Hundreds of meters under the surface of a rocky valley in Oman, the sultanate on the south-eastern coast of the Arabian Peninsula, microbes are thriving even though there is no oxygen. In the past, and in fact until quite recently, scientists thought that oxygen was vital for life, but unique habitats around the world are increasingly showing that life is more diverse than we initially expected – and might be found in many more places than had previously been assumed.

The valley, known as the Semail Ophiolite, is a unique treasure for scientists looking to study not only the origins of life on Earth, but also other hypothetical types of life that could possibly populate the Solar System, and the Universe. It was once an ancient sea bed, but shifting tectonic plates pushed it up onto the continental crust, making it the largest exposed piece of oceanic crust in the world, ideal for study without the expensive technical feat that would be required to reach deep into the Earth elsewhere in the world.

Scientists believe that interfaces such as this – between the Earth’s rocky mantle and the ocean that covers most of the planet – could have been where life began on our planet, and that similar frontiers elsewhere in the Universe could be prime locations for life.