moon is completely inside the umbra. And the moment of greatest eclipse happens with the Moon is halfway through the umbra as shown in this graphic. Credit: NASA | + Enlarge image

As the Moon moves completely into the umbra, something interesting happens: The Moon begins to turn reddish-orange. The reason for this phenomenon? Earth’s atmosphere. As sunlight passes through it, the small molecules that make up our atmosphere scatter blue light, which is why the sky appears blue. This leaves behind mostly red light that bends, or refracts, into Earth’s shadow. We can see the red light during an eclipse as it falls onto the Moon in Earth’s shadow. This same effect is what gives sunrises and sunsets a reddish-orange color.

The Moon as seen during a total lunar eclipse at the point of greatest eclipse

As the Moon moves completely into the umbra, it turns a reddish-orange color. Credit: NASA | + Enlarge image

A variety of factors affect the appearance of the Moon during a total lunar eclipse. Clouds, dust, ash, photochemical droplets and organic material in the atmosphere can change how much light is refracted into the umbra. Additionally, the January 2019 lunar eclipse takes place when the full moon is at or near the closest point in its orbit to Earth – a time popularly known as a supermoon. This means the Moon is deeper inside the umbra shadow and therefore may appear darker. The potential for variation provides a great opportunity for students to observe and classify the lunar eclipse based on its brightness. Details can be found in the “Teach It” section below.

At 9:43 p.m. PST (12:43 a.m. EST), the edge of the Moon will begin exiting the umbra and moving into the opposite side of the penumbra. This marks the end of the total lunar eclipse.

At 10:50 p.m. PST (1:50 a.m. EST), the Moon will be completely outside the umbra. It will continue moving out of the penumbra until the eclipse ends at 11:48 p.m (2:48 a.m. EST).

What if it’s cloudy where you live? Winter eclipses always bring with them the risk of poor viewing conditions. If your view of the Moon is obscured by the weather, explore options for watching the eclipse online, such as the Time and Date live stream.

Why It’s Important

Lunar eclipses have long played an important role in understanding Earth and its motions in space.

In ancient Greece, Aristotle noted that the shadows on the Moon during lunar eclipses were round, regardless of where an observer saw them. He realized that only if Earth were a spheroid would its shadows be round – a revelation that he and others had many centuries before the first ships sailed around the world.

Earth wobbles on its axis like a spinning top that’s about to fall over, a phenomenon called precession. Earth completes one wobble, or precession cycle, over the course of 26,000 years. Greek astronomer Hipparchus made this discovery by comparing the position of stars relative to the Sun during a lunar eclipse to those recorded hundreds of years earlier. A lunar eclipse allowed him to see the stars and know exactly where the Sun was for comparison – directly opposite the Moon. If Earth didn’t wobble, the stars would appear to be in the same place they were hundreds of years earlier. When Hipparchus saw that the stars’ positions had indeed moved, he knew that Earth must wobble on its axis!

Lunar eclipses are also used for modern-day science investigations. Astronomers have used ancient eclipse records and compared them with computer simulations. These comparisons helped scientists determine the rate at which Earth’s rotation is slowing.

Teach It

Ask students to observe the lunar eclipse and evaluate the Moon’s brightness using the Danjon Scale of Lunar Eclipse Brightness. The Danjon scale illustrates the range of colors and brightness the Moon can take on during a total lunar eclipse, and it’s a tool observers can use to characterize the appearance of an eclipse. View the lesson guide below. After the eclipse, have students compare and justify their evaluations of the eclipse.

Use these standards-aligned lessons and related activities to get your students excited about the eclipse, Moon phases and Moon observations:

TAGS: Lunar Eclipse, Moon, Teachers, Educators, K-12 Education, Astronomy

  • Lyle Tavernier
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Lean Teodoro at JPL

When Lean Teodoro was growing up on the remote island of Saipan in the middle of the Pacific Ocean, her dream of one day working for NASA always seemed a bit far-fetched to those around her. Now, a geophysics student on the premed track at the University of Hawaii and a summer 2018 intern at NASA’s Jet Propulsion Laboratory, Teodoro is making her dream a reality. This summer, she took a short break from her internship searching for asteroids with NASA’s NEOWISE team to tell us about her career journey so far, what inspired her to study STEM and how she hopes to play a role in human space exploration of the future.

