Part of the show Forensics, DNA Fingerprinting and Human Origins
Matthew in New York asked:
Matthew has emailed us with an addition to an answer last week.
On the 27th edition of the Naked Scientists, John from Clacton said he saw a bright flash in the sky, and wondered if it was a gamma ray burst. Our guest on the show, Mike Hobson, said it definitely couldn't be a gamma ray burst because our eyes aren't sensitive to gamma rays. However, without having seen it, he wasn't sure what it could have been. Matthew says that there are a network of satellites used for a satellite telephone system called Iridium. They're in a low Earth orbit and have large solar panels that can catch sun light and reflect it down to the Earth. They appear as a bright flash that lasts several seconds. This is a potential explanation for what John saw that night.