NASA's Psyche Spacecraft, Exploring Solar System Origins, Is Back on Track after Thrusters Lost Power
Why It Matters
About 4.5 billion years ago, our solar system was a cloud of gas and dust with no planets. Astronomers used to think planets grew very slowly, over hundreds of millions of years, as gravity gradually clumped the gas and dust together. But more recent evidence points to a much faster process involving high-energy hit-and-run collisions among dust, pebbles and rocks that crashed together and then got blown apart within a short time. Some of these crashes might have melted metals to form a core (such as the one found at the center of Earth) and surrounded it with a rocky rind. Our planet's core is many hundreds of miles deep, however—too far down to observe directly and accurately.
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But the asteroid Psyche, circling the sun between Mars and Jupiter, may have an exposed metal core. Radar reflections indicate this is at least partially so, says Jim Bell, an Arizona State University planetary scientist, who is in charge of the Psyche spacecraft's multispectral imaging cameras. 'If it was covered by rock, we wouldn't get the signal that we're seeing,' he says. That signal indicates substances composed primarily of nickel and iron. So a flyby of the asteroid could provide the first close-up view of what a planet's core looks like and answer questions about how it formed.
What's Next
The problem with the craft's xenon gas thrusters appeared to be caused by a defective valve, and when engineers switched to a second fuel line, the craft regained motion. When Psyche meets up with its asteroid namesake in 2029, the probe's instruments should be able to detect any uncovered core metal that collisions have blasted clean of rock. The orientation of magnetic particles in that core, like tiny compass needles, could indicate whether the asteroid once had a magnetic dynamo, as Earth's core does. Remarkably, if there were impacts of debris on the molten metal, they could have splashed up and then frozen, leaving sharp cliffs for spacecraft cameras to show us.
More about Psyche
The asteroid Pysche orbits at about three astronomical units, or AU, from the sun (Earth's orbit is at one AU). It's often described as 'potato shaped,' with a diameter of 140 miles and a surface area of 64,000 square miles.
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a day ago
- Yahoo
You've met 'Lucy.' Now ASU scientists unearth another clue to the origin of humans
Though she works thousands of miles from home, Arizona State University research scientist Kaye Reed is used to 110-degree heat. For days at a time, Reed and her colleagues walk through Ethiopia's baking Awash Valley, scanning the ground with their eyes. It's uncomfortable, Reed said, but it's all worth it when they make the kind of discovery revealed in a paper released on Aug. 13. Reed and a team of international scientists believe they have added a new member to humanity's family tree — a yet undocumented species of hominid, or upright ape, that walked the east African grasslands more than 2.6 million years ago. She and the team made the discovery when they found three collections of ancient primate teeth lying on the ground during fossil searches at the Ledi-Geraru Research Project Area led by ASU. Scientists believe the new species could offer clues about the conditions that produced humanity's ancestors, though this species was likely not a direct predecessor to homo sapiens. The species lived in an area and time at which future humans may have first emerged, according to the fossil record. Scientists know very little about the new species so far, Reed said. A collection of teeth is useful for understanding the animal's diet, but arms, legs, and skulls provide a fuller picture of how it moved around its habitat. Those clues help researchers understand the conditions in which the species survived. 'Evolution doesn't work like that' Those insights could shine light on a critical, but poorly understood, chapter in human evolution. The new species may have been one of the last members of a dying family of human ancestors known as the australopithecus genus, which includes the famous 'Lucy,' whose fossil was unearthed in 1974. As its relatives were dying out, this new species would have watched the rise of humanity's genus, homo, which was the first to commonly use stone tools and eat meat. 'If it's a different species of Australopithecus… that means (Lucy) either went extinct or somehow evolved into this new species,' said Reed, part of the Institute of Human Origins at ASU. 