One of the greatest mysteries that life on Earth holds is, “Are we alone?”
At NASA, we are working hard to answer this question. We’re scouring the universe, hunting down planets that could potentially support life. Thanks to ground-based and space-based telescopes, including Kepler and TESS, we’ve found more than 4,000 planets outside our solar system, which are called exoplanets. Our search for new planets is ongoing — but we’re also trying to identify which of the 4,000 already discovered could be habitable.
Unfortunately, we can’t see any of these planets up close. The closest exoplanet to our solar system orbits the closest star to Earth, Proxima Centauri, which is just over 4 light years away. With today’s technology, it would take a spacecraft 75,000 years to reach this planet, known as Proxima Centauri b.
How do we investigate a planet that we can’t see in detail and can’t get to? How do we figure out if it could support life?
This is where computer models come into play. First we take the information that we DO know about a far-off planet: its size, mass and distance from its star. Scientists can infer these things by watching the light from a star dip as a planet crosses in front of it, or by measuring the gravitational tugging on a star as a planet circles it.
We put these scant physical details into equations that comprise up to a million lines of computer code. The code instructs our Discover supercomputer to use our rules of nature to simulate global climate systems. Discover is made of thousands of computers packed in racks the size of vending machines that hum in a deafening chorus of data crunching. Day and night, they spit out 7 quadrillion calculations per second — and from those calculations, we paint a picture of an alien world.
While modeling work can’t tell us if any exoplanet is habitable or not, it can tell us whether a planet is in the range of candidates to follow up with more intensive observations.
One major goal of simulating climates is to identify the most promising planets to turn to with future technology, like the James Webb Space Telescope, so that scientists can use limited and expensive telescope time most efficiently.
Additionally, these simulations are helping scientists create a catalog of potential chemical signatures that they might detect in the atmospheres of distant worlds. Having such a database to draw from will help them quickly determine the type of planet they’re looking at and decide whether to keep observing or turn their telescopes elsewhere.
From the first-ever image of a black hole, to astronaut Christina Koch breaking the record for the longest single spaceflight by a woman – 2019 was full of awe-inspiring events!
As we look forward to a new decade, we’ve taken ten of our top Instagram posts and put them here for your viewing pleasure. With eight out of ten being carousels, be sure to click on each title to navigate to the full post.
In a historic feat by the Event horizon Telescope and National Science Foundation, an image of a black hole and its shadow was captured for the first time. At a whopping 3.4 million likes, this image takes home the gold as our most loved photo of 2019. Several of our missions were part of a large effort to observe this black hole using different wavelengths of light and collect data to understand its environment. Here’s a look at our Chandra X-Ray Observatory’s close-up of the core of the M87 galaxy with the imaged black hole at its center.
When you wish upon a star… Hubble captures it from afar ✨On April 18, 2019 our Hubble Space Telescope celebrated 29 years of dazzling discoveries, serving as a window to the wonders of worlds light-years away.
Hubble continues to observe the universe in near-ultraviolet, visible, and near-infrared light. Over the past 29 years, it has captured the farthest views ever taken of the evolving universe, found planet-forming disks around nearby stars and identified the first supermassive black hole in the heart of a neighboring galaxy. Want more? Enjoy the full 10 photo Instagram carousel here.
Patriotism was in the air June 14 for Flag Day, and coming in at number three in our most liked Instagram line up is a carousel of our stars and stripes in space! One of the most iconic images from the Apollo 11 missions is of Buzz Aldrin saluting the American flag on the surface of the Moon. But did you know that over the years, five more flags joined the one left by Apollo 11 – and that many other flags have flown onboard our spacecraft? Scroll through the full carousel for flag day here.
Since 2003, our Spitzer Space Telescope has been lifting the veil on the wonders of the cosmos, from our own solar system to faraway galaxies, using infrared light! Thanks to Spitzer, we’ve confirm the presence of seven rocky, Earth-size planets, received weather maps of hot, gaseous exoplanets and discovered a hidden ring around Saturn. In honor of Spitzer’s Sweet 16 in space, enjoy 16 jaw-dropping images from its mission here.
