More
specific estimates were given on the lifetime of the solar nebula. A team from
MIT determines that the solar nebula lasted around 3 to 4 million years. From
this estimates it will provide a greater insight on the evolution of the solar
system.
Previous estimates
of the solar nebula’s lifetime were in between 1 and 10 million years, but now it
is more defined. The team was led by Benjamin Weiss, a professor of earth,
atmospheric and planetary sciences at Massachusetts Institute of Technology (or
MIT) and MIT postdoc Huapei Wang and has published their results in the journal
Science this year.
They
carefully studied the magnetic orientations in four angrites, which are old
planetary rocks which are thought to be from asteroids. The properties such as
their composition and paleomagnetic signal, of these angrites were retained due
to a freezing temperature.
These
well-preserved samples fell to earth at different times and different
places—Argentina, Brazil, Antartica, and the Sahara dessert.
They are
considered to be an excellent records of the history of the solar system due to
its high content of Uranium, an element used to determine a rock’s age, i.e.
Uranium-lead dating.
From their
experiment, electrons were introduced making the rock become magnetize. The
rocks’ magnetization was measured from using a precision magnetization in the
MIT Paleomagnetic Laboratory.
The team
found that the samples’ magnetization could
have been produced by an extremely weak magnetic field of no more than 0.6
microteslas, about 4 million years after the beginning of the solar system.
Solar Nebula
The nebular
hypothesis is one of the accepted hypotheses where the solar system originated.
It was believed that the sun was formed at the center of the molecular
clouds that decrease in size due to its own gravity. The remaining cloud of
gas flattened to form shape is like a disc that undergoes accretion thus
forming the planets, moons and asteroids.
However, it seems that this study is not totally new and only new meteorite samples were considered. For scientists have continually studied oldest known minerals on earth. Likewise meteorites like the Canyon Diablo meteorite are found to be 4.6 billion years, which suggest that the Solar System must be at least this old.
For more information, visit MIT news.
