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, according
to research published today in the journal Geochimica et
Cosmochimica Acta. 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 di