Experts discuss unsolved mysteries of Red Planet

The close proximity means that scientists are getting incredibly detailed images - in particular the Hubble Space Telescope which has captured some stunning pictures of the planet’s active surface, including some rarely seen weather conditions.

In Leicester, John Bridges, Professor of Planetary Science of the University’s Space Research Centre, will also be keeping a close eye on the distant world - which he has invested so much of his time in.

Professor Bridges is part of the NASA team gathering data sent back by the Mars Science Laboratory - more affectionately called, Curiosity. He is also a member of the European Space Agency (ESA) mission, ExoMars.

He said: “Mars’s orbit goes in 26 month cycles and every 26 months it makes its closest pass to the Earth and that’s the time when missions are launched.

“Currently, the ExoMars Trace Gas Orbiter, which launched earlier this month, is heading for Mars and will send down a small, static lander in October. We are planning a Leicester@Mars day with the National Space Centre to mark this and a meeting at the Royal Astronomical Society in November to discuss our new understanding of Mars.

“I’m on the camera team and we will be using it to help select a landing site for the second stage of the mission which is ExoMars 2020.”

The ESA 2020 mission, which aims to build on the discoveries made by Nasa’s Mars Science Laboratory (MSL), which in 2013 confirmed that the Red Planet did show signs that it was once a habitable place for microbes, will travel across the Martian surface to also search for signs of life.

“First we have to determine a landing site,” said Professor Bridges. “But once the 2020 mission lands the plan is to drill at least six times, to a depth of 2m to get below the radiation zone. Then we’ll use a mass spectrometer to look for organic compounds.”

Mars’s orbital divergence has already given NASA an advantageous view of the surface and climate, said Professor Bridges.

“Even before its closest pass, Hubble has taken some close up images of the planet which clearly show clouds, something which we don’t often see in this much detail,” he said.

“They are more wispy than the clouds we get here on Earth but it shows that Mars has an active surface and atmosphere.”

Just like Earth, Mars has seasons, said Professor Bridges.

The planet’s southern hemisphere summer period has just ended and it is moving into autumn, which has a bearing on the kind of science MSL can do.

“In southern summer, Mars is closest to the Sun so it’s warmer and there is more dust in the atmosphere, because it’s thicker.

“This means MSL’s Mastcam has less sharp images - but with less dust we can now get clearer pictures of the surface.”

Professor Mark Sims, Interim Director of the University’s Space Research Centre, said that the Red Planet has been the focus of our fascination since it was first imaged with a telescope by a Dutch astronomer Christian Huygens, in 1659.

“It’s our closest neighbour,” he said. “So it has always been an obsession of ours - to learn everything we can about it. But even now, there are still mysteries we don’t quite understand, like ‘why was it warm and wet?’.

“Mars probably lost most of its atmosphere 3.5bn years ago. Before that there were oceans and even evidence of tsunamis. But the problem we have is that all the theories we have say the Sun was much dimmer, and Mars is much further away than the Earth, so how would liquid water have been possible?”

Professor Sims said that another mystery could hold the key to finding life on the Red Planet.

He said: ”We also have the evidence of methane in the atmosphere.

“Using Occam’s razor, where the simplest explanation is usually the best, it’s probably caused by hydrothermal activity. But methane is also a by-product of microbial life – so we could have already discovered life on Mars, but we just don’t know it. Hopefully, the Trace Gas Orbiter will go a long way to helping us understand the origins of these emissions.”

Image credit: ESA/ATG medialab