Would you hear it coming before it hit you? I know it would be moving faster than sound but I seem to remember some property of sound from high school physics that make it so you would hear it anyway.

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I really can't imagine we'd hear anything, unless somehow there's a pressure-wave ahead of it??? #-o #-o #-o #-o

3. I imagine you would hear, "weeeeeee!"

4. Maybe some shock-wave stuff arrives a little bit earlier. But before your nerves gives the info to the brain and you conciously "hear" something, I guess you're burnt, smashed, atomized and a few things more.

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Not likely. It would traverse the atmosphere in a few seconds. Always torques me when I see in the movies the asteroid cruising for minutes across the sky. Sheesh... You can't hear a supersonic jet approaching you. What is the chance of hearing something going mach 60?

Shock waves in air are limited to the speed of sound and no faster. Your only clue would be the bright light for a couple of seconds.

You might hear the "electrophonic" meteor sounds -- if they really exist. I don't know if you'd call that hearing the asteroid, or hearing its effect on the rocks and vegetation around you.

7. If you saw it coming someone next to you might hear "What the " BANG!

8. Shock waves in air are limited to the speed of sound and no faster. Your only clue would be the bright light for a couple of seconds.
Shock waves travel slightly faster than the speed of sound. That is why you here the "crack" from a close lightning strike before you here the "boom" of thunder. The energy of a shock wave falls off faster than inverse square (inverse cube???), which is why you do not hear a "crack" from distant lightning.

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Lightning creates a "driven" shockwave as does any explosive. As soon as the pressure behind the shockwave falls to below the pressure in front of the wave it drops almost instantly to the speed of sound. Since it is a volumetric expansion it is third order. The rumble is actually the sound from more distant parts of the bolt that arrive later. It is possible to estimate the length of the bolt by how long the rumble lasts, minus echos. It is very approximate but is around ten seconds per mile of bolt length.

The shockwave from a supersonic object is not a driven shockwave and immediately drops to the speed of sound.

10. You wouldn't hear anything but see.
It would take the body about three seconds to penetrate the atmosphere, and you would see a light getting brighter and brighter but no "shooting star streak", since it's coming right at you.

11. Originally Posted by Evan
Lightning creates a "driven" shockwave as does any explosive. As soon as the pressure behind the shockwave falls to below the pressure in front of the wave it drops almost instantly to the speed of sound. Since it is a volumetric expansion it is third order. The rumble is actually the sound from more distant parts of the bolt that arrive later. It is possible to estimate the length of the bolt by how long the rumble lasts, minus echos. It is very approximate but is around ten seconds per mile of bolt length.

The shockwave from a supersonic object is not a driven shockwave and immediately drops to the speed of sound.
So, how is the "driven shockwave" caused by the heat of a lightning bolt different from the shockwave caused by the heat of a meteor's passage through the atmosphere?

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The lightning bolt heats the air instantaneously to plasma temps causing an explosion. The explosion causes the gases to expand above the speed of sound as long as the temperature is sufficient (Boyles law). The asteroid or other supersonic object leaves in it's wake a low pressure area that immediately causes the pressure wave to drop to sonic speed. There is a "stacking" effect ahead of the asteroid but above mach three or four the object begins to interact with the shockwave as it is so compressed as to approximate a plane boundary. The angle of the shockwave is entirely dependent upon the speed of the object in relation to the speed of sound in the medium, also called the mach number. That angle is directly dependent upon the speed of the object and always exceeds 90 degrees and therefore always lags the object.

The shockwave caused by the asteroid is not caused by heat. It is simply caused by the object exceeding the speed of sound in the medium.

13. I once read what happened excactly during the Tuskagena (sp?) event in 1908 in Siberia- a few witness accounts. Supposedly people from the more or less immediate area below where the meteoroid exploded (people right below were killed) didn't hear anything at all: people further away did. The comparison drawn was to how when Mount St. Helens erupted in 1980 people immediately in the area did not hear anything but the explosion was heard as far away as Canada by others- some "cone of silence" happened due to some scientific principle I can't lay my finger on right now.

