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.
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.
I put it @ the end of my report.