Up to now, scientists have identified over 30,000 near-Earth objects (NEOs), a term used to refer to any space object with a trajectory close to Earth’s orbit. The majority of these NEOs are asteroids, although over a hundred comets are also listed in this catalog.
Simulation of an asteroid flying past Earth. Image: Dima Zel.
Some NEOs are classified as “potentially hazardous.” These are objects with a diameter larger than 140 meters and orbits within a range of 0.05 astronomical units (about 7.4 million kilometers, or 0.05 times the distance from Earth to the Sun) compared to Earth’s orbit.
In reality, there are no potentially hazardous objects that scientists are aware of with a chance of colliding with Earth in the near future. The designation of potentially hazardous NEOs simply means that their trajectories could develop into orbits with the potential to impact Earth in the distant future. In the event of a collision, these NEOs, which are large enough to cause significant damage to our planet, would pose a threat, at least on a regional scale.
Below is a list of the largest potentially hazardous NEOs, all of which are asteroids, that will pass by Earth in 2023, meaning they will approach the planet within a range of 0.05 astronomical units, according to the database from NASA’s Center for Near-Earth Object Studies (CNEOS).
363505 (2003 UC20)
This is likely the largest asteroid approaching Earth this year. The CNEOS database indicates that it has a width of approximately 1.9 kilometers, which is 2.3 times the height of the Burj Khalifa tower (828 meters), the tallest building in the world located in Dubai. This colossal object takes 252 days to orbit the Sun and will pass by Earth on November 2nd at the closest distance of 5.2 million kilometers. At that time, it will be traveling at a speed of 7,971 km/s.
199145 (2005 YY128)
Estimated to have a width ranging from 0.566 to 1.265 kilometers, this asteroid is comparable in size to the Golden Gate Bridge. 199145 (2005 YY128) completes one orbit around the Sun every 774 days. It will come closest to Earth on February 16th at a distance of approximately 4.6 million kilometers and will be moving at a speed of 24,649 km/s.
436774 (2012 KY3)
According to the CNEOS database, 436774 (2012 KY3) has an estimated width ranging from 0.538 to 1.202 kilometers, slightly smaller than 199145 (2005 YY128). This asteroid has an orbital period of 500 days around the Sun and is projected to approach Earth on April 13th. At that time, it will be approximately 4.7 million kilometers away from us, moving at a speed of 17,552 km/s.
139622 (2001 QQ142)
Based on its brightness and light reflection, 139622 (2001 QQ142) is estimated to have a diameter ranging from 0.347 to 1.552 km. It completes one orbit around the Sun every 620 days. At its closest approach to Earth on December 6th, the celestial object will be approximately 5.5 million km away from us, traveling at a speed of 6,660 km/s.
349507 (2008 QY)
349507 (2008 QY) orbits the Sun in 461 days. CNEOS data shows that it has a diameter ranging from 0.518 to 1.159 km. This space rock will have its closest approach to Earth on October 3rd at a distance of about 6.3 million km, moving at a speed of 20,960 km/s at that time.
(Source: Newsweek/Space Reference)