Good news regarding the likelihood of getting hit by an asteroid: the estimated count of those bodies that cross Earth’s orbit has gone down. Although the probability that any one rock might hit us has always been very low, the calculation shrunk even further after data from the WISE spacecraft (Wide-field Infrared Survey Explorer) was analyzed. The number shrunk by almost half (35,000 to 19,500). Finding small objects (less than about a mile across) is challenging because they’re not very bright to begin with, and past surveys have relied on visible light to see them. WISE uses heat (infrared radiation) emitted from the object, which doesn’t depend on how reflective the surface is. Since asteroid surface brightness varies across a wide range, it was difficult to determine how big each of them was (observations could be bright because the asteroid was large, or because it had a very high surface…
Tag: asteroids
The small bodies in our solar system.