Jupiter, the biggest planet in the solar system, might have gained its dominant position after swallowing up a smaller planet, scientists believe.
Studies on Jupiter have revealed that the giant planet, which is more than 120 times bigger than the Earth, has an extremely small core that weighs just two to 10 Earth masses.
Now scientists have claimed that Jupiter's core might have been vaporised in huge collision with a planet up to ten times the size of Earth, the New Scientist reported.
Researchers led by by Shu Lin Li of Peking University in China have modelled what might have happened in the wake of the collision. Their simulations showed that the incoming rocky body flattened like a pancake when it hit the gas giant's atmosphere.
Then it barrelled into the giant's core about half an hour later and the energy of the collision could have vaporised much of the core.
These vaporised heavy elements would then have mixed with the hydrogen and helium of the gas giant's atmosphere, leaving only a fraction of the gas giant's former core behind.
This could explain not only why Jupiter's core is so small, but also why its atmosphere is richer in heavy elements compared with the Sun, the scientists said.
Study co-author Douglas Lin at the University of California, Santa Cruz, said the super-Earth might have grown into a gas giant itself one day if it had not collided with Jupiter.
"It may very well have been on its way to becoming a gas giant, but lost the race and got gobbled up."
Saturn has a similar overabundance of heavy elements in its atmosphere and the scientists believe this could also be due to impacts by rocky objects smaller than Earth that decelerated and broke up before they could reach Saturn's core.
The team's simulations suggest that this would have left the core intact, or even added to its mass as fragments rained down onto it.
"It's an interesting explanation of why you might have a variety of core masses in giant planets," said William Hubbard of the University of Arizona in Tucson. "It's a very useful contribution."
According to scientists, the planets in the solar system were created by collisions between small dwarf planets orbiting the newborn Sun.
In the collisions the small planets melted together and formed larger planets. The Earth and Moon are the result of a gigantic collision between two planets the size of Mars and Venus, they said.