London, Nov 29 : A new research has found evidence that indicates a lack of comet collisions in our solar system's history, which may have provided a safe ground for life to evolve on the Earth.
Though the rate of comet collisions in other solar systems can't directly be measured, signs of the dust that such smashes kick up can be detected, because the dust gets warmed by the star and so gives off infrared radiation.
That radiation shows up as extra infrared in the spectrum of light coming from the star. Because such dust should dissipate quickly, it is thought to provide a good snapshot of the recent collision rate.
According to a report in New Scientist, Jane Greaves of the University of St Andrews, UK, analysed observations by the Spitzer Space Telescope and found that the vast majority of sun-like stars near us have more dust than our solar system does and therefore have had more collisions in their vicinity.
Our solar system may be one of the few that have been safe for life, suggests the research.
The vast majority of sun-like stars near us have had more collisions in their vicinity than our solar system has.
About 25 per cent of the stars have a very strong dust signature. The rest of them have too little dust for it to be readily apparent when each spectrum is studied in isolation.
Adding the measurements from these stars together, however, is like looking through a stack of slightly dusty windowpanes, making the total amount of dust easier to see. Greaves's analysis revealed that 90 per cent of solar systems are dustier and so more collision-ridden than our own.
According to Mark Wyatt of the University of Cambridge, the rate of comet impacts is probably lower in our neck of the woods.
But, as the temperature of the dust found by Greaves indicates it tends to sit far from the parent stars, the impacts might not have affected life on habitable planets, which would sit closer to their star, Wyatt added.