Re: Sun will vaporise the Earth unless we can change our orbit (Forwarded)
- From: "Androcles" <Headmaster@xxxxxxxxxxxxxxxx>
- Date: Tue, 26 Feb 2008 19:18:53 GMT
"Andrew Yee" <ayee@xxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:Pine.LNX.4.30.0802261218360.12923-100000@xxxxxxxxxxxxxxxxxxxxxxxxx
| Press and Communications Office
| University of Sussex
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| For more information, contact:
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| Jacqui Bealing or Maggie Clune
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| 21 February 2008
|
| The Sun will vaporise the Earth unless we can change our orbit
|
| New calculations by University of Sussex astronomers predict that the
| Earth will be swallowed up by the Sun in about 7.6 billion years unless
| the Earth's orbit can be altered.
|
| Dr Robert Smith, Emeritus Reader in Astronomy, said his team previously
| calculated that the Earth would escape ultimate destruction, although be
| battered and burnt to a cinder. But this did not take into account the
| effect of the drag caused by the outer atmosphere of the dying Sun.
|
| He says: "We showed previously that, as the Sun expanded, it would lose
| mass in the form of a strong wind, much more powerful than the current
| solar wind. This would reduce the gravitational pull of the Sun on the
| Earth, allowing the Earth's orbit to move outwards, ahead of the expanding
| Sun.
|
| "If that were the only effect the Earth would indeed escape final
| destruction. However, the tenuous outer atmosphere of the Sun extends a
| long way beyond its visible surface, and it turns out the Earth would
| actually be orbiting within these very low density outer layers. The drag
| caused by this low-density gas is enough to cause the Earth to drift
| inwards, and finally to be captured and vaporised by the Sun."
|
| The new paper was written in collaboration with Dr Klaus-Peter Schroeder,
| previously at Sussex, who is now in the Astronomy Department of the
| University of Guanajuato in Mexico.
|
| Life on Earth will have disappeared long before 7.6 billion years,
| however. Scientists have shown that the Sun's slow expansion will cause
| the temperature at the surface of the Earth to rise. Oceans will
| evaporate, and the atmosphere will become laden with water vapour, which
| (like carbon dioxide) is a very effective greenhouse gas. Eventually, the
| oceans will boil dry and the water vapour will escape into space. In a
| billion years from now the Earth will be a very hot, dry and uninhabitable
| ball.
|
| Can anything be done to prevent this fate? Professor Smith points to a
| remarkable scheme proposed by a team at Santa Cruz University, who suggest
| harnessing the gravitational effects of a close passage by a large
| asteroid to "nudge" the Earth's orbit gradually outwards away from the
| encroaching Sun. A suitable passage every 6000 years or so would be enough
| to keep the Earth out of trouble and allow life to survive for at least 5
| billion years, and possibly even to survive the Sun's red giant phase.
|
| "This sounds like science fiction," says Professor Smith. "But it seems
| that the energy requirements are just about possible and the technology
| could be developed over the next few centuries." However, it is a
| high-risk strategy -- a slight miscalculation, and the asteroid could
| actually hit the Earth, with catastrophic consequences. "A safer solution
| may be to build a fleet of interplanetary 'life rafts' that could
| manoeuvre themselves always out of reach of the Sun, but close enough to
| use its energy," he adds.
|
| Notes for editors
|
| * 'Distant Future of the Sun and Earth Revisted', by Dr Klaus-Peter
| Schroeder and Professor Robert Smith, Astrophysics
| http://uk.arxiv.org/abs/0801.4031
|
| * Earlier press release, 2002
| http://www.sussex.ac.uk/press_office/media/media191.shtml
|
| * 'Astronomical engineering: a strategy for modifying planetary orbits'. D
| G Korycansky of the University of California at Santa Cruz, with
| colleagues Greg Laughlin and Fred Adams: (Astrophysics & Space Science,
| 275, 349-366, 2001)
Hmm... very serious. Of course being British, Professor Smith and his team
mean a British 7.6 billion (7,600,000,000,000) and not a paltry American
7.6 billion. But nevertheless, still very worrying. <yawn>
.
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