An international team of hundreds of scientists is finishing construction of the LSST telescope, or Large Synoptic Survey Telescope. It will search for asteroids that are on a collision course with Earth. Despite our best technology it’s difficult to detect asteroids, let alone asteroids that are speeding toward our planet. The reason is that asteroids are dark; they don’t give off visible light and are hard to detect in the blackness of space.
With significant funding from the U.S. National Science Foundation, LSST will search for PHAs during its 10-year mission by observing the same area of sky at hourly intervals searching for objects that have changed position. Anything that moves in just one hour has to be so close that it is within our solar system.