Two 20-year-olds, students of the Indian Institute of Technology, Bombay (IIT Bombay), Kunal Deshmukh and Kritti Sharma, have discovered the asteroid known to have flown closest to the earth earlier this week. Designated Asteroid 2020 QG, this soared just 2,950 kilometres above the surface of earth and went past without impacting the planet.
On Sunday, Deshmukh and Sharma, who were working on a research project from their respective homes in Pune and Haryana, discovered this object while scanning the day's images just hours later using data from the robotic Zwicky Transient Facility (ZTF), California. On being asked how they discovered the asteroid, Sharma told The Free Press Journal, "Initially, when we were flagging the candidates, it was just like any other asteroid for us because the streak looked almost similar. We could further comment on its orbit and location only after doing the orbit estimation and other processing of its image and data. However, we were quite excited on getting the findings the following day, after orbital estimation was done."
Deshmukh explained they were analysing the ZTF data on Sunday afternoon when they reported five “streaks” in the data as potential asteroids. Deshmukh, a final-year student in the department of Metallurgy and Materials Science at IIT Bombay, said, “The data looked like all other near earth asteroids we have seen so far." As for Sharma, the third-year student of mechanical engineering, it was only her third day on the project. "It was my third day of working on the research project and helping make a discovery like this so early was beyond what I had ever imagined," she exulted.
Following the observation, the ZTF team reported their finding to the International Astronomical Union Minor Planet Center, after which several telescopes followed up to learn more about the asteroid's size and orbit, proving that it had passed very close to earth. The study said, Asteroid 2020 QG is about 10 to 20 feet (3 to 6 metres) across, or roughly the size of an SUV, so it was not big enough to do any damage even if it had been pointed at the Earth; instead, it would have burned up in the planet's atmosphere.
Professor Varun Bhalerao, IIT Bombay, and the adviser to these students, said, "The asteroid flew very close to the earth, considering the recorded distance of 2,950 km. This discovery of the students will contribute to astrophysics research."
Asteroid 2020 QG is the closest to fly by the earth in recent times, with the previous known record-holder is Asteroid 2011 CQ1, discovered by the Catalina Sky Survey in 2011, whizzing past closer to Earth, at about 1,550 miles (2,500 kilometres).
Asteroids of this size that fly roughly as close to Earth as the 2020 QG do occur about once a year or less, but many of them are never detected, said ZTF co-investigator Tom Prince, the Ira S. Bowen Professor of Physics at Caltech and a senior research scientist at JPL, which Caltech manages for NASA.
The ZTF, funded by the National Science Foundation (NSF) and other collaborators, scans the entire northern sky every three nights, seeking supernovas, erupting stars and other objects that otherwise change or move in the sky. As part of a NASA-funded programme, ZTF team members search for near-Earth asteroids. When these space rocks speed across the sky, they leave streaks in the ZTF images. Each night, machine-learning programmes automatically sort through about 100,000 images in search of these streaks and then narrow down the best asteroid candidates to be followed up by humans. This results in about 1,000 images that team members and students visually sort through, every day.