Life on Rogue Planets And The Moons Around

A rogue planet basically refers to a free-floating planet or may be an orphan planet which can also be termed as interstellar planet or wandering planet that is starless or may be sunless and is basically a planetary-mass object that orbits a galactic center directly. Such objects have been withdrawn from the planetary system in which they were formed or have never been gravitationally bound to any star or center of galaxy.

During the formation of planetary-system, various small prototype planetary bodies may be ejected from the system. An ejected body would receive less of the stellar-generated ultraviolet light or properly called a sunlight that can take away the lighter elements of its atmosphere. Even a body equal to the size of Earth would have enough gravity to prevent the escape of the hydrogen and helium in its atmosphere.  In many objects which may be equal to or bigger than Earth has a kilobar atmospheric pressure of hydrogen and a convective gas adiabatic, the geothermal energy from residual core radioisotope decay which could possibly  maintain a surface temperature above the melting point of water, thus allowing liquid-water oceans to exist inside it. These planets are likely to remain geologically active for long periods of time as per the observations and research if they have geodynamo-created protective magnetospheres and sea floor volcanism which could provide energy for life to be sustained. Therefore, a living being could live on such a star-less planet, although food sources would be limited. A layer of ice found on a planet’s surface can actually act as a strong insulator that helps locking in a planet’s heat. If the ice layer is thick enough, then a planet can maintain an ocean of liquid water beneath the ice. But to prevent the ocean from freezing for billions of years, the ice layer needs to be at least 10 km (6 miles) thick. Two of Jupiter’s large moons – Europa and Ganymede – have oceans lurking under miles-deep ice layers and might be analogs for these icy rogue planets.  Gravitational micro lensing observations of 50 million stars in the Milky Way found 10 Jupiter-sized rogue planets. These helped scientists to calculate that there are at least 2 rogue planets for every star in the galaxy. This means that there are potentially billions of rogue planets out there, lurking silently in the dark. A dead and desolate planet with no heat and light from a sun seems like the last place to look for Life. However, there are ways rogue planets can retain heat and have suitable conditions for Life. Free floating planetary-mass objects can eventually form a mini planetary system around them, much like the Jupiter mini-system. The sub-brown dwarf OTS-44 is known to be surrounded by a disk of at least 10 Earth masses. OTS-44 is believed to have a set of moons going around it in the future. Scientists at the University of Aberdeen and University of St Andrews, Scotland, have concluded that extraterrestrial life is far more prevalent than previously thought. In a paper titled “Circumstellar habitable zones for deep terrestrial biospheres,” released in the journal, Planetary and Space Science, Scotland they have explained the concept of “Goldilocks Zone”, the optimal zone for life to exist on planets. They have found that life can develop beneath a planet’s surface where liquid water can be found at varying depths.

By: Anuja Arora

Content: http://www.abc.net.au/news/science/2018-10-11/rogue-planets-moons-life-gas-giants-jupiter-solar-system/10334026