Interstellar planets — those without stars to orbit — could serve as havens for life, according to a new study. They are often thought to be nearly invisible, since they are much dimmer than stars and do not have any suns nearby to illuminate them. Now, however, research suggests these worlds might be detected by their auroras.
Interstellar planets might either be rogue planets that were originally born around a star and were later cast out by gravitational tugs of war, or sub-brown dwarfs that formed alone in interstellar space. Scientists have suggested that interstellar planets could support life under or even on their surfaces.
"It has been speculated that Earth-like rogue planets could have very thick atmosphere that keeps them relatively warm, or moons of giant rogue planets could experience tidal heating and have oceans beneath their icy surface," said planetary scientist Heikki Vanhamaki at the Finnish Meteorological Institute in Helsinki.
Planet hunters have used a variety of methods to detect the indirect effects extrasolar planets have on their host stars, because the planets themselves are too small and dim to be seen by our telescopes. For example, the slight gravitational wobble an orbiting planet induces in its parent star -- called the radial velocity method -- is one way to detect a far-off world. Another way to find a planet is when it passes directly in front of its star from our point of view, causing a momentary dimming of starlight.
Scientists recently suggested that alien worlds around distant stars also could be detected by looking for radio waves given off by their auroras. Now Vanhamaki calculates the same technique might work for interstellar planets. Read More
