Searching the heavens for evidence of life

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Inspiring a fresh generation ... Nasa scientist Dr Jen Blank, left, chats to University of Hong Kong academic Dr Angelica Angles at Oxford Area School. PHOTO: DAVID HILL

By DAVID HILL

Local students are being encouraged to join the search for life beyond Earth.

Nasa scientists Dr Mitch Schulte and Dr Jen Blank and University of Hong Kong academic Dr Angelica Angles spent last week at Oxford Area School sharing their experiences as part of the search for evidence of life on Mars.

Information garnered from Nasa’s various missions to Mars suggests it was similar to Earth 3.5 billion years ago, with an atmosphere and liquid water on the surface, says Dr Schulte, who is the lead scientist for the Opportunity rover and for the planned 2020 Mars mission.

Because of the planet’s small size, its gravity is unable to hold the atmosphere against the harsh solar winds, leaving the red planet’s surface sterile and covered in dust.

“There was water, there was a nice atmosphere, a nice temperature, so all the ingredients were there, so probably yes, the only thing is that we cannot find it,” Dr Angles says about life on Mars.

But it is possible there is life below the surface.

Dr Blank, a geochemist who has worked on the science team for the Curiosity rover’s “ChemCam” instrument, says the main focus of Nasa’s missions to date has been about finding evidence of “habitability”, whether in the past, present or future, rather than life itself.

Curiosity’s main discovery has been identifying that the crater it landed in was once a lake containing drinkable water.

A keen cave explorer, Dr Blank says she hopes Nasa will send future rovers into Mars’ caves.

“If life exists on Mars today it probably exists in the sub-surface, and caves give us the best way to access the sub-surface without drilling; and drilling on another planet is pretty challenging.”

The search for evidence of life, whether extinct or living, on Mars is set to take off with Nasa’s InSight mission due to arrive in November, and both Nasa and the European Space Agency have missions set to launch in 2020.

Dr Schulte says studying other planets such as Venus and Mars can also teach us what could go wrong on Earth.

“Venus is an example of greenhouse gases gone wild.”

As carbon dioxide builds up in the atmosphere, it traps heat from the sun.

“When we look at Earth and the amount of carbon dioxide we are putting into the atmosphere, we know that that’s actually increasing global temperatures and we can take lessons from Venus that the effect is real and there are some serious consequences on a global scale.”

Dr Schulte says Nasa is also interested in exploring Jupiter’s icy moon Europa, Saturn’s moons, Titan, which has an atmosphere and liquid methane rivers, and the icy Enceladus, and Neptune’s moon Triton, as it extends the search for evidence of life beyond Earth.