Space & Astronomy

Subterms

    More stories

    • 163 Shares199 Views

      in Space & Astronomy

      Most stars may have much more time to form planets than previously thought

      by

      Good news for late bloomers: Planets may have millions of years more time to arise around most stars than previously thought.

      Planet-making disks around young stars typically last for 5 million to 10 million years, researchers report in a study posted October 6 at arXiv.org. That disk lifetime, based on a survey of nearby young star clusters, is a good deal longer than the previous estimate of 1 million to 3 million years.

      “One to three megayears is a really strong constraint for forming planets,” says astrophysicist Susanne Pfalzner of Forschungszentrum Jülich in Germany. “Finding that we have a lot of time just relaxes everything” for building planets around young stars.

      Sign Up For the Latest from Science News

      Headlines and summaries of the latest Science News articles, delivered to your inbox

      Thank you for signing up!

      There was a problem signing you up.

      Planets large and small develop in the disks of gas and dust that swirl around young stars (SN: 5/20/20). Once a disk vanishes, it’s too late to make any more new worlds.

      Past studies have estimated disk lifetimes by looking at the fraction of young stars of different ages that still have disks — in particular, by observing star clusters with known ages. But Pfalzner and her colleagues discovered something odd: The farther a star cluster is from Earth, the shorter the estimated disk lifetime. That made no sense, she says, because why should the lifetime of a protoplanetary disk depend on how far it is from us?

      The answer is quite simple: It doesn’t. But in clusters that are farther away, it’s harder to see most stars. “When you look at larger distances, you see higher-mass stars,” Pfalzner says, because those stars are brighter and easier to see. “You basically don’t see the low-mass stars.” But the lowest-mass stars constitute the vast majority. These stars, orange and red dwarfs, are cooler, smaller and fainter than the sun.

      So Pfalzner and her colleagues examined only the nearest young star clusters, those within 650 light-years of Earth, and found that the fraction of stars with planet-making disks was much higher than that reported in previous studies. This analysis showed that “the low-mass stars have much longer disk lifetimes, between 5 and 10 megayears,” than astronomers realized, she says. In contrast, disks around higher-mass stars are known to disperse faster than this, perhaps because their suns’ brighter light pushes the gas and dust away more quickly.

      “I wouldn’t say that this is definite proof” for such long disk lifetimes around orange and red dwarfs, says Álvaro Ribas, an astronomer at the University of Cambridge who was not involved with the work. “But it’s quite convincing.”

      To bolster the result, he’d like to see observations of more distant star clusters — perhaps with the James Webb Space Telescope — to determine the fraction of the faintest stars that have preserved their planet-making disks between 5 million and 20 million years (SN: 10/11/22).

      If the disks around the lowest mass stars do indeed have long lifetimes, that may explain a difference between our solar system and those of most red dwarfs, Pfalzner says. The latter often lack gas giants like Jupiter and Saturn, which are about 10 times the diameter of Earth. Instead, those stars frequently have numerous ice giants like Uranus and Neptune, about four times the diameter of Earth. Perhaps Neptune-sized planets arise in larger numbers when a planet-making disk lasts longer, Pfalzner says, accounting for why these worlds tend to abound around smaller stars. More

    • 163 Shares169 Views

      in Space & Astronomy

      For the first time, astronomers saw dust in space being pushed by starlight

      by

      A pair of stars in our galaxy is revealing how light pushes around matter. It’s the first time anyone has directly seen how the pressure of light from stars changes the flow of dust in space.

      Such radiation pressure influences how dust clears from the regions near young stars and guides the formation of gas clouds around dying stars (SN: 9/22/20). The dust pattern surrounding a stellar pair 5,600 light-years away in the Cygnus constellation is providing a rare laboratory to observe the effect in action, astronomer Yinuo Han and colleagues report in the Oct. 13 Nature. 

      Sign Up For the Latest from Science News

      Headlines and summaries of the latest Science News articles, delivered to your inbox

      Thank you for signing up!

