An ancient meteor site in Germany is being studied to help scientists develop a better understanding of how past life could have existed on Mars.
An international research team analysed samples from Nordlinger Ries, a 15-mile-wide impact crater in southern Germany.
The site’s geology and chemistry bear similarities to the Martian surface – in particular the Jezero crater north of the Martian equator.
Both Jezero and Nordlinger Ries featured liquid water in their distant past, making their chemical compositions comparable.
The Ries crater – in which a whole city was built more than 1,000 years ago – has layers of rock and minerals better preserved than almost anywhere on Earth.
Specifically, nitrogen isotopes in rock samples from the Ries crater are estimating the pH of ancient waters on Mars.
A sample of suevite rock formed nearly 15 million years ago by the Ries Crater meteorite impact. Similarly impact-generated rocks exist on the rims of ancient crater lakes on Mars
The Mars 2020 rover will land in a similarly structured and well-preserved ancient crater on Mars next year, called the Jezero crater.
Comparisons between the two will help scientists gain an understanding of how Mars once hosted oceans and life billions of years ago.
WHAT IS THE NÖRDLINGEN RIES CRATER?
Nördlingen Ries is an impact crater that formed on Earth about 14.8 million years ago from an asteroid that smashed into the surface of the Earth.
The crater, which is 15 miles in diameter, is most commonly referred to simply as Ries crater or the Ries.
The town of Nördlingen was built inside the crater in the 9th century at the very latest.
The Ries is recognised as an analog for Martian craters.
Ries was a rampart crater, which are almost exclusively found on Mars.
Rampart craters exhibit a ‘fluidized ejecta’ flow after impact of the meteorite.
‘The question that drives our interests isn’t whether there’s life on present-day Mars,’ said Professor Timothy Lyons at the Department of Earth Sciences at the University of California, Riverside.
‘We are driven instead by asking whether there was life on Mars billions of years ago, which seems significantly more likely.’
Mars is currently too cold – minus 81 degrees Fahrenheit – to support life as we know it.
NASA research already shows that Mars had a liquid water ocean around 4 billion years ago, but how that was possible is not completely certain.
Mars is further from the Sun than Earth is, and billions of years ago the Sun generated less heat than it does today.
‘To have made the planet warm enough for liquid surface water, its atmosphere would likely have needed an immense amount of greenhouse gas, carbon dioxide specifically,’ said Chris Tino, co-author of the study, which has been published in Science Advances.
It’s unlikely that ancient Mars had enough oxygen to have been home to complex life forms such as humans and animals, although microorganisms may have survived in alkaline lakes.
High-pH alkaline lakes are among the most productive ecosystems on Earth and are prime targets in the search for life on Mars.
Alkaline lakes also suggest sufficient carbon dioxide in the atmosphere to warm the planet and make liquid water possible.