Planet Earth is parting company with an asteroid that’s been tagging along as a "mini moon" for the past two months.
The harmless space rock will peel away on Monday, overcome by the stronger tug of the sun’s gravity. But it will zip closer for a quick visit in January.
NASA will use a radar antenna to observe the 33-foot asteroid then. That should deepen scientists’ understanding of the object known as 2024 PT5, quite possibly a boulder that was blasted off the moon by an impacting, crater-forming asteroid.
While not technically a moon — NASA stresses it was never captured by Earth’s gravity and fully in orbit — it’s "an interesting object" worthy of study.
The astrophysicist brothers who identified the asteroid’s "mini moon behavior," Raul and Carlos de la Fuente Marcos of Complutense University of Madrid, have collaborated with telescopes in the Canary Islands for hundreds of observations so far.
Currently more than 2 million miles away, the object is too small and faint to see without a powerful telescope. It will pass as close as 1.1 million miles of Earth in January, maintaining a safe distance before it zooms farther into the solar system while orbiting the sun, not to return until 2055. That’s almost five times farther than the moon.
First spotted in August, the asteroid began its semi jog around Earth in late September, after coming under the grips of Earth’s gravity and following a horseshoe-shaped path.
By the time it returns next year, it will be moving too fast — more than double its speed from September — to hang around, said Raul de la Fuente Marcos.
NASA will track the asteroid for more than a week in January using the Goldstone solar system radar antenna in California’s Mojave Desert, part of the Deep Space Network.
Current data suggest that during its 2055 visit, the sun-circling asteroid will once again make a temporary and partial lap around Earth.
A NASA spacecraft is ready to set sail for Jupiter and its moon Europa, one of the best bets for finding life beyond Earth.
Europa Clipper will peer beneath the moon’s icy crust where an ocean is thought to be sloshing fairly close to the surface. It won’t search for life, but rather determine whether conditions there could support it. Another mission would be needed to flush out any microorganisms lurking there.
"It’s a chance for us to explore not a world that might have been habitable billions of years ago, but a world that might be habitable today — right now," said program scientist Curt Niebur.
Its massive solar panels make Clipper the biggest craft built by NASA to investigate another planet. It will take 5 1/2 years to reach Jupiter and will sneak within 16 miles of Europa's surface — considerably closer than any other spacecraft.
Liftoff is targeted for this month aboard SpaceX’s Falcon Heavy rocket from NASA’s Kennedy Space Center. Mission cost: $5.2 billion.
One of Jupiter’s 95 known moons, Europa is almost the size of our own moon. It's encased in an ice sheet estimated to be 10 miles to 15 miles or more thick. Scientists believe this frozen crust hides an ocean that could be 80 miles or more deep. The Hubble Space Telescope has spotted what appear to be geysers erupting from the surface. Discovered by Galileo in 1610, Europa is one of the four so-called Galilean moons of Jupiter, along with Ganymede, Io and Callisto.
What type of life might Europa harbor? Besides water, organic compounds are needed for life as we know it, plus an energy source. In Europa’s case that could be thermal vents on the ocean floor. Deputy project scientist Bonnie Buratti imagines any life would be primitive like the bacterial life that originated in Earth’s deep ocean vents. "We will not know from this mission because we can’t see that deep," she said. Unlike missions to Mars where habitability is one of many questions, Clipper’s sole job is to establish whether the moon could support life in its ocean or possibly in any pockets of water in the ice.
When its solar wings and antennas are unfurled, Clipper is about the size of a basketball court — more than 100 feet end to end — and weighs nearly 13,000 pounds. The supersized solar panels are needed because of Jupiter’s distance from the sun. The main body — about the size of a camper — is packed with nine science instruments, including radar that will penetrate the ice, cameras that will map virtually the entire moon and tools to tease out the contents of Europa’s surface and tenuous atmosphere. The name hearkens to the swift sailing ships of centuries past.