“That’s here. That’s home. That’s us.” – Carl Sagan
Seeing Earth from space can alter an astronauts’ cosmic perspective, a mental shift known as the “Overview Effect.” First coined by space writer Frank White in 1987, the Overview Effect is described as a feeling of awe for our home planet and a sense of responsibility for taking care of it. See Earth from the vantage point of our astronauts in a carousel of perspective-changing views here.
Astronaut Christina Koch (@Astro_Christina) set a record Dec. 28, 2019 for the longest single spaceflight by a woman, eclipsing the former record of 288 days set by Peggy Whitson. Her long-duration mission is helping us learn how to keep astronauts healthy for deep space exploration to the Moon and Mars. Congrats to Christina on reaching new heights! Join in the celebration and view few photos she captured from her vantage point aboard the Space Station here.
Earth is special. It’s the only place in the universe that we know contains life.
On July 7, 2019, two million people joined us in celebrating its beauty with a jaw dropping carousel of our home planet, as captured by crew members aboard the International Space Station. Bright blue oceans, glowing city lights and ice-capped mountain peaks come to life in a collection of breathtaking images, found here.
Every 29 days our Moon turns over a new leaf, and on May, 18 we saw a very special one of its faces. Appearing opposite the Sun at 5:11 p.m. EDT, the world looked up to find a Blue Moon! Though the Moon didn’t actually look blue, the site of one is kind of rare. They occur on average about every two-and-a-half years when a season ends up having four full moons instead of three. Click through a carousel of high-definition lunar phases here.
On December 23, a new gallery of Hubble Space Telescope images highlighting celestial objects visible to amateur and professional astronomers alike was released. All of the objects are from a collection known as the Caldwell catalog, which includes 109 interesting objects visible in amateur-sized telescopes in both the northern and southern skies. Flip through the jaw-dropping carousel here, and learn more about how you can study the night sky with Hubble here.
We’re working on it, Moon. Under the Artemis program, we’re sending the first woman and the next man to walk on your surface by 2024. Find out how we’re doing it here.
There’s never been a better time to ponder this age-old question. We now know of thousands of exoplanets – planets that orbit stars elsewhere in the universe.
So just how many of these planets could support life?
Scientists from a variety of fields — including astrophysics, Earth science, heliophysics and planetary science — are working on this question. Here are a few of the strategies they’re using to learn more about the habitability of exoplanets.
Squinting at Earth
Even our best telescopic images of exoplanets are still only a few pixels in size. Just how much information can we extract from such limited data? That’s what Earth scientists have been trying to figure out.
One group of scientists has been taking high-resolution images of Earth from our Earth Polychromatic Imaging Camera and ‘degrading’ them in order to match the resolution of our pixelated exoplanet images. From there, they set about a grand process of reverse-engineering: They try to extract as much accurate information as they can from what seems — at first glance — to be a fairly uninformative image.
Credits: NOAA/NASA/DSCOVR
So far, by looking at how Earth’s brightness changes when land versus water is in view, scientists have been able to reverse-engineer Earth’s albedo (the proportion of solar radiation it reflects), its obliquity (the tilt of its axis relative to its orbital plane), its rate of rotation, and even differences between the seasons. All of these factors could potentially influence a planet’s ability to support life.
Avoiding the “Venus Zone”
In life as in science, even bad examples can be instructive. When it comes to habitability, Venus is a bad example indeed: With an average surface temperature of 850 degrees Fahrenheit, an atmosphere filled with sulfuric acid, and surface pressure 90 times stronger than Earth’s, Venus is far from friendly to life as we know it.
The surface of Venus, imaged by Soviet spacecraft Venera 13 in March 1982
Since Earth and Venus are so close in size and yet so different in habitability, scientists are studying the signatures that distinguish Earth from Venus as a tool for differentiating habitable planets from their unfriendly look-alikes.
