We tend to think of the high energy particles spewed out by the Sun during solar flares, which then rain down on the planets, as purely damaging to the life that clings onto the rocky worlds. But new evidence suggests that might not always be the case.

A new study published in The Astrophysical Journal has found that as well as being harmful to life, these bombardments might actually be necessary for it to begin in the first place.

A team from Harvard University set out to explore how the organic molecules that form you, me, and all other life on the planet, might have been formed in the first place. In order to turn molecules like carbon dioxide and nitrogen gas into things such as amino acids and nucleobases, there needs to be a source of energy.

The researchers decided to use computer modeling to see what different sources of energy – including that from solar flares – may be sufficient to form the building blocks of life. There are a number of ways that this could happen, including volcanic activity, radioactivity, meteor impacts raining down on the surface, and even just ultraviolet light from a nearby star.  

They found that on Mar and Earth at least, the deadly solar flares could indeed have helped create some of the organic molecules that make up life, but only between 10 and 20 percent of them. The main source that is likely to have supplied the energy to create the building blocks was probably the UV light coming from the Sun. But this doesn’t mean that on other worlds solar flares might not be a more significant contributor.

For example, many planets have been found to be orbiting red dwarfs, which don’t emit nearly as much UV light as our own star. But for those planets close enough to the red dwarf, getting a massive hit of high energy particles from solar flares could be sufficient for starting life. So, these particles might be able to act as both creator and destroyer. 

“In some situations, life doesn’t exist, and then this bombardment creates all these organic compounds that can turn into life as we know it,” explained Dimitra Atri, who was not involved in the study, to New Scientist. “But if there are already organisms there, this same bombardment can kill them. It’s a double-edged sword.”

This is because the strong energy emitted from solar flares can also strip a planet of its atmosphere, which would obviously kill any life that might have evolved there.

[H/T: New Scientist]