A few years ago, a team of researchers dedicated to finding killer asteroids before they killed us all came up with a clever trick.
Instead of scanning the sky with a telescope for asteroids, scientists created an algorithm that sifted through old photographs of the night sky and discovered about 100 asteroids that had been overlooked in those images.
On Tuesday, these scientists, along with the Asteroid Research Institute and the University of Washington, revealed an even bigger bounty: 27,500 newly identified Solar System objects.
This is more than was discovered by all telescopes in the world last year.
“This is a huge change” in the way astronomical research is conducted, said Ed Lu, executive director of the institute, which is part of the nonprofit B612 Foundation, which Lu helped found.
The discoveries include about 100 near-Earth asteroids and space rocks that pass within Earth's orbit. None of the 100 seem likely to collide with Earth in the near future. But the algorithm could be an important tool for finding potentially dangerous asteroids, and the research will aid planetary defense efforts by NASA and other agencies around the world. Become.
Most of the space rocks the institute has identified are located in the main asteroid belt between the orbits of Mars and Jupiter. Others, known as Trojan Horses, are trapped in Jupiter's orbit. The search also discovered several smaller worlds beyond Neptune's orbit, known as Kuiper Belt objects.
Dr. Lu, a former NASA astronaut, said, “There's a lot of great science here,'' and that the key to future astronomical discoveries is not increasing the number of hours spent observing with telescopes, but rather the huge amount of observational results already available. He pointed out that it could become a more powerful computer than the one that stirs things up. collected.
Historically, astronomers discovered new planets, asteroids, comets, and Kuiper Belt objects by photographing the same strip of the sky multiple times in a single night. The pattern of distant stars and galaxies remains the same. However, closer objects in our solar system move significantly within a few hours.
Multiple observations of a moving object, called a “tracklet,” outline its path and provide enough information for astronomers to know where to look on different nights to determine its orbit. You can
Other astronomical observations necessarily involve asteroids, but only at a single time and place, rather than the multiple observations needed to assemble a tracklet.
The 412,000 images in the National Optical and Infrared Astronomy Laboratory's (NOIRLab) digital archive contain approximately 1.7 billion points of light that appear in just one image.
The algorithm used in the current study, known as Tracklet-less Heliocentric Orbit Recovery (THOR), combines a point of light seen in one image with another point of light in another image taken on a different night. You can connect the points. Using another telescope, we can see that these two points are actually the same object. Usually an asteroid that has shifted position as it orbits the sun.
THOR's ability to identify asteroid candidates from disparate images is a daunting computational task that was impossible not long ago. But using Google Cloud, a distributed computing system, they were able to perform the calculations in about five weeks.
“This is an example of what's possible,” said Massimo Mascaro, technical director in Google Cloud's Office of the Chief Technology Officer. “We can't even quantify how much opportunity there is in terms of the data that's already being collected. If we can analyze it with the right calculations, we could potentially get even more results.”
Dr Lu said improved software tools have made it easier to harness computing power. When scientists no longer need large software engineering teams to search for data, “really interesting things can happen,” he said.
The THOR algorithm could also transform the operation of Chile's new Vera C. Rubin Observatory, which is scheduled to become operational next year. Funded by the National Science Foundation and the Department of Energy, the 8.4-meter-diameter telescope repeatedly scans large portions of the night sky to track what changes over time.
Currently, the Rubin telescope is supposed to scan the same part of the sky twice a night, in cycles designed to spot asteroids. With THOR, the telescope does not require his second pass and has the potential to cover twice the area.
“Most science programs would be willing to go from a baseline cadence of two observations per night to just one observation per night,” said Rubin, director of construction. said Zeljko Ivezic, a professor of astronomy at the University of Washington.
The algorithm could increase the number of asteroids Rubin can find, perhaps enough to meet a mandate passed by Congress in 2005 to find 90 percent of near-Earth asteroids larger than 460 feet in diameter. It could be a large number.
“Our latest estimates say it's about 80 percent,” Dr. Ivezic said. “With THOR, we can probably push that to 90%.”