Astronomers have revealed the tracks of nearly 1,500 new asteroids hidden in data collected by NASA’s most venerable space telescope.
In a new study, astronomers and a team of amateur scientists worked together to sift through archival data from the Hubble Space Telescope. The project began on International Asteroid Day in 2019, when a team of astronomers launched the “Hubble Asteroid Hunter” project on Zooniverse, a popular platform for crowdsourcing science. The project’s goal was to identify asteroids in old Hubble data; signals that in other studies might have been simply filtered out as noise.
“One astronomer’s trash can be another astronomer’s treasure,” Sandor Kruk, study leader and researcher at the Max Planck Institute for Extraterrestrial Physics in Germany, said in a statement. “The amount of data in the astronomy archive is growing exponentially and we wanted to use this amazing data.”
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The team used observations captured by Hubble’s ACS and WFC3 cameras between April 30, 2002 and March 14, 2021. In this data, asteroid hunters combed through more than 37,000 composite images.
Since the typical observation time for these instruments is 30 minutes, the team knew that moving asteroids would show up in the images as trails. But such sequences can be difficult for automated computer systems to detect, making the team’s efforts especially valuable.
“Due to the orbit and motion of Hubble itself, the streaks appear curved in the images, making it difficult to classify asteroid trails – or rather, it’s hard to tell a computer how to detect them. automatically,” Kruk said. “So we needed volunteers to perform an initial classification, which we then used to train a machine learning algorithm.”
For the project, 11,482 citizen science volunteers scoured those thousands of images for the footage. Through their efforts, they made 1,488 attempts to identify asteroids in about 1% of the images provided by Hubble, according to the release. With the citizen scientists’ classifications, the astronomers leading the study trained an automated machine-learning algorithm to look for additional asteroid trails in the data that might have been missed. The algorithm added about 900 detections to the batch, which now totaled 2,487 possible asteroids.
This total was later reduced by Kruk and the other authors of the study, astronomers Pablo García Martín of the Autonomous University of Madrid and Marcel Popescu of the Institute of Astronomy of the Romanian Academy. The three scientists inspected the images further, detecting streaks and ruling out cosmic rays or other non-asteroid objects that might have created them. This reduced the number of images with asteroids, resulting in a final total of 1,701 asteroid trails from 1,316 Hubble images.
About a third of the confirmed tracks have further been identified as known asteroids listed in the Center of minor planetsthe database of solar system objects. Two-thirds of the contrails remain unidentified, although even identified asteroids will require further observation, the statement said.
So far, researchers know that the asteroids identified “are consistently fainter and therefore likely smaller than typical asteroids detected from the ground, with similar velocity and distribution across the sky as known asteroids in the so-called main belt”. statement reads.
The team aims to follow up on the new study by using the shape of asteroid contrails to try to determine how far space rocks are from Earth and derive information about their orbits.
“Asteroids are remnants of the formation of our solar system, which means we can learn more about the birth conditions of our planets,” Kruk said. “Using such a combination of human and artificial intelligence to sift through large amounts of data is a game-changer and we will also use these techniques for other future investigations, such as with the EUCLID telescope.”
The EUCLID telescope, which will be launched next year if all goes well, is a European observatory designed to study dark matter and dark energy in the universe. However, scientists estimate it will also spot 150,000 objects in the solar system, the statement said.