It is as inevitable as the sunrise and the turning of the tides. One day another big rock from space will crash into the Earth. It happened billions of years in the past and will continue to happen billions of years into the future. So far humanity has been fortunate, as we have not had to face such a catastrophic threat. But if we want to survive on this planet in the long term, we will have to come to terms with the reality of dangerous asteroids and prepare ourselves.
Organizations around the world continue to monitor the sky. They create maps and catalogs of all potentially hazardous NEOs or NEOs. Obviously, larger boulders pose a greater threat, but fortunately they are less numerous. And although the census of hazardous NEOs is almost incomplete, we have reliable maps of all areas potentially dangerous asteroids greater than a kilometer across.
This is beneficial, to say the least, because kilometer-sized asteroids not only have the potential to wipe out entire cities, but can cause significant environmental damage worldwide.
To estimate the risks posed by these near-Earth objects, a team of astronomers projected their orbits over the next thousand years. Their analysis is available on a prepress server arXiv, indicates that none of these kilometer-sized NEOs pose a significant threat to us over the next century. However, we find it difficult to predict the orbits of these NEOs after that. This is because in orbital dynamics small changes can lead to large effects on huge time scales. A slight difference in the amount of heat an asteroid receives from the Sun, or an unexpected pull from Jupiter, can send an asteroid on a trajectory that in a few thousand years will end up intersecting Earth.
Astronomers have studied the possible closest encounter between NEOs and Earth. They have specifically studied how this closer distance changes over hundreds and thousands of years. They did this through a series of simulations that determined as many orbital trajectories as possible given uncertainties in the current orbital positions and velocities of near-Earth objects.
Astronomers have identified one near-Earth object, asteroid 7482, as particularly dangerous. This asteroid will spend a lot of time near Earth over the next millennium. While this does not necessarily mean that it will strike our planet, it does mean that this rock poses the greatest chance of a collision within the next thousand years. The researchers also highlighted another asteroid, 143651, which has such a chaotic orbit that it is impossible to predict its exact location over the past few decades. Thus, while he may or may not pose a threat at all, based on our current understanding of his location and speed, we cannot say for sure.
Altogether Astronomy scientists He identified 28 candidates who had a non-zero probability of a “deep encounter,” meaning they would pass a distance less than the distance to the moon. None of these objects will hit Earth in the next 100 or 1000 years, but if we want to survive for that long, we definitely need to take care of them.
Oscar Fuentes-Muñoz et al, Hazardous Kilometer-Size NEOs in the Next Thousands of Years, arXiv (2023). doi: 10.48550/arxiv.2305.04896
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the quote: Astronomers Prepare for the Next Thousand Years of Hazardous Asteroid Impacts (2023, May 18) Retrieved May 18, 2023 from https://phys.org/news/2023-05-astronomers-years-hazardous-asteroid-impacts.html
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