Diamond is forever? Tell that to an asteroid with lots of debris.
The asteroid Itokawa is a 1,640-meter (500-foot) pile of rock debris. Some call it peanut-shaped; Some say it resembles a sea otter, with a head, neck and body. Whatever Itokawa may look like, new research suggests it’s staying intact — despite the constant bombardment of asteroids inside. solar system – since it formed more than 4.2 billion years ago. The proposal could be important for any future project aimed at conservation The world from a debris-laden asteroid, researchers argue.
“In short, we found that Itokawa is like a giant space pillow, and it’s very difficult to destroy it,” Fred Jourdan, an astronomer at Curtin University in Australia and lead author of the new paper, said. a statement.
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The team calculated Itokawa’s age using bits of asteroid dust taken by the Japanese Hayabusa spacecraft and returned to Earth in 2010. By analyzing the dust particles, Jourdan’s team found that Itokawa is almost as old as the solar system itself. In a new paper, the team explains how Itokawa has survived multiple asteroid collisions over 4.2 billion years.
Although researchers he already knows that a massive collision destroyed the body of Itokawa’s parent, this is the first time that the exact age and endurance of Itokawa has been directly studied.
“Large area pillow”
The team behind the new research studied the structure and composition of three dust particles collected on Itokawa. Scientists used a radioactive dating method called argon-argon dating to estimate Itokawa’s age, which they put at 4.2 billion years.
As part of the study, the team also measured how many dust particles, and by extension Itokawa, were affected by the wake of the asteroid collision. For this, the researchers used a technique called electron backscatter diffraction to measure the structures and patterns of the crystals embedded in the dust particles.
The team found that the dust particles were mostly pure, suggesting they were dug up deep within the parent asteroid, perhaps when it broke up during a large collision. Scientists concluded that Itokawa could withstand extreme collisions, due to the asteroid’s porous nature.
As a collection of debris from an asteroid impact, Itokata holds rocks of different shapes and sizes that are held together under the force of gravity. The pile of rubble “is composed of rocks and loose rocks, about half of which is empty space,” Jourdan said in the statement.
When asteroids impact Itokawa, the large holes or pores between these rocks absorb most of the energy produced by the impact, protecting the structure of the asteroid from breaking. In this way, the pores help break-up piles like Itokawa to survive an asteroid collision at least 10 times longer than normal, single-body asteroids, also known as monoliths, the researchers find them.
The case for deflecting debris asteroids
The new research will help planetary defense experts, who discover near-Earth asteroids, monitor their paths and determine whether there is a threat of collision with Earth.
The scientists say that their analysis of Itokawa suggests that because of their resilience in the face of impacts, asteroids with more debris may be more common, in the asteroid belt closer to Earth, than previously expected.
“There is a high probability that if a large asteroid hits Earth, it will be a pile of rocks,” Nick Timms, also an astronomer at Curtin University, said in the same statement.
And the shape of the asteroid can make a difference if people need to choose a strategy to deflect the threat. For example, NASA’s Double Asteroid Redirection Experiment (THE TRAVELER) mission rammed into Dimorphos, a similar pile of debris that wasn’t on a collision course with Earth, but that was a perfect target to test how humans might respond to a future threatening asteroid. The impact shortened Dimorphos’ orbit around the larger asteroid Didymos in 33 minutes, a huge mission success.
Upon colliding with Dimorphos, the DART transferred its energy and momentum to the asteroid. Although this method, called kinetic impact, has been successful with DART, the authors of the new study warn that it may not be very effective at deflecting porous absorbing asteroids.
The kinetic impactor method is also very effective when we see asteroids in early impact studies, leaving enough time for a small change in orbit to build up. If a threatening asteroid is detected too late for the kinetic impactor method, “we can use a more aggressive method such as using a nearby nuclear detonator beam to push the asteroid into a pile of rubble without to destroy it,” Timms. that said.
Research is described in a paper published Monday (Jan. 23) in the journal Proceedings of the National Academy of Sciences (PNAS).
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