      There was a problem signing you up.

      Astronomers have long known that the dust emerging from the star WR 140 and its companion is formed by gas from these two stars colliding and condensing into soot. But images of the pair taken over the course of 16 years show that the dust is accelerating as it travels away from the stars.

      Dust initially departs the stars at about 6.5 million kilometers per hour, the researchers report, and over the course of a year accelerates to nearly 10 million km/h. At that speed, the dust could make the trip from our sun to Earth in a mere 15 hours.

      The revelation came from comparing the positions of concentric dust shells year to year and deducing a speed. The researchers’ calculations show that the force accelerating the dust is the pressure exerted by light radiated from the stars, says Han, of the University of Cambridge. “Radiation pressure [becomes apparent] only when we put all the images next to each other.”  

      Not only are those layers of dust feeling light’s push, they also extend out farther than any telescope could see — until this year. Images from the James Webb Space Telescope, or JWST, depict more of the dusty layers around WR 140 and its companion than ever seen before, Han and another team report October 12 in Nature Astronomy.

      At first glance, the intricate patterns surrounding the stars resemble a gigantic spiderweb. But the researchers’ analysis reveals that they are actually enormous, expanding, cone-shaped dust shells. They’re nested inside each other, with a new one forming every eight years as the stars complete another journey around their orbits. In the new images, the shells look like sections of rings because we observe them from the side, Han says.  

      A computer simulation that takes radiation pressure from starlight into account shows how a dust plume (expanding arc and line) emerges from a pair of orbiting stars (not visible).Y. Han/Univ. of Cambridge

      The patterns don’t completely surround the stars because the distance between the stars changes as they orbit one another. When the stars are far apart, the density of the colliding gas is too low to condense to dust — an effect the researchers expected. 

      What surprised them is that the gas doesn’t condense well when the stars are closest together either. That suggests there’s a “Goldilocks zone” for dust formation: Dust forms only when the separation between the stars is just right, creating a series of concentric dust shells rippling away from the duo.

      “Their Goldilocks zone is a new idea,” says astrophysicist Andy Pollock of the University of Sheffield in England, who was not part of either study. “A similar sort of thing happens in my field of X-rays.”

      In his work, Pollock has observed that WR 140 and its partner emit more X-rays as the stars approach each other, but then fewer as they get very close together, suggesting there’s a Goldilocks zone for X-rays coming from the stars as well. “It would be interesting to see if there’s any connection” between the two types of Goldilocks zones, he says. “All of this must somehow fit together.” More

    • 163 Shares179 Views

      in Space & Astronomy

      A 3-D model of the Cat’s Eye nebula shows rings sculpted by jets

      by

      Roughly 3,000 light-years from Earth sits one of the most complex and least understood nebulae, a whirling landscape of gas and dust left in the wake of a star’s death throes. A new computer visualization reveals the 3-D structure of the Cat’s Eye nebula and hints at how not one, but a pair of dying stars sculpted its complexity.

      The digital reconstruction, based on images from the Hubble Space Telescope, reveals two symmetric rings around the nebula’s edges. The rings were probably formed by a spinning jet of charged gas that was launched from two stars in the nebula’s center, Ryan Clairmont and colleagues report in the October Monthly Notices of the Royal Astronomical Society.

      Sign Up For the Latest from Science News

      Headlines and summaries of the latest Science News articles, delivered to your inbox

      Thank you for signing up!

      There was a problem signing you up.

      “I realized there hasn’t been a comprehensive study of the structure of the nebula since the early ’90s,” says Clairmont, an undergraduate at Stanford University. Last year, while a high school student in San Diego, he reached out to a couple of astrophysicists at a scientific imaging company called Ilumbra who had written software to reconstruct the 3-D structure of astronomical objects.

      The team combined Hubble images with ground-based observations of light in several wavelengths, which revealed the motions of the nebula’s gas. Figuring out which parts were moving toward and away from Earth helped reveal its 3-D structure.

