The Stars are Exploding?

April 14, 2012 4:58 AM

My housemate and I just saw a bright pinpoint flash (approx intensity and size of Rigel) in the sky, lasting about an eighth of a second, what's it likely to have been?

Seen from Perth, Western Australia at 7.24pm or so Western Australian standard time, at az/alt +296 degrees / +41 degrees (just up and right from Orion's belt at the time).

It had no visible sideways movement, and was just a very short sharp flash.

Short lived space junk coming down? Meteorite headed straight for me? The shortest supernova ever? What could it have been?

posted by Ahab to science & nature (10 answers total)

I would guess meteor. (It's not a meteorite unless it makes it to the ground.)
posted by fullerenedream at 5:09 AM on April 14, 2012 [1 favorite]

Thanks fullerenedream, I was wondering about the terminology as well. If it was a meteor, does the pinpoint appearance imply a trajectory straight towards us? Or just that its period of burn was super short, so it could have been going any which way?
posted by Ahab at 5:15 AM on April 14, 2012

Iridium flare? http://www.heavens-above.com/iridiumhelp.asp
posted by sarahdal at 5:34 AM on April 14, 2012 [1 favorite]

Probably not a gamma-ray burst, which is the most likely type of exploding star you're going to be able to see with the naked eye like this. The brightness could work out, but the timescale (it would be longer than 1/8th of a second) and sharpness (it would fade much slower) of the light doesn't match with what astronomers see.
posted by Tooty McTootsalot at 5:43 AM on April 14, 2012 [1 favorite]

I'd guess meteor, with a trajectory straight toward you, as you suggest.

The only other plausible thing I can imagine would be an odd glint from an artificial satellite. (An Iridium flare would have lasted much longer—many seconds.)
posted by BrashTech at 6:11 AM on April 14, 2012 [1 favorite]

It was a reflection from an artificial satellite.

If your eyes were dark-adapted, and you think it was about 0.1 seconds, it was probably a lot less. Human retinas have terrifying lag.

The sun had just set. That's your light source. It was a very short, very bright flash high in the sky. William Occam and orbital geometry point to:
- Solar panels on a low-periapsis polar-orbit satellite. Flash, gone. It's flying from South to North (or vice versa) , panels are facing the set sun. As it hurtles over a longitude slightly in front of you, you would get a brief flash.
- An iridium flare (no - they would appear to last a second or two)
- The ISS - You saw people in space!!!!!!! (Unlikely - it's easy to track with the naked eye)
- An earth-sensing satellite happened to be dumping unwanted sunshine in your general direction. (Possible - there are some huge light buckets up there)

Unlikely:
- A local astronomical catastrophe: Supernovae generate gossip.
- A remote astronomical apocalypse - GRBs generate bugger-all in the visible spectrum
- Meteors. They're messy. The don't fly straight, and the air keeps glowing for a lot more than 0.1s.

Also, I envy your dark skies.
posted by Combat Wombat at 6:42 AM on April 14, 2012 [12 favorites]

I would agree with Combat Wombat -- sunflare off a satellite. I came in to say that, but he beat me to it.
posted by Guy_Inamonkeysuit at 7:07 AM on April 14, 2012 [1 favorite]

thirding the sunflare. I've seen these before, too, and have always been surprised by their brilliance. If you enter your location at the Heavens Above website, it might be able tell you which satellite it was
posted by jquinby at 8:39 AM on April 14, 2012 [1 favorite]

Could have been a high flying plane catching the sun on one of its windows. I would think that a satellite's flare would have lasted longer.

I saw a meteor once, and it was one of the fastest things I've ever seen. Across the entire sky in a matter of a second. But if it had been pointed right at me, it would have lasted much longer because I'd have seen its whole "lifespan". I'm also not sure a meteor can come right at any point on the earth, because don't they skip across the atmosphere?
posted by gjc at 8:48 AM on April 14, 2012

Alrighty, thank you all.

No need to envy what we usually have Combat Wombat - most of the year we have dust, smoke and/or salt spray off the ocean. And the same light pollution as every other city in the western world. We've actually been a bit surprised that we could see Orion's sword/dong the past couple of nights.

Thank you to everyone who said a satellite flare or flash. I didn't realize they could flash or appear as short streaks - I've only seen little blobs tracking across the sky before.

(That said, I would have loved for it to be a Gamma Ray Burst or meteor barreling towards our back sandpit. Just for the drama of it).

Thanks especially to you jquinby. Checking out Heavens Above, it seems like there's a more than fair chance my watch/time was a few minutes wrong (which puts the azimuth and altitude figures given above a bit off as well), that HST is what we saw and that we caught a flash off it to the Northwest at about 7.20 or 7.21 pm as it headed west to north east. That we didn't see the rest of the pass could easily be due to light pollution.

(Ie the location seems to be almost spot on. Thanks!)
posted by Ahab at 10:44 AM on April 14, 2012