'Twilight telescope' finds 'city killer' asteroid in unexplored region of our solar system
When it comes to searching for asteroids, we have a blind spot. It may seem counterintuitive, but the asteroid’s most important discoveries are now being made at dusk, when astronomers can see up close to the horizon – and close to the sun – for what little is known. asteroids orbiting within the orbits of Earth, Venus and even Mercury. In perspective published in Science today, asteroid hunter Scott Sheppard of the Carnegie Institution of Science highlights the new “twilight telescope” surveys and the riches they are beginning to discover. It includes the first asteroid with an interior orbit to Venus and the one with the shortest known orbital period around the sun, both of which have been unearthed in the past two years. It also includes “city killers”, asteroids large enough that if they hit Earth the damage will be severe. “We’re doing a full survey looking for anything moving around the orbit of Venus, which is somewhere we haven’t surveyed very deeply in the past with anyth