      The team identified two partial rings to either side of the nebula’s center. The rings’ symmetry and unfinished nature suggest they are the remains of a plasma jet launched from the heart of the nebula, then snuffed out before it could complete a full circle. Such jets are usually formed through an interaction between two stars orbiting one another, says Ilumbra partner Wolfgang Steffen, who is based in Kaiserslautern, Germany.

      The work won Clairmont a prize at the 2021 International Science and Engineering Fair, an annual competition run by the Society for Science, which publishes Science News. Steffen was skeptical about the tight deadline — when Clairmont reached out, he had just two months to complete the project.

      “I said that’s impossible! Not even Ph.D. students or anybody has tried that before,” Steffen says. “He did it brilliantly. He pulled it all off and more than we expected.” More

    • 88 Shares149 Views

      in Space & Astronomy

      NASA’s DART mission successfully shoved an asteroid

      by

      It worked! Humanity has, for the first time, purposely moved a celestial object.

      As a test of a potential asteroid-deflection scheme, NASA’s DART spacecraft shortened the orbit of asteroid Dimorphos by 32 minutes — a far greater change than astronomers expected.

      The Double Asteroid Redirection Test, or DART, rammed into the tiny asteroid at about 22,500 kilometers per hour on September 26 (SN: 9/26/22). The goal was to move Dimorphos slightly closer to the larger asteroid it orbits, Didymos.

      Sign Up For the Latest from Science News

      Headlines and summaries of the latest Science News articles, delivered to your inbox

      Thank you for signing up!

      There was a problem signing you up.

      Neither Dimorphos nor Didymos pose any threat to Earth. DART’s mission was to help scientists figure out if a similar impact could nudge a potentially hazardous asteroid out of harm’s way before it hits our planet.

      The experiment was a smashing success. Before the impact, Dimorphos orbited Didymos every 11 hours and 55 minutes. After, the orbit was 11 hours and 23 minutes, NASA announced October 11 in a news briefing.

      A small spacecraft called LICIACube, short for Light Italian CubeSat for Imaging of Asteroids, detached from DART just before impact, then buzzed the two asteroids to get a closeup view of the cosmic smashup. Starting from about 700 kilometers away, this series of images captures a bright plume of debris erupting from Dimorphos (right in the first half of this gif), evidence of the impact that shortened its orbit around Didymos (left). At closest approach, LICIACube was about 59 kilometers from the asteroids.ASI, NASA

      “For the first time ever, humanity has changed the orbit of a planetary body,” said NASA planetary science division director Lori Glaze.

      Four telescopes in Chile and South Africa observed the asteroids every night after the impact. The telescopes can’t see the asteroids separately, but they can detect periodic changes in brightness as the asteroids eclipse each other. All four telescopes saw eclipses consistent with an 11-hour, 23-minute orbit. The result was confirmed by two planetary radar facilities, which bounced radio waves off the asteroids to measure their orbits directly, said Nancy Chabot, a planetary scientist at Johns Hopkins Applied Physics Laboratory in Laurel, Md.

      The minimum change for the DART team to declare success was 73 seconds — a hurdle the mission overshot by more than 30 minutes. The team thinks the spectacular plume of debris that the impactor kicked up gave the mission extra oomph. The impact itself gave some momentum to the asteroid, but the debris flying off in the other direction pushed it even more — like a temporary rocket engine.

      “This is a very exciting and promising result for planetary defense,” Chabot said. But the change in orbital period was just 4 percent. “It just gave it a small nudge,” she said. So knowing an asteroid is coming is crucial to future success. For something similar to work on an asteroid headed for Earth, “you’d want to do it years in advance,” Chabot said. An upcoming space telescope called Near Earth Asteroid Surveyor is one of many projects intended to give that early warning. More

    • 150 Shares189 Views

      in Space & Astronomy

      The James Webb Space Telescope spied the earliest born stars yet seen

      by

      Some of the earliest stars yet seen are now coming to light in one of the first images from the James Webb Space Telescope.

