Summary
Melvyn Bragg and guests discuss the Kuiper Belt, a vast region of icy objects at the fringes of our Solar System, beyond Neptune, in which we find the dwarf planet Pluto and countless objects left over from the origins of the solar system, some of which we observe as comets. It extends from where Neptune is, which is 30 times further out than the Earth is from the Sun, to about 500 times the Earth-Sun distance. It covers an immense region of space and it is the part of the Solar System that we know the least about, because it is so remote from us and has been barely detectable by Earth-based telescopes until recent decades. Its existence was predicted before it was known, and study of the Kuiper Belt, and how objects move within it, has led to a theory that there may be a 9th planet far beyond Neptune.
With
Carolin Crawford Public Astronomer at the Institute of Astronomy and Fellow of Emmanuel College, University of Cambridge
Monica Grady Professor of Planetary and Space Sciences at the Open University
And
Stephen Lowry Reader in Planetary and Space Sciences, University of Kent
Producer: Simon Tillotson.
Transcript
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| 0:00.0 | This is the BBC. |
| 0:02.0 | Thanks for downloading this episode of In Our Time. |
| 0:05.0 | There's a reading list to go with it on our website and you can get news about our programs |
| 0:09.0 | if you follow us on Twitter at BBC In Our Time. |
| 0:12.0 | I hope you enjoyed the programs. |
| 0:14.0 | Hello, about 4.5 billion years ago, a vast cloud of dust and gas collapsed and gave rise to our solar system. |
| 0:21.0 | Much of the gas became the sun, as much of the dust became the planets. |
| 0:26.0 | At the free use of the solar system, some dust combined with ice to make smaller objects and there in what's called a kuiper belt, they've largely remained unchanged. |
| 0:35.0 | Occasionally, they come much closer as comets. |
| 0:38.0 | There are larger objects among them too, like Pluto, which we once thought to be a planet. |
| 0:43.0 | These distant objects orbit the sun in patterns which suggest not only where our known planets used to be, millions of years before, |
| 0:50.0 | but at the possible existence of a nine-massive planet far beyond Neptune. |
| 0:55.0 | We'd need to discuss the kuiper belt R, Carolyn Crawford, public astronomer at the Institute of Astronomy and fellow Emmanuel College University of Cambridge. |
| 1:04.0 | Monica Grady, professor of planetary and space sciences at the Open University, and Stephen Lary, reader in planetary and space sciences at the University of Kent. |
| 1:14.0 | Monica Grady, where is the kuiper belt? |
| 1:17.0 | It's a long, long way away. |
| 1:20.0 | If we think of Neptune as being 30 times as far away as from the sun as the earth is, the kuiper belt is beyond that, up to maybe 50,000 times as far away, to the outermost fringes of the solar system. |
| 1:38.0 | If one astronomical unit is 150 million kilometers, you're talking about 150 million times 50,000 kilometers. |
| 1:46.0 | Well, that's a starter, isn't it? |
| 1:48.0 | Yes, it's a long way. |
| 1:49.0 | It's just got our minds round out and known settled back, I think, really. |
| 1:51.0 | Why do you call it a belt? |
... |
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