Latest news with #LunarandPlanetarySciencesConference
Yahoo
21-05-2025
- Science
- Yahoo
After the Arecibo collapse in 2020, a lone NASA radar dish in the Mojave desert stepped up as a leading asteroid hunter
When you buy through links on our articles, Future and its syndication partners may earn a commission. Rising out of the remote Mojave Desert, NASA's Goldstone Solar System Radar is a solitary satellite dish that communicates with spacecraft. In its downtime, the facility's antennas can track objects in space as they pass by Earth, improving measurements of their orbits that help scientists calculate if a particular target has a chance of colliding with our planet. By the end of 2024, Goldstone had detected 55 Near-Earth Asteroids, setting a new annual record for the facility. In 1968, scientists used Goldstone to make the first radar asteroid observations. In the decades that followed, researchers leaned more heavily on the Arecibo Observatory, a larger dish in Puerto Rico that could make more detailed studies. "While Arecibo was in operation, about 2.5 times as many binary system satellites had been found there relative to Goldstone," asteroid hunter and planetary scientist Lance Benner, of the Jet Propulsion Laboratory, told by email. But the unexpected 2020 collapse of Arecibo left Goldstone as the new heavy hitter. According to Benner, the number of binaries identified by Goldstone is comparable to those found at Arecibo. Benner, who uses Goldstone to observe known asteroids, updated the planetary science community on the status of steroid radar observations made to Goldstone in March, at the 56th annual Lunar and Planetary Sciences Conference in Houston, Texas. Asteroids are leftover bits from the dawn of the solar system, and have the potential to reveal information about those formative years. Of the 37,255 known near-Earth asteroids, only 1127 have been observed by radar, and 512 of those were observed by Goldstone. Since the fall of Arecibo, 199 NEAs have been detected at Goldstone; 154 of them were detected for the first time by radar. Of those, 112 were classified as potentially hazardous asteroids. While asteroids are more easily discovered with optical telescopes, radar images shine when it comes to details. Radar can help astronomers study the physical properties of the asteroids, including their shapes, sizes, rotation states, surface features like roughness, and radar reflectivity. "Some images obtained with radar […] rival the resolutions of spacecraft flyby missions," Benner said. All of this can help scientists better understand the structure and composition of the asteroids as they buzz by Earth. Radar can also help to refine the asteroid's path through space, which can help researchers determine how likely it is to collide with Earth in the future. And radar shines when it comes to companions. Because it provides the equivalent of an up-close look at the space rocks, it can determine when asteroids are in binary pairs or even triple systems. Of the 75 binary and triple asteroid systems observed by radar since 2000, 70% were discovered using radar. From 2021 to 2024, Goldstone's DSS-14 radar antenna observed 19 binary systems, identifying 14 of these for the first time. Goldstone even helped revise some of Arecibo's findings; the system 1998 ST27 was formerly classified as a binary from previous observations, but has now been reclassified as a triple thanks to Goldstone. Observations of these NEAs are generally scheduled well in advance, though there are occasionally opportunities to study a newfound asteroid on short notice. In some months, Benner said, there might be observations anywhere from 10 to 15 days, while in other months hunting asteroids is regulated to only a handful of days. The process has become more flexible in recent years. In the past, would-be-observers had to obtain permission from more then 20 government agencies or military units who control restricted airspace surrounding the Goldstone Deep Space Communications Complex. "Obtaining approval could take several days, and in some cases, the asteroids had moved too far from Earth by the time we got approval to take full advantage of the observing opportunities," Benner said. That requirement is no longer necessary. Observers no longer need to get approval to transmit toward specific parts of the sky and at specific times. "This gives us the ability to change targets on the fly," Benner said. That, in turn, allows for a rising number of asteroids to be studied. "There are now so many asteroids known — and being discovered, sometimes more than 200 per month — that there are usually multiple asteroids within our range of detection every day, so flexibility with observing is really important," Benner said. The greater flexibility has led to an increase in