      Formed roughly 800 million years after the Big Bang, the stars live in dense groups called globular clusters and surround a distant galaxy dubbed the Sparkler,  astronomers report in the Oct. 1 Astrophysical Journal Letters. Globular clusters often host some of the oldest stars in contemporary galaxies such as our own, but it’s hard to tell their exact age. The new finding could help researchers pinpoint when such clusters began to form.

      Sign Up For the Latest from Science News

      Headlines and summaries of the latest Science News articles, delivered to your inbox

      Thank you for signing up!

      There was a problem signing you up.

      Compared to a galaxy, globular clusters are tiny, which makes them hard to see from across the universe. But this time, a gargantuan natural lens in space helped. The Sparkler is one of thousands of galaxies that lie far behind a massive, much closer galaxy cluster called SMACS 0723, which was the subject of the first publicly released science image from the James Webb Space Telescope, or JWST (SN: 7/11/22). The cluster distorts spacetime such that the light from the more distant galaxies behind it is magnified.

      For all those remote galaxies, that extra magnification brings out details that have never been seen before. One elongated galaxy surrounded by yellowish blobs got the attention of astronomer Lamiya Mowla and her colleagues.

      “When we first saw it, we noticed all those little dots around it that we called ‘the sparkles,’” says Mowla, of the University of Toronto. The team wondered if the sparkles could be globular clusters, close-knit families of stars that are thought to have been born together and stay close to each other throughout their lives (SN: 10/15/20).

      “The outstanding question that there still is, is how were the globular clusters themselves born?” Mowla says. Were they born at “cosmic noon,” 10 billion years ago, when star formation throughout the universe peaked? Or did they form 13 billion years ago at “cosmic dawn,” when stars were first able to form at all (SN: 3/4/22)?

      Light from the Sparkler takes about 9 billion years to reach Earth, so if the sparkles are globular clusters that shone that long ago, they might help astronomers answer that question.

      Zooming into one part of JWST’s image of the galaxy cluster SMACS 0723, astronomers zeroed in on the yellow dots around this one elongated background galaxy, which they called the Sparkler. Some of the dots may be globular clusters of same-age stars formed just a few hundred years after the Big Bang.L. Mowla et al/The Astrophysical Journal Letters 2022

      Mowla and her colleagues used data from JWST to analyze the wavelengths of light coming from the sparkles. Some of them appear to be forming stars at the time when their light left the clusters. But some had formed all their stars long before.

      “When we see them, the stars are already about 4 billion years old,” says astrophysicist Kartheik Iyer, also of the University of Toronto.

      That means the oldest stars in the sparkles could have formed roughly 13 billion years ago. Since the universe is 13.8 billion years old, “there’s only a short amount of time after the Big Bang when these could have formed,” he says.

      In other words, these clusters were born at dawn, not at noon.

      Studying more globular clusters around ancient galaxies could help determine if such clusters are common or rare early on in the universe’s history. They could also help unravel galaxies’ formation histories, say Mowla and Iyer. Their team has proposed observations to be made in JWST’s first year that could do just that.

      Being able to pick out tiny structures like globular clusters from so far away was almost impossible before JWST, says astronomer Adélaïde Claeyssens of Stockholm University. She was not involved in the new work but led a similar study earlier this year of multiple galaxies magnified by the SMACS 0723 cluster.

      “It’s the first time we showed that, with James Webb, we will observe a lot of these type of galaxies with really tiny structures,” Claeyssens says. “James Webb will be a game changer for this field.” More

    • 138 Shares189 Views

      in Space & Astronomy

      Mars’ buried ‘lake’ might just be layers of ice and rock

      by

      “Follow the water” has long been the mantra of scientists searching for life beyond Earth. After all, the only known cradle of life in the cosmos is the watery planet we call home. But now there’s more evidence suggesting that a potential discovery of liquid water on Mars might not be so watertight, researchers report September 26 in Nature Astronomy.

