Bad Astronomy with Frost

This morning on the BBC's Breakfast with Frost, Sir David Frost interviewed Michael Foale who is currently on the International Space Station. At the beginning of the Interview Sir David commented on the fact that they use Greenwhich Mean Time on board the ISS. He seemed quite suprised at this as he points out that they could use any time as they circle the Earth once every 90 minutes. However if you can pick any time, especially in an international project, the most obvious one is Universal Time (UT) which is more commonly known as GMT.

Michael Foale was born in Lough, England so is one of Britain's few astronauts (the first was Helen Sharman). He talks, in the interview, about having afternoon tea with the Russian cosmonaut, carrying out some scientific experiments and checking his email.

My only problem is with the bad astronomy that Sir David Frost uses when he asks "Does the earth seem smaller, less important, when you're looking at it from so far away, like just another planet?". Thinking that space is a long way away from us on the surface of the Earth is a common misconception as people don't realise that the ISS (and the MIR space station before it) is only a couple of hundred kilometres above the surface of the Earth. In fact at the moment, the ISS is only about 370km above the surface (somewhere over Papua New Guinea as I write this) so it is only slightly further away from the studio in London than Manchester is! The worst thing about the question was that it came right after Michael Foale had told him how far above the surface they were.

Perhaps this misconception was helped by the talk of the 'zero-g' environment which is another misconception. Most people seem to think that there is no gravity when you are in space and that is why astronauts are weightless. In fact the force due to Earth's gravity at the ISS is only 0.9 times the force of gravity at the surface (using a radius of 6378km). The reason that things float around inside the ISS is that both the ISS and the people are in free fall towards the Earth - just like a skydiver. The only difference is that they are moving sideways at the same time (at about 17,000mph) so never actually reach the surface as it is curved.

Despite the bad astronomy, it was good to see Michael Foale interviewed 'live' on BBC One.

Posted in astro blog by Stuart on Sunday 07th Dec 2003 (23:26 UTC) | Permalink
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