Using data from our Kepler Space Telescope, scientists are working to define the “Venus Zone,” an area where planetary insolation – the amount of light a given planet receives from its host star – plays a key role in atmospheric erosion and greenhouse gas cycles.
Planets that appear similar to Earth, but are in the Venus Zone of their star, are, we think, unlikely to be able to support life.
Modeling Star-Planet Interactions
When you don’t know one variable in an equation, it can help to plug in a reasonable guess and see how things work out. Scientists used this process to study Proxima b, our closest exoplanet neighbor. We don’t yet know whether Proxima b, which orbits the red dwarf star Proxima Centauri four light-years away, has an atmosphere or a magnetic field like Earth’s. However, we can estimate what would happen if it did.
The scientists started by calculating the radiation emitted by Proxima Centauri based on observations from our Chandra X-ray Observatory. Given that amount of radiation, they estimated how much atmosphere Proxima b would be likely to lose due to ionospheric escape — a process in which the constant outpouring of charged stellar material strips away atmospheric gases.
With the extreme conditions likely to exist at Proxima b, the planet could lose the equivalent of Earth’s entire atmosphere in 100 million years — just a fraction of Proxima b’s 4-billion-year lifetime. Even in the best-case scenario, that much atmospheric mass escapes over 2 billion years. In other words, even if Proxima b did at one point have an atmosphere like Earth, it would likely be long gone by now.
Imagining Mars with a Different Star
We think Mars was once habitable, supporting water and an atmosphere like Earth’s. But over time, it gradually lost its atmosphere – in part because Mars, unlike Earth, doesn’t have a protective magnetic field, so Mars is exposed to much harsher radiation from the Sun’s solar wind.
But as another rocky planet at the edge of our solar system’s habitable zone, Mars provides a useful model for a potentially habitable planet. Data from our Mars Atmosphere and Volatile Evolution, or MAVEN, mission is helping scientists answer the question: How would Mars have evolved if it were orbiting a different kind of star?
Scientists used computer simulations with data from MAVEN to model a Mars-like planet orbiting a hypothetical M-type red dwarf star. The habitable zone of such a star is much closer than the one around our Sun.
Being in the habitable zone that much closer to a star has repercussions. In this imaginary situation, the planet would receive about 5 to 10 times more ultraviolet radiation than the real Mars does, speeding up atmospheric escape to much higher rates and shortening the habitable period for the planet by a factor of about 5 to 20.
These results make clear just how delicate a balance needs to exist for life to flourish. But each of these methods provides a valuable new tool in the multi-faceted search for exoplanet life. Armed with these tools, and bringing to bear a diversity of scientific perspectives, we are better positioned than ever to ask: are we alone?
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Space is a global frontier. That’s why we partner with nations all around the world to further the advancement of science and to push the boundaries of human exploration. With international collaboration, we have sent space telescopes to observe distant galaxies, established a sustainable, orbiting laboratory 254 miles above our planet’s surface and more! As we look forward to the next giant leaps in space exploration with our Artemis lunar exploration program, we will continue to go forth with international partnerships!
Teamwork makes the dream work. Here are a few of our notable collaborations:
Artemis Program
Our Artemis lunar exploration program will send the first woman and the next man to the Moon by 2024. Using innovative technologies and international partnerships, we will explore more of the lunar surface than ever before and establish sustainable missions by 2028.
During these missions, the Orion spacecraft will serve as the exploration vehicle that will carry the crew to space, provide emergency abort capability and provide safe re-entry from deep space return velocities. The European Service Module, provided by the European Space Agency, will serve as the spacecraft’s powerhouse and supply it with electricity, propulsion, thermal control, air and water in space.
The Gateway, a small spaceship that will orbit the Moon, will be a home base for astronauts to maintain frequent and sustainable crewed missions to the lunar surface. With the help of a coalition of nations, this new spaceship will be assembled in space and built within the next decade.
