The hunt for an Earth-like planet that contains life has been a cornerstone of human exploration in space and now, a new study could change the way that we search for such a planet by implying that Jupiter-sized planets and asteroid belts may be the keys to finding water and life.
We usually look at asteroids as a doomsday scenario. An asteroid impact has the potential to wipe out life as we know it, but the flipside is that asteroid impacts can actually jumpstart life by introducing various elements and building blocks that are crucial to biology.
Rebecca Martin, a NASA Sagan Fellow from the University of Colorado in Boulder and astronomer Mario Livio of the Space Telescope Science Institute in Baltimore have put forth a theory that asteroids provide a boost to biological evolution.
The theory of punctuated equilibrium states that asteroid impacts affect biological evolution because they disrupt the environment and force species to adapt. This leads to the higher, more complex forms of life needed survive in such scenarios.
The presence of a Jupiter-sized planet is also important, because of its gravitational influence in helping create an asteroid belt.
"To have such ideal conditions you need a giant planet like Jupiter that is just outside the asteroid belt [and] that migrated a little bit, but not through the belt," Mario Livio said. "If a large planet like Jupiter migrates through the belt, it would scatter the material. If, on the other hand, a large planet did not migrate at all, that, too, is not good because the asteroid belt would be too massive. There would be so much bombardment from asteroids that life may never evolve."
In fact, the pair of scientists found that less than 4 percent of their observed systems harbored such ideal conditions. Only 19 of the 520 Jupiter-sized planets they studied were found to be in the right place within their solar system to help foster an asteroid belt similar to the one in our solar system. Both Martin and Livio are proposing that their findings could help narrow and intensify the search for life in space.
"Based on our scenario, we should concentrate our efforts to look for complex life in systems that have a giant planet outside of the snow line," Livio said.
The study is published in the Monthly Notices of the Royal Astronomical Society: Letters from the Oxford University Press.