A new research has claimed that bombardments of 'micro-meteorites' on Earth and Mars four billion years ago may have caused the planets' climates to cool dramatically, hampering their ability to support life.
Scientists from Imperial College London studied the effects of the Late Heavy
Bombardment (LHB), a period of time in the early Solar System when meteorite showers lasting around 100 million years barraged Earth and Mars.
This bombardment discharged sulphur dioxide into the upper atmospheres of both planets and the researchers'' analysis suggests that this may have had a catastrophic impact on their environments.
Micro-meteorites come from the rocky asteroid belt between Mars and Jupiter. These space rocks, which are the size of sugar grains, get dragged by gravity towards Earth and Mars.
As they enter the planets' upper atmospheres, they heat up to temperatures of approximately 1000 degrees Celsius, releasing gases including sulphur dioxide. Sulphur dioxide in the atmosphere forms aerosols, consisting of solid and liquid particles, which deflect sunlight away from the surface, making planets cooler.
The authors of the new study have calculated that showers of micro-meteorites delivered approximately 20 million tonnes of sulphur dioxide each year into the upper atmosphere of Earth during the LHB.
The team deduced that on Mars, these micro-meteorites delivered up to half a million tonnes of sulphur dioxide each year for the same period of time.
The study has been published in the journal Geochimica et Cosmochimica Acta.