Space agencies continuously assess the impact risk of an asteroid. Here you will find the objects that top that list.
Numerous observatories with telescopes around the world scan the sky for moving objects continuously. Because asteroids are relatively small, they are very, very difficult to spot most of the time. A number of space craft and satellites are also used to search in space for asteroids and other moving objects, free from atmospheric haze.
NASA and ESA compile an asteroid impact risk list that identifies the currently know asteroids that have the highest change of impact. Thankfully, there is currently no immediate risk identified!
The following notable objects are on this list:
|Asteroid Apophis||(#1 on the Torino scale)|
|Asteroid 2012RF12||(#1 on the Sentry List)|
|Asteroid 1979XB||(#2 on ESA’s list)|
|Asteroid 2018VP1||(#3 on ESA’s list)|
|Asteroid 2000SG344||(#4 on ESA’s list)|
|Asteroid 2006QV89||(#6 on ESA’s list)|
|Asteroid 2009JF1||(#7 on ESA’s list)|
The Torino Scale is a method for categorizing the impact risk associated with near-Earth objects (NEOs) such as asteroids and comets.
The Planetary Society has a nice graphic explaining the hazards of Near-Earth Asteroids, and the statistical chance of an event happening in our time.