The Catalina Sky Survey 60-inch telescope observes the cosmos from Mount Lemmon in Arizona. (Credit: Catalina Sky Survey)
You, too, can be an asteroid hunter — thanks to a citizen-science project launched by the University of Arizona’s Lunar and Planetary Laboratory. And you might even get a scientific citation.
The project is enlisting human spotters to verify potential detections of space rocks moving through the field of view of the Catalina Sky Survey’s telescopes. The NASA-funded survey is charged with keeping track of more than a million asteroids, with a principal goal of identifying near-Earth objects that could pose a risk to our planet.
More than 14,400 near-Earth objects, or NEOs, have been discovered by the Catalina Sky Survey during the past 30 years, including 1,200 that were identified just in the past year. That adds up to nearly half of the known NEO population.
The problem is, astronomers know there are still lots of unknown asteroids out there — too many for them to spot without an assist from amateurs. “We take so many images of the sky each night that we cannot possibly look through all of our potential real asteroids,” Carson Fuls, a science engineering specialist for the Catalina Sky Survey, said in a NASA news release.
A visualization from NASA's "Eyes on Asteroids" app shows asteroid 2023 DW's location in space. (Credit: NASA)
A newly discovered asteroid called 2023 DW has generated quite a buzz over the past week, due to an estimated 1-in-670 chance of impact on Valentine’s Day 2046. But despite a NASA advisory and the resulting scary headlines, there’s no need to put an asteroid doomsday on your day planner for that date.
The risk assessment doesn’t have as much to do with the probabilistic roll of the cosmic dice than it does with the uncertainty that’s associated with a limited set of astronomical observations. If the case of 2023 DW plays out the way all previous asteroid scares have gone over the course of nearly 20 years, further observations will reduce the risk to zero. (Update: After further observations, 2023 DW was removed from the list of potential impacts on March 20.)
The hubbub over a space rock that could be as wide as 165 feet (50 meters) highlights a couple of trends to watch for: We’re likely to get more of these asteroid alerts in the years to come, and NASA is likely to devote more attention to heading off potentially dangerous near-Earth objects, or NEOs.
A Hubble Space Telescope image shows debris blasted from Dimorphos by NASA's DART spacecraft. (Credit: NASA / ESA / STScI / Hubble)
NASA says its DART spacecraft caused a larger-than-expected change in the path of its target asteroid when they collided two weeks ago — marking a significant milestone in the effort to protect our planet from killer space rocks.
Before the crash, DART’s science team said they expected the collision to reduce the time it took for Dimorphos to go around Didymos by about 10 minutes. NASA would have regarded any change in excess of 73 seconds as a success.
After the crash, detailed observations from ground-based observatories showed that the orbit was actually 32 minutes shorter — going from 11 hours and 55 minutes to 11 hours and 23 minutes. That’s three times as much of a change as scientists were expecting. Scientists also said Dimorphos appears to be slightly closer to Didymos.
“This is a watershed moment for planetary defense, and a watershed moment for humanity,” NASA Administrator Bill Nelson said today. “All of us have a responsibility to protect our home planet. After all, it’s the only one we have.”
An image from the DART spacecraft shows Dimorphos (center) and Didymos (right). Credit: NASA / JHUAPL
Ten months after NASA’s DART spacecraft was aimed at a mini-asteroid, the probe hit the bull’s eye today in a practice round for planetary defense that got an assist from engineers at Aerojet Rocketdyne in Redmond, Wash.
DART — an acronym that stands for “Double Asteroid Redirection Test” — was designed to find out how much impact a projectile could have for diverting a potentially threatening asteroid away from Earth.
In this case, the object posed no actual threat. DART’s target was Dimorphos, an asteroid the size of Egypt’s Great Pyramid that’s in orbit around a half-mile-wide asteroid called Didymos. Both celestial bodies are on a path that ranges out beyond Mars’ orbit and comes close enough to Earth’s orbit for study. At the time of today’s impact, the double-asteroid system was nearly 7 million miles from our planet.