Gateway already has far-reaching international support, with 14 space agencies agreeing on its importance in expanding humanity’s presence on the Moon, Mars and deeper into the solar system.
International Space Station
The International Space Station (ISS) is one of the most ambitious international collaborations ever attempted. Launched in 1998 and involving the U.S., Russia, Canada, Japan and the participating countries of the European Space Agency — the ISS has been the epitome of global cooperation for the benefit of humankind. The largest space station ever constructed, the orbital laboratory continues to bring together international flight crews, globally distributed launches, operations, training, engineering and the world’s scientific research community.
Hubble Space Telescope
The Hubble Space Telescope, one of our greatest windows into worlds light-years away, was built with contributions from the European Space Agency (ESA).
ESA provided the original Faint Object Camera and solar panels, and continues to provide science operations support for the telescope.
The Deep Space Network (DSN) is an international array of giant radio antennas that span the world, with stations in the United States, Australia and Spain. The three facilities are equidistant approximately one-third of the way around the world from one another – to permit constant communication with spacecraft as our planet rotates. The network supports interplanetary spacecraft missions and a few that orbit Earth. It also provides radar and radio astronomy observations that improve our understanding of the solar system and the larger universe!
Mars Missions
Information gathered today by robots on Mars will help get humans to the Red Planet in the not-too-distant future. Many of our Martian rovers – both past, present and future – are the products of a coalition of science teams distributed around the globe. Here are a few notable ones:
We partner with space agencies around the globe on space-analog missions. Analog missions are field tests in locations that have physical similarities to the extreme space environments. They take astronauts to space-like environments to prepare as international teams for near-term and future exploration to asteroids, Mars and the Moon.
The European Space Agency hosts the Cooperative Adventure for Valuing and Exercising human behavior and performance Skills (CAVES) mission. The two week training prepares multicultural teams of astronauts to work safely and effectively in an environment where safety is critical. The mission is designed to foster skills such as communication, problem solving, decision-making and team dynamics.
We host our own analog mission, underwater! The NASA Extreme Environment Mission Operations (NEEMO) project sends international teams of astronauts, engineers and scientists to live in the world’s only undersea research station, Aquarius, for up to three weeks. Here, “aquanauts” as we call them, simulate living on a spacecraft and test spacewalk techniques for future space missions in hostile environments.
International Astronautical Congress
So, whether we’re collaborating as a science team around the globe, or shoulder-to-shoulder on a spacewalk, we are committed to working together with international partners for the benefit of all humanity!
If you’re interested in learning more about how the global space industry works together, check out our coverage of the 70th International Astronautical Congress (IAC) happening this week in Washington, D.C. IAC is a yearly gathering in which all space players meet to talk about the advancements and progress in exploration.
We launched our Spitzer Space Telescope into orbit around the Sunday on Aug. 25, 2003. Since then, the observatory has been lifting the veil on the wonders of the cosmos, from our own solar system to faraway galaxies, using infrared light.
Thanks to Spitzer, scientists were able to confirm the presence of seven rocky, Earth-size planets in the TRAPPIST-1 system. The telescope has also provided weather maps of hot, gaseous exoplanets and revealed a hidden ring around Saturn. It has illuminated hidden collections of dust in a wide variety of locations, including cosmic nebulas (clouds of gas and dust in space), where young stars form, and swirling galaxies. Spitzer has additionally investigated some of the universe’s oldest galaxies and stared at the black hole at the center of the Milky Way.
In honor of Spitzer’s Sweet 16 in space, here are 16 amazing images from the mission.
Giant Star Makes Waves
This Spitzer image shows the giant star Zeta Ophiuchi and the bow shock, or shock wave, in front of it. Visible only in infrared light, the bow shock is created by winds that flow from the star, making ripples in the surrounding dust.
The Seven Sisters Pose for Spitzer
The Pleiades star cluster, also known as the Seven Sisters, is a frequent target for night sky observers. This image from Spitzer zooms in on a few members of the sisterhood. The filaments surrounding the stars are dust, and the three colors represent different wavelengths of infrared light.