asteroid observations from the Mojave. The 55 NEAs detected at Goldstone in 2024 represents a 1.5x increase relative to the average from 2012 to 2018, and a five-fold increase compared to 15 years ago. "Overall, there has been a significant uptick in time allocated at Goldstone for radar observations," as priority for radar observations is now considered comparable to space missions, Benner said. RELATED STORIES: — 2 asteroids just zipped by Earth, and NASA caught footage of the action — NASA radar images show stadium-size asteroid tumbling by Earth during flyby (photos) — Radar could help scientists find potentially threatening asteroids. Here's how Goldstone saw first light in December 1958, immediately after NASA was created and just in time to support the agency's Pioneer 3 mission to the moon. The Pioneer Station, an 85-foot (26-meter) polar mounted antenna, was the first to be constructed at Goldstone, and went on to support multiple spacecraft as well as the Apollo missions. It was officially shut down in 1981, and in 1985 was declared a National Historic Monument due to its role as the first deep space antenna in the Deep Space Network. The first observation of an asteroid using a radar telescope was made of asteroid (1566) Icarus in 1968 at Goldstone and later the then-functioning Haystack Observatory. At the time, Icarus was a subject of extreme interest as it made its closest approach to Earth. Goldstone antennas have also been used to study other objects in the solar system, such as the moon. Goldstone was the first of three instruments that today make up NASA's Deep Space Network. Along with dishes in Canberra, Australia and Madrid, Spain, the network communicates with ongoing missions, including continuing to keep in contact with the Voyager 1 and Voyager 2 spacecraft, the most distant human-made objects in the solar system. More than 40 missions have depended on the network, and it is expected to support twice that number in the coming years.
Yahoo
15-05-2025
- Science
- Yahoo
Our moon may have once been as hellish as Jupiter's super volcanic moon Io
When you buy through links on our articles, Future and its syndication partners may earn a commission. The moon spent a few million years as a volcanic wasteland, covered with ongoing eruptions that spewed from mountains and even from the ground itself. New research suggests that the moon's orbit could have turned it into a molten monster for a few tens of millions of years. The result may have been comparable to Jupiter's moon Io, the most volcanic body in the solar system. Early in the history of the solar system, a massive protoplanet plowed into a young Earth. The colliding material intermixed, then reformed into two separate bodies that would become Earth and the moon. The two orbited almost on top of one another, but over time, the moon slowly drifted away, solidifying as it went. Eventually, the sun's gravity exerted a stronger pull on the moon. Although it was farther away than the sun, the two bodies tugged on the moon equally. "The moon gets sort of confused," planetary scientist Francis Nimmo, of the University of California, Santa Cruz, told "It doesn't know exactly what orbit it should be adopting, and so it can develop kind of a weird orbit." Nimmo presented the results of his study in March at the 56th annual Lunar and Planetary Sciences Conference. The resulting gravitational mishmash churns up the lunar interior, melting rock to create a magma layer that erupts to the surface. The new research suggests that the lunar surface may have been reset by the lava flows roughly 4.35 billion years ago. The lava flows would have filled in any existing craters and helped to reset the ages measured by moon rocks and lunar zircons. Figuring out when the moon formed presents its own challenges. There are a number of methods, from studying samples returned to Earth to examining zircons within those rocks to trying to figure out how the planets and their satellites danced billions of years ago. But those methods can all give conflicting answers. Probing the age of moon rocks was one of the first ways scientists attempted to calibrate the age of the moon. Samples brought back from NASA's Apollo progam were studied and measured. Today, new samples continue to come in, now from China's ongoing series of Chang'e program. These provide new objects to study and test. A second line of evidence for the lunar age comes from zircons within the rocks themselves. Zircons are silicate minerals found inside of rocks on both Earth and moon and are some of the oldest objects in the solar system. While rocks can melt and reform, the zircons themselves are tough enough to resist melting at all but the highest temperatures. "Zircons are very tough," Nimmo said. "It takes a lot to destroy a zircon once it's