2000 SG344
A small Aten asteroid with a notable impact risk rating.
Last updated
2000 SG344 is a small Aten asteroid first observed in 2000, with an estimated diameter of about 37 meters and an assumed mass of 71,000 tonnes. As of February 2025, it is the largest object known to have a better than 0.1% chance of impacting Earth and holds the fifth highest cumulative Palermo scale rating at −2.77. Its very Earth-like orbit and proximity to Earth in 1971 led to speculation that it might be a man-made object, such as an S-IVB booster stage from a Saturn V rocket.
Possible impacts with Earth
Until December 2004, this object was considered to have the highest likelihood of any near-Earth object to impact Earth in the next 100 years, though the chance remained very low. It is ranked zero on the Torino scale due to its small size and is listed on the Sentry Risk Table.
In December 2004, it was briefly surpassed by 99942 Apophis. Based on 31 observations from May 1999 to October 2000, there is about a 1 in 360 chance of collision between 2069 and 2121, with the greatest single chance on 16 September 2071 at 1 in 1000. If it were a rocky asteroid reaching the surface, the impact energy would be an estimated 1.0 megatons of TNT, comparable to the Tunguska and Chelyabinsk events, potentially creating a crater about 100 feet wide.
Did You Know?
- In 2008, NASA considered this asteroid as a possible target for a crewed mission (Artemis II) using the Orion spacecraft, prior to a projected 2030 push to Mars.
- 2000 SG344 will be observable in May 2028 at an apparent magnitude of 19.
- The next good chance to observe the object will be in May 2028 when it passes 0.02 AU from Earth.
More in Potential Impact Events Caused by near-Earth Objects
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: 2000 SG344 (CC BY-SA 4.0).
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