Young Stars in Their Baby Blanket of Dust
Newborn stars peek out from beneath their blanket of dust in this image of the Rho Ophiuchi nebula. Called “Rho Oph” by astronomers and located about 400 light-years from Earth, it’s one of the closest star-forming regions to our own solar system.
The youngest stars in this image are surrounded by dusty disks of material from which the stars — and their potential planetary systems — are forming. More evolved stars, which have shed their natal material, are blue.
The Infrared Helix
Located about 700 light-years from Earth, the eye-like Helix nebula is a planetary nebula, or the remains of a Sun-like star. When these stars run out of their internal fuel supply, their outer layers puff up to create the nebula. Our Sun will blossom into a planetary nebula when it dies in about 5 billion years.
The Tortured Clouds of Eta Carinae
The bright star at the center of this image is Eta Carinae, one of the most massive stars in the Milky Way galaxy. With around 100 times the mass of the Sun and at least 1 million times the brightness, Eta Carinae releases a tremendous outflow of energy that has eroded the surrounding nebula.
Spitzer Spies Spectacular Sombrero
Located 28 million light-years from Earth, Messier 104 — also called the Sombrero galaxy or M104 — is notable for its nearly edge-on orientation as seen from our planet. Spitzer observations were the first to reveal the smooth, bright ring of dust (seen in red) circling the galaxy.
Spiral Galaxy Messier 81
This infrared image of the galaxy Messier 81, or M81, reveals lanes of dust illuminated by active star formation throughout the galaxy’s spiral arms. Located in the northern constellation of Ursa Major (which includes the Big Dipper), M81 is also about 12 million light-years from Earth.
Spitzer Reveals Stellar Smoke
Messier 82 — also known as the Cigar galaxy or M82 — is a hotbed of young, massive stars. In visible light, it appears as a diffuse bar of blue light, but in this infrared image, scientists can see huge red clouds of dust blown out into space by winds and radiation from those stars.
A Pinwheel Galaxy Rainbow
This image of Messier 101, also known as the Pinwheel Galaxy or M101, combines data in the infrared, visible, ultraviolet and X-rays from Spitzer and three other NASA space telescopes: Hubble, the Galaxy Evolution Explorer’s Far Ultraviolet detector (GALEX) and the Chandra X-Ray Observatory. The galaxy is about 70% larger than our own Milky Way, with a diameter of about 170,000 light-years, and sits at a distance of 21 million light-years from Earth. Read more about its colors here.
Cartwheel Galaxy Makes Waves
Approximately 100 million years ago, a smaller galaxy plunged through the heart of the Cartwheel galaxy, creating ripples of brief star formation. As with the Pinwheel galaxy above, this composite image includes data from NASA’s Spitzer, Hubble, GALEX and Chandra observatories.
The first ripple appears as a bright blue outer ring around the larger object, radiating ultraviolet light visible to GALEX. The clumps of pink along the outer blue ring are X-ray (observed by Chandra) and ultraviolet radiation.
Spitzer and Hubble Create Colorful Masterpiece
Located 1,500 light-years from Earth, the Orion nebula is the brightest spot in the sword of the constellation Orion. Four massive stars, collectively called the Trapezium, appear as a yellow smudge near the image center. Visible and ultraviolet data from Hubble appear as swirls of green that indicate the presence of gas heated by intense ultraviolet radiation from the Trapezium’s stars. Less-embedded stars appear as specks of green, and foreground stars as blue spots. Meanwhile, Spitzer’s infrared view exposes carbon-rich molecules called polycyclic aromatic hydrocarbons, shown here as wisps of red and orange. Orange-yellow dots are infant stars deeply embedded in cocoons of dust and gas.
A Space Spider Watches Over Young Stars
Located about 10,000 light-years from Earth in the constellation Auriga, the Spider nebula resides in the outer part of the Milky Way. Combining data from Spitzer and the Two Micron All Sky Survey (2MASS), the image shows green clouds of dust illuminated by star formation in the region.
