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Meteors may emit radio waves as they burn up in the atmosphere. The radio waves could be converted to sound by vibrating objects near the ground, explaining why some observers "hear" meteors in real time despite the discrepancy between the speeds of light and sound:
For centuries, some observers have claimed that shooting stars or meteors hiss as they arc through the night sky. And for just as long, skeptics have scoffed on the grounds that sound waves coming from meteors should arrive several minutes after the light waves, which travel nearly a million times faster. Now, scientists have proposed a theory to explain how our eyes and ears could perceive a meteor at nearly the same time. The hypothesis might also explain how auroras produce sound, a claim made by many indigenous peoples living at high latitudes.
Meteors release huge amounts of energy as they disintegrate in the atmosphere. They also produce low frequency radio waves that travel at the speed of light. Some scientists have suggested that those radio waves produce the sound that accompanies meteors. The waves can cause everyday objects—including fences, hair, and glasses—to vibrate, which our ears pick up as sound between 20 and 20,000 Hertz. This phenomenon, called electrophonics, is a well-known principle: "The conversion from electromagnetic waves to sound waves ... is exactly how your radio works," says Colin Price, an atmospheric scientist at Tel Aviv University in Israel and co-author of the new study. "But in this case nature provides the conversion between electromagnetic waves and acoustic waves."
On the electrophonic generation of audio frequency sound by meteors (DOI: 10.1002/2017GL072911) (DX)
Photoacoustic Sounds from Meteors (open, DOI: 10.1038/srep41251) (DX)
(Score: 2) by bob_super on Tuesday April 18 2017, @09:44PM (7 children)
So, even after I bother to paint my meteor black, and shove it in the right orbit, I'd also need to put an EMI shield on it to be sure it won't get detected too early?
Come on, guys! Give me a break, it should work anyway. The guys from DC are typically actively ignoring any change in the atmosphere's content.
(Score: 0) by Anonymous Coward on Tuesday April 18 2017, @09:58PM
tbh (to be hoenest) there is nooo way you can do everything alone. some things need the right time ( shared time) and four hands (not a mutant).
(Score: 2) by takyon on Tuesday April 18 2017, @10:33PM (3 children)
Whatever happened to relativistic kill vehicles?
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by bob_super on Tuesday April 18 2017, @10:46PM
Can't talk about those when the relatives are in town.
(Score: 2) by DannyB on Wednesday April 19 2017, @04:09PM (1 child)
Has anyone actually developed any to talk about?
To the target of such a weapon, due to relativistic length contraction, such weapons would appear to be much shorter in length.
There was a certain runner carrying a javelin. There was a barn with both it's front and back door wide open. The javelin is the exact length of the barn from front door to back door. The farmer is in the barn, off to the side, trying to hack the micro controllers on his John Deere farm equipment. The runner is approaching the barn at nearly the speed of light. He runs all the way through the barn. Through the front door and out the back door.
Incident report from the farmer.
I saw the runner approaching carrying the javelin. The runner entered through the front door. After he entered the barn through the front door, I was able to slam the front door closed. He was still inside running, and then after a short time, he reached the back door and ran right on out of the barn. The javelin easily fit completely within the barn with lots of room to spare.
Incident report from the runner.
I was approaching the barn. I saw the farmer using some hex editing software on a laptop. I ran into the barn. From the midpoint of the barn I could see that the front end of the javelin was already far outside of the barn's back door. I glanced over my shoulder and could see that the other end of the javelin was still far outside of the still open front door of the barn. So clearly the javelin was much much longer than the length of the barn. After I exited the barn, the farmer closed the barn's front door.
So which is true?
Both of them are true. Each is absolutely true. One isn't any more right than the other. The barn and javelin are approach each other with a closing velocity nearly light speed. From the farmer's POV the javelin is foreshortened. From the runner's POV the barn is foreshortened. No matter what physics experiments you do, no matter what sensors and instruments you put on either the barn or the javelin, both accounts are correct as reported.
The lower I set my standards the more accomplishments I have.
(Score: 2) by bob_super on Wednesday April 19 2017, @08:48PM
> Both of them are true
Only if the barn contains frictionless spherical cows in a vacuum.
Otherwise, a blast of high-speed plasma made up of former organic and metallic molecules blew the barn, and the rest of the farm, down.
No word on whether the local spacetime warp helped to hack the JD controller.
(Score: 2) by Immerman on Wednesday April 19 2017, @12:14AM (1 child)
Once it hits the atmosphere all bets are off regardless. Doesn't matter how black it is when it's preceded by a white-hot ball of plasma created by the insane compression of a Mach 23+ bow wave. Actually, I'm curious how much of the low-frequency radio noise is produced by the bow wave itself, rather than the meteor disintegrating in its heat.
(Score: 2) by PiMuNu on Wednesday April 19 2017, @03:49PM
I think black because he is worried about those dang visible light telescopes spotting whatever orbital maneuvres are necessary to get the trajectory right...