      In 2018, scientists announced the discovery of a large subsurface lake near Mars’ south pole (SN: 7/25/18). That claim — and follow-up observations suggesting additional buried pools of liquid water on the Red Planet (SN: 9/28/20) — fueled excitement about finally finding an extraterrestrial world possibly conducive to life.

      Sign Up For the Latest from Science News

      Headlines and summaries of the latest Science News articles, delivered to your inbox

      Thank you for signing up!

      There was a problem signing you up.

      But researchers have since proposed that those discoveries might not hold up to scrutiny. In 2021, one group suggested that clay minerals and frozen brines, rather than liquid water, might be responsible for the strong radar signals that researchers observed (SN: 7/16/21). Spacecraft orbiting Mars beam radio waves toward the Red Planet and measure the timing and intensity of the reflected waves to infer what’s beneath the Martian surface.   

      And now another team has shown that ordinary layers of rock and ice can produce many of the same radar signals previously attributed to water. Planetary scientist Dan Lalich of Cornell University and his colleagues calculated how flat layers of bedrock, water ice and carbon dioxide ice — all known to be plentiful on Mars — reflect radio waves. “It was a pretty simple analysis,” Lalich says.

      The researchers found that they could reproduce some of the anomalously strong radar signals thought to be due to liquid water. Individual radar signals from different layers of rock and ice add together when the layers are a certain thickness, Lalich says. That produces a stronger signal, which is then picked up by a spacecraft’s instruments. But those instruments can’t always tell the difference between a radio wave coming from one layer and one that’s the result of multiple layers, he says. “They look like one reflection to the radar.”

      These results don’t rule out liquid water on Mars, Lalich and his colleagues acknowledge. “This is just saying that there are other options,” he says.

      The new finding is “a plausible scenario,” says Aditya Khuller, a planetary scientist at Arizona State University in Tempe who was not involved in the research. But until scientists get a lot more data from the Red Planet, it’ll be difficult to know whether liquid water truly exists on Mars, Khuller says. “It’s important to be open-minded at this point.” More

    • 100 Shares189 Views

      in Space & Astronomy

      Robin Wordsworth re-creates the atmosphere of ancient Mars

      by

      Visitors to the village of Drumnadrochit, on the western shore of Scotland’s murky Loch Ness, come to see the nearby ruins of Urquhart Castle or to chance a glimpse of the elusive Loch Ness Monster. But growing up in Drumnadrochit, planetary scientist Robin Wordsworth says it was the unobscured view of the cosmos that seized his attention. “There are incredibly clear skies up there,” he says.

      Today, Wordsworth lives on the other side of the Atlantic. He’s a researcher and professor at Harvard University. But his gaze is still set on the solar system and beyond. From studying how rocky planets may occasionally become encased in glaciers to exploring the sizes of alien raindrops or the details of how humans might one day settle Mars, Wordsworth’s scientific explorations vary widely. His research group tends to “do a lot of different things at once,” he says. “If I was to summarize it in a sentence, it would be to understand what drives habitability on planets through time.”

      Standout research

      Wordsworth defines a planet’s habitability as its ability to support life. The idea that life could survive elsewhere in the cosmos has always fascinated Wordsworth, a science fiction fan. Apart from Earth, astronomers have discovered roughly 20 potentially habitable worlds in the universe. With data collected by ground-based observatories, satellites and rovers, he uses supercomputers to construct simulations of planets and the evolution of their climates. Climate is a big focus because it determines whether a planet’s surface can harbor liquid water — a necessity for all known forms of life. 

