Essay About First Method And Extrasolar Planets

How Scientists Decet Extrasolar Planets
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EXTRASOLAR PLANETS
For hundreds of years, scientists knew nothing of the world
outside our little planet earth. Now in the 21st century, science is
gathering more knowledge about the depths of the universe than
could have ever been imagined. Light years away, bodies outside of
our solar system are almost inconceivable, but new technology is
allowing us to not only detect these distant planets but also to take
pictures of them.
In the year 1993, a polish astronomer by the name of
Aleksander Wolszczan claimed to have discovered the first extrasolar
planet. His discovery was later confirmed, orbiting around a pulsar.
Planets around pulsars are believed to come from the remnants of
the supernova that produced the pulsar, or the cores of the gas
giants that survived the supernova. In the 1990s, more and more
planets were being discovered due to a vast improvement in
telescope technology, measuring gravitational influence upon stars
moreso than visually, although it is being done as well. To date more
than 150 extrasolar planets have been accounted for, most of which
being larger in mass than Jupiter.
There are several ways to detect planets that are too faint and
far away to be directly detected with a conventional telescope or
other method. Some of them are more effective than others, but
each has been a stepping stone in the field of detecting extrasolar
planets. The first method, pulsar timing, has been refuted before,
but the method did lead to the discovery of the first planets. Pulsar
timing involves observing abnormalities in the pulses from a pulsar
deep in space. The first “discovery” of a planet using pulsar timing
turned out to be inaccurate, since it failed to take into account the
motion of the Earth. This method involves precise measurements of
the pulsars signal, but because of this the method is more
commonly used to detect pulsar companions than planets. However,
Aleksander Wolszczan used this method to discover the first solar
system outside of our own. This method also helped in the discovery
of the oldest known planet, which happens to also be the only
known planet to orbit two stars.
The oldest method, and consequently the most unreliable one
used in the search for extrasolar planets is astrometry. Astrometry
involves measuring the motion of a star in hopes of finding an
influence by its planets. Unfortunately, changes in the motion are so
small that they can not be detected accurately, nor confirmed by
other method. Since more successful methods have been found and
are easier, most scientists have given up on astrometry, and moved
to more efficient methods such as radial velocity.
Radial velocity measures differences in the speed that a star
moves either away or towards us. It is known as the “Doppler
Method” because the radial velocity can be derived from the
displacement of the parent stars spectral lines because of the
Doppler effect.
This method is the more successful one used by people in search of
planets, but it only works for stars that are relatively close, out to
about 160 light years. The radial velocity method easily finds planets
that are nearby to stars, and can be used to confirm the transit
method.
The transit method is a relatively new method that can detect a
planets shadow when it passes in front of its host star. It only works
for a small percentage of planets when their orbits are perfectly
aligned from the point that we look from, but this method can be
used on stars much further away than the Doppler method. The
transit method can also be used to measure the radius of a planet,
and so scientists can determine the density of these planets by using
this method and another mass-determining method. The picture
below is a rendition of a planets transit across a foreign star.
Not only have