NASA’s Goldstone antenna is down for major repairs for an extended period of time
But the real answer is that asteroids are small, cold, and dark. It’s very hard to see such an object against space, which is very large, and also very cold and dark. It’s like trying to find a grain of sand floating around in a dark room.
tl;dr:
But the real answer is that asteroids are small, cold, and dark. It’s very hard to see such an object against space, which is very large, and also very cold and dark. It’s like trying to find a grain of sand floating around in a dark room.