It’s long been established that planet earth is about 4.5 billion years old, but an equally important fact for snow lovers has never really been established: when did it first snow?
This year a team from the University of Oregon has set to work to try to get an answer to that very question, and their conclusion, the mirror image of the famous answer to the question of life, the universe and everything in The Hitch Hiker’s Guide to the Galaxy, not 42, but 2.4 billion years ago.
The team decided that 2.4 billion years ago was the time when large land masses rose relatively swiftly from the oceans, kick starting the same climate models we have today.
Those new geological and meteorological conditions made it possible for snow to start forming in the atmosphere, and falling, although it’s unlikely there was much life around to witness it.
“What we speculate is that once large continents emerged, light would have been reflected back into space and that would have initiated runaway glaciation. Earth would have seen its first snowfall,” said geologist Professor Ilya Bindeman from the Department of Earth Sciences at University of Oregon and the study’s lead author.
According to a report in the journal Nature, Bindeman’s teams looked at shale samples from every continent showing rainwater erosion dating back as far as 3.5 billion years.
They found that at the 2.4-billion-year-old mark many of the hundreds of samples showed a major change, coinciding with the timing of the emergence of one of earth’s first ‘supercontinents’ known as Kenorland and the planet’s first high mountain ranges.