What is the largest asteroid and comet considered to be a near-Earth object? How large are they?
Doug Kaupa
Council Bluffs, Iowa
Doomsday impactors are a staple of modern science fiction. The most famous real-world example of an impact wiping out much of the life on Earth is, of course, the object that took out the dinosaurs some 66 million years ago.
Thankfully, events of that magnitude are fairly uncommon, happening about once every few hundreds of millions of years. But the possibility is