Washington: A new research has revealed that Neptune was struck by a giant comet about two centuries ago.
The discovery suggests that comet collisions with gas giant planets may be more frequent than astronomers thought.
Gas giants like Jupiter, Uranus, and Neptune have turbulent atmospheres with just tiny cores of rock, making it much harder to find evidence of past impacts.
The data show that the amount of carbon monoxide in Neptune`s upper atmosphere is higher than in the planet`s lower atmosphere.
Since gas would normally thin out as it reaches higher atmospheric layers, the extra gas had to come from some outside source, the scientists say.
Mathematical models for Neptune have suggested that a major comet hits the gas giant planet every 8,000 years, said study co-author Paul Hartogh of the Max Planck Institute for Solar System Research.
Adding the Neptune find to the relatively recent Saturn and Jupiter smash-ups implies that comet collisions might be more frequent than astronomers had thought.
"Maybe there are more impacts than we think," National Geographic News quoted him as saying.
The find is published in the July 16 issue of the journal Astronomy & Astrophysics.