Over 100 hidden asteroids detected thanks to new algorithm studying old telescope data

An animation showing the location of the near-Earth asteroids discovered as of January 2018; Earth's orbit is marked by the white line.
An animation showing the location of the near-Earth asteroids discovered as of January 2018; Earth's orbit is marked by the white line. (Image credit: NASA/JPL-Caltech)

Researchers using an innovative astrodynamics algorithm have uncovered over 100 asteroids that had gone undetected in archived images of the sky. 

Asteroids are rocky objects left over from the formation of the solar system more than 4 billion years ago. Ranging in size from several feet to hundreds of miles across, these rocky bodies are too small to be considered planets. 

The 104 previously undiscovered asteroids were detected using a new algorithm called Tracklet-less Heliocentric Orbit Recovery (THOR), which is a part of the Asteroid Institute's Asteroid Discovery Analysis and Mapping (ADAM) cloud-based astrodynamics platform. This algorithm recognizes asteroids and calculates their trajectories by linking points of light in different sky images that are consistent with asteroid orbits, according to a statement from the B612 Foundation, a nonprofit that supports research and technologies for mapping and navigating the solar system. 

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"Discovering and tracking asteroids is crucial to understanding our solar system, enabling development of space and protecting our planet from asteroid impacts," Ed Lu, executive director of the Asteroid Institute, a program of the B612 Foundation, said in the statement.

"With THOR running on ADAM, any telescope with an archive can now become an asteroid search telescope," said Lu, who is also a former NASA astronaut. "We are using the power of massive computation to enable not only more discoveries from existing telescopes, but also to find and track asteroids in historical images of the sky that had gone previously unnoticed because they were never intended for asteroid searches."

The newfound asteroids were discovered using historical data from the NOIRLab Source Catalog. These data were analyzed by the THOR algorithm on the ADAM platform, which runs on Google Cloud. The NOIRLab data included a collection of nearly 68 billion observations taken by the National Optical Astronomy Observatory between 2012 and 2019. The asteroid candidates were submitted to the International Astronomical Union's Minor Planet Center for confirmation. 

"A comprehensive map of the solar system gives astronomers critical insights both for science and planetary defense," Matthew Holman, a dynamicist and search algorithm expert at the Harvard & Smithsonian Center for Astrophysics and the former director of the IAU Minor Planet Center, said in the statement. "Tracklet-less algorithms such as THOR greatly expand the kinds of datasets astronomers can use in building such a map.” 

Identifying these first 104 asteroids using the THOR algorithm opens the door for even more asteroid discoveries using historical telescope data sets in the future, the researchers said. 

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Samantha Mathewson
Contributing Writer

Samantha Mathewson joined Space.com as an intern in the summer of 2016. She received a B.A. in Journalism and Environmental Science at the University of New Haven, in Connecticut. Previously, her work has been published in Nature World News. When not writing or reading about science, Samantha enjoys traveling to new places and taking photos! You can follow her on Twitter @Sam_Ashley13.