[Homestead] Evolution---Supernova, not God-duh
tvoivozd at infionline.net
Sat Feb 5 11:35:29 EST 2005
Meteorite gives clues to Sun birth
*New meteorite data lends support to a controversial theory that the
violent explosion of a star was involved in the creation of the Sun and
its planets. *
The primitive space rock contains signs that a short-lived, radioactive
form of the element chlorine may have been present in the early Solar
A US-Chinese team claims the most likely source of this isotope was a
supernova - or exploding star.
The findings appear in Proceedings of the National Academy of Sciences.
For years, astronomers have believed that the Solar System formed
inconspicuously, from a slowly condensing cloud of dust and gas; but
this traditional view is now being challenged.
The new theory proposes that our star and its planetary system were born
in a dense interstellar cloud, or nebula, filled with short-lived,
massive stars that exploded with immense energy and an intense release
Supernovae occur at the end of a star's lifetime, when its nuclear fuel
is exhausted and it is no longer supported by the release of nuclear
* Ancient relic *
Researchers from Arizona State University and the Chinese Academy of
Sciences studied a primitive meteorite from China known as the Ningqiang
This space relic formed shortly after the creation of the Solar System.
The team found a rare isotope of sulphur - sulphur-36 - in the
meteorite, which can be produced through the radioactive decay of a form
of chlorine called chlorine-36.
Because the sulphur isotope was found in an ancient mineral "inclusion"
in the meteorite called sodalite, the researchers believe chlorine-36
could have been present in the early Solar System.
Chlorine-36 can form in two ways: by a supernova explosion, or by a
nebular cloud being bombarded by radiation near the forming Sun.
The researchers consider the latter explanation is unlikely since
sodalite must have formed some distance away from our star.
"There is no ancient live chlorine-36 in the Solar System now," said
co-author Laurie Leshin, director of Arizona State's Center for
Meteorite Studies. But this is direct evidence that it was here in the
early Solar System."
Dr Leshin and others had previously found evidence for another
radioactive isotope (or radionuclide) in the early Solar System called
iron-60, which could also have been formed in a supernova.
"It's producing a really strong argument that these radionuclides were
produced in a supernova that exploded near the forming Solar System and
seeded [it] with these isotopes," Dr Leshin added.
If the controversial theory is supported by future work, it may have
implications for understanding properties such as the size and shape of
the Solar System, the physical make-up of the Earth and the chemistry
that led to life.
Story from BBC NEWS:
Published: 2005/01/25 13:13:04 GMT
More information about the Homestead