'The fact that it also occurs at roughly the same time as the genus Homo suggests to us that there was a change in the climate and the habitats, which you had to change to survive.' With the new species, Reed believes at least four species of upright apes were living in east Africa at the same time, including two australopithecus, one homo, and a species from an offshoot called paranthropus. Scientists don't know much about the transition from Australopithecus to homo because the fossil record during that period is surprisingly slim, Reed said. But this new discovery makes at least one thing clear: As with much of evolution, this transition was not a straightforward line. The process of human evolution is full of dead ends and overlaps, with multiple species of upright apes evolving alongside each other, some successful and some not. 'Everybody always posts that thing where there's a hunched over ape, and then there's a kind of upright ape, and then something with a bigger brain, and it's just from one to one to one," Reed said. "Evolution doesn't work like that.' Even the distinctions between ancestors and descendants is sometimes unclear. Reed had to grapple with this complexity when she and her colleagues attempted to identify the teeth they had found. The team considered multiple alternatives, including the possibility that the teeth belonged to transitional forms of already known species. While some species distinctions are obvious, Reed said, some are almost a matter of opinion, pointing out that some scientists might have classified the new teeth as a variant of the 'Lucy' species. 'Another scientist that I know might put these teeth into (Lucy's species). He doesn't care about what he would consider the minor differences,' Reed said. A famous discovery: On a November day 50 years ago, a scientist found 'Lucy' and rewrote our origin story Still searching for more clues The appearance of the new species could also help scientists better understand why humanity's closest ancestors, the homo group, emerged when they did. Some scientists have argued that homo species evolved partially as a response to a drier habitat with more grasslands, but this new species shows that an Australopithecus species could also survive in that new, dry environment. 'You have longer dry seasons, so animals are stressed. Many that we see in Lucy's time are eating trees, but then they switch to grass, and in that time period we find the Australopithecus is different from what it was,' Reed said. More clues about the new species' diets will help Reed and other researchers understand how it interacted with other walking apes and whether this was a case where humanity's ancestors had to out-compete their relatives to grab hold of the future. 'If they ate the same thing, it's going to be tough for one of them to survive … and so maybe one of them out-competed the other,' Reed said. 'But maybe they weren't eating the same thing, and that's how they split when it got really dry.' Traces of carbon and nitrogen in ancient teeth can indicate what kinds of plants or meat the animal ate. To discover that an australopithecus was scavenging meat would make it a much more direct competitor with human ancestors, Reed said. Otherwise, scientists have many miles to walk before they can fully understand the new creature they might have brought to light. That will mean many more hours searching for the right sediments and pacing, meticulously, in the east African heat. 'To find this stuff is really exciting,' Reed said. 'We just have to find more information to put the puzzle together.' Austin Corona covers environmental issues for The Arizona Republic and azcentral. Send tips or questions to Environmental coverage on and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. This article originally appeared on Arizona Republic: ASU scientists may have found a new species related to humans Solve the daily Crossword
Los Angeles Times
2 days ago
- Los Angeles Times
Ethiopian fossil Lucy leaves for her first exhibition in Europe
ADDIS ABABA, Ethiopia — The human ancestor fossil known as Lucy left Ethiopia for display in a European museum, Ethiopian national media reported Friday, citing Tourism Minister Selamawit Kassa. Lucy's skeleton, which is 40% complete, left Ethiopia on Friday and will be displayed at the Czech National Museum in Prague for approximately two months. Lucy was recovered in Ethiopia in 1974 from what was an ancient lake near fossilized remains of crocodiles, turtle eggs and crab claws. She was a member of Australopithecus afarensis, an early human species that lived in Africa between about 4 million and 3 million years ago. This is the second time Lucy has left Ethiopia. The first was in 2013, when she toured the United States. Lucy's fragmented bones will be exhibited alongside Selam, the fossil of an Australopithecus baby that is about 100,000 years older than Lucy and was discovered in the same region 25 years later. 'As an iconic specimen, she belongs to the whole world, so sharing her with the rest of humanity is something that everyone would love to see,' said Yohannes Haile-Selassie, Director of the Institute of Human Origins at Arizona State University. While many experts believe Lucy's trip to Europe presents a once-in-a-lifetime opportunity for people in Europe and beyond, there are safety concerns about the transportation of her fragile bones. 