formed." Melting the lunar surface through extensive volcanism is one way to reset the zircons. Both methods of dating can be a challenge. Zircons are more precise but require incredibly precise measurements, which is why scientists have only been able to examine them over the last two decades or so. Moon rocks, on the other hand, can be more complicated to interpret, and have been providing a variety of ages. Together, the two processes suggest the moon is about 4.35 billion years old. Scientists also rely on insights from dynamical models. Studies of Earth show that it collected a lot of iron-loving metals after it had already formed an iron core. Those metals settled in the mantle, making up roughly a half of a percent of Earth's mass after core formation was completed, and are referred to as the Late Veneer. But those metals had to be absorbed while material was still flying around in the chaotic, cluttered early solar system — and 4.35 billion years ago, that material was already gone. With the new results, published in the journal Nature at the end of last year, Nimmo and his colleagues are suggesting that a 4.5-billion-year-old moon would fit into measurements of younger lunar rocks. When the moon suffered from a tug-of-war between Earth and the sun, the melting would have caused lunar rocks and zircons to melt and reform, providing a younger age that doesn't necessarily reflect when the moon itself was born. For a few tens of millions of years, volcanism would have covered the moon. But it wouldn't necessarily have been expressed as massive spewing mountains. On Earth, volcanic material is rich in silicate, which thickens the lava and allows it to pile up into massive mountains. On the moon, the lava was likely thinner, seeping through the crust and out to the side rather than piling up on itself. "There was certainly lots of volcanism, it just didn't really produce volcanoes that we're familiar with," Nimmo said. RELATED STORIES: — Earth's moon had a magma ocean for 200 million years — The far side of the moon was once a vast magma ocean, Chinese lunar lander confirms — A giant crater on the moon may hold remnants of an ancient magma ocean. Artemis astronauts could bring home samples of it The constant seepage may have inhibited the formation of a magma ocean layer because the newly formed liquid wouldn't remain stuck in the mantle. As the material melted and became buoyant, it would have oozed upward to the crust. Some of it would have broken through, but some of it may have simply filled in the crust, creating outward buckles like those seen on Earth. At the time, the Earth would have been far closer to the moon than it is today, making it perhaps twice as large in the lunar sky as it is today. "You would see glowing lava flows all over the place, and maybe the odd volcanic eruption," Nimmo said. The Io-like state would have only lasted maybe a few tens of millions of years, according to Nimmo. "This was kind of a brief but very energetic event," he said.
Yahoo
03-05-2025
- Science
- Yahoo
A whole 'population' of minimoons may be lurking near Earth, researchers say
When you buy through links on our articles, Future and its syndication partners may earn a commission. Earth's minimoon may be a chip off the old block: New research suggests that 2024 PT5 — a small, rocky body dubbed a "minimoon" during its discovery last year — may have been blown off the moon during a giant impact long ago, making it the second known sample traveling near Earth's orbit. The discovery hints at a hidden population of lunar fragments traveling near Earth. "If there were only one object, that would be interesting but an outlier," Teddy Kareta, a planetary scientist at Lowell Observatory in Arizona, said in March at the 56th annual Lunar and Planetary Sciences Conference in the Woodlands, Texas. "If there's two, we're pretty confident that's a population." Earth travels through and with a cloud of debris as the planet makes tracks around the sun. Some of that material is human-made — satellites and space junk. Other material is rocky debris left over from collisions in the early solar system. These near-Earth objects (NEOs) can be a concern, so they are tracked to ensure they are not a threat to our planet. Related: Just how many threatening asteroids are there? It's complicated. In August 2024, astronomers in South Africa identified a new rock, known as 2024 PT5, traveling near Earth. 