What would happen if a large asteroid (for example the one alleged to have killed off the dinosaurs) didn’t impact directly but entered the Earth’s atmosphere and skimmed past? Would enough energy be dumped into the atmosphere to cause major problems or would it just be history’s best fireworks display?
Considered putting ‘need answer fast!’ in the title 
Since the earth’s atmosphere doesn’t end at a specific height, you’d have to be more specific. At 250 km, there would probably be no effect as negligible energy would be released. At 80 km, I would imagine substantial portions of the meteor would be vaporized with enough released energy to cause a sonic boom so loud that many people would become deaf. At 40 km, the shock wave would probably cause tsunamis that might kill a million shore residents.
Last time it was like a high-altitude nuke, and melted the sand of the Sahara to a depth of a few inches, but over a long stripe instead of a small circle.
So think of thousands of H-bombs lined up in a row across the sky.
See Lybian Desert Glass
Thanks for the answers, basically even a near miss would be a Very Bad Thing.
How big was the 1972/08/10 bright atmosphere-grazing meteor compared to this hypothetical asteroid? The only known effect it had on the earth was to make humans exclaim “Wow, way cool!”
P.S. the word you want is Libyan.
I think it was about three metres.
This is one explanation put forth, but it isn’t really known how it was formed. See the Wikipedia page, and the External links there.
Libyan Desert glass: A review is a recent paper on the subject. From the abstract:
ETA: This link gives ten possible explanations:
The question would be, did the object shed eough velocity that it would not escape earth’s gravitational pull? Then it would loop around for another pass, and anouther, until it finally lost enough velocity that it stopped grazing and became a big splat…
Estimate, let’s say, that he grazing approach was 50Km up; to go from say, 150km to 50km and back again on a roughly linear path (at which point it’s pretty much back outside the atmosphere) would be a path of about 18 degrees across the earth, or about 2000 km with omst of the heat dissipated at the central closest approach.
Pick a size for your asteriod, about 10km^3 of rock; then figure if the earth escape velocity is about 10km/s and the rock sheds, let’s say, 1/10 of its kintetic energy - you will see/feel/hear a fireball dumping X TJ of energy into an oval about 2000km by, say, 300km.
