London, Feb 19 (UNI) Thousands of planets like Earth and larger than that could be hidden in the outer reaches of the solar system , NASA scientists claim.
It is believed, some of them could have warm oceans in their interiors, opening up the possibility of the presence of extraterrestrial life.
According to NASA expert Dr Alan Stern, there are forensic evidence for the existence of large numbers of undiscovered planets in the Oort Cloud -- an immense spherical cloud surrounding the planetary system and extending approximately 3 light years, about 30 trillion kilometers from the Sun.
''We may very well have miniature gas giants, or super-Earth gas giants, orbiting out there. It's still to be seen, and I think the discoveries will be very exciting and very enlightening, '' said Dr Stern.
The Oort Cloud planets are believed to have formed in a zone between the terrestrial such as the Earth and Mars and the gas giants like include Jupiter and Saturn. They would then have been thrown to the edge of the solar system by the gravitational pull of the gas giants.
Dr Stern said it was possible that some of the planets had warm liquid water oceans beneath their icy surfaces, like the one believed to exist on Jupiter's moon Europa.
Heated by forces from gravitational forces or radioactive energy, these could provide conditions suitable for life.
He said the angle of Uranus's rotation suggested it had been struck by an object three to five times the mass of Earth at some time in its history.
''If you calculate how likely that was if there was only one such object around, you find that the probability is nil, In fact there ought to have been several dozen of these three to five Earth mass class objects around in order to make that event probable, '' Dr Stern said.
''Where have they gone? Computer models show us that they were probably scattered to the Oort Cloud, and we will eventually find them.'' Hardly any sunlight penetrates the region, making any planets there invisible to ordinary telescopes. Only powerful instruments that can detect the faintest infrared signals would have any chance of finding them, the Daily Telegraph reported.
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