Largest asteroid flyby of 2021 to occur Sunday
The largest asteroid expected to fly by the Earth in 2021 will make its closest approach Sunday.
Asteroid 2001 FO32, measuring between 1,300 and 2,230 feet wide, will be about 1.25 million miles from the Earth. That’s 5 ¼ times the distance from Earth to the moon.
It won’t be this close again until 2052, when the asteroid will be 1.75 million miles away.
Scientists have been tracking 2001 FO32 since 2001. It was initially believed to be about 3,000 feet wide, but more recent observations have reduced its size to the 1,300-to-2,230-foot range.
Sunday, as it whizzes past the Earth at 77,000 mph, will provide an opportunity to study the asteroid’s size, composition and how bright or reflective its surface is.
“Currently, little is known about this object, so the very close encounter provides an outstanding opportunity to learn a great deal about this asteroid,” Lance Benner, principal scientist at NASA’S Jet Propulsion Laboratory in California, said in a news release.
NASA’S Infrared Telescope Facility located atop Hawaii’s Mauna Kea will observe the asteroid in the days leading up to its close approach.
Electromagnetic energy trav
els in waves that span a continuum from very long radio waves to very short gamma rays. The human eye can see only a small section of this spectrum, visible light, whereas machines such as radios and Xrays use other portions of the spectrum.
Chemical elements and molecules have unique signatures that show up as different patterns of light and dark at different wavelengths. So when sunlight hits the asteroid’s surface, minerals in the rock will absorb some wavelengths and reflect others. By studying the spectrum of light reflecting off the surface, astronomers can measure the chemical “fingerprints” of the minerals on the surface of the asteroid.
Scientists will determine the asteroid’s chemical makeup and then compare this to meteorites on Earth, which will help determine what minerals 2001 FO32 contains.
And to study the asteroid’s orbit, dimensions and rotation, the Deep Space Network may conduct radar observations — using dish antennas to bounce radio signals off the asteroid so other radio antennas can receive them — that provide a detailed view of the rock. It also might provide a glimpse of features on the surface, such as large boulders or craters, and whether the asteroid has a small moon. About 15 percent of similarly sized near-earth asteroids have a small moon, according to NASA.
Amateur astronomers might be able to see this asteroid, too. Using a moderate-size telescope, with an aperture of at least 8 inches, people in the Southern Hemisphere and at low northern latitudes should be able to see the asteroid in the nights leading up to its closest approach. Star charts will be useful in finding it.