London, September 5 : A new study has indicated that a star in a distant solar system may have thrown the building blocks of life our way, which were then caught by our star - the Sun.
Previous studies into whether material could travel between solar systems predicted that such an exchange would be unlikely, because the speed matter would need to be traveling at to escape one star would mean it was moving too fast to be caught by another.
Now, according to a report in New Scientist, Edward Belbruno and colleagues at Princeton University have shown that planetary systems in young, densely packed star clusters could throw out rocks at a slower pace.
They showed that for rocks in certain orbital positions, the gravitational pull of the central star is equal to the pull of other stars in the cluster.
This sends the rocks into chaotic orbits that eventually allow them to wander off at about 0.1 kilometres per second - slow enough for other stars to catch them.
The team estimates that up to 1018 individual rocks could leave such a system in the first 100 million years of a cluster's life, before the stars drifted too far apart.
The research team believes these rocks could have carried basic biological components like amino acids to our solar system.