2024 PT5 was moving slowly, with a relative velocity of only 4.5 mph (2 meters per second), making it a strong target for the Mission Accessible Near-Earth Object Survey (MANOS). Only nine other asteroids have been seen traveling so slowly at their closest approach. Kareta, along with MANOS principal investigator Nick Moskovitz, also at Lowell, have been intrigued by the idea of finding moon rocks in space since just after the first such fragment was identified in 2021. MANOS is designed to hunt for and characterize the near-Earth asteroids that might be the easiest to visit with a spacecraft. According to Kareta, that meant the survey was ideal for looking at lunar castoffs. Within a week of 2024 PT5's discovery, they had turned the Lowell Discovery Telescope in the space rock's direction. After studying 2024 PT5 in both visible and near-infrared data, they concluded that it wasn't an ordinary asteroid. Its composition proved similar to that of rocks carried back to Earth during the Apollo program, as well as one returned by the Soviet Union's Luna 24. The researchers also found that 2024 PT5 was small — 26 to 39 feet (8 to 12 meters) in diameter. Kareta and his colleagues suspect that 2024 PT5 was excavated when something crashed into the moon. By studying the asteroid's composition, they hope to tie the material back to its source and perhaps even identify its parent crater. Cratering events are one of the most important processes that shape planetary bodies without tectonics or liquids to remold them. But impacts can be affected by a variety of variables, and understanding them can be a challenge. Matching debris to its crater can provide another way to understand what happens when two bodies collide. That's what makes identifying lunar rocks in space so intriguing. "It's like realizing a crime scene has a totally new kind of evidence you didn't know you had before," Kareta told by email. "It might not help you solve the crime right away, but considering the importance of the task, new details to compare are always welcome." Material from the Earth-moon system should be some of the easiest to fall into orbit near Earth. After an impactor collides with the moon, all but the fastest-moving material flung into space should continue traveling near our system. Although 2024 PT5 was dubbed a minimoon in September, it only briefly fell in line with the planet. Kareta compared it to two cars on the highway. Earth is blazing along in its own lane, while 2024 PT5 chugged along the interior path, closer to the sun. In 2024, the tiny chunk of rock changed lanes, falling into Earth's path at roughly the same speed. By the end of September, it had moved on, shifting outward. Earth left it behind, but on the solar race track, the pair should be parallel again in 2055, scientists estimate. 2024 PT5 is the second lunar fragment identified by researchers. Another small rock, Kamo'oalewa, was traced to the moon in 2021, five years after its discovery. That could hint at a new population, hidden in plain sight. Both objects are traveling in Earth-like orbits, but they don't have much else in common. Kamo'oalewa is larger and appears to have been battered by cosmic rays, solar radiation and other processes longer than 2024 PT5 has. That might suggest it has been in space longer, Kareta said. Their orbits are also a bit different. Kamo'oalewa's quasi-satellite orbit keeps it in Earth's immediate vicinity for several consecutive orbits, even though it isn't actually spinning around the planet. Unlike the lane-changing 2024 PT5, Kamo'oalewa is more like a car that stays one lane over, moving at roughly the same speed. Researchers are trying to match Kamo'oalewa to a crater. A recent study suggested that it could have come from a smashup that created Giordano Bruno crater, a 14-mile-wide (22 km) impact basin on the far side of the moon. Kareta is hopeful that more will be identified. While a single sample is an oddity, two could be part of a crowd. He suspects that some asteroids that have been identified as unusual may be lunar rocks in disguise. RELATED STORIES: —Goodnight moon! Astronomers snap photo of Earth's departing mini-moon —Earth's mini-moon has finally departed. Will it ever return as a 'second moon?' —Earth's recent asteroid visitor might've been a piece of the moon When the orbits of NEOs are calculated, their source region is often estimated based on their current travels. If some objects have been misclassified and their sources are incorrect, that could mean other aspects of their orbits are misunderstood. Although that could potentially increase the long-term chances of Earth being hit by an asteroid, Kareta said it is "almost certainly not" the case, "but we'll need to prove it." For now, Kareta and his colleagues will continue to use MANOS to search for other potential lunar fragments. He's hopeful that the doubled population will convince other researchers to take a closer look, too. Upcoming large-scale surveys — like the Vera Rubin Observatory, a ground-based telescope expected to see first light this year — should also help to reveal other dim objects. The research was published in January in The Astrophysical Journal Letters.