What are you working on at JPL?

I work with the NEOWISE team, the Near-Earth Object Wide-field Infrared Survey Explorer. My focus is on near-Earth asteroids. I do a lot of image analysis and processing. Not all of the time do asteroids get detected through our automated system, so my job is to look at archives to find previously undetected asteroids.

What is a near-Earth object and how do you look for them?

Near-Earth objects are objects [such as asteroids and comets] that are very near to Earth's orbit. There are other asteroids that are located roughly between the orbits of Mars and Jupiter, but my focus is on those that are closer to Earth. The way that we detect them is we have this [space telescope called NEOWISE] that surveys the sky in two wavelengths. It senses the heat of asteroids. So I look at images from NEOWISE and, if I see a red dot that is bright, then that's usually an asteroid. But I go through several search techniques to see if the signal-to-noise ratio is good. So there are several processes that work.

NASA's asteroid-hunting NEOWISE mission uses infrared to detect and characterize asteroids and comets. Since the mission was restarted in December 2013, NEOWISE has observed or detected more than 29,000 asteroids in infrared light, of which 788 were near-Earth objects. Credit: NASA/JPL-Caltech | Watch on YouTube

What is the ultimate goal of the project?

My ultimate goal is to try to increase the number of known near-Earth objects so that, in the future, we can get more precise measurements for their positions and movements -- just in case they pose a risk to Earth.

What's an average day like for you?

I go through, I'd say, hundreds of images per day. I also took part in a side project where I had to get the measurements of an asteroid that was observed 39 years before it was officially discovered. We looked at this astronomical plate from the 1950s. You can see a very small arrow pointing to an asteroid. Positions for the asteroid hadn’t been discovered yet, so my job was also to find those. It had a lot to do with coding and I had very little experience with coding, so it was nice.

What other skills have you been able to pick up at JPL?

My major is geophysics, so I had little knowledge about astronomy. My whole research team exposed me to an exciting world of astronomy, so that was really nice. They were very encouraging. I've learned so much more about astronomy this summer than I did throughout my whole undergrad career. I mean, there is some connection between geophysics and astronomy, in a way, but this summer, I really learned so much.

JPL Interns

Meet JPL Interns

Read stories from interns pushing the boundaries of space exploration and science at the leading center for robotic exploration of the solar system.

You grew up on the remote island of Saipan in the Northern Mariana Islands. How did you get exposed to STEM and what got interested in pursuing it as a career?

When I was young, my dad would always make us go fly kites at night on the beach. There was this one night where I was just looking at the Moon. I was like, "Oh my god, I really want to learn more about astronomy.” I think since then, I've been interested in STEM. But when you're coming from a really small island, you feel very limited. So I didn't have that strong foundation in STEM. And that's the reason why I wanted to move off the island -- because I knew that I couldn't get the opportunities if I stayed. That's the reason I moved to the University of Hawaii. They have a strong geology and geophysics program, and it's a great research university. Since I started there, I've been doing research related to NASA -- like the NASA Hawaii Space Grant Consortium. I feel like if I didn't move to the University of Hawaii, I wouldn't be where I am today, interning at JPL.

So you moved from one island to another?

[Laughs.] Yeah, I couldn't leave the island vibe, I guess. I think it's just a little closer to home. I feel more at home when I'm in Hawaii. Not only that, but also they have a great program, so that was a plus, too. And they have close affiliations with NASA, so that was really great, because my goal was to work for NASA.

Was it a challenge to move away from the island where you grew up?

It was definitely a challenge leaving family and friends behind. I was there on my own. The reason why I chose the University of Hawaii is because of their program. I had a really hard time choosing my major because I was interested in health, but I was interested in geology as well. I'm doing premed as well [as geology and geophysics]. I'm really interested in how humans or organisms can adapt to extreme environments and in learning about geology – for example on Mars – and health, and seeing how we can combine those two fields to contribute to future human space exploration.

