Why the planet Mars is more like a 'rocky road' chocolate bar

Have you ever thought about what the inside of a planet looks like?

Perhaps you imagine smooth layers like you might find in a chocolate bar.

Well, a new Nasa study shows that certainly isn't the case when it comes to what's going on underneath the surface of Mars.

Research suggests that due to ancient collisions, there are giant lumps spread throughout the red planet's mantle, a bit like a chunky rocky road bar!

What did experts find?

Experts at the US space agency and Imperial College London took a close look at data from Nasa's InSight lander.

The robotic explorer was the first outer spacecraft to study the interior of Mars, before the mission's end in 2022.

The team of researchers discovered that vibrations from the lander offered clues about Mars' underground and its ancient past.

Data suggests that the planet's surface contains ancient rocks up to 2.5 miles wide, due to massive impacts that took place on Mars 4.5 billion years ago.

Experts think that once Mars had largely taken shape, it was struck by giant, planet-sized objects in a series of huge collisions - the kind that also likely formed Earth's Moon.

In 2019, Nasa's InSight lander took this selfie using a camera on its robotic arm

These collisions melted pieces of crust the size of continents into large oceans of hot liquid rock, or magma, mixing the fragments and debris deep inside Mars' interior.

Dr Constantinos Charalambous from Imperial College London explained: "As those magma oceans cooled... they left behind... distinct lumps of material - and we believe it's these we're now detecting deep inside Mars."

Dr Charalambous added: "Most of this chaos likely unfolded in Mars's first 100 million years.

"The fact that we can still detect its traces after four and a half billion years shows just how sluggishly Mars's interior has been churning ever since."