SoylentNews is people
SoylentNews
from the queue-the-uranus-jokes-in-5,4,3,2,1 dept.
Many asteroids might be remnants of 5 destroyed worlds, scientists say
For years, asteroids were thought of as the leftovers of planet formation - chunks of material that never quite made it to planet size and that were drawn into the crowded belt of rocky remnants that circles the sun between Mars and Jupiter.
But according to a study published Monday in the journal Nature Astronomy, these were once pieces of worlds, too. A vast majority of the half-million bodies in the inner asteroid belt may in fact be shrapnel from as few as five parent bodies called "planetesimals," scientists say. But the tangled orbits of those lost worlds meant they were doomed to collide, producing fragments that also collided, producing still more fragments in a cataclysmic cascade that's been going on for more than 4 billion years.
The finding doesn't only illuminate a "mystery" of the asteroid belt, said Katherine Kretke, a planetary scientist at the Southwest Research Institute who was not involved in the study. It could also help resolve a debate about the formation of the eight planets - including Earth. "I find it really exciting that we can look back in time and potentially see evidence of what were the building blocks that built up our solar system," she said. "If we can turn back the clock and see the asteroid belt was made by these big planetesimals, that really is telling us something quite definitive about the circumstances that formed our own planet."
[...] Scientists have previously known that roughly half of inner-belt asteroids belong to five "families." But Dermott and his colleagues say their analysis suggests that number is as high as 85 percent.
Another ancient collision is suspected of causing the unusual tilt and low temperature of Uranus:
Uranus was hit by a massive object roughly twice the size of Earth that caused the planet to tilt and could explain its freezing temperatures, according to new research. Astronomers at Durham University led an international team of experts to investigate how Uranus came to be tilted on its side and what consequences a giant impact would have had on the planet's evolution. The team ran the first high-resolution computer simulations of different massive collisions with the ice giant to try to work out how the planet evolved.
The research confirms a previous study that said Uranus' tilted position was caused by a collision with a massive object – most likely a young proto-planet made of rock and ice - during the formation of the solar system about 4 billion years ago. The simulations also suggested that debris from the impactor could form a thin shell near the edge of the planet's ice layer and trap the heat emanating from Uranus' core. The trapping of this internal heat could in part help explain Uranus' extremely cold temperature of the planet's outer atmosphere (-216 degrees Celsius, -357 degrees Fahrenheit), the researchers said.
Also at University of Florida.
The common origin of family and non-family asteroids (DOI: 10.1038/s41550-018-0482-4) (DX)
Consequences of Giant Impacts on Early Uranus for Rotation, Internal Structure, Debris, and Atmospheric Erosion (DOI: 10.3847/1538-4357/aac725) (DX)
(Score: 2) by inertnet on Thursday July 05 2018, @09:37AM (2 children)
I'm wondering if it would be possible to create a planet out of the asteroid belt. It might take a century or even longer, but maybe a plan could be made to gently nudge the asteroids off course, so they will eventually merge instead of collide and break up again. Does anybody have an idea how big such a planet could become, based on the available material?
I can't think of any benefits for humanity right away, but those might emerge during the time it takes to form this new planet.
(Score: 3, Informative) by takyon on Thursday July 05 2018, @10:08AM
https://en.wikipedia.org/wiki/Asteroid_belt [wikipedia.org]
Another point to think about is that there is already a "planet" in the asteroid belt. It's Ceres [wikipedia.org], which should be considered one of the best human colonization/exploration targets in the solar system. It already has about 3% of Earth's surface gravity, which is minuscule but might be healthier than zero-G. It contains the largest portion of the asteroid belt's mass, so if you were to make a "planet" out of the entire belt, you would be aiming other asteroids right at Ceres. This catastrophic process could disturb the subsurface ocean and eliminate potential lifeforms there.
Vesta [wikipedia.org] and Pallas [wikipedia.org] are not gravitationally rounded [wikipedia.org] like Ceres, but they are kind of close. Maybe enough material could be scraped together to (eventually) make them spherical. Mimas [wikipedia.org] is the smallest object known to be gravitationally rounded. Enceladus [wikipedia.org] is also pretty small, yet it is one of the most interesting objects in the solar system and could have life.
Combining all of the asteroids could be counterproductive given the goals of asteroid mining [wikipedia.org]. If you could make a planet out of it all, valuable materials would be trapped in the center. Instead, I wonder if we could soft land boulder-like asteroids onto the surfaces of some of these bodies, make them temporary satellites of our Moon, or make them permanent satellites of Ceres or somewhere else. We could also slam a few into Mars to induce some climate change. If you have the thrust available to manipulate the positions of asteroids, you might want to do something like turn one into a spacecraft shield instead [mysteriousuniverse.org].
The minimum we should hope for with asteroid mining is in-situ resource utilization, aka building stuff in space using materials from asteroids, or refueling using water, etc. However, if we ever figure out how to cheaply land asteroid materials on the Earth, Moon, or Mars without causing devastation, then we could utilize the precious metals where they will be demanded most.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by bitstream on Thursday July 05 2018, @11:21AM
Sounds like a Kessler syndrome in waiting. Ie collisions creating more collisions..