JPL intern Lean Teodoro with her mentors

Teodoro's first mentor at the University of Hawaii, Heather Kaluna (middle), helped connect her with JPL scientist Joseph Masiero (left) for an internship at the laboratory. Photo courtesy Lean Teodoro | + Expand image

What do your family and people back home think of your career path?

It's so funny because I remember, in middle school, I would always tell my friends and family how I wanted to work for NASA, and they would laugh about it because I don't think anyone back home has ever done something big like that. Having them see me working here -- it just kind of opened their eyes, like, “Wow, it's possible,” you know? Most of the time, people back home just stay for financial reasons. It was really expensive moving to Hawaii. But I really wanted to do it. So here I am, and I'm so happy.

Did you know that we have a group of student teachers from the Northern Mariana Islands that has come to NASA’s MUREP Educator Institute at JPL the past couple summers?

Yeah! So three weeks ago, I was walking to my office, and I saw a few friends from back home. I was like, “Oh my god, what are you guys doing here?” We all went to the same high school and everything! They were telling me about that whole program. I was like, “Oh my god, I feel so happy. That's so great.” The chances -- it was mind-blowing. I'm so happy for them. I'm really excited for the future of Saipan and the whole Northern Mariana Islands.

What's the most JPL- or NASA-unique experience you've had so far?

Of all the internships I've had in the past, JPL is really unique because everyone is just so passionate about the work that they do, so it really rubs off on you. Not only that, but also the intern community here is just amazing. And not only the interns, but also my mentors and the other scientists and engineers I've met. I've made so many friends throughout my summer here from all over the nation and all over the world, which is nice because I'm from this small island, and it just makes me realize how big the world is.

I feel like interning at JPL builds a foundation for me. And with my mentors here at JPL and in Hawaii, I do feel more confident in being a minority and a woman in STEM. I feel more driven to be successful and to inspire people from back home to go and pursue what they want to do. Don't let the confinements of your environment stop you from what you want to do.

What’s your ultimate career goal?

My ultimate goal is to try and contribute to future human space exploration. That's what I really want to do. I'm still trying to figure out how I can pave my path by combining health and geosciences. We'll see how it goes.


Explore JPL’s summer and year-round internship programs and apply at: https://www.jpl.nasa.gov/edu/intern

The laboratory’s STEM internship and fellowship programs are managed by the JPL Education Office. Extending the NASA Office of Education’s reach, JPL Education seeks to create the next generation of scientists, engineers, technologists and space explorers by supporting educators and bringing the excitement of NASA missions and science to learners of all ages.

TAGS: Women in STEM, Internships, Higher Education, Science, Astronomy, Asteroids and Comets, NEOWISE, Asian Pacific American Heritage Month, Asteroids, Women at NASA

  • Kim Orr
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Moon Phases Calendar and Calculator Project from NASA/JPL Edu

Looking for a stellar 2018 calendar? Try this new Moon Phases Calendar and Calculator DIY from the Education Office at NASA’s Jet Propulsion Laboratory!

Download the free, decoder-ring style calendar and assemble it to see when and where to view the Moon every day of the year. The calendar features daily moon phases, moonrise, moonset and overhead viewing times, a listing of Moon events including supermoons and lunar eclipses, plus graphics depicting the relative positions of Earth and the Moon during various moon phases. Use it to teach students about the phases of the Moon, for sky-gazing or simply as a unique wall calendar.

In the classroom, it makes a great addition to this Teachable Moment and related lessons about supermoons – two of which will ring in the new year in January 2018.

Explore these and more Moon-related lessons and activities from NASA/JPL Edu at the links below:


For Students

Project: Moon Phases Calendar and Calculator

Like a decoder wheel for the Moon, this calendar will show you where and when to see the Moon and every moon phase throughout the year!


Project: Look at the Moon! Journaling Project

Draw what you see in a Moon Journal and see if you can predict the moon phase that comes next.


