All patriotism, no politics

[beetiger]

A sound I like: the deep boom of fireworks loud enough that you can feel them as well as see and hear them.

A sound I don't like: Loud cell phone conversations during a public display. (*ringring* "Yeah, we're over here... no, no, past the flagpole, on the other side...you know where there are a bunch of trees behind the stage...)

I heard an interview on NPR a few days ago with the composer of a new comic opera called Fireworks, the plot of which concerns an alien trying to find out about the source of strange colored fires emanating from certain parts of Earth at the same time each year. It made me wonder. Could one actually see a typical city's fireworks display from space? If you know more about this than I do, please let me know.

Comments

[cowboy-r.livejournal.com]

No, you couldn't.

Minimum optical resolution for an earth-bound object, because of atmospheric refraction, is 30cm. Though some fireworks fill an area that is fairly large, the individual bits of phosphor are quite small... well smaller than 30cm.

[postrodent.livejournal.com]

I didn't know about the atmospheric refraction, but it makes sense.
I suspect -- not quite sure -- that with decent optics and a big chunk of image processing hardware, the reflection of the explosions off the ground would be detectable. But then, that's not quite the same thing. :)

[(Anonymous)]

I disagree. We're not talking about resolving small pieces of inert matter here... we're talking about detecting tens of pounds of magnesium and other goodies burning at sunlike temperatures (albeit briefly). Anybody advanced enough to be up there in the first place looking down should be able to see the brief flashes in the optical spectrum... but in the infrared, they'll shine like crazy.

Fun fact: I read somewhere that Earth puts out enough radio signals to look like a star of some sort to any extraterrestrial radio astronomers pointing their antennae our way.

Loxley

[cowboy-r.livejournal.com]

Keep in mind that it doesn't matter how big your optics are... if you're looking down, optically, atmospheric difusion and oxygen aborbsion mean that you can't resolve smaller than 30cm. Period.

You might be able to see a flash of light, but remember that most places they have fireworks, there's a lot of ground clutter... you'd probably lose the light there.

Now, if you had a ship at sea, out in the middle of the ocean, sending up fireworks, then you'd catch flashes of light... but you still wouldn't be able to see the pattern of the fireworks.

What you'd see....

[fenton.livejournal.com]

Is a lot of closely-grouped 30cm 'hits', all of brief but notable intensity. Each magnesium flare would fill one, and the average firework spreads to quite a bit farther than a third of a meter... with dozens or hundreds of spots.

Now, I'll grant, 'fountains' probably wouldn't show up so well. But you can see the Luxor from space, and that's only about 10m across, if that, at the apeture - much smaller than many fireworks bursts.