Earth life 'may have come from Mars'

Gale crater, Mars Life would face challenges on Mars today, but billions of years ago conditions might have been better

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Life may have started on Mars before arriving on Earth, a major scientific conference has heard.

New research supports an idea that the Red Planet was a better place to kick-start biology billions of years ago than the early Earth was.

The evidence is based on how the first molecules necessary for life were assembled.

Start Quote

The evidence seems to be building that we are actually all Martians; that life started on Mars and came to Earth on a rock”

End Quote Prof Steven Benner Westheimer Institute for Science and Technology

Details of the theory were outlined by Prof Steven Benner at the Goldschmidt Meeting in Florence, Italy.

Scientists have long wondered how atoms first came together to make up the three crucial molecular components of living organisms: RNA, DNA and proteins.

The molecules that combined to form genetic material are far more complex than the primordial "pre-biotic" soup of organic (carbon-based) chemicals thought to have existed on the Earth more than three billion years ago, and RNA (ribonucleic acid) is thought to have been the first of them to appear.

Simply adding energy such as heat or light to the more basic organic molecules in the "soup" does not generate RNA. Instead, it generates tar.

RNA needs to be coaxed into shape by "templating" atoms at the crystalline surfaces of minerals.

The minerals most effective at templating RNA would have dissolved in the oceans of the early Earth, but would have been more abundant on Mars, according to Prof Benner.

Red or dead

This could suggest that life started on the Red Planet before being transported to Earth on meteorites, argues Prof Benner, of the Westheimer Institute of Science and Technology in Gainesville, US.

Why is Mars so lifeless?

Mars taken by Mars Global Surveyor
  • No magnetic shield: Mars' magnetic field disappeared four billion years ago, allowing the solar wind to strip away the planet's atmosphere
  • The missing atmosphere: Mars has just 1% of Earth's atmospheric pressure, so heat from the Sun escapes into space, making the planet very cold
  • Too cold for liquid water: Mars sits outside the so-called Goldilocks Zone where the temperature is 'just right' for water to remain liquid - vital for life as we know it

The idea that life originated on Mars and was then transported to our planet has been mooted before. But Prof Benner's ideas add another twist to the theory of a Martian origin for the terrestrial biosphere.

Here in Florence, Prof Benner presented results that suggest minerals containing the elements boron and molybdenum are key in assembling atoms into life-forming molecules.

The researcher points out that boron minerals help carbohydrate rings to form from pre-biotic chemicals, and then molybdenum takes that intermediate molecule and rearranges it to form ribose, and hence RNA.

This raises problems for how life began on Earth, since the early Earth is thought to have been unsuitable for the formation of the necessary boron and molybdenum minerals.

It is thought that the boron minerals needed to form RNA from pre-biotic soups were not available on early Earth in sufficient quantity, and the molybdenum minerals were not available in the correct chemical form.

Shergottite meteorite from Mars Meteorites from Mars have been arriving on Earth throughout our planet's history

Prof Benner explained: "It’s only when molybdenum becomes highly oxidised that it is able to influence how early life formed.

"This form of molybdenum couldn’t have been available on Earth at the time life first began, because three billion years ago, the surface of the Earth had very little oxygen, but Mars did.

"It’s yet another piece of evidence which makes it more likely life came to Earth on a Martian meteorite, rather than starting on this planet."

Early Mars is also thought to have had a drier environment, and this is also crucial to its favourable location for life's origins.

"What’s quite clear is that boron, as an element, is quite scarce in Earth’s crust," Prof Benner told BBC News, “but Mars has been drier than Earth and more oxidising, so if Earth is not suitable for the chemistry, Mars might be.

"The evidence seems to be building that we are actually all Martians; that life started on Mars and came to Earth on a rock," he commented.

"It’s lucky that we ended up here, nevertheless - as certainly Earth has been the better of the two planets for sustaining life. If our hypothetical Martian ancestors had remained on Mars, there may not have been a story to tell."


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  • rate this

    Comment number 24.

    Now all we need to prove is that women are from venus, and the prophecy is complete.

    Being serious, research like this is awesome. I can't think of anything more interesting and useful in the long term than knowing our origins and how life came to exist.

    Hows about we forget invading Syria and put those funds into science... imagine what we could achieve with billions to fund our research.

  • rate this

    Comment number 155.

    @ GlobalYawn
    "So science as telling us we're all aliens now. And atheist in here have the gall to mock religion!!
    We were all from Africa yesterday. At least religions stick to their stories"

    If you're going to mock science at least get your facts straight - evidence suggests that the *human race* originated in Africa, but this story is about where the basic molecules of life originated!

  • rate this

    Comment number 13.

    Every day, the "rigidly defined areas of doubt and uncertainty" (tips hat to the late, great Douglas Adams) are being chipped away.
    One day we'll have an answer to how and where life began.
    I just hope I'm still around when they find out!

  • rate this

    Comment number 201.

    I love it when people say, "But evolution is only a theory". In just six words they tell me they know nothing about science.

  • rate this

    Comment number 214.


    "Scientists are constantly changing the views"

    This is a good thing, this is how science operates. Theories change based on evidence. Law and science are similar in that they use evidence. Imaging a case going to court, it's an open and close case, then some evidence comes along that shows the defendant categorically could not be guilty; would you still want them locked up?


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