      The swirling clouds of Jupiter, captured by NASA’s Juno spacecraft, could release semisolid ammonia slushballs of precipitation. Work by Robin Wordsworth and a colleague suggests that the size of such alien raindrops is similar no matter what they’re made of or what planet they fall on.GERALD EICHSTADT/MSSS/SWRI, JPL-CALTECH/NASA

      Wordsworth’s most notable research reconstructs the climate of early Mars. Martian river valleys and other geologic clues suggest that abundant liquid water once flowed across the Red Planet, and the early Martian climate has thus become a hot topic for scientists seeking signs of alien life. But for decades, the best researchers could do was build one-dimensional models that struggled to replicate key atmospheric components, such as clouds.

      In 2013 while at the Laboratory of Dynamic Meteorology in Paris, Wordsworth and colleagues presented a 3-D model of the early Martian climate, with clouds and an atmosphere containing large amounts of carbon dioxide. Those are key components for studying how the early Martian atmosphere may have reflected and trapped heat, says astrobiologist James Kasting of Penn State.

      Wordsworth was the one who figured out how to incorporate clouds into the model, thanks to his strong programming skills, handle over mathematics and determination, Kasting says. “He’s been publishing the best climate calculations for early Mars. There’s really nobody else who is in his lane.”

      Sign Up For the Latest from Science News

      Headlines and summaries of the latest Science News articles, delivered to your inbox

      Thank you for signing up!

      There was a problem signing you up.

      What’s next

      Wordsworth’s otherworldly reconstructions may help us better understand whether life might have emerged on Mars or elsewhere. Another strand of his research could help humans one day settle the Red Planet.

      Today, most of Mars’ surface is too cold to sustain liquid water, and the planet’s thin atmosphere offers little protection from the sun’s intense ultraviolet radiation. These conditions make it inhospitable to would-be Martian settlers. But in a 2019 study, Wordsworth and colleagues proposed that sheets of insulating silica aerogel deployed over ice-covered areas might make survival possible.

      In lab tests, layers of aerogel just centimeters thick filtered out 60 percent of UVA and UVB radiation and almost all of the more dangerous UVC rays, while permitting enough light through for photosynthesis. What’s more, the shields warmed the air underneath by more than 50 degrees Celsius, which could make liquid water and growing crops possible. Looking ahead, Wordsworth plans to investigate how settlers on Mars might use bioplastics or other renewable materials to become self-sustaining.

      And far beyond the Red Planet, the exoplanets await. “The James Webb Space Telescope has just begun to collect new exoplanet data,” Wordsworth says. Observations of their atmospheres will help researchers test ideas about how these distant planets and their climates evolve, he says. “It’s just an incredibly exciting time.”

      Want to nominate someone for the next SN 10 list? Send their name, affiliation and a few sentences about them and their work to sn10@sciencenews.org. More

    • 138 Shares189 Views

      in Space & Astronomy

      NASA’s DART spacecraft just smashed into an asteroid — on purpose

      by

      Mission control rooms rarely celebrate crash landings. But the collision of NASA’s DART spacecraft with an asteroid was a smashing success.

      At about 7:15 p.m. EDT on September 26, the spacecraft hurtled into Dimorphos, an asteroid moonlet orbiting a larger space rock named Didymos. The mission’s goal was to bump Dimorphos slightly closer to its parent asteroid, shortening its 12-hour orbit around Didymos by several minutes.

      The Double Asteroid Redirection Test, or DART, is the world’s first attempt to change an asteroid’s motion by ramming a space probe into it (SN: 6/30/20). Neither Dimorphos nor Didymos poses a threat to Earth. But seeing how well DART’s maneuver worked will reveal how easy it is to tamper with an asteroid’s trajectory — a strategy that could protect the planet if a large asteroid is ever discovered on a collision course with Earth.

      “We don’t know of any large asteroids that would be considered a threat to Earth that are coming any time in the next century,” says DART team member Angela Stickle, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. “The reason that we are doing something like DART is because there are asteroids that we haven’t discovered yet.”

