Everyone likes a winner, particularly when the winner is paying. The stakes with exoplanets that resemble Earth mean that there could be hope of an oasis Earth that offers potential, however small, for post-terrestrial migration. The Biosphere 2 project in the 80’s and 90’s of the 20th century led to proving such notion that a space ship could host all the accouterments for perpetuating generations of humans on an extended light-year mission to just such an Earth. Today, astronomers and scientists think that the best option for life on other planets may be found on one of the Moons of Saturn called Titan, but the thrust of human interest at minimum is human habitability where Titan does not even come close (nor does Titan technically qualify as an exoplanet).
The first exoplanet, indicating any planet found beyond Earth’s solar system, was labeled 51 Pegasi b. Nicknamed “Bellerophon,” its discovery in 1995 by the Swiss team of Michel Mayor and Didier Queloz was the product of an early exoplanet lensing technique called radial velocity. Now scientists, including astronomers and astrophysicists, are understudies of two major space satellite telescopes. One of these is the NASA Kepler space telescope and the other the French Convection, Rotation and Planetary Transits (CoRoT) space-based telescope. In the case of the CoRoT, it measures the planet’s radius, and then an observatory can be used to determine planetary mass.
Together or apart, teams work with additional, independent earth-based observatories at such locations as Alcantara (Brazil), Aussaguel (France), Hartebeesthoek (South Africa), Kiruna (Spain), Kourou (French Guyana), Mauna Kea (United States Pacific island state of Hawaii), Santiago (Chilé), and Vienna (Austria) to corroborate and fine-tune hopeful findings from satellite images.
“Earth-size planets in our galaxy are like grains of sand sprinkled on a beach — they are everywhere,” estimates Andrew Howard of the University of California, primary co-author of a study sponsored by NASA. The 2010 analysis sized up the proposition that 23% of Sol-sized stars in the Milky Way held planets massed like our very own Earth — amounting to 46 billion proto-Earths isolated unto the transit zone where astrophysicists such as Geoff Marcy have been using the latest in lensing methodology to estimate planetary atmosphere and check for solid, liquid or gaseous terra firma with expectation to find water in rocky soil. Marcy explicitly mentions that Earths in the habitable zone are not included in their studied estimate. Any single one of these exoplanets is statistically more likely to be a smaller, Earth-sized planet but based on such geological trend that there are more smaller bodies in any macrosystemetology to find than larger ones. Greater bodies are simply easier to spot from Earth. Incredibly, only since 1989 have exoplanets become detected, distinguishable in fact to objective science.
In February 2009, CoRoT-7b was discovered by a French astronomy team via the CoRoT satellite, at the time considered the most Earth-like planet in known existence — and a former red giant next to a star of the constellation Monoceros just 480 light years away. But its 3,600°F daytime, solar proximity, and tidal migration toward its sun was just a little too much on the uninhabitable side to be Earth-like in fact, other than according to size. It was also thought to be the first example of a planet fit to be termed an “evaporated remnant core,” indicates Brian Jackson in Greenbelt, Maryland where NASA’s Goddard Space Flight Center situates. The planet itself of CoRoT-7b has a 20-hour year and resembles Mercury.
The most likely consideration for water until December this year was Gilese 581g, a triple-sized Earth discovered by astronomers under the management of Paul Butler and Steven Vogt, as revealed at the end of September 2010 at the University of California at Santa Cruz. Together, they share the Keck I telescope of the W.M. Keck Observatoryin association with the Carnegie Institution of Washington. The telescope itself situates on Mauna Kea. The general consensus is that if there is water on Gilese 581g, then there is life. It’s a 20 light year long trip to the star Gilese 581 in the constellation of Lyra for a planet that doesn’t even rotate on its axis, and its year lasts 37 days. But since it appears to have a circular orbit, it is compared to planets in our own solar system.
NASA’s Kepler space telescope has turned up its own share of tantalizing, speculative Earths, starting with Earth-sized Kepler-20f, clocking in at x1.03 the size of Earth, situated 945 light years away and now being studied by astronomers from available satellite imaging data. The planet’s year lasts only 9 days but is expected to make history for being definitively Earth-like and orbiting its own sun. At 426° Celsius, its proximity from Kepler-20, 20f’s central star positioned technically in the constellation Lyra suggests its presence to be significantly out of the habitable zone.
Breaking out fancy new terms such as “habitable zone,” referring to a region where conditions for water to exist — and therefore life — the search for life itself, and particularly for planets that can be inhabited by humans, continues as new findings and research continue to accumulate with automated sophistication sidelong eviscerated opportunities that have before never existed in the history of the human species. The Kepler telescope currently claims 207 qualified Earth-sized planets and 680 super-Earths thus far out of 2,326 apparent “hits,”only 28 validated as of December 21st as so boldly we go next week into 2012’s year, while the CoRoT has identified 401 planets that orbit around their central star or stars with 24 planets validated since its launch in 2006.
Habitability, while among critical reasons for popular appeal of planetary discovery and exploration, remains accompanied by other popular motives that vary from science to science. Nor is it necessarily the sort of habitability synonymous with human habitability. Here on Earth, life forms are known that survive in extremes of cold and some that somehow endure extremes of heat. Any new information that is learned can be critical in yielding insights that may help explain more about the nature of the universe and even uncover missing clues relevant to sciences such as physics, geology, meteorology, environmental studies, biology and chemistry. Just as some speculate that Mars was prevented from achieving an atmosphere of its own by meteor impact, science could even hope to learn whether a planet’s atmosphere could be activated or in other cases reduced by some orchestrated method of inducing nuclear chain reaction. The prospects are as limitless as our ignorance of what may be out there to be discovered.
In sum, recent discoveries of exoplanets may be just the beginning of realizing much more than hypothetical potential to colonize planets with varied ultra-durable, biosphere-type space ship endeavors with arrival taking unknown generations. The possibilities in fact remain as wide open as the sciences themselves and available libraries devoted to astroscience and speculative science fiction. But so far, there has been no confirmation that an Earth twin does in fact exist, even in the habitable zone, and the ultimate question is whether science can determine positively and without error that the existence of any inhabitable Earth “twin” can in fact support human life indefinitely like that Earth.
Space satellites, high-altitude observatories and teams of scientists versed in astrophysics and astronomy have recently discovered, with requisite aid from the essential Kepler and CoRoT satellites, 52 confirmed exoplanets validated out of mostly unrefined space telescope data that qualifies over 2,300 certifiable bodies of classifiable interest. Teams working on the projects are well aware of how far away these planets and their stars can be found, the type of star or star system that lies at their center, how to spot planets in the transit and rotation zones around a central star, and to some extent how to spot at least some planets in the estimable “habitable zone.” They can estimate a planet’s surface temperature with some degree of confidence, recognize rocky planets, and even make educated guesses as to the type of atmosphere both above and below as well as its mass despite its size.
These discoveries so awesome and inspiring demonstrate that the science and technology of astrophysics has neared mastery of Earth’s own solar system only to extend and focus new efforts to learn other planets starting with such greater macrocosm of our very own galaxy, the Milky Way. The science of astronomy may be about to boom, with much greater potential than in the past where once confined only to one star, nine planets, and assorted space oddities such as comets. A new, exciting era has already just started, and the potential yield could hold any unique speculative opportunity to unify certain sciences on behalf of the new raw materials of astrophysical data that may enhance scientific discoveries qualitatively from how they are known today.