The mission team clapped and cheered at Johns Hopkins University’s Applied Physics Laboratory in Maryland as near-real-time imagery from the spacecraft’s DRACO camera showed Dimorphos looming larger in the metaphorical windshield. The DART spacecraft body, which NASA says weighed about 1,260 pounds and was roughly the size of a vending machine, struck the mini-moon at an estimated velocity of 14,000 mph.
“Oh, fantastic!” Lori Glaze, the director of the Planetary Science Division at NASA’s Science Mission Directorate, said as the camera went dead. “Now is when the science starts.”
After the impact, APL director Ralph Semmel joked about the spacecraft’s destruction. “Never before have I been so excited to see a signal go away,” he said.
This visualization shows trajectories for scores of newly identified asteroids. (B612 Asteroid Institute / UW Dirac Institute / OpenSpace Project)
Astronomers have used a cloud-based technique pioneered at the University of Washington to identify and track asteroids in bunches of a hundred or more. Their achievement could dramatically accelerate the quest to find potentially threatening space rocks.
Teaming up ADAM and THOR may sound like a cross between a Bible story and a Marvel comic, but this dynamic duo’s superpower is strictly scientific: When ADAM runs the THOR algorithm, the software can determine the orbits of asteroids, even previously unidentified asteroids, by sifting through any large database of astronomical observations.
“Discovering and tracking asteroids is crucial to understanding our solar system, enabling development of space, and protecting our planet from asteroid impacts,” former NASA astronaut Ed Lu, the Asteroid Institute’s executive director, said today in a news release. “With THOR running on ADAM, any telescope with an archive can now become an asteroid search telescope.”
Jennifer Lawrence and Leonardo DiCaprio portray scientists who find a killer comet in "Don't Look Up." (Netflix Photo / Niko Tavernise)
The science adviser for “Don’t Look Up,” a star-studded comedy about a killer comet, has some serious advice for dodging a threat from the skies: Take the title of the movie, and do the exact opposite.
“The sensible thing to do about this particular problem is … just go look up and see if it’s out there,” said Amy Mainzer, a planetary scientist at the University of Arizona’s Lunar and Planetary Laboratory. “And do a thorough enough job of it that we have a reasonable chance of spotting something that’s large enough to cause appreciable damage, well before it could make its way here.”
The roughly 5-mile-wide comet that’s heading for Earth in “Don’t Look Up,” with only about six and a half months of advance warning, is totally fictional. Nevertheless, the movie is a teachable moment for the science surrounding asteroids, comets and planetary defense. And Mainzer said the stars of the show, including Leonardo DiCaprio and Jennifer Lawrence, were unusually eager students.
“These actors wanted to know everything,” she said. “I would say they’re approaching some pretty solid knowledge of just how do we find asteroids and comets, and what do we do about them.”
Mainzer discusses what’s going on with the search for potentially threatening near-Earth objects, as well as her experience as a science adviser for “Don’t Look Up,” in the latest episode of the Fiction Science podcast, coming to you from the place where science and technology intersect with fiction and popular culture. You can listen to the episode via your favorite podcast channel — or right here:
SpaceX's Falcon 9 rocket launches NASA's DART asteroid probe from Vandenberg Space Force Base in California. (NASA Photo / Bill Ingalls)
A space probe the size of a school bus is on its way to smash into an asteroid the size of Egypt’s Great Pyramid, directed by thruster systems built by Aerojet Rocketdyne in Redmond, Wash.
This is no “Armageddon,” and there’s no need for Bruce Willis to ride to the rescue. But the experiment is expected to help scientists figure out how to divert a dangerous asteroid heading for Earth should the need arise. That’s one giant leap for planetary defense — and for Aerojet Rocketdyne, whose made-in-Redmond thrusters have been used on dozens of space missions.
“We’ve been to every planet in the solar system,” said Joseph Cassady, Aerojet’s executive director for space. “But this is the first time we’ve ever done something that’s really truly planned as a defense against threats to life on Earth. The test we’re going to do here is really the first step in getting ourselves ready as a species to react and respond if we ever are threatened in that way.”
