New study finds your suntan is intergalactic, but only a little

12 Aug 2016

A new study has revealed that suntan you’ve been working on isn’t just coming from the sun, but also from light far away in the distant universe.

The suntan that comes from sitting on the beach all day is largely the result of your skin being hit by more than one sextillion photons from our sun every second.

While this might not be a surprise to many, a new study published in the Astrophysical Journal which analysed the photons hitting our Earth, has found that not all of our suntan is coming directly from the sun.

According to the International Centre for Radio Astronomy Research (ICRAR), its researchers determined that, of those sextillion photons, 10bn of them every second come from deep within intergalactic space.

So, while the onset of darkness might remove many of these Earth-bound photons, interstellar sources continue to hit Earth 24 hours a day, referred to by lead researcher Prof Simon Driver as ‘extra-galactic background light’.

“These photons are minted in the cores of stars in distant galaxies, and from matter as it spirals into supermassive black holes,” he said.

Suntan infographic

Infographic via ICRAR/Dan Hutton

Nothing to be worried about

Easing any fears of our skin being damaged by cosmic bombardment, the ICAR team has calculated that, despite these huge numbers, this extra-galactic background light only contributes 10 trillionths of a person’s suntan.

We would need to bask in it for trillions of years for it to cause any real damage to us.

The findings of this study are part of Prof Driver and his team’s efforts to better understand the evolution of the universe.

Specifically, how we went from a smooth distribution of atoms to the mass of stars and galaxies that exist today.

“The processes which shape and shuffle mass generate vast quantities of energy, dwarfed only by the vastness of space,” Prof Driver said.

“The precise physics as to how this energy is released is still not fully understood and work continues to build numerical models capable of explaining the energy that we’ve now measured.”

Man on beach image via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic