Curiosity has just come across a new and exciting rock during its travels in the Gale Crater on Mars.
Just a few centimeters across, the tiny formation is notable for its amazing resemblance to branch corals that can be found living in Earth’s oceans, or a piece of fulgurite; minerals fused in the heat of a lightning strike as it slams into the ground.
Mars, of course, has no surface oceans (at least, not any more), and the rock isn’t fulgurite – but it is a fascinating testament to the way the same patterns repeat in different contexts throughout the Universe, from the micro-scale to the cosmic.
Related: Curiosity Cracked Open a Rock on Mars And Discovered a Huge Surprise
The strange formation is, actually, a product of a once-wet environment. Water seeping through cracks in the bedrock carried dissolved minerals, depositing it therein as the water drained away. The mineral concentrations eventually dried and hardened, setting in the shape of the crack it filled.
Mars may no longer have surface water, but it does have two things in abundance: dust and wind. Its wild sandstorms can shroud the entire planet for months at a time, dramatically different from the weather here on Earth. They scour and sculpt the surface with powerful erosive force.
Formations on Mars that contain different kinds of mineral with different compositions can respond differently to this sandblasting. In the case of this coral-like rock, the sand blasted away the matrix containing the deposit of sedimentary material, leaving behind only the material that filled the crack – an inverse to the original formation.
Other, similar formations Curiosity has found include weird, spindly spires and a rock that looks a bit like a flower. Other strange formations include a bubbly rock that resembles frogspawn, a rock that looks a bit like a shrunken face, and one that looks like a bone.
Makes you wish you could go rock collecting on Mars, really.
