Exoplanets, or Extra-solar planets are planets outside our home planet’s solar system. Our little solar system and its planets orbiting the sun are but a fraction of the heavens. There are many more planets than our little system, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune orbiting the Sun, our star, in their elliptical orbits. Astronomers, scientists who study planets and stars, believed for centuries that there were many more planets outside our own solar system but because they are billions of light years away, until astronomers had access to modern equipment, they did not really know that there were other solar systems with their own planets.
Some Canadian astronomers identified a possible exoplanet, in 1988, but independent verification was impossible until 2003. The Hubble telescope greatly assisted astronomers in finding more exoplanets, as did the Spitzer Space telescope, CoRoT and the large Binocular Space Telescope. The pictures taken by the telescope enabled astronomers to find more exoplanets and the American National Aeronautics and Space Administration’s (NASA) Kepler mission are finding many more. Astronomers have now found 2326 candidates, likely discoveries requiring independent verification, and 709 confirmed exoplanets, planets that astronomers have observed several times using two or more instruments, and the scientists are extremely confident in their findings.
Finding planets outside our own solar system is important in answering humanity’s oldest question, “Are we alone”. Scientists theorize that any extra-terrestrial life must have evolved on a similar planet to Earth. Astronomers sometimes call such planets, Goldilocks planets, because their conditions are just right for the evolution of life. Humanity had to be able to observe the stars from space to be able to identify exoplanets. The Hubble and other space telescopes were part of this aim; the other was the Kepler mission. The Kepler spacecraft detects planets as they pass in front of their stars, during their orbits. The Kepler mission is presently looking at one area of the sky between the Cygnus and Lyra constellations. During its mission, the Keplar spacecraft will measure the brightness variations as planets pass their stars of more than 100,000 stars.
Currently, most discovered exoplanets are huge gas giants, like Jupiter, Saturn, Uranus, and Neptune in our own solar system, but there are some possible “Goldilocks” planets, Kepler 22b, discovered in May 2011, is a planet just under two and a half times the size of Earth, orbiting a star similar to our Sun, in 289 days. Kepler 22b is the smallest planet to orbit in the area around a star where temperatures are right for liquid water, an elemental ingredient for life.
The Kepler mission is turning Science fiction into science fact. Thirty years ago, the film Star Wars a science fiction epic portrayed a then imaginary world with two suns in its sky. The Kepler mission, in September 2011 discovered and confirmed a planet orbiting twin suns, two hundred light years from Earth.
The Kepler mission, the telescopes and other NASA missions, such as the Gemini and others, continually further astronomers’ understanding and knowledge of planets beyond our own solar system. In discovering exoplanets, astronomers will understand more about our own planet. They will share their share their discoveries with millions of amateur astronomers and others who wonder whether there is anyone else out there.