balloon high about the u.s. that we reported on earlier is not the only object in this kind of people are talking about tonight. we just got this new image in of a historic event at a equally historic location, a green huge comet that has not been visible and the night sky since the stone age, about 50,000 years ago. it was recently photographed above stonehenge in england. as close as they commit got to earth, it was still a ways away, more than 100 times the distance to the, moon but it is a rare and historic tree to see it. i'm joined now by adam frank, professor of astrophysics at the university of rochester. professor frank, thank you for being with us. how significant is this comet, and did you get a chance to see it yourself? >> the thing that is really cool about this is time. if you think about the comment as it goes around and it's orbit, as like a clock, then the last time that the hands were pointing to where it is now was the ice age,