Life might have started on Mars, or Earth

Chemists have found that certain minerals would make the initiation of life easier. Geologists say those minerals are not available on Earth, but they are plentifly available on Mars. Therefore they propose that these chemical precurors for life first appeared on Mars and then were transferred to earth.

Geochemist Professor Steven Benner proposes that the “seeds” of life most likely are to have arrived on Earth in meteorites blasted off Mars by impacts or volcanic eruptions.

All living things are made from organic matter, but simply adding energy to organic molecules will not create life. Instead, left to themselves, organic molecules become something more like tar or asphalt.

Certain elements seem able to control the propensity of organic materials to turn to tar, particularly boron and molybdenum, so we believe that minerals containing both were fundamental to life first starting.

Analysis of a Martian meteorite recently showed that there was boron on Mars; we now believe that the oxidised form of molybdenum was there too.

— Prof. Brenner as reported by the Gaurdian

Many kg of Mars land on earth each week. When asteroids hit Mars material is ejected into space and some of that hits us.

It is thought that around the time life is thought to have initiated on earth (6.5 billion years ago) that the planet was mostly covered in water, and therefore these minerals wouldn’t be stable in earth conditions.

But if many kg of Mars land on earth each week, that means that the minerals from Mars are also available on earth. What also needs to be considered is how large a volume of matter is needed in the correct conditions to start life. If we try to image a watery planet with no life we will have a tendancy to image a simple model and ignore the heterogeneity that would have been present at various scales.