Extra Solar Planets
Earths Beyond Earth: The Search for Other Worlds In early 1990, the
first
extrasolar planet was detected, surprising everyone by its strangeness.
More
planets have now been discovered outside our solar system than in it.
These
planets present many great mysteries to the astronomical world.
Extrasolar
planets are planets that exist outside our solar system; they are
orbiting a
star other than our Sun. So far, eighteen have been found, all of
them defying
well-established theories about planets and how they operate
(Winters, 46). As
Stephen Maran said, "The new discoveries remind us that
ignorance is not just
bliss, it is also a lack of imagination. The newfound
planets show us not only
that a solar system is not a rare commodity, but
that ours may be plain
vanilla." (73) Finding extrasolar planets is both
difficult and complicated.
The average star, for instance, is one hundred
million times brighter than any
planet orbiting it (De Grasse Tyson, 87).
"Picking out a planet against the
glare of a star is like trying to spot a
100-watt light bulb next to a
100-billion-watt searchlight," says Michael
Lemonick (54). Also, earth-size
planets are too small to have any significant
effect on their star, so they are
almost impossible to detect (De Grasse
Tyson, 88). There is, however , a way to
find extrasolar planets without
using direct sight: the Doppler Effect. When a
star has a planet in its
gravitational field, it makes the star appear as if it
is "wobbling" by
stretching the light waves and slightly changing the
star’s color (Maran,
75). A second method of finding a planet is to search
through a disk of
debris surrounding a star, such as Vega. Chances are that a
planet will exist
there (De Grasse Tyson, 87). Out of the detected planets, only
a few have
actually been "seen," being found by accident by either the
Hubble Space
Telescope or the Infrared Space Observatory (Lemonick, 53). In
short, planets
can only be found in a limited number of ways, and under very
specific
conditions. In general, most extrasolar planets are alike in that they
are
all very odd compared to what humans are accustomed. For example, most
of
them orbit around sun-like stars no further than 100 light years from the
Sun.
Also, they are gas giants, almost all of them being larger than
Jupiter, and
have temperatures up to 1800 degrees Fahrenheit (Maran, 74). On
the other hand,
these planets all have very different orbital patterns; some
of them have orbits
that are extremely close to the star that they orbit,
while others have odd
elliptical orbits (Naeye, 45). Either way, almost all
of these planets differ
significantly from the planets in our solar system.
Very little specific
information is known about most extrasolar planets, but
a few have been
researched extensively and found to have interesting
characteristics. For
instance, 51 Pegasi (all planets being named after their
host stars) was the
first extrasolar planet found, being discovered by Swiss
astronomers Mayar and
Queloz. This planet is half the mass of Jupiter
(seventy-five times more massive
than Mercury), and has the least mass of any
of the new planets (Maran, 74).
Also, it is 5 million miles from its
star, but still manages one orbit in only a
little more than four days
(Flamsteed, 80). 70 Virginis, another odd planet, is
six times the mass of
Jupiter, has extreme weather conditions, and orbits
elliptically (Lemonick,
53). Likewise, 47 Ursae Majoris has fierce hurricanes,
and is also larger
than Jupiter. The planet with the most elliptical orbit known
to man is 16
Cygni B; it travels from 56 million to 250 million miles of its
sun. In
contrast, 55 Cancri B is an example of a tight-orbiting planet, circling
the
sun closer than mercury is to our sun (Maran, 74). In summary, what we
know
about these planets shows that they are very diverse and strange.
Though
strangeness may promote curiosity, a major goal in searching for
extrasolar
planets is to discover one that resembles ours or possibly harbors
life. Though
strangeness may bring curiosity, the main motive behind finding
extrasolar
planets is to discover one that resembles ours or possibly harbors
life (De
Grasse Tyson, 86). "The Holy Grail," says Alan Boss, an
Astronomer at
Carnegie Institute, "is to find an extrasolar planet that
is capable of
supporting life" (Lemonick, 56). However, out of the planets
discovered so
far, none are thought to be compatible with life for various
reasons. First,
planets that orbit close to their sun are too hot for life.
Second, Pulsars,
stars that are most likely to host Earth-like planets, give
off too much deadly
radiation. Third, elliptical planets are gaseous and
unstable, being up to ten
times more massive than Jupiter. One hope for the
possibility of life is if the
large gas planets have moons like that of
Jupiter. Scientists believe that these
moons may have conditions which would
be conducive to support life (Maran, 74).
Though the chances of there
being life on one of these planets is extremely
slim, we may someday detect
one that is suitable. Although there has been a
great deal of speculation and
optimism about these newly discovered planets,
some irrational scientists
still refuse to believe in their existence. In the
1600s, Giordano Bruno
was burned at the stake for saying that there was other
worlds outside our
solar system (De Grasse Tyson, 86). Today’s punishment is
not nearly as
harsh, but often planetary scientists are ridiculed for their
discoveries,
because in the opinion of some scientists there is "a lack of
substantial
evidence" (Maran, 75). How can we be so silly as to assume that we
are the
only planetary island in a vast ocean of stars? Also, many theories are
being
eliminated by extrasolar planets, causing stubborn astronomers to
become
uneasy. One instance is the theory of a star’s formation; when a star
is being
made, strong winds blow away all debris orbiting near it. The
presence of large
planets with tight orbits contradict this theory. There are
also some doubts
about the Doppler effect, in that it may simply be the
result of fluctuations of
the star’s surface, and not planets at all (De
Grasse Tyson, 88). What
constitutes most doubt, however, is the existence of
Brown Dwarf Stars. Brown
Dwarfs are stars in elliptical orbits around
other stars that do not have enough
mass for nuclear reactions in their cores
(Winters, 47). They "bridge the
gap in mass between stars and planets," as
Robert Naeye says (45), and
almost always have elliptical orbits (Winters,
46). In fact, brown dwarfs would
explain many of these odd "planets" that
have been located. Thus,
extrasolar planets are not only unstable in
structure, but in existence as well,
being doubted and contradicted just as
much as supported and proven. The
extrasolar planets that have been found
raise more questions, rather than giving
answers. They have shot down
theories, confused speculators, and left us with
puzzle pieces that simply do
not fit together, according to current theories. At
the same time, they have
opened up doors to new possibilities, expanded our
knowledge, and given us
hope for life elsewhere. These new discoveries help us
to realize how
ignorant we are to the processes of the universe.
Bibliography
De
Grasse Tyson, Neil. "The Search for Planets." Natural History Oct.
1997:
86-9. Flamsteed, Sam. "Impossible Planets." Discover Sep. 1997:
78-83.
Lemonick, Michael. "Searching for Other Worlds." Time Feb. 1997:
52-7. Maran,
Stephen. "Planets Around Other Stars are Hot Hot Hot."
Smithsonian Sep.
1997: 72-6. Naeye, Robert. "The Strange New Planetary
Zoo." Astronomy Apr.
1997: 42-9. Winters, Jeffrey. "Planets by the
Dozen." Discover Jan.
1997:
46.