For Educators

Teachable Moment: What’s a Supermoon and Just How Super Is It?

What are supermoons, why do they occur and how can they be used as an educational tool?


Observing the Moon (Grades K-6)

Students identify the Moon’s location in the sky and record their observations over the course of the moon-phase cycle in a journal.


Whip Up a Moon-Like Crater (Grades 1-6)

Whip up a Moon-like crater with baking ingredients as a demonstration for students.


Moon Phases (Grades 1-6)

Students take measurements of the Moon during its full phases over multiple Moon cycles to compare and contrast results.


Modeling the Earth-Moon System (Grades 6-8)

Whip up a Moon-like crater with baking ingredients as a demonstration for students.


Measuring the Supermoon (Grades 5-12)

Students take measurements of the Moon during its full phase over multiple Moon cycles to compare and contrast results.

TAGS: Moon, Supermoon, Moon Phases, Moon Phases Calendar, Projects, DIY, For Students, Astronomy

  • NASA/JPL Edu
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Image showing the difference in size and brightness between a full moon at apogee and a full moon at perigee, also called a "supermoon"

The term “supermoon” has been popping up a lot in the news and on social media over the past few years. But what are supermoons, why do they occur and how can they be used as an educational tool. Plus, are they really that super?

How it Works

As the Moon orbits Earth, it goes through phases, which are determined by its position relative to Earth and the Sun. When the Moon lines up on the opposite side of Earth from the Sun, we see a full moon. The new moon phase occurs when the Moon and the Sun are lined up on the same side of Earth.

The Moon doesn’t orbit in a perfect circle. Instead, it travels in an ellipse that brings the Moon closer to and farther from Earth in its orbit. The farthest point in this ellipse is called the apogee and is about 405,500 kilometers from Earth on average. Its closest point is the perigee, which is an average distance of about 363,300 kilometers from Earth. During every 27-day orbit around Earth, the Moon reaches both its apogee and perigee.

Full moons can occur at any point along the Moon’s elliptical path, but when a full moon occurs at or near the perigee, it looks slightly larger and brighter than a typical full moon. That’s what the term “supermoon" refers to.

What makes a supermoon super? Watch this short animation to find out. Credit: NASA/JPL-Caltech

Because supermoon is not an official astronomical term, there is no definition about just how close to perigee the full moon has to be in order to be called “super." Generally, supermoon is used to refer to a full moon 90 percent or closer to perigee. (When the term supermoon was originally coined, it was also used to describe a new moon in the same position, but since the new moon isn’t easily visible from Earth, it’s rarely used in that context anymore.)

A more accurate and scientific term is “perigee syzygy.” Syzygy is the alignment of three celestial bodies, in this case the Sun, Moon and Earth. But that doesn’t quite roll off the tongue as easily as supermoon.

Why It’s Important

As the largest and brightest object in the night sky, the Moon is a popular focal point for many amateur and professional astronomers pointing their telescopes to the sky, and the source of inspiration for everyone from aspiring space scientists to engineers to artists.

The supermoon is a great opportunity for teachers to connect concepts being taught in the classroom to something students will undoubtedly be hearing about. Students can practice writing skills in a Moon journal, study Moon phases and apply their math skills to observing the supermoon. (Click here for related activities from JPL’s Education Office.)

Incorrect and misleading information about the Moon (and supermoons) can lead to confusion and frustration. It’s important to help students understand what to expect and be able to identify inaccurate info.

What to Expect

Size

As with anything that moves closer to the person viewing it, the supermoon will appear bigger than an average full moon. At its largest, it can appear 14% larger in diameter than the smallest full moon. Keep in mind that a 14% increase in the apparent size of something that can be covered with a fingernail on an outstretched arm won’t seem significantly bigger. Unlike side-by-side comparisons made in science and everyday life, students will not have seen the full moon for at least 30 days, and won’t see another for at least 30 more days. Comparing a supermoon with a typical full moon from memory is very difficult.