The roundabout trip to Jupiter will span 1.8 billion miles. For extra oomph, the spacecraft will swing past Mars early next year and then Earth in late 2026. It arrives at Jupiter in 2030 and begins science work the next year. While orbiting Jupiter, it will cross paths with Europa 49 times. The mission ends in 2034 with a planned crash into Ganymede — Jupiter’s biggest moon and the solar system's too.
There’s more radiation around Jupiter than anywhere else in our solar system, besides the sun. Europa passes through Jupiter’s bands of radiation as it orbits the gas giant, making it especially menacing for spacecraft. That’s why Clipper’s electronics are inside a vault with dense aluminum and zinc walls. All this radiation would nix any life on Europa’s surface. But it could break down water molecules and, perhaps, release oxygen all the way down into the ocean that could possibly fuel sea life.
Earlier this year, NASA was in a panic that the spacecraft's many transistors might not withstand the intense radiation. But after months of analysis, engineers concluded the mission could proceed as planned.
NASA’s twin Pioneer spacecraft and then two Voyagers swept past Jupiter in the 1970s. The Voyagers provided the first detailed photos of Europa but from quite a distance. NASA’s Galileo spacecraft had repeated flybys of the moon during the 1990s, passing as close as 124 miles. Still in action around Jupiter, NASA’s Juno spacecraft has added to Europa’s photo album. Arriving at Jupiter a year after Clipper will be the European Space Agency’s Juice spacecraft, launched last year.
Like Europa, Jupiter’s jumbo moon Ganymede is thought to host an underground ocean. But its frozen shell is much thicker — possibly 100 miles thick — making it tougher to probe the environment below. Callisto’s ice sheet may be even thicker, possibly hiding an ocean. Saturn’s moon Enceladus has geysers shooting up, but it’s much farther than Jupiter. Ditto for Saturn’s moon Titan, also suspected of having a subterranean sea. While no ocean worlds have been confirmed beyond our solar system, scientists believe they’re out there — and may even be relatively common.
Like many robotic explorers before it, Clipper bears messages from Earth. Attached to the electronics vault is a triangular metal plate. On one side is a design labeled "water words" with representations of the word for water in 104 languages. On the opposite side: a poem about the moon by U.S. poet laureate Ada Limon and a silicon chip containing the names of 2.6 million people who signed up to vicariously ride along.
Two pioneers of artificial intelligence — John Hopfield and Geoffrey Hinton — won the Nobel Prize in physics Tuesday for helping create the building blocks of machine learning that is revolutionizing the way we work and live but also creates new threats for humanity.
Hinton, who is known as the godfather of artificial intelligence, is a citizen of Canada and Britain who works at the University of Toronto, and Hopfield is an American working at Princeton.
"These two gentlemen were really the pioneers," said Nobel physics committee member Mark Pearce. "They ... did the fundamental work, based on physical understanding which has led to the revolution we see today in machine learning and artificial intelligence."
The artificial neural networks — interconnected computer nodes inspired by neurons in the human brain — the researchers pioneered are used throughout science and medicine and "have also become part of our daily lives, for instance in facial recognition and language translation," said Ellen Moons, a member of the Nobel committee at the Royal Swedish Academy of Sciences.
Hopfield, whose 1982 work laid the groundwork for Hinton's, told The Associated Press Tuesday, "I continue to be amazed by the impact it has had."
Hinton predicted that AI will end up having a "huge influence" on civilization, bringing improvements in productivity and health care.
"It would be comparable with the Industrial Revolution," he said in an open call with reporters and officials of the Royal Swedish Academy of Sciences.
"Instead of exceeding people in physical strength, it’s going to exceed people in intellectual ability. We have no experience of what it’s like to have things smarter than us. And it’s going to be wonderful in many respects," Hinton said.
"But we also have to worry about a number of possible bad consequences, particularly the threat of these things getting out of control."
