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Why Meteoroids Explode Before Hitting the Earth (qz.com)
According to a new study from Purdue University, scientists have figured out why meteoroids explode before hitting the Earth. "The research, published in the December issue of the journal Meteoritics & Planetary Science, shows that as meteoroids plunge, the high-pressure air they push against find its way into the objects' pores and cracks, forcing their bodies apart from the inside," reports Quartz. "The result is a kind of detonation that looks like an explosion." From the report: To explain the astrophysics, researchers focused their work on a widely viewed February 2013 meteoroid explosion place over Chelyabinsk, Russia, a city of 1.1 million north of the Kazakhstan border. Researchers ran a computer program that allowed for them to simulate what happened to the meteoroid in the atmosphere. "Our simulations reveal a previously unrecognized process in which the penetration of high-pressure air into the body of the meteoroid greatly enhances the deformation and facilitates the breakup of meteoroids similar to the size of Chelyabinsk," the study states. The researchers added that while the air pressure is effective at breaking apart small meteoroids, larger ones would likely withstand the force as they come to Earth.
>> Why Meteoroids Explode Before Hitting the Earth
I'm not saying it's Missile Command, but it's Missile Command.
https://www.youtube.com/watch?v=nokIGklnBGY
There is more to the study then meets the eye. This will lead to knowing how to build kinetic weapons for kt/mt range drops with out the fuss and muss of fallout.
So, aliens are basically bombarding us with meteoroids armed with the old "pull my finger" gag. The gall of them! Can't we build a space wall to keep these stinking meteoroids out?
"Memo to the engineering team on the dark side of the moon, building the blimps that will be used to conquer the Earth:"
"Avoid pores and cracks in the outer skin of the weapon. These could lead to premature explosion, which would be a major bummer for the Führer,"
"-- Donald Zuckerberg, Reich Minister of Armaments and War Production."
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
I called it firework.
I mean, look at the number of cars stop to stare at it when it comes!
Meteroids explode because they activate self destruction, as a way to prevent earthlings to discover top alien tech.
This study is probably funded by aliens.
Obviously none of these people doing "research" have ever gone camping .... just throw a couple moist rocks into a camp fire and see what happens....
I swear I read "Why Metroids Explode Before Hitting the Earth"
How soon until small meteorites become target practice for new weapon systems I wonder.
Something about the OP doesn't make sense.
And no, not the fact that there isn't much in the way of "high-pressure air" at the outermost fringes of our atmosphere...
The part which seems a little odd is to suggest that altering the apparent pressure [i.e. by the velocity of entry] can in some way "force" air into the cracks within a meteorite/meteorid to induce some form of break-up.
Isn't it much more likely to be induced by the coefficient of expansion of the material concerned? If you take a meteorite and then flash-heat the outer surface very, very, very quickly - like for example by slamming it into an atmosphere at several thousand kph - then the outer layer will become very, very hot very quickly - and start to expand. The interior, meanwhile, simply won't have had time to warm up and thus will remain space-cold... As the outer layer warms, it expands. This would easily be enough to cause cracks in the material [think of the way that you can split a rock by pouring water into a crack and then waiting for the water to freeze...].
It's been a while since I studied CFD [computational fluid dynamics - which is the science that would show how atmospheric gases would "flow" around an meteorite as it entered the atmosphere - but I think it's fair to say that a "boundary layer" would form that might in fact make it ridiculously difficult for "high pressure air" to be "forced" into tiny cracks in the surface.
So... very interesting theory, but I think we might find that things like the irregular shape and density of the material [which causes non-uniform stress on the material] coupled with very high speed heating, might be significant factors too...
No, it really won't.
We already have a good understanding of how to drop something from orbit and have it hit the ground intact. At most, this study just confirms that cracked rocks aren't the best choice for that task, which we already knew.
Joke Alert
"facilitates the breakup of meteoroids similar to the size of Chelyabinsk" :-)
Never realised it was that big
Do asteroids or comets have "tails' outside of the atmosphere in the vacuum of space -- ie, plumes of particulates given off? Are they "burning"?
Or is this just what happens when they cross into an atmosphere and experience friction?
I guess maybe I could see solar heating causing them to erode, but at the same time is there enough solar heating much outside Earth's orbital distance?
So that's what happened to these columbia space shuttle astronauts !
Sad and horrible !
Feel sorry for those poor fokkers !
May they rest in pieces ! Chear up ! ;) =D
I would have thought that differential thermal strain and poor internal structure of the rock was the culprit. The inside is at the temperature of deep space. The outside gets hot. The expansion on the outer parts places the inner parts under tension. Rocks are not so good at withstanding tensile stress. A crack is propagated and the rock fails. Did the simulation also examine thermal strain? Thermal strain generates enormous forces. The lack of ductility in rock makes the problem even worse.
The air pressure would have to be in the 10,000 psi region to break a rock that had any internal structural consistency. I don't buy it. All of the air pressure posited to be acting on the inside of the rock would also be acting on the outside of the rock compressing it. The internal air pressure and the external air pressure would cancel each other out.
The range of mechanical strengths given in the summary of the article 1 MPa - to 330 MPa implies that 329 MPa of air pressure makes up the difference to cause the rock to fail. That's 47,000 psi. Is there an aerodynamicist here who can tell us how fast you have to be going to generate 47,000 psi of air pressure at the stagnation point?
duh.
We've found another round object infiltrated with air- this guys head!
when I read the headline I thought, because of friction from the atmosphere.
And are willing to die to destroy us.
Damping absorbs vibrations. Dampening is caused by moisture.
You should get in an argument with other posters here who declare that this conclusion is obviously impossible.
The arrogance of the lazy boy 'scientist'.
Second class citizen of the New Gilded Age
They also use the wrong term. A meteoroid that has entered the atmosphere is called a meteor and if it reaches the ground, it's a meteorite.
Trees explode when lightning hits them because the water in their sap is instantaneously converted to superheated steam and the immense pressure created blows the trunk apart. Same as river rocks thrown into camp fires.
Guess what happens to the ice in meteoroids when they get superheated by atmospheric entry?