The Perseids are reliable, regular shooting stars, a meteor shower that shows up nights in late July every year. I didn’t see the Perseids this year myself because Baltimore’s skies are a rich carnelian haze that hold nothing much and certainly not meteorites. And Heather didn’t see them because, she thinks, of light pollution. To comfort ourselves, we post this video of the Perseid meteor shower, taken against the Milky Way. It must have been done over several nights or from several different angles or something. Nevertheless, astounding. I’m astounded.
Joshua Tree Under the Milky Way from Henry Jun Wah Lee on Vimeo.
this is pretty awesome, but also terrifying. it seems to foreshadow our eventual destruction, like a cosmic warning shot across our bow. and while i’m not exactly excited about that event, i’m trying to derive comfort in the fact that it will at least be a beautiful destruction.
but for now i’ll keep the carnelian haze and hopefully sleep better.
I’m so tempted to say, Oh shut up Spence. But that wouldn’t lead to good blogger/commenter relations, would it. Instead I’ll say, Nice of you to read it, Spence, and nice of you to write. And the Perseids have been coming around for at least centuries and probably won’t kill us one bit. Moreover, I’m truly happy that you like the carnelian haze. I fancy it myself.
One of my enduring memories is of watching this, in August 1968, lying flat on my back on a beach in Ischea, for what seemed like hours (some of which may have been chemically induced, it was 1968 remember). Ever since then, I’ve tried whenever possible to re-view this cosmic lightshow, once or twice with some success. This year, my skies were not so much carnelian as puce – but thanks anyway for a beautiful word…
How lovely, Tim, chemical or not. Puce doesn’t sound much better than carnelian — a word Spence likes too. So now I’ll use it more often.
Earlier this year, in the latter part of May, I was out for a late night walk when I heard a strange whoop, whoop, whoop, whoop sound out of the sky.
I looked up and saw a brilliant and colourful red, orange and white meteorite falling.
The fireball was about twice as large as the average star, and it appeared to burn itself out before it could disappear over the northern horizon.
I’d never heard a shooting star before.
Does anyone know if that’s a common phenomenon?
I think that’s called a bolide, Dan. I’d guess it was either big or close. I saw one once and won’t forget it.
This one wasn’t just a bolide – i.e., a fireball that explodes in the atmosphere – it was close enough to be heard before being seen.
And that is a very rare occurrence!
How would that work, sound arriving before light? I’m easily confused.
I heard the sound and looked up, and the object was already passing overhead, so there was lots of time for the sound to arrive – much like hearing an airplane before it travels past.
But you are correct. The sound could have been something else.
My great wonderment – besides the flare of colours – came from the odd noise … a “whoop, whoop, whoop” rather than the “hissing” sound usually associated with bolides.
I’m thinking the acoustics may have been caused by a repeated breaking of the sound barrier as the object passed through the atmosphere and approached the ground.
Could an object falling from space break the sound barrier more than once? (i.e., if sound travels at different speeds depending on the temperature of the atmosphere, could an object pass through more than one sound barrier?)
This is what Wikipedia says, under the Speed of Sound:
“In the Earth’s atmosphere, the most important factor affecting the speed of sound is the temperature. Since temperature and thus the speed of sound normally decrease with increasing altitude, sound is refracted upward, away from listeners on the ground, creating an acoustic shadow at some distance from the source. The decrease of the sound speed with height is referred to as a negative sound speed gradient. However, in the stratosphere, the speed of sound increases with height due to heating within the ozone layer, producing a positive sound speed gradient.”
I, too, am easily confused.
My husband the physicist was unable to clarify these vexed issues. Natural phenomena are more complex than the theories about them, he says. What I say is, that’s no help whatever. We’ll just have to find another physicist.