14. Meteorites can indeed produce sound, here's an explanation that covers it well.

Snip from the article:

And now there is a growing body of knowledge that suggests that the fireball emits a type of electromagnetic radiation called "Very Low Frequency radiation" in the tens of kilohertz range and what then happens is this: The electromagnetic radiation is given off by the fireball, and it is so intense that objects around the person like hair or steel objects like glasses or wire or wire-meshes of fences vibrate, actually physically vibrate, as a result of this electromagnetic field. And as they vibrate, if it is intense enough, this can actually produce the sound at a few tens of kilohertz at exactly the same frequency in the VLF as people hear normal sounds. Thus you end up with a fireball passing nearby and at the same time they see the object, they hear this whistling or crackling sound from the transduction of the VLF waves. And they're not actually hearing sound from the fireball but rather hearing sound from local objects vibrating in response to the intense VLF emission of the fireball; this is called transduction. And so people have heard these sounds for years,
I've heard this myself when I saw one coming in over the beach...it landed in the ocean and I was close enough to hear the hiss as the hot object hit the water...very cool!

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The terminal velocity of a meteorite in the under several kilo size range is less than 500 kph. By the time it hits the earth it is no longer hot enough to "hiss" when it hits the water. This has been confirmed by people that have had meterorites hit their car. Generally, by the time it reaches the ground it has cooled. Keep in mind that the interior of a sizeable chunk of rock is probably around -200 or so.

http://antwrp.gsfc.nasa.gov/apod/ap021118.html

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It's definitely enough to kill a person though!

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So, if an asteroid hit the earth, would it be called a meteroite or an asteroidite?

I think you could hear the hissing of an asteroid heading for your head if you are on a beach and listening to it through a conch shell.

Originally Posted by Kebsis
Would you hear it coming before it hit you? I know it would be moving faster than sound but I seem to remember some property of sound from high school physics that make it so you would hear it anyway.
When I saw the title of this thread, I initially thought it had to have been posted by bmpbmp (of Can Earth explode as a result of Global Warming?, I hope this person is kidding (GLP doomsday post), Is 4 Lunar Distances concidered a close call?, Aussie Bloke-Dr. Gartrell, Why does this last paragragh worry me a little? (black hole heading for Earth), Canis Major dwarf galaxy colliding with our own, and Genesis reentry over NW United States fame.

Surprise!

Also surprised there's no commentary by bmpbmp.

19. Originally Posted by Evan
The terminal velocity of a meteorite in the under several kilo size range is less than 500 kph. By the time it hits the earth it is no longer hot enough to "hiss" when it hits the water. This has been confirmed by people that have had meterorites hit their car. Generally, by the time it reaches the ground it has cooled. Keep in mind that the interior of a sizeable chunk of rock is probably around -200 or so.

http://antwrp.gsfc.nasa.gov/apod/ap021118.html
Interesting, I did hear a hissing sound though and I interpreted it as being something hot hitting the water (as the fireball came in over the ocean). I guess the "hiss" was just a "vibrating response" after all!

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(Sorry, couldn't help it.)

21. Originally Posted by iFire

(Sorry, couldn't help it.)
I've been watching this thread... and that is funny.

22. Not me, I have a solid-titanium noggin'.

23. Originally Posted by iFire

(Sorry, couldn't help it.)

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Or:

Asteroid,

Or:

There once was an asteroid from space,
It flew towards the Earth at a race,
and a very big hole in that place.

25. Originally Posted by Evan
There once was an asteroid from space,
It flew towards the Earth at a race,
and a very big hole in that place.
Ok, this one is much better! =D>

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## Maybe

I read somewhere that someone acutally was hit with a space particle that made it's way to Earth. The person wasn't badly injured at all. Good post. #-o

27. ## Re: Maybe

Originally Posted by deetles
I read somewhere that someone acutally was hit with a space particle that made it's way to Earth. The person wasn't badly injured at all. Good post. #-o
That was just recently, wasn't it? It was a lady outside hanging her laundry or something. I think she got hit in the shoulder. I must google now. 8-[

28. ## Re: Maybe

Originally Posted by Candy
Originally Posted by deetles
I read somewhere that someone acutally was hit with a space particle that made it's way to Earth. The person wasn't badly injured at all. Good post. #-o
That was just recently, wasn't it? It was a lady outside hanging her laundry or something. I think she got hit in the shoulder. I must google now. 8-[
Too funny! I google meteorite shoulder woman hit 2004, and what do I find! #-o

I can only find other stories that are considered fiction. 8-[

Here's a rather interesting list of newspaper articles about meteors/meteorites. It includes the story I remember reading back in 1954 about an Alabama woman who was hit by a meteorite. It's about halfway down the list. The story in the New York papers somewhat discretely described the injury location as her "upper thigh".

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i once read a manga about an asteroid hitting a boy right in the head and a piece of the asteriod got implented into his head, then that boy gained superpower...

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