The Solar System Planets Orbiting Other Stars - Essay Example

A Journey Beyond The Solar System 'There things that are known; there are things that are unknown'- Anonymous Issues on the origin of the solar system have long been debated, and perhaps will stay with us as long as we live. In search for a valid explanation for such phenomenon, scientists have formulated theories to support their speculations. Among these theories are as follows: 1) the nebular theory, which ascertains that hydrogen and other gases swirled around and condensed into our sun and its planets (or our solar system); 2) the fission theory, which asserts that the sun broke out and planets and moons shot out at high speeds and went to their respective places, then stopped, and started orbiting the sun, as the moons began orbiting the planets; 3) the capture theory, which claims that planets and moons were flying around and some were captured by our sun and began circling around it; 4) the accretion theory, which states that a pile of space dust and rock chunks pushed together into our planet, and another pile pushed itself into our moon. Then the moon got close enough and began encircling the earth; 6) the gas cloud theory, which presupposes that gas clouds were captured by our sun but instead of being drawn into it, they began whirling and pushing themselves into planets and moons; and the 8) the expanding universe or the big-bang theory, which depends on two major assumptions, namely: the universality of physical laws, and the cosmological principles. 1 However the origin of our solar system is explained questions still remain unanswered and are the focus of research by scientists around the globe. Are there other planets outside of our solar system If there are, are they able to sustain life What techniques have been employed to study these planets and other heavenly bodies when they are light years away from us These are just a few of the crucial questions that scientists try to answer since Galileo Galile' invented the telescope in the early 1600s. How does one differentiate a planet from an asteroid or from any other celestial body In an article by Samantha Harvey posted at the NASA e-magazine, planets have been defined as "a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape and (c) has cleared the neighborhood around its orbit." At the same time, new moons are also being discovered, both around existing planets and within these mysterious new worlds. Once the existence of a moon is confirmed and its orbit determined, the moon is given a final name by the International Astronomical Union (IAU), the organization that assumed this task since 1919.2 Though space has always been there, it was only in 1957 that a spacecraft was actually sent into space to measure what it is like. Until 1991, only the planets in our solar system are the only known planets. Nevertheless, astronomers did not believe that our Sun's environment was the only planet producer in the universe. Yet they had no evidence of planets outside our solar system. Not until 1991 that radio astronomers detected the first extrasolar planets orbiting a dying pulsar star. This extrasolar planet is a remnant of a supernova explosion in the constellation Virgo hence is not able to sustain life because of the deadly radiation it emits. Then, in 1995, Swiss astronomers found another extra-solar planetary candidate. This star, found in the constellation of Pegasus, is much more like our Sun with respect to its temperature, size, rotation speed and emitted radiation. Although this is also considered not a good candidate to sustain life, it was the first ever evidence of an extrasolar planet around a Sun-like star.3 Other concern in studying extrasolar worlds is whether life may exist there. Variables like size, distance and temperature will serve as indicators that a particular extrasolar planet may be considered a life-bearing planet. Basic techniques being employed to accomplish such mission, according to J. Schneider,4 are as follows: 1) astronometric detection (astrometry looks at how a planet's gravity tugs on its star. But instead of measuring the Doppler shift of the starlight, astrometry measures the star's position relative to distant background stars. As a planet completes an orbit around a star, the star appears to move back and forth in the sky); 2) direct imaging; 3) radial velocity (this technique looks at how stars are affected by the gravity of an orbiting planet. Over the course of an orbit, the planet will pull at the star from different sides); 4) ground based photometry (transit photometry measures the apparent change in a star's brightness when a planet passes in front of it. The planet blocks some of the starlight reaching us, making the star to appear slightly dimmer. This loss of light magnitude depends on the size of the planet. In order for transit photometry to work, we must view the planetary system right at the orbital plane. If we're watching from either too far above or too far below the planet's orbit, the planet won't pass in front of our view and we won't witness any apparent dimming of the star); 5) gravitational microlensing, another type of extrasolar planet detection. This technique uses foreground stars as a sort of magnifying glass to help detect distant stars and their planets. When a star that is closer to us passes in front of a more distant star, its gravity bends and amplifies the light from the distant star. This results in an apparent increase of light from the distant star. Any planets that orbit the more distant star will perturb the gravitational lens, creating a brief variation in the amplified starlight. The duration of this change depends on the mass of the planet and the distance between the planet and its star, as well as the star velocity perpendicular to our lline of sight; and 6) occultation.4 Of the various techniques used in determining the existence of a planetary body, the measurement of the radial velocity of a star, using doppler shift method, has been