How does a collision shape an asteroid?
This image shows the regoliths and small boulders in the lower regions of the asteroid Eros, as well as degraded craters, nearly erased "ghost" craters and few small craters. (Image source: NASA and JHU/APL)
NASA will crash a heavy detector the size of a trash can into a comet with the aim of creating a crater the size of a football field for observation. However, as for what exactly will happen, no one can really know
Despite several close-up observations of comets and asteroids in recent years, including a dramatic landing on Eros by a NASA spacecraft in 2001, the composition of the space rocks remains largely uncertain. Scientists aren't even sure about the structural and chemical differences between comets and asteroids.
In particular, astronomers want to know how strong or loose the asteroid is. This will help them better understand the history of the solar system. It will come in handy if we need to transform or disrupt the path we are on.
This new study, which rings the bell by simulating how other asteroids might have an impact, further reveals the structure of Eros. The model supports previous research that Eros is a potato-shaped rock 21 miles (33 kilometers) long that is not solid but instead consists of a series of fragile blocks, each as large as a small town.
The many craters on Eros represent a record of its past violent impacts. James Richardson Jr., a researcher at the University of Arizona, explained that preliminary studies of THE NEAR's pictures and data suggest that it once might have been a rock, but over millions of years, a collision with a smaller asteroid broke it.
These rock blocks, each a mile wide, are grouped together like a 3D jigsaw puzzle game, albeit with weak gravity.
In the new study, Richardson hypothesized the structure and inserted it into a computer model of seismic activity. These results seem to explain how previous craters on the asteroid were masked and washed away by post-impact shocks.
"When an asteroid hits a larger asteroid, such as Eros, it will have four main effects on the surface and structure of the larger asteroid," Richardson said.
A crater is carved on the surface of the target asteroid.
A thin layer of debris is distributed on the target asteroid, mainly near the site of impact; some of the debris disappears into space. Bottom bedrock fracture.
When seismic waves reverberate in them, the asteroid vibrates; the shaking can last from a few minutes to an hour or so. Just like Eros.
While the computer model is not intended to show all the consequences of the downward migration of the regolith, it does show a mechanism for generating landslides, avalanches, and low-altitude regolith aggregation. Richardson said it also correctly simulated the degradation and clearance of small craters. These are the characteristics seen on Eros.
The computer model took rocks ranging in diameter from 2.2 feet (0.7 meters) to nearly half a mile (700 meters) of impact. It created virtual craters ranging from 66 feet (20 meters) to 12.4 miles (20 kilometers) wide. Richardson said the study should apply to all rocky, fractured asteroids about 62 miles (100 kilometers) in diameter.
The problem is that scientists don't know how many asteroids are like this. Other space rocks may be more like loose piles of rubble, without large stones. However, some are sturdy. The seismic effect will also vary depending on the size of the asteroid being hit
Richardson said: "Larger asteroids will only have local seismic effects after impact, not the seismic effects as a whole, because they are larger in size and have greater gravity. ”
A better grasp of asteroid vibrations could help scientists plan actual seismic studies of these objects, so scientists can finally figure out how asteroids are actually constructed.
Richardson's study, published Friday in the journal Science, said Eric Aspger of the University of California, "Which lays the foundation for a detailed geomechanical understanding of asteroid bodies," and Santa Cruz Espager also wrote a review for the journal.
Several missions to explore the internal structure of asteroids and comets are underway. One problem, Espager writes, is to secure the probe to an object with little gravity.
The European Space Agency's Rosetta spacecraft is entering the orbit of Comet Chulyumov-Gracimenko, which will deploy a probe and then use radio waves to explore its interior.
The Japanese Hayabusa spacecraft operated in parallel with the orbit of the Itokawa asteroid in 2005. It touches the asteroid's surface and fires a small bullet, then shoots the resulting particles into a jar in order to bring it back to Earth.
NASA's Deep Impact Mission will launch a 770-pound (350-kilogram) launch bomb at Comet Tempel 1, then take pictures of the impact and analyze the new crater.
NASA's Dawn mission, launched in 2006, orbited the asteroid Ceres, the largest known asteroid with a diameter of 578 miles (930 kilometers).
Confusing outer solar system
Some asteroids are like onions.
BY: Robert Roy Britt
FY: Cybele
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