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The Question

(Submitted October 16, 2000)

I was in South Carolina last night Oct 15th on a lake looking at the night sky. I was looking straight up and slightly to the north and I saw a medium sized star get really bright and then it disappeared as if it exploded. This event occurred around 7:00pm. Was this a supernova???? If not what was it????? Please let me know.

The Answer

What you saw was probably an "Iridium Flare." This is caused by the satellites of the Iridium mobile phone system, when they happen to line up just right. The Iridium consortium is now bankrupt (apparently nobody wanted to carry around a 10 kg mobile phone when 90% of where most business travelers go is served by cell phones), and the satellites will be deorbited unless a buyer is found. In the meantime, there are web-based programs to predict when you might see such a flare in the future (unfortunately, we don't know of one to tell you if what you saw in the past was a flare).

Anything lasting just a few seconds is much too short a time to be a supernova, or any other such astronomical event. It could have been a meteor that happened to be heading directly toward you so that you didn't see any streak, but your description sounds like an Iridium flare.

One prediction service is at

You can read about the Iridium satellites and why they flare, as well as look at some photos at

Hope that helps.

-Kevin Boyce and Martin Still,
for "Ask an Astrophysicist"

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