used to a greater degree than any of the aforementioned. At the telescope, the change in the wavelength (color) of light coming from a star is measured over the course of days, months, and years. This changing wavelength is the Doppler shift of the light, resulting from the star orbiting a common center of mass with a companion planet of the starlight to tell when the star is moving slightly away from us or toward us. Methodology and instruments used being considered in this continuous search may include the following possibilities: 1) extending the array of optical telescopes (i.e. add additional telescopes and spread them further apart for interferometric studies), which may be used for both ground-based and space-based operations; 2) using an interferometer that has two pairs of mirrors arranged in a straight line designed by Angel and Woolf working out of the University of Arizona; 3) using a telescope with a large aperture in high-precision astrometric studies, like the Palomar 5-meter telescope on an open cluster (NGC 2420); and 4) using the Hubble Space Telescope is part of NASA's great observatories and has been named after American Astronomer Edwin Hubble. It is the only telescope ever designed to be serviced in space by astronauts.5 The rate of planet discovery has sped up recently, and many more planets will likely be discovered in the weeks and years to come. New search techniques such as the one recently conducted by two participating astronomers from the U.S. are Rachel Street and Tim Lister. "The new international collaboration is called "SuperWASP," for Wide Area Search for Planets. The SuperWASP technique involves two sets of cameras to watch for events known as transits, where a planet passes directly in front of a star and blocks out some of the star's light. From the Earth the star temporarily appears a little fainter. (In the last six months the SuperWASP team has used two batteries of cameras, one in Spain's Canary Islands and one in South Africa, to discover the 10 new extra solar planets. ) The SuperWASP cameras work as robots, surveying a large area of the sky at once. Each night astronomers receive data from millions of stars. They can then check for transits and planets. The transit technique also allows scientists to infer the size and mass of each planet. A total of 46 planets have been found to transit their stars. Since they started operation in 2004, the SuperWASP cameras have found 15 of these. SuperWASP is the most successful transit survey in the world.6 The findings add to a growing list of more than 270 so-called extrasolar planets. Ane Greaves of the University of St Andrews in Scotland and colleagues, in another article, said that they found a baby planet while using radio astronomy to examine a disk of gas and rocky particles around the star HL Tau. This star is also thought to be young - 100,000 years old compared to our 4.6 billion-year-old Sun. 7 ]A number of these new worlds are very exotic. For example, a year, or one orbit, on WASP-12b, is just a bit over one day. This planet is so close to its star that its daytime temperature could reach a searing 2300 degrees Celsius. Programs have been developed for future space programs. Among these are the following: 1) The Darwin project. A ten-year program whose main purpose is to accumulate evidence that would indicate primitive life on an extrasolar planet. At present this project is being considered. However, it will not be realized until sometime in the twenty-first century.; and 2) The High Resolution Microwave Survey (HRMS), which was initiated by the National Aeronautics and Space Administration (NASA) in October 1992.8 These are just a few of the types of instrumentations, methodologies, and programs or missions that are either underway or may be underway shortly in the future. This will open up new ventures, perhaps lead to the discovery of other earth-like planets in other solar system. Great advances in technology as well as in human understanding on the sciences, including its acceptance of the notion of planets beyond our solar system, have taken place and will continue to take place. With these advances, man became more aware of the changes in seasons temperature, causes and consequent effects of such, and are given insights on the future. Much needs to be done but with the persistent effort and inspiration, things that still remains unknown, may, in time, be made known. References: 1"Creationism vs. evolution," Bible Study Manuals. Accessed on 04 April 2008 from 2 Samanth Harvey (updated 10 March 2008), "Moons and Planets of the Solar System," Solar System Exploration. National Aeronautics and Space Administration. Accessed on 04 April 2008 from < http://solarsystem.nasa.gov/faq/index.cfmCategory=Beyond#q1> 3 "Beyond Our Solar System" (updated 10 March 2008). National Aeronautics and Space Administration. Accessed on 04 April 2008 from 4 Schneider, Jean and Laurance R. Doyle. "Ground-Based detection of terrestrial extrasolar planets by photometry: the case for CM Draconis." Earth, Moon and Planets 71(1-2):153-173, 1995. Pg 154-155) in Bell, George H.(May 1997). Section 4: Future Considerations. The Search for Extrasolar Planets.: A Brief History of the Search, Findings, and the Future Implications. Accessed on 03 April 2008 from 5 Bell, George H (1997), "Section 4: Future Considerations," The Search for Extrasolar Planets.: A Brief History of the Search, Findings, and the Future Implications. Last revised April 5, 2001. Accessed on 03 April 2008 from 6 University of California - Santa Barbara (1 April 2008). "10 New Planets Discovered Outside Our Solar System" Spaceflight Now. Accessed on 3 April 2008 from 7 "SuperWASP robots spot new planets near solar ," 03 April 2008 The Daily Telegraph Accessed on 03 April 2008 from 8 Bell, George H (1997), "Section 4: Future Considerations," The Search for Extrasolar Planets.: "A Brief History of the Search, Findings, and the Future Implications. Last revised April 5, 2001. Accessed on 03 April 2008 from Read More