North America Nebula in Different Lights
This view of the North America nebula combines visible light collected by the Digitized Sky Survey with infrared light from NASA’s Spitzer Space Telescope. Blue hues represent visible light, while infrared is displayed as red and green. Clusters of young stars (about 1 million years old) can be found throughout the image.
Spitzer Captures Our Galaxy’s Bustling Center
This infrared mosaic offers a stunning view of the Milky Way galaxy’s busy center. The pictured region, located in the Sagittarius constellation, is 900 light-years agross and shows hundreds of thousands of mostly old stars amid clouds of glowing dust lit up by younger, more massive stars. Our Sun is located 26,000 light-years away in a more peaceful, spacious neighborhood, out in the galactic suburbs.
The Eternal Life of Stardust
The Large Magellanic Cloud, a dwarf galaxy located about 160,000 light-years from Earth, looks like a choppy sea of dust in this infrared portrait. The blue color, seen most prominently in the central bar, represents starlight from older stars. The chaotic, bright regions outside this bar are filled with hot, massive stars buried in thick blankets of dust.
A Stellar Family Portrait
In this large celestial mosaic from Spitzer, there’s a lot to see, including multiple clusters of stars born from the same dense clumps of gas and dust. The grand green-and-orange delta filling most of the image is a faraway nebula. The bright white region at its tip is illuminated by massive stars, and dust that has been heated by the stars’ radiation creates the surrounding red glow.
Managed by our Jet Propulsion Laboratory in Pasadena, California, Spitzer’s primary mission lasted five-and-a-half years and ended when it ran out of the liquid helium coolant necessary to operate two of its three instruments. But, its passive-cooling design has allowed part of its third instrument to continue operating for more than 10 additional years. The mission is scheduled to end on Jan. 30, 2020.
Our James Webb Space Telescope is the most ambitious and complex space science observatory ever built. It will study every phase in the history of our universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.
In order to carry out such a daring mission, many innovative and powerful new technologies were developed specifically to enable Webb to achieve its primary mission.
Here are 5 technologies that were developed to help Webb push the boundaries of space exploration and discovery:
1. Microshutters
Microshutters are basically tiny windows with shutters that each measure 100 by 200 microns, or about the size of a bundle of only a few human hairs.
The microshutter device will record the spectra of light from distant objects (spectroscopy is simply the science of measuring the intensity of light at different wavelengths. The graphical representations of these measurements are called spectra.)
Other spectroscopic instruments have flown in space before but none have had the capability to enable high-resolution observation of up to 100 objects simultaneously, which means much more scientific investigating can get done in less time.
Webb’s backplane is the large structure that holds and supports the big hexagonal mirrors of the telescope, you can think of it as the telescope’s “spine”. The backplane has an important job as it must carry not only the 6.5 m (over 21 foot) diameter primary mirror plus other telescope optics, but also the entire module of scientific instruments. It also needs to be essentially motionless while the mirrors move to see far into deep space. All told, the backplane carries more than 2400kg (2.5 tons) of hardware.
This structure is also designed to provide unprecedented thermal stability performance at temperatures colder than -400°F (-240°C). At these temperatures, the backplane was engineered to be steady down to 32 nanometers, which is 1/10,000 the diameter of a human hair!
One of the Webb Space Telescope’s science goals is to look back through time to when galaxies were first forming. Webb will do this by observing galaxies that are very distant, at over 13 billion light years away from us. To see such far-off and faint objects, Webb needs a large mirror.
Webb’s scientists and engineers determined that a primary mirror 6.5 meters across is what was needed to measure the light from these distant galaxies. Building a mirror this large is challenging, even for use on the ground. Plus, a mirror this large has never been launched into space before!
If the Hubble Space Telescope’s 2.4-meter mirror were scaled to be large enough for Webb, it would be too heavy to launch into orbit. The Webb team had to find new ways to build the mirror so that it would be light enough - only 1/10 of the mass of Hubble’s mirror per unit area - yet very strong.
