SETI Re: tech: ASTRO: Sterilisation of planets


Robert Owen (rowen@technologist.com)
Fri, 24 Sep 1999 17:23:16 -0400


Larry Klaes wrote:

> >X-Sender: patrickw@molly.cs.monash.edu.au
> >From: <eugene.leitl@lrz.uni-muenchen.de>
> >To: extropians@extropy.com
> >Subject: tech: ASTRO: Sterilisation of planets
> >Date: Thu, 23 Sep 1999 23:43:27 +1000
> >Sender: owner-transhumantech@excelsior.org
> >Reply-To: transhumantech-l@excelsior.org
> >
> >
> >From: patrickw@cs.monash.edu.au (Patrick Wilken)
> >
> >Thursday, September 23, 1999 Published at 10:04 GMT 11:04 UK
> >
> >Sci/Tech
> >
> >Sterilisation of planets
> >
> >By BBC News Online's Science Editor Dr David Whitehouse
> >
> >Could our Sun suddenly experience a so-called "superflare" on its
> >surface that could wipe out all life on Earth?
> >
> >That is the possibility, albeit a remote one, that emerges from
> >observations of nearby stars that are similar to our own Sun.
> >
> >Bradley Schaefer of Yale University, along with Jeremy King of the
> >Hubble Space Telescope Science Institute and Constantine Deliyannis of
> >Indiana University, have documented nine cases of other stars, seemingly
> >well-behaved like our Sun, that have suddenly erupted superflares.
> >
> >Two events, seen on the stars K Ceti and pi-Uma, are especially
> >significant because these two stars have been called solar analogues,
> >that is they are almost exactly identical to our Sun.
> >
> >Yet they have been observed to emit superflares, energetic explosions on
> >their surfaces that spray radiation and charged particles out into
> >space. The effect on any planets orbiting them would be catastrophic.
> >
> >Sterilised planets
> >
> >If a superflare occurred on our Sun, then the Earth would be subject to
> >rapid heating, aurorae would ripple in every sky, the ionosphere would
> >break up and the ozone layer would be destroyed.
> >
> >This would allow lethal radiation and charged particles from the Sun to
> >reach the ground, destroying all life-forms except those protected in
> >the deep oceans.
> >
> >However, all geolical data, suggests our Sun has never experienced a
> >superflare. Although researchers cannot rule out the possibility
> >entirely.
> >
> >So what is going on? How can stars like our Sun exhibit such superflares
> >but our own Sun seem well-behaved?
> >
> >Squeezed and amplified
> >
> >The answer may be given in an accompanying paper in a forthcoming issue
> >of the Astrophysical Journal. Bradley Shaefer and Eric Rubenstein of
> >Yale suggest that the superflares are caused by a large planet, the size
> >of Jupiter or larger, orbiting these Sun-like stars.
> >
> >What they believe happens is that the planet's magnetic field gets
> >tangled up with the star's magnetic field and they both become squeezed
> >and amplified, like pulling a knot tighter and tighter.
> >
> >Something eventually gives and the pent-up magnetic energy is
> >explosively released in a gigantic superflare. This is highly unlikely
> >to happen in our Solar System, say these astronomers, because there is
> >no large planet close enough to our Sun.
> >
> >But their analysis has implications for the possibility of life in
> >space.
> >
> >In recent years, many Jupiter-class planets have been discovered closely
> >orbiting some of the nearest stars to our Solar System, raising the
> >possibility that some of these newly-discovered planetary systems may
> >harbour life.
> >
> >If superflares are common in these systems then they may sterilise the
> >surfaces of accompanying planets, making life harder to develop.
> >Alternatively, it may mean that life in these systems would evolve in
> >protected regions such as deep caves or beneath the surface of an ocean.
> >
> >
> >
> >
> >
> >
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> >
> ==
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=======================
Robert M. Owen
Director
The Orion Institute
57 W. Morgan Street
Brevard, NC 28712-3659 USA
=======================



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