We are hit constantly by meteors. Most of them are dust particle size and generally aren’t seen. Most never make it through our atmosphere and burn up. The ones who don’t we find out about on the information sphere that is our electronic media. Remember Russia a few years ago?
And here’s another great point of trivia. It is NOT friction that causes the bits to heat up and burn! NASA calls it “ram pressure” and it is what they use to shed kinetic energy and slow returning aircraft enough to use parachutes. Scientists call it a normal function of the natural gas law. PV=nRT. The gas in front of the high-velocity object is rapidly compressed, which heats up that gas, which in turn heats up the object. Kinetic energy is converted into thermal energy.
Tune your FM radio (you still have one, right?) to a clear frequency where there’s no station, and leave it. Occasionally you will hear a distant station for a split second. This is “meteor scatter”, where distant radio signals are reflected off of the ionized meteor trails.
What’s the difference between friction and “ram pressure” when moving through a gas?!
How about a related question. Is the bright streak we see due to the meteor burning up or due to the excited, heated air around the dust grain?
Worth noting that, in most cases, the glow (the meteor streak) has been created by only a small bit of dust!
The Geminids, by the way, are brighter than many meteors, and the shower reportedly produces more meteor streaks than the August Perseids do! Lay back on a chaise longue facing the direction of the constellation — and be sure to bundle, over-dress, especially the feet and head for cold winter observing. This year, alas, with the Moon in the sky, the show will hardly be worth it unless you are under really dark skies.
The bestest ones are “Shadowcasters”, so big and bright (and close!) that you will see shadows of objects around you for a few seconds. What’s really cool is when you can hear them. I miss Northern Washington, that was the best. I’m in “rural” Nevada now. Not bad, but still too many lights from the nearby city.
The end result is the projectile slows down. The lost kinetic energy must go somewhere – heating up the projectile and the air in its wake.
How does the projectile get hot? Three ways I can think of:
1) air molecules impact the projectile, transfering kinetic energy to it – the projectile’s molecules vibrate = projectile gets hot;
2) the air molecules bounce off, piling up in front of the projectile, which pressurizes & thus heats the air. So infrared radiates from the hot gas, hits the projectile and heats it.
3) there are also chemical reactions. Lots of materials burn in the presence of oxygen, if there’s sufficient mixing (the little rock is melting and vaporizing) and an initial ignition (yep, it’s really hot).
Incidently, all this dust and stuff eventually filters down onto the surface to a certain depth per century, and our crops turn it into food, and our bodies grow from it. Like Joni Mitchell sez, “We are stardust”.
Bilan about 8 years ago
Hurry. We need to build a wall to keep those Geminids out.
Argythree about 8 years ago
Great posts today! You all win the Internet…
Night-Gaunt49[Bozo is Boffo] about 8 years ago
We are hit constantly by meteors. Most of them are dust particle size and generally aren’t seen. Most never make it through our atmosphere and burn up. The ones who don’t we find out about on the information sphere that is our electronic media. Remember Russia a few years ago?
pulpitpoundingpoliticalpundit about 8 years ago
And here’s another great point of trivia. It is NOT friction that causes the bits to heat up and burn! NASA calls it “ram pressure” and it is what they use to shed kinetic energy and slow returning aircraft enough to use parachutes. Scientists call it a normal function of the natural gas law. PV=nRT. The gas in front of the high-velocity object is rapidly compressed, which heats up that gas, which in turn heats up the object. Kinetic energy is converted into thermal energy.
Kroykali about 8 years ago
Try this during meteor showers:
Tune your FM radio (you still have one, right?) to a clear frequency where there’s no station, and leave it. Occasionally you will hear a distant station for a split second. This is “meteor scatter”, where distant radio signals are reflected off of the ionized meteor trails.
Astroman007 about 8 years ago
What’s the difference between friction and “ram pressure” when moving through a gas?!
How about a related question. Is the bright streak we see due to the meteor burning up or due to the excited, heated air around the dust grain?
Worth noting that, in most cases, the glow (the meteor streak) has been created by only a small bit of dust!
The Geminids, by the way, are brighter than many meteors, and the shower reportedly produces more meteor streaks than the August Perseids do! Lay back on a chaise longue facing the direction of the constellation — and be sure to bundle, over-dress, especially the feet and head for cold winter observing. This year, alas, with the Moon in the sky, the show will hardly be worth it unless you are under really dark skies.
WaitingMan about 8 years ago
An area away from lights? In 21st Century America? HA!
What? Me worried ? about 8 years ago
I always LOVE science Sundays !
Packratjohn Premium Member about 8 years ago
The bestest ones are “Shadowcasters”, so big and bright (and close!) that you will see shadows of objects around you for a few seconds. What’s really cool is when you can hear them. I miss Northern Washington, that was the best. I’m in “rural” Nevada now. Not bad, but still too many lights from the nearby city.
kaffekup about 8 years ago
I was always excited to see a meteor “shower” until I found out the average might be one a minute. Like taking a shower under one drop a minute.
Bob. about 8 years ago
If it’s cloudy that night, the moon won’t bother us.
PappyFiddle about 8 years ago
If I put a lot of clothing on my head, I won’t be able to see the meteors.
PappyFiddle about 8 years ago
The end result is the projectile slows down. The lost kinetic energy must go somewhere – heating up the projectile and the air in its wake.
How does the projectile get hot? Three ways I can think of:
1) air molecules impact the projectile, transfering kinetic energy to it – the projectile’s molecules vibrate = projectile gets hot;
2) the air molecules bounce off, piling up in front of the projectile, which pressurizes & thus heats the air. So infrared radiates from the hot gas, hits the projectile and heats it.
3) there are also chemical reactions. Lots of materials burn in the presence of oxygen, if there’s sufficient mixing (the little rock is melting and vaporizing) and an initial ignition (yep, it’s really hot).
Incidently, all this dust and stuff eventually filters down onto the surface to a certain depth per century, and our crops turn it into food, and our bodies grow from it. Like Joni Mitchell sez, “We are stardust”.