Meteor traveling through atmosphere without hitting Earth
Is it possible (however unlikely) to have a meteorite miss Earth so narrowly and at such flat angle that it would enter atmosphere, travel few (dozens, hundreds, thousands?) kilometers getting as close as few kilometers to the ground without hitting anything and then leave atmosphere without any significant, leaving millions of humans staring agape at the sky?
Or does gravity and air friction prevent this by either making such flat trajectory impossible or by slowing down meteorite enough to make it fall to the ground?
Strictly speaking it's impossible by definition for a meteor*ite* to miss the earth, but I expect that's not the answer you're looking for ;-)
Here is a much more dramatic example that you may remember: https://youtu.be/dpmXyJrs7iU
@fractalspawn That one certainly did hit the Earth! However there was a bright Earth grazer in 1972 that was captured on film https://www.youtube.com/watch?v=4WlCfuPrszU Its lowest point was about 60km
@SteveJessop I can't remember which one is which to save my life, but looking back at topic and question body, looks like I was correct at least once :)
yes it is possible,they are called Earth grazers or Earth-grazing fireball.
they are not rare but only few incidents are recorded.
for more details read this Wikipedia page https://en.wikipedia.org/wiki/Earth-grazing_fireball
Very interesting, thanks! I checked the wiki, and listed examples had distance from Earth at least 70km. Would it be possible to have them graze by at the height less than 10km? Or is the atmosphere too thick?
@Lope The angle of approach and the mass and toughness of the asteroid are factors so there's no one answer other than it would depend on a few things. If the Earth had no atmosphere, very near misses could happen where the asteroid kind of flies and just misses the Earth, never touching it. An asteroid, in theory, could miss the Moon by a few inches, but with atmospheric drag slowing down the asteroid, on Earth, it's much harder. A larger, faster moving asteroid would have a better chance, but even so, 10 KM sounds impossibly close to me. I wouldn't want to try to do the math though.
@Lope It would have to be unbelievably dense: see Newton's impact depth approximation
@Lope G-force would be much greater than 70 km height, but it would be acting in favor of meteor and accelerating it. there would not be straight line motion. An avg meteor enters atmosphere with 20 km/s and impact velocity is around 11 km/s, even though gravity is accelerating it. so we know what aerodynamic heat can do. here's more about it https://en.wikipedia.org/wiki/Aerodynamic_heating and impact event https://en.wikipedia.org/wiki/Impact_event
I think that there is also another element that makes them rarer. They have to come in quite on the edge of the planet. This means quite a shallow angle of entry. Is that not possibly also meaning they may bounce off the atmosphere when coming in too shallow?
@userLTK Ok now for some reason I want it to be possible for this hypothetical fireball to come within only a few meters of the ground without hitting or destroying anything...
@Michael i think it would be easy to catch this hypothetical fireball before it makes any mass destruction if we use "our" patented "super big meteor damper".
@Michael: "or destroying" is probably out of the question. Anything that comes close to the earth and then leaves, must be travelling at escape velocity (actually much more than that since it'll be slowed by air on the way out as well as in). Anything travelling that fast in air is going to heavily scathe stuff within a few metres of it. I suppose as a special case, very very tiny "meteors" made of a single neutrino do what the questioner describes all the time but especially at sunrise/set. Their trick is they don't interact with air :-)
... similarly I'm not sure, but I suspect that if you build an LHC in orbit, and point it near a tangent to the Earth, you'll get some proportion of high-energy protons penetrating the atmosphere and coming out the other side? I wouldn't have thought it's 100% opaque, although I may be wrong. But "high energy particles" is not what we usually mean by meteors, regardless of the fact that there is high-energy garbage coming at us all the time, along with the bigger slower stuff.