Read more about how we designed and created Webb’s unique mirrors HERE.
4. Wavefront Sensing and Control
Wavefront sensing and control is a technical term used to describe the subsystem that was required to sense and correct any errors in the telescope’s optics. This is especially necessary because all 18 segments have to work together as a single giant mirror.
The work performed on the telescope optics resulted in a NASA tech spinoff for diagnosing eye conditions and accurate mapping of the eye. This spinoff supports research in cataracts, keratoconus (an eye condition that causes reduced vision), and eye movement – and improvements in the LASIK procedure.
Webb’s primary science comes from infrared light, which is essentially heat energy. To detect the extremely faint heat signals of astronomical objects that are incredibly far away, the telescope itself has to be very cold and stable. This means we not only have to protect Webb from external sources of light and heat (like the Sun and the Earth), but we also have to make all the telescope elements very cold so they don’t emit their own heat energy that could swamp the sensitive instruments. The temperature also must be kept constant so that materials aren’t shrinking and expanding, which would throw off the precise alignment of the optics.
Each of the five layers of the sunshield is incredibly thin. Despite the thin layers, they will keep the cold side of the telescope at around -400°F (-240°C), while the Sun-facing side will be 185°F (85°C). This means you could actually freeze nitrogen on the cold side (not just liquify it), and almost boil water on the hot side. The sunshield gives the telescope the equivalent protection of a sunscreen with SPF 1 million!
Astronomers used three of NASA’s Great Observatories to capture this multiwavelength image showing galaxy cluster IDCS J1426.5+3508. It includes X-rays recorded by the Chandra X-ray Observatory in blue, visible light observed by the Hubble Space Telescope in green, and infrared light from the Spitzer Space Telescope in red. This rare galaxy cluster has important implications for understanding how these megastructures formed and evolved early in the universe.
How Astronomers Time Travel
Let’s add another item to your travel bucket list: the early universe! You don’t need the type of time machine you see in sci-fi movies, and you don’t have to worry about getting trapped in the past. You don’t even need to leave the comfort of your home! All you need is a powerful space-based telescope.
But let’s start small and work our way up to the farthest reaches of space. We’ll explain how it all works along the way.
Are we alone in the universe? So far, the only life we know of is right here on Earth. But here at NASA, we’re looking.
We’re exploring the solar system and beyond to help us answer fundamental questions about life beyond our home planet. From studying the habitability of Mars, probing promising “oceans worlds,” such as Titan and Europa, to identifying Earth-size planets around distant stars, our science missions are working together with a goal to find unmistakable signs of life beyond Earth (a field of science called astrobiology).
Launch: Viking 1 on August 20, 1975 & Viking 2 on September 9, 1975
Status: Past
Role in the search for life: The Viking Project was our first attempt to search for life on another planet. The mission’s biology experiments revealed unexpected chemical activity in the Martian soil, but provided no clear evidence for the presence of living microorganisms near the landing sites.
Role in the search for life: Galileo orbited Jupiter for almost eight years, and made close passes by all its major moons. The spacecraft returned data that continues to shape astrobiology science –– particularly the discovery that Jupiter’s icy moon Europa has evidence of a subsurface ocean with more water than the total amount of liquid water found on Earth.
Role in the search for life: Our first planet-hunting mission, the Kepler Space Telescope, paved the way for our search for life in the solar system and beyond. Kepler left a legacy of more than 2,600 exoplanet discoveries, many of which could be promising places for life.
Role in the search for life: Our newest robot astrobiologist is kicking off a new era of exploration on the Red Planet. The rover will search for signs of ancient microbial life, advancing the agency’s quest to explore the past habitability of Mars.
Role in the search for life: Webb will be the premier space-based observatory of the next decade. Webb observations will be used to study every phase in the history of the universe, including planets and moons in our solar system, and the formation of distant solar systems potentially capable of supporting life on Earth-like exoplanets.
