Exoplanets twilight zones may be germane for harbouring life

December 11th, 2007 - 6:30 pm ICT by admin  

London, December 11 (ANI): NASA scientists say that rocky planets beyond the solar system, called exoplanets, may support life.

The researchers say that exoplanets may rock back and forth to create large swathes of twilight zones with temperatures suitable for life.

Gravitational tugs with the other orbiting objects often cause exoplanets to settle into trajectories in which they always show the same face to their hosts.

Due to this characteristic of exoplanets, they are believed to be bad candidates for life. Scientists believe that the hemisphere facing the planets host stars would roast, while the dark side would freeze.

However, Anthony Dobrovolskis of NASA Ames Research Center in California has now created a computer model that suggests that the case is not the same always.

He says that exoplanets can rock to and fro if they travel on elongated or eccentric orbits, and thus create a ‘twilight zone’ that could be hospitable to life.

According to him, the Moon also experiences a similar rocking motion and shows the same face to Earth, taking the same amount of time to rotate around its axis as it does to circle our planet once.

But since the Moon’s path around the Earth is not perfectly circular, its orbital speed is sometimes faster or slower than its rotational speed.

Dobrovolskis says that it is the difference between the two motions that causes the Moon to rock slightly.

“If you’re standing on the Moon, you’ll see the Earth rock back and forth a little bit,” New Scientist magazine quoted Dobrovolskis as saying.

He believes that exoplanets experience pronounced rocking motions on very elongated orbits, and may have much more temperate climes than previously thought.

Dobrovolskis says that “there is no permanent day or permanent night side anymore” if the planet rocks by 90 degrees or more.

“The whole thing becomes a twilight zone,” he adds.

Dobrovolskis says that his results may have implications for attempts to directly observe new worlds.

He suggests that astronomers look for planets the temperatures of which are relatively even all across their surfaces, not just for planets sporting one very hot and one very cold hemisphere. (ANI)

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