'The fragmented bones of Lucy are truly unique and need utmost care. Traveling to Europe has its own risks,' said Gidey Gebreegziabher, an archaeologist and Ph.D. candidate at the University of Warsaw, Poland, 'She will also be exposed to different climate conditions, which could potentially have negative impacts on her preservation.' Even in Ethiopia, the public has only occasionally seen the real Lucy fossil. At the National Museum of Ethiopia, a replica of Lucy is exhibited while the actual remains are stored in a secure vault. 'I've seen how she was packed, so I have no worries about anything happening to Lucy anymore,' Yohannes said. Lucy's quiet departure on Thursday night also raises questions about transparency as many Ethiopians —who take pride in her — were unaware of her journey to Europe. 'It's unbelievable! The government appears to be deliberately sidelining its people from the narrative of their own heritage,' Gebreegziabher said. Bekele Reta, 43, a resident who lives just 164 feet from the museum where Lucy is housed, was unaware of Lucy's departure until he saw it on social media. 'I learned this morning on Facebook that Lucy has departed for Prague. It's unfortunate that most Ethiopians only have the opportunity to see her showcased elsewhere.' he said. Early this year, the director general of the Czech National Museum, Michal Lukeš, in a statement announcing the exhibition of Lucy and Selam, expressed his appreciation of the Ethiopians for agreeing to 'lend' the remains. 'These priceless exhibits give us a unique insight into the past and deepen our understanding of humanity's roots,' said Lukeš. Birhane writes for the Associated Press. AP writer Evelyne Musambi contributed to this report from Nairobi, Kenya.
2 days ago
Ethiopian fossil Lucy leaves for her first exhibition in Europe
ADDIS ABABA, Ethiopia -- The human ancestor fossil known as Lucy left Ethiopia for display in a European museum, Ethiopian national media reported Friday, citing Tourism Minister Selamawit Kassa. Lucy's skeleton, which is 40% complete, left Ethiopia on Friday and will be displayed at the Czech National Museum in Prague for approximately two months. Lucy was recovered in Ethiopia in 1974 from what was an ancient lake near fossilized remains of crocodiles, turtle eggs and crab claws. She was a member of Australopithecus afarensis, an early human species that lived in Africa between about 4 million and 3 million years ago. This is the second time Lucy has left Ethiopia. The first was in 2013, when she toured the United States. Lucy's fragmented bones will be exhibited alongside Selam, the fossil of an Australopithecus baby that is about 100,000 years older than Lucy and was discovered in the same region 25 years later. 'As an iconic specimen, she belongs to the whole world, so sharing her with the rest of humanity is something that everyone would love to see,' said Yohannes Haile-Selassie, Director of the Institute of Human Origins at Arizona State University. While many experts believe Lucy's trip to Europe presents a once-in-a-lifetime opportunity for people in Europe and beyond, there are safety concerns about the transportation of her fragile bones. 'The fragmented bones of Lucy are truly unique and need utmost care. Traveling to Europe has its own risks,' said Gidey Gebreegziabher, an archaeologist and Ph.D. candidate at the University of Warsaw, Poland, 'She will also be exposed to different climate conditions, which could potentially have negative impacts on her preservation.' Even in Ethiopia, the public has only occasionally seen the real Lucy fossil. At the National Museum of Ethiopia, a replica of Lucy is exhibited while the actual remains are stored in a secure vault. 'I've seen how she was packed, so I have no worries about anything happening to Lucy anymore,' Yohannes said. Lucy's quiet departure on Thursday night also raises questions about transparency as many Ethiopians —who take pride in her — were unaware of her journey to Europe. 'It's unbelievable! The government appears to be deliberately sidelining its people from the narrative of their own heritage,' Gebreegziabher said. Bekele Reta, 43, a resident who lives just 50 meters (164 feet) from the museum where Lucy is housed, was unaware of Lucy's departure until he saw it on social media. 'I learned this morning on Facebook that Lucy has departed for Prague. It's unfortunate that most Ethiopians only have the opportunity to see her showcased elsewhere.' he said. Early this year, the director general of the Czech National Museum, Michal Lukeš, in a statement announcing the exhibition of Lucy and Selam, expressed his appreciation of the Ethiopians for agreeing to 'lend' the remains. 'These priceless exhibits give us a unique insight into the past and deepen our understanding of humanity's roots,' said Lukeš.
