When I was a little girl I loved to play “space” and make spaceships, don space costumes made from paper bags, and pretend-play about our nine planets and the universe. As an adult, we lost one of our nine planets when Pluto suffered an identity crisis. The International Astronomical Union (IAU) determined Pluto to not be a planet anymore. Criteria established by the IAU in order to be classified as a planet are an orbit around a sun, enough gravity to form a ball shape, and an orbit path that is clear or has been cleared by the planet itself.
Despite only having 8 planets in our solar system, children today have a wealth of imaginative possibilities when they play this game as galactic discoveries are seemingly never ending now.
EXOPLANETS
In 2010, 490 exoplanets were discovered. An exoplanet is one that is outside of our solar system. Most exoplanets are gas giants like Jupiter and uninhabitable and hostile. On September 12, 2011 BBC in the United Kingdom announced that a HARPS (High Accuracy Radial Velocity Planet Searcher) telescope at Chile’s La Silla Observatory has discovered 50 new exoplanets. HARPS seeks planets by looking for wobbly stars indicating that there is an orbiting planet’s gravity tugging at the star.
Out of this 50, there may be 16 “super-Earths.” A super-Earth must have more mass than Earth, but not as much as Jupiter. Of these 16, one is located around a star similar to ours that could possibly support life though it would be extremely steamy. These discoveries will appear in the Astronomy and Astrophysics journal soon. The star of interest for astronomy buffs is 35 light-years from Earth and is named HD 85512b in the constellation Vela. The planet is located at the edge of the narrow band around the star that may allow water in liquid form to be present on the surface of a planet. Note: One light year is 5.8 trillion miles and that narrow band is nicknamed the Goldilocks Zone.
Goldilocks Zones
Per the Detroit News, this is only the second exoplanet that exists in a habitable zone, often referred to as a Goldilocks Zone where the planet is far enough away from its star to not be too hot for liquid water, not too cold, and may be just right. It is 3.6 times the mass of our Earth and temperatures hypothetically span 85 to 120 degrees of extreme humidity. As the mass is greater than Earth, life on Vela’s planet would likely be smaller due to gravity intensity of about 1.4 times Earth’s gravity, and the year would equal just 50 days.
The first Goldilocks planet, Gliese 581g (GLEE-za), discovered in 2007, is now seen shaky at best as being habitable. 20 Light Years away is the red dwarf star Gliese 581 which hosts 6 planets including Gliese 581g located in the ‘Goldilocks zone’ of its solar system, where liquid water could exist, and it became a strong contender to be a habitable world. Scientists using the Keck telescope in Hawaii tracked the Gliese 581 system in such detail as to detect that Gliese 581g is 3 or 4 times the mass of our Earth with a 37 day orbit and likely is rocky with ample gravity to grip an atmosphere. The planet has a dark side that never faces the star and theoretically life might be possible between the sunlit infernally hot side and forever dark freezing side of this planet.
Discover Magazine’s blog sums it up rather neatly. There are a lot of planets, period. Very roughly, 25 percent of the stars in the galaxy resemble our Sun, or 50 billion Sun-like stars, many with Goldilock Zones and super-Earth type planets. New planets will be discovered, and some believed to be in the Goldilocks habitable zone will fall from favor due to gleaning new facts and hypotheses. However, many believe that out there somewhere is a new super-Earth planet that will sustain life similar to our own Earth. Keep exploring from Planet Earth!