NASA’s Double Asteroid Redirection Test mission, or DART, got off to a showy start with tonight’s launch of a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California. Liftoff occurred at 10:21 p.m. PT, at the end of a smooth countdown.
Minutes after launch, the rocket’s second stage separated from the first-stage booster and proceeded to orbit, while the booster flew itself back to an at-sea landing on a drone ship stationed in the Pacific. Within an hour after launch, the second stage deployed the DART spacecraft and sent it on its way.
Tonight’s launch marked the first leg of a 10-month journey to a double-asteroid system that’ll be nearly 7 million miles away from Earth at the time of the encounter. The larger asteroid, called Didymos, is about half a mile wide — but that’s not DART’s target. Instead, Aerojet’s thrusters will guide the spacecraft to hit the smaller asteroid, known as Dimorphos.
Gerard Butler stars in the comet-disaster movie "Greenland." (Image Courtesy of STXfilms)
If a killer asteroid or comet comes our way, don’t expect Bruce Willis or Robert Duvall to try flying to the rescue. And don’t expect doom to arrive in one big dose.
Those are two of the lessons that Hollywood has learned since 1998, when “Armageddon” and “Deep Impact” put death from the skies on the big screen. The killer-comet theme returns in “Greenland,” a big-budget movie that’s making its debut on premium video-on-demand this weekend. But the plot twists are dramatically different.
There’s a different look to the movie as well, thanks in part to the research that was done by visual effects supervisor Marc Massicotte.
“The movies of the past have had a large creative influence on the direction we wanted to take, but at the same time, we didn’t want to repeat what had been done,” he told me. “We wanted to update and also be as close [as possible] to what reality as we know it now is.”
Massicotte discussed his vision of doomsday for the Fiction Science podcast, which focuses on the intersection of science and fiction. And to even out the proportion of science to fiction, I also checked in with Danica Remy, president of the B612 Foundation. Remy’s group focuses on the threats posed by asteroids and comets, as well as strategies to head off such threats — none of which involve Bruce Willis.
“Every movie that talks about this subject is a way to educate the public and raise awareness about the issue,” Remy told me. “The science in the movies may not be correct, but certainly the discussion and the education aspect — you know, the fact that these things do happen — we think is a plus.”
Massicotte was especially taken by the idea that incoming space objects may not hit the ground at all, but instead break apart as they plunge through the atmosphere, setting off a powerful airburst.
That was the case for the Tunguska blast that flattened half a million acres of Siberian forest in 1908, and for the Chelyabinsk meteor that injured hundreds of Russians in 2013.
For Massicotte, the fact that an airburst would look so good on the big screen was a bonus. “You’d have an asteroid that would come in and have an airburst — and in nighttime it would pretty much light up the sky, and light up its whole environment as if we were in total daytime, having beautiful shifting shadows and shadow play on vehicles that were driving at night on the road,” he said.
Several other choices were made with a nod toward scientific findings. For example, the filmmakers went with a killer comet rather than a killer asteroid, because comets are typically harder to track than asteroids. Virtually all of the near-Earth asteroids capable of causing mass extinctions are already being monitored, thanks largely to an effort that started around the time that “Armageddon” made its debut.
Even better, the comet in “Greenland” is an interstellar object, which plays off the first-ever detection of an interstellar asteroid in 2017. And the filmmakers set up the plot so that the comet broke up as it rounded the sun, turning a single object into thousands of unpredictable pieces.
As Massicotte and his teammates created the visuals for the movie’s latter scenes, they took their cues from the wildfires that were sweeping over Australia while the movie was being made. That explains the reddish sky that gives everything an eerie glow as the world burns.
“Considering the time frame within the film, the time that has passed, the amount of impacts that have hit the Earth and the devastation of ongoing fires from these impacts, we wanted to show how it had started to affect the climate,” Massicotte said.
There are also parallels to yet another real-world crisis, the coronavirus pandemic. The movie’s name, “Greenland,” refers to the location of a huge military shelter that was held over from the Cold War. Who decides which people survive? How do the deciders enforce their will? The failings and sacrifices that come to light in the course of the comet crisis may strike a chord for those concerned about COVID-19.