The Nobel committee also mentioned fears about the possible flipside.
Moons said that while it has "enormous benefits, its rapid development has also raised concerns about our future. Collectively, humans carry the responsibility for using this new technology in a safe and ethical way for the greatest benefit of humankind."
Hinton shares those concerns. He quit a role at Google so he could speak more freely about the dangers of the technology he helped create.
"I am worried that the overall consequence of this might be systems more intelligent than us that eventually take control," Hinton said.
For his part, Hopfield, who signed early petitions by researchers calling for strong control of the technology, compared the risks and benefits of machine learning to work on viruses and nuclear energy, capable of helping and harming society.
Neither winner was home when they received the news. Hopfield, who was staying with his wife at a cottage in Hampshire, England, said that after grabbing coffee and getting his flu shot, he opened his computer to a flurry of activity.
"I’ve never seen that many emails in my life," he said. A bottle of champagne and bowl of soup were waiting on his desk for him, he added, but he doubted there were any fellow physicists in town to join the celebration.
Hinton said he was shocked at the honor.
"I’m flabbergasted. I had no idea this would happen," he said when reached by the Nobel committee on the phone. He said he was at a cheap hotel with no internet.
Hinton, 76, helped develop a technique in the 1980s known as backpropagation that has been instrumental in training machines how to "learn" by fine-tuning errors until they disappear. It’s similar to the way a student learns from a teacher, with an initial solution graded and flaws identified and returned to be fixed and repaired. This process continues until the answer matches the network’s version of reality.
His team at the University of Toronto later wowed peers by using a neural network to win the prestigious ImageNet computer vision competition in 2012. That win spawned a flurry of copycats and was "a very, very significant moment in hindsight and in the course of AI history," said Stanford University computer scientist and ImageNet creator Fei-Fei Li.
"Many people consider that the birth of modern AI," she said.
Hinton and fellow AI scientists Yoshua Bengio and Yann LeCun won computer science’s top prize, the Turing Award, in 2019.
"For a long time, people thought what the three of us were doing was nonsense," Hinton told told the AP in 2019. "They thought we were very misguided and what we were doing was a very surprising thing for apparently intelligent people to waste their time on."
"My message to young researchers is, don’t be put off if everyone tells you what are doing is silly."
And Hinton himself uses machine learning in his daily life, he said.
"Whenever I want to know the answer to anything, I just go and ask GPT-4," Hinton said at the Nobel announcement. "I don’t totally trust it because it can hallucinate, but on almost everything it's a not-very-good expert. And that’s very useful."
Hopfield, 91, created an associative memory that can store and reconstruct images and other types of patterns in data, the Nobel committee said.
"What fascinates me most is still this question of how mind comes from machine," Hopfield said in a video posted online by The Franklin Institute after it awarded him a physics prize in 2019.
Hinton used Hopfield's network as the foundation for a new network that uses a different method, known as the Boltzmann machine, that the committee said can learn to recognize characteristic elements in a given type of data.
Bengio, who was mentored by Hinton and "profoundly shaped" by Hopfield’s thinking, told the AP that the winners both "saw something that was not obvious: Connections between physics and learning in neural networks, which has been the basis of modern AI."
He said he was "really delighted" that they won the prize. "It’s great for the field. It’s great for recognizing that history."
Six days of Nobel announcements opened Monday with Americans Victor Ambros and Gary Ruvkun winning the medicine prize for their discovery of tiny bits of genetic material that serve as on and off switches inside cells that could one day lead to powerful treatments for diseases like cancer.
The prize carries a cash award of $1 million from a bequest left by the award's creator, Swedish inventor Alfred Nobel. The laureates are invited to receive their awards at ceremonies on Dec. 10, the anniversary of Nobel’s death.
Nobel announcements continue with the chemistry prize on Wednesday and literature on Thursday. The Nobel Peace Prize will be announced Friday and the economics award on Oct. 14.
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