A nearly full Moon sets as the space shuttle Discovery sits atop Launch pad 39A at the Kennedy Space Center in Cape Canaveral, Florida, Wednesday, March 11, 2009. Photo Credit: (NASA/Bill Ingalls

While they make for great photographs, images like this one that rely on a special photographic technique aren't an accurate representation of what the supermoon will look like to the naked eye. Credit: NASA/Bill Ingalls | Full image and caption on Flickr

Graphic showing the position of the moon at apogee and perigee

A supermoon looks bigger than a "micromoon" (when the full moon is at apogee) because it's about 40,000 kilometers closer to Earth on average. Credit: NASA/JPL-Caltech

Graphic showing the position of the moon at apogee and perigee

It's nearly impossible to compare the apparent size of the supermoon with a micromoon from memory, but when seen side-by-side as in this graphic, it becomes clear. Credit: NASA/JPL-Caltech

Leading up to a supermoon, there are often misleading images on popular media. A technique that involves using a long telephoto lens to take photographs of the Moon next to buildings or other objects makes the Moon look huge compared with its surroundings. This effect can make for great photographs, but it has nothing to do with the supermoon. In fact, these photos can be taken during any Moon phase, but they will likely be used in stories promoting the supermoon.

There are also images that have been edited to inaccurately dramatize the size of the supermoon. Both of these can lead students, and adults, taking pictures with their cell phone to think that they’ve done something wrong or just aren’t cut out for observing the sky, which isn’t true!

Your students may have noticed that when they see a full moon low on the horizon, it appears huge and then seems to shrink as it rises into the night sky. This can happen during any full moon. Known as the Moon Illusion, it has nothing to do with a supermoon. In fact, scientists still aren’t sure what causes the Moon Illusion.

Brightness

The full moon is bright and the supermoon is even brighter! Sunlight reflecting off the Moon during its full phase is bright enough to cast shadows on the ground. During a supermoon, that brightness can increase up to 30 percent as a result of the Moon being closer to Earth, a phenomenon explained by the inverse square law. (Introduce students to the inverse square law with this space-related math lesson for 6th- through 8th-graders.) As with the size of the Moon, students may not remember just how bright the last full moon was or easily be able to compare it. Powerful city lights can also diminish how bright a supermoon seems. Viewing it away from bright overhead street lights or outside the city can help viewers appreciate the increase in brightness.

What Not to Expect

A supermoon will not cause extreme flooding, earthquakes, fires, volcanic eruptions, severe weather, nor tsunamis, despite what incorrect and non-scientific speculators might suggest. Encourage your students to be good scientists and research this for themselves.

Teach It

The excitement and buzz surrounding a supermoon is a great opportunity to teach a variety of Moon topics with these lessons from JPL’s Education Office:

  • *NEW* Observing the Moon (Grades K-6) – Students identify the Moon’s location in the sky and record their observations over the course of the moon-phase cycle in a journal.
  • *NEW* Measuring the Supermoon (Grades 5-12) – Students take measurements of the Moon during its full phase over multiple Moon cycles to compare and contrast results.
  • *NEW* Moon Phases Calendar and Calculator – Like a decoder wheel for the Moon, this calendar will show you where and when to see the Moon and every moon phase throughout the year!
  • *NEW* Look at the Moon! Journaling Project – Draw what you see in a Moon Journal and see if you can predict the moon phase that comes next.
  • Moon Phases (Grades 1-6) – Students learn about the phases of the Moon by acting them out. In 30 minutes, they will act out one complete Moon cycle.
  • Whip Up a Moon-Like Crater (Grades 1-6) – Whip up a Moon-like crater with baking ingredients as a demonstration for students.
  • Modeling the Earth-Moon System (Grades 6-8) – Using an assortment of playground and toy balls, students will measure diameter, calculate distance and scale, and build a model of the Earth-Moon system.

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For the record: This story originally stated a supermoon would be visible in January and February 2018. The two supermoons of 2018 are both in January.

TAGS: Supermoon, Moon Phases, Moon, Earth's Moon, What's Up, Astronomy, K-12, Educators

  • Lyle Tavernier
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