Last weekend, an asteroid the size of a giraffe was discovered, and it will make an extremely close approach to Earth this Thursday, just as a much more distant “green comet” brightens.
At that point, the space rock will be approximately 6,500 miles from the center of the Earth and traveling at a speed of approximately 33,300 miles per hour.
Asteroid Passes Extremely Close to Earth
Given that the average radius of the Earth—the distance from its center to its surface—is estimated to be around 4,000 miles, the 2023 BU will fly by at an altitude of around 2,500 miles above the ground.
While this may appear to be a long distance, it is actually a very short distance in astronomical terms. In fact, the 2023 BU flyby is the fourth closest of more than 35,000 past and future Earth approaches in the CNEOS Center for Near Earth Object Studies database, which spans 300 years from 1900 to 2200.
The approach is so near that it accounts for less than 3% of the average distance between Earth and the moon. The asteroid will also travel across the orbits of geostationary satellites, which circle the Earth at a height of 22,236 miles above the equator.
2023 BU was only discovered this past Saturday, but astronomers have precisely calculated its orbit, and there is no possibility of it colliding with our planet this time.
According to certain definitions, the asteroid will even pass through the “exosphere,” the topmost part of the Earth’s atmosphere that may stretch anywhere from 6,000 miles to 120,000 miles above the Earth, depending on the interpretation.
However, because the air is so thin in this region, many scientists do not believe the exosphere, which progressively fades into the vacuum of space, to be a true element of the atmosphere.
Virtual Telescope Project
The Virtual Telescope Project, a pair of powerful 14-inch and 17-inch robotic telescopes stationed in Ceccano, Italy, will display the close flyby in real time. Gianluca Masi, an astronomer, will provide a live YouTube feed showing images of 2023 BU through a telescope. On Thursday, Jan. 26, coverage will begin at 19:15 UTC.
Because it is so little, it will shine at a maximum magnitude of 11.3, which is too dim for the human eye to see. As a result, only those with powerful telescopes will be able to observe 2023 BU.
2023 BU is an Apollo-type asteroid, a kind of object named after the archetypal asteroid Apollo in 1862. Such asteroids have a greater orbit around the Sun than Earth, and their path intersects Earth’s. 2023 BU circles the Sun every 425 days, and its course crosses Earth’s orbital path around the Sun on occasion.
Even if the asteroid collided with our world, there would be little cause for concern. According to CNEOS data, the object is only 12.4 to 27.8 feet across.
Space pebbles less than 25 meters across (about 82 feet) will most likely burn up if they approach the Earth’s real atmosphere, causing little to no damage on the ground, according to NASA.