Role in the search for life: Europa Clipper will investigate whether Jupiter’s icy moon Europa, with its subsurface ocean, has the capability to support life. Understanding Europa’s habitability will help scientists better understand how life developed on Earth and the potential for finding life beyond our planet.
Role in the search for life: Dragonfly will deliver a rotorcraft to visit Saturn’s largest and richly organic moon, Titan. This revolutionary mission will explore diverse locations to look for prebiotic chemical processes common on both Titan and Earth.
For more on NASA’s search for life, follow NASA Astrobiology on Twitter, on Facebook, or on the web.
Six Answers to Questions You’re Too Embarrassed to Ask about the Hottest Year on Record
You may have seen the news that 2023 was the hottest year in NASA’s record, continuing a trend of warming global temperatures. But have you ever wondered what in the world that actually means and how we know?
We talked to some of our climate scientists to get clarity on what a temperature record is, what happened in 2023, and what we can expect to happen in the future… so you don’t have to!
Simply put, an exoplanet is a planet that orbits another star.
All of the planets in our solar system orbit around the Sun. Planets that orbit around other stars outside our solar system are called exoplanets.
Just because a planet orbits a star (like Earth) does not mean that it is automatically stable for life. The planet must be within the habitable zone, which is the area around a star in which water has the potential to be liquid…aka not so close that all the water would evaporate, and not too far away where all the water would freeze.
Exoplanets are very hard to see directly with telescopes. They are hidden by the bright glare of the stars they orbit. So, astronomers use other ways to detect and study these distant planets by looking at the effects these planets have on the stars they orbit.
One way to search for exoplanets is to look for “wobbly” stars. A star that has planets doesn’t orbit perfectly around its center. From far away, this off-center orbit makes the star look like it’s wobbling. Hundreds of planets have been discovered using this method. However, only big planets—like Jupiter, or even larger—can be seen this way. Smaller Earth-like planets are much harder to find because they create only small wobbles that are hard to detect.
How can we find Earth-like planets in other solar systems?
In 2009, we launched a spacecraft called Kepler to look for exoplanets. Kepler looked for planets in a wide range of sizes and orbits. And these planets orbited around stars that varied in size and temperature.
Kepler detected exoplanets using something called the transit method. When a planet passes in front of its star, it’s called a transit. As the planet transits in front of the star, it blocks out a little bit of the star’s light. That means a star will look a little less bright when the planet passes in front of it. Astronomers can observe how the brightness of the star changes during a transit. This can help them figure out the size of the planet.
By studying the time between transits, astronomers can also find out how far away the planet is from its star. This tells us something about the planet’s temperature. If a planet is just the right temperature, it could contain liquid water—an important ingredient for life.
So far, thousands of planets have been discovered by the Kepler mission.
We now know that exoplanets are very common in the universe. And future missions have been planned to discover many more!
Next month, we’re launching an explorer-class planet finder — the Transiting Exoplanet Survey Satellite (TESS). This mission will search the entire sky for exoplanets — planets outside our solar system that orbit sun-like stars.
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ALT: This video shows blades of grass moving in the wind on a beautiful day at NASA’s Michoud Assembly Facility in New Orleans. In the background, we see the 212-foot-core stage for the powerful SLS (Space Launch System) rocket used for Artemis I. The camera ascends, revealing the core stage next to a shimmering body of water as technicians lead it towards NASA’s Pegasus barge. Credit: NASA
The SLS (Space Launch System) Core Stage by Numbers
Technicians with NASA and SLS core stage lead contractor Boeing, along with RS-25 engines lead contractor Aerojet Rocketdyne, an L3Harris Technologies company, are nearing a major milestone for the Artemis II mission. The SLS (Space Launch System) rocket’s core stage for Artemis II is fully assembled and will soon be shipped via barge from NASA’s Michoud Assembly Facility in New Orleans to the agency’s Kennedy Space Center in Florida. Once there, it will be prepped for stacking and launch activities.
