Life might survive a meteoric fall to Earth

Phytoplankton: foundation of the ocean's food web...and possibly of life's origins? Photo courtesy of NOAA via flickr Creative Commons.
Phytoplankton: foundation of the ocean’s food web…and possibly of life’s origins? Photo courtesy of NOAA via flickr Creative Commons.

by Mark Zastrow
BU News Service

Are we the aliens we’ve been looking for?

The notion that the seeds of life originated in outer space and fell to Earth on a meteorite may seem like science fiction. After all, the theory, known as panspermia supposes that life could survive the violent impact. But now, that survival act looks possible, according to research presented last month at a conference in London.

To test life’s resilience, the researchers froze phytoplankton—the microscopic organisms that permeate the ocean—into pellets, as if stuck on a rock sailing through interstellar space. They loaded the ice-bound algae into a powerful gas gun, which shot them into water at over 13,500 miles per hour. Then they thawed the samples and left them to culture.

But despite the violent impact, a small portion of plankton survived. “This sort of impact velocity would be what you would expect if a meteorite hit a planet similar to the Earth,” Dina Pasini, a scientist at University College London and the study’s lead author, said in a statement.

Panspermia has recently received a boost of media coverage. A study published September 15 in the journal Nature Geoscience suggested that comets smashing into primordial Earth could have formed amino acids, the building blocks of life. And in late August, a team of scientists claimed that Mars, not Earth, was the best place in the early Solar System to find molybdenum, a key element in enzymes required by complex life.

Pasini notes that a round of headlines doesn’t mean the theory is proven. But she says that her research shows that questions like whether we fell from the sky, or if aliens out there are our distant relatives, are “not as farfetched as one might assume.”