The script for “Greenland” doesn’t include parts for the brave astronauts who try to subdue the killer comet — which is pretty much how it would be in real life.
Remy said that none of the three generally accepted methods for diverting a potentially hazardous asteroid would involve sending humans. One calls for a kinetic impactor to smash into the asteroid, changing its course just enough to result in a miss. Another would use a “gravity tractor” to tug the asteroid into a slightly different orbit.
“The third one, which we hope we never have to use, is a nuclear standoff,” Remy said, “where you don’t blow it up, like in ‘Armageddon,’ but where you would explode it near the asteroid, and then the explosion will push the asteroid away.”
Scientists still have a lot to learn about comets, asteroids and interstellar objects — and about the best ways to keep our planet safe from cosmic threats — but perhaps the most promising plot development is that scientists are quick learners.
Even Massicotte is fascinated by the real-life science behind big-screen tales of killer asteroids and comets. “It’s all these little aspects that I’m still very curious about and would love to learn more about, obviously,” he told me. “It has shone a light on our little place in the universe — and how we’re not so indestructible.”
An artist's conception shows Hayabusa 2’s sample return capsule descending to Earth while the mothership flies above. (JAXA Illustration)
Japan’s Hayabusa 2 probe zoomed past Earth today and dropped off a capsule containing bits of an asteroid, finishing a six-year round trip.
But the mission is far from over: While Hayabusa 2’s parachute-equipped sample capsule descended to the Australian Outback, its mothership set a new course for an encounter with yet another asteroid in 2031.
Hayabusa 2’s prime objective was to deliver bits of Ryugu, an asteroid that’s currently 7.2 million miles from Earth. Mission controllers at the Japan Aerospace Exploration Agency, or JAXA, cheered and laughed when word came that the capsule had survived atmospheric re-entry.
Imagery captured by tracking cameras — and from the International Space Station — showed the capsule streaking like a fireball across the sky as it decelerated from an initial speed of more than 26,000 mph.
The University of Arizona’s Dante Lauretta, principal investigator for the $800 million mission, said the sample should amount to much more than the 2 ounces (60 grams) that was considered the minimum for mission success.
That leakage forced NASA to hustle up the procedure for securing the sample, culminating in the closure of the sample return capsule on Oct. 28. Scientists got a sense of the size of the sample by checking photos of the sample collection head, but they didn’t have time to use other methods to measure the sample’s mass.
“Even though my heart breaks for the loss of sample, it turned out to be a pretty cool science experiment, and we’re learning a lot,” Lauretta said today during a teleconference.
OSIRIS-REx — which takes its Egyptian-sounding name from the acronym for “Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer” — was launched in 2016 and took two years to get to Bennu. The probe surveyed the 1,600-foot-wide asteroid during the two years that followed, leading up to last week’s sample collection effort.
I’ve officially closed the Sample Return Capsule! The sample of Bennu is sealed inside and ready for our voyage back to Earth. The SRC will touch down in the Utah desert on Sep. 24, 2023. Thanks, everyone, for being a part of my journey #ToBennuAndBackpic.twitter.com/z75ITNiGBf
If the mission sticks to its schedule, OSIRIS-REx will begin its homeward journey next March, and drop off its sample capsule over the Utah desert during a 2023 flyby.
Scientists hope that studying a pristine sample from Bennu will bring new insights into the origins of the solar system and the chemical building blocks for life on Earth. There’s also a chance they’ll learn more about the resources that could be extracted from near-Earth asteroids, and about the strategies that would work best if threatening space rocks had to be diverted.
OSIRIS-REx is the first NASA mission to bring back samples from an asteroid, but Japan’s Hayabusa mission did something similar a decade ago. A follow-up mission, Hayabusa 2, is due to deliver yet another asteroid sample in December. Comparing such samples should add to the prospects for scientific discoveries.
But wait … there’s more. NASA has two other asteroid missions in the works: The Lucy spacecraft, set for launch next year, will visit a series of asteroids anchored in Jupiter’s orbit. And in 2022, NASA will send the Psyche probe to study a metal-rich asteroid, also named Psyche.
