The presence of water in the Earth has long been an enigma. However, computer modelling techniques have shown that the adsorption of water onto the fractal surfaces of interplanetary dust particles, which are present in the planetary accretion disk, is sufficiently strong to provide a viable origin of terrestrial water.
“Some of the Earth’s water probably came from this source, and quite possibly most of it,” says co-author Michael Drake of the University of Arizona, Tucson. As the planet coalesced from the dust, pressures and temperatures would have grown high enough to detach the water from the grains, freeing it up to become streams and oceans.
2. The Earth has plunged into a deep freeze several times in the past, with ice covering the land and sea for millions of years. Researchers are studying how the planet eventually escaped these cold spells, and whether Earth-like planets elsewhere in the galaxy may be susceptible to the same climate catastrophe.
Researchers have shown that the world’s tropical forests thrived in the far distant past when temperatures were 3 to 5C warmer than today.
They believe that a wetter, warmer future may actually boost plants and animals living the tropics.
The findings, published in the respected journal Science, come from a study of pollen trapped in rocks during a natural period of global warming 56.3million years ago.
The extreme warm spell – called the Paleocene-Eocene Thermal Maximum – saw global temperatures soar by 6C (11F) within a few thousand years.