London: Researchers have now discovered how earth looked at various stages in its history - from the age of the dinosaurs to more recent times- and what would come into focus for alien astronomers.
Researchers from the Astrophysical Institute of the Canary Islands and the Massachusetts Institute of Technology used cloud models to piece together Earth’s appearance at several stages.
To help them they used landform models from paleogeologist Ron Blakely to give them a layout of the Earth over four different geologic time frames, the Daily Mail reported.
The researchers observed how the brightness of the planet would have varied over millions of years as the continents shifted.
Five hundred million years ago the landmasses were much closer together implying that there were much bigger areas of ocean than there are at present.
The shifting landmasses resulted in different cloud patterns and clouds reflect light the best, which would end up in differing levels of brightness when viewed from space.
According to their analysis, among other things, E.T. could most likely tell that our planet’s surface is divided between oceans and continents, and learn a little bit about the dynamics of our weather systems.
“Maybe somebody’s looking at us right now, finding out what our rotation rate is - that is, the length of our day,” said Sara Seager, associate professor of physics and the Ellen Swallow Richards Associate Professor of Planetary Sciences at MIT.