      NASA’s DART spacecraft (illustrated) just crashed into the asteroid moonlet Dimorphos on purpose in the world’s first test of a strategy for planetary defense.Johns Hopkins APL/NASA

      Astronomers have spotted almost all the kilometer-size asteroids in the solar system that could end civilization if they hit Earth, says Jessica Sunshine, a planetary scientist at the University of Maryland in College Park who’s also on the DART team. But when it comes to space rocks around 150 meters wide, like Dimorphos, “we only know where about 40 percent of those are,” Sunshine says. “And that is something that, if it did hit, would certainly take out a city.”

      Dimorphos is a safe asteroid to give an experimental nudge, says Mark Boslough, a physicist at Los Alamos National Laboratory in New Mexico who has studied planetary protection but is not involved in DART. “It’s not on a collision course” with Earth, he says, and DART “can’t hit it hard enough to put it on a collision course.” The DART spacecraft weighs only as much as a couple of vending machines, whereas Dimorphos is thought to be nearly as hefty as Egypt’s Great Pyramid of Giza.

      After a 10-month voyage, DART met up with Didymos and Dimorphos near their closest approach to Earth, about 11 million kilometers away. Up until the very end of its journey, DART could see only the larger asteroid, Didymos. But about an hour before impact, DART spotted Dimorphos in its field of view. Using its onboard camera, the spacecraft steered itself toward the asteroid moonlet and slammed into it at some 6.1 kilometers per second, or nearly 14,000 miles per hour.

      After traveling about 11 million kilometers, NASA’s DART spacecraft closed in on its target: the asteroid moonlet Dimorphos. This image of the space rock was taken by DART just seconds  before the spacecraft smashed into it. NASA

      DART’s camera feed went dark after impact. But another probe nearby is expected to have caught the collision on camera. The Light Italian CubeSat for Imaging of Asteroids rode to Dimorphos aboard DART but detached a couple of weeks before impact to watch the event from a safe distance. Its mission was to whiz past Dimorphos about three minutes after DART’s impact to snap pictures of the crash site and the resulting plume of asteroid debris launched into space. The probe is expected to beam images of DART’s demise back to Earth within a couple of days.

      “I was absolutely elated, especially as we saw the camera getting closer and just realizing all the science that we’re going to learn,” said Pam Melroy, NASA Deputy Administrator, after the impact. “But the best part was seeing, at the end, that there was no question there was going to be an impact, and to see the team overjoyed with their success.”

      [embedded content]
      This animation shows how DART’s impact on Dimorphos will affect the space rock’s orbit around its larger parent asteroid, Didymos. DART should shove Dimorphos into a slightly tighter, shorter orbit.

      DART’s impact is expected to shove Dimorphos into a closer, shorter orbit around Didymos. Telescopes on Earth can clock the timing of that orbit by watching how the amount of light from the double asteroid system changes as Dimorphos passes in front of and behind Didymos.

      “It’s really a beautifully conceived experiment,” Boslough says. In the coming weeks, dozens of telescopes across every continent will watch Dimorphos to see how much DART changed its orbit. The Hubble and James Webb space telescopes may also get images.

      Sign Up For the Latest from Science News

      Headlines and summaries of the latest Science News articles, delivered to your inbox

      Thank you for signing up!

      There was a problem signing you up.

      “It’ll be really interesting to see what comes out,” says Amy Mainzer, a planetary scientist at the University of Arizona in Tucson who is not involved in DART. “Asteroids have a way of surprising us,” she says, because it’s hard to know a space rock’s precise chemical makeup and internal structure based on observations from Earth. So Dimorphos’ motion post-impact may not exactly match researchers’ expectations.

      The DART team will compare data on Dimorphos’ new orbit with their computer simulations to see how close those models were to predicting the asteroid’s actual behavior and tweak them accordingly. “If we can get our models to reproduce what actually happened, then you can use those models to [plan for] other scenarios that might show up in the future” — like the discovery of a real killer asteroid, says DART team member Wendy Caldwell, a mathematician and planetary scientist at Los Alamos National Laboratory.

      “No matter what happens,” she says, “we will get information that is valuable to the scientific community and to the planetary defense community.”  More