Credit: ESA – P.Carril

 

Research using an artificial neural network has shown that some asteroids that are now thought not dangerous can impact the Earth in the future.

Astronomers at Leiden University in The Netherlands have used a supercomputer, integrating the orbits of the Sun and its planets forward in time for 10,000 years. They then traced the orbits back in time while launching asteroids from the Earth’s surface.

Library of asteroids

During the backwards calculation, they included the asteroids in the simulations in order to study their orbital distributions at today’s date. The result: they acquired a database of hypothetical asteroids for which the researchers knew the space rocks would land on the Earth’s surface.

Credit: Hefele, John D., et al.

Astronomer and simulation expert Simon Portegies Zwart explains: “If you rewind the clock, you will see the well-known asteroids land again on Earth. This way, you can make a library of the orbits of asteroids that landed on Earth.”

The library of asteroids then served as training material for the neural network.

Hazardous objects

According to a Leiden University press statement, the first set of calculations was performed on the new Leiden super computer ALICE. The neural network runs on a simple laptop.

The researchers labeled their method Hazardous Object Identifier (HOI), which means ‘hi’ or ‘hello’ in Dutch.

The neural network can recognize well-known near-Earth objects. In addition, HOI also identifies a number of hazardous objects that were not previously classified as such. For example, HOI discovered eleven asteroids that, between the years 2131 and 2923, come closer than ten times the Earth-Moon distance and are larger than a hundred meters in diameter.

Credit: Hefele, John D., et al.

That these asteroids have not previously been identified as potentially dangerous is because the orbit of these asteroids is so chaotic, explains the press statement. “As a result, they are not noticed by the current software from space organizations, which is based on probability calculations that use expensive brute force simulations.”

The tricky part

The research is only a first exercise, Zwart notes. “We now know that our method works, but we would certainly like to delve deeper in the research with a better neural network and with more input. The tricky part is that small disruptions in the orbit calculations can lead to major changes in the conclusions.”

The research team says they hope in the future an artificial neural network can be used to detect potentially hazardous objects. Such a method is much faster than the traditional methods currently in use by space organizations. By noticing asteroid on a collision course earlier, the researchers say, organizations can sooner think of a strategy to prevent impact.

Earth has been on the receiving end of several incoming objects resulting in human injury.
Credit: NASA

 

 

 

 

 

Go to their paper — “Identifying Earth-impacting asteroids using an artificial neural network” — in the journal Astronomy and Astrophysics, Volume 634, February 2020, by going to:

https://www.aanda.org/articles/aa/full_html/2020/02/aa35983-19/aa35983-19.html

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