Study sees a watery bombardment

A massive bombardment of meteorites billions of years ago could have brought in enough water and carbon dioxide to jump-start the chemistry that enabled the Earth to develop into the garden spot of our solar system.

By studying meteorites and other evidence from this bombardment, a team of researchers at Imperial College, England, has calculated that the meteorites could have carried in as many as 10 billion tons of water vapor and carbon dioxide to the young Earth every year for millions of years.

That volume of water, about 10 times the daily outflow of the Mississippi River, and carbon dioxide would have been enough to set off a greenhouse effect that eventually made the Earth warm and wet enough to harbor plants and creatures. Meanwhile, the other planets entered existences of torture by fire and ice.

The incident at the heart of the study is known as the Late Heavy Bombardment, a time about 4 billion years ago, not long after the Earth was formed from the dust and debris swirling around the young sun. According to the scientists, the Late Heavy Bombardment lasted 20 million years and rained millions of space rocks onto the surfaces of the Earth, moon and Mars.

According to the scientists’ theory, the frictional heat of passing through the thin atmosphere that surrounded the Earth at that time would have been enough to strip the oxygen-and water-rich outer layers from the meteorites as they plunged toward the planet. That process would have caused a slow buildup of oxygen and water in the atmosphere.

Gene sequencing getting cheaper, faster

They’ll be as small as your microwave and cheaper than your laptop. And the powerful tools—future gene sequencing machines—will be able to tell you exactly what you’re made of. Someday, they could help keep you healthy.

It took 10 years and $4 billion for the federal government to complete just one sequence of the human genome in 2000. Its equipment filled vast rooms.

Now rival scientific teams are racing to build tests that can accurately sequence an entire human genome in less than 30 minutes for $1,000—about a hundred-fold drop from current prices. The cheaper tests will make it possible to sequence the genomes of thousands more people, providing vital data about human traits, such as susceptibility to disease.

Virtuoso bioengineers predict that within two years their tests will start to transform medicine much as PCs rocked the world of mainframe computing.

As more genomes are sequenced, correlations between genes and diseases will become more apparent. And over time, sequencing will move into more diagnostic settings, like community hospitals.

—San Jose Mercury News