Fox News reports that astronomers have discovered seven planets orbiting a star designated as Gliese 667, which 22 light-years away from Earth, in the constellation of Scorpius (The Scorpion). The septuple-planetary system is very like our own solar system.
Five of the planets provide signals strong enough for the planets to be identified by obsrvationms subject to two methods of data analysis that are designed for multi-planet signal detection
There may be as many as twelve planets circling the star, but seven of them have low mass. Three planets have been identified as habitable, and are regarded as “super-Earths,” with greater mass than Earth but with less mass than larger planets in our solar system, such as like Uranus and Neptune. They are in a position of orbit, i.e., not too close and not too far, that would allow for the presence of water. This is the first time that three planets in the same solar system so arranged as to be habitable that have been identified.
In astronomy and astrobiology, the circumstellar habitable zone (CHZ) (or simply the habitable zone) is the region around a star within which objects with a planetary-mass have sufficient atmospheric pressure can support liquid water at the surface.
Earth is located in an ideal position from the sun, because its distance from the sun creates just the right temperature for things to live and grow. If it were smaller, it wouldn’t be able to retain its atmosphere, and if it were larger, it might have become be a gas giant too hot for life. Some scientists contend that the Earth could be up to 25.6 million miles closer to the Sun before it would be incapable of supporting life. Others hold that the CHZ is narrower.
Similar systems have been located before. In fact they are common in the Milky Way, but many of the planets encircling Sun-like stars and are too hot to be habitable. The discovery of systems like Gliese 667C suggests that there may be more potentially habitable planets in our galaxy.
But habitable bodies than the planets circling Gliese 667 could exist in our own solar system.
There is growing evidence of liquids below the surface of several moons in the Solar System that may consist of liquid water, and may even feature oceans, though this hypothesis has yet to be supported by evidence.
Titan, whch is a moon of Saturn is similar in appearance to Earth in that it has river channels, lava beds, winds, dunes and an extended atmosphere– unique among moons–composed of nitrogen and methane, just Earth had in its early stages of development.
In sunlight, such a nitrogen-methane atmosphere could stimulate the growth of organic compounds, which would float to the surface. Methane is one if the principal elements of natural gas.
The natural process by which life arises from simple organic compounds is called abiogenesis or biopoiesis. The earliest known life on Earth existed between 3.9 and 3.5 billion years ago, when a crust had solidified sufficiently from the molten surface.
Encéladas, another moon of Saturn’s moons, has geysers erupting in its southern hemisphere, covering the surface with ice and snow. Frictional heat as a result of the gravitational pull of Saturn, plus heat below the surface, could be the cause of these water vapor geysers. The geysers could be erupting from pockets of liquid water.
Triton, Neptune’s largest moon, is colder than Pluto because 70% of the light from the sun is reflected back. Nevertheless, observations and analyses suggest that there could be heated water under its frigid exterior.
Liquid water may be present under the surface of several satellites of Jupiter, such as Europa Callisto and Ganymede, due to tidal heating
There are a hundred billion stars in the Milky Way, which is 100,000 light years across and 3,000 light years thick. The number of planets in our galaxy with Earth-like composition, orbiting within habitable zones, has been estimated to be anywhere from 500 million to over 150 billion. It is estimated that there are 400 billion galaxies in the universe.
Habitable planets are not unique and may be closer to Earth than imagined.
By: Tom Ukinski