Life on Earth could have grown from the broken remains of alien viruses that, although dead, still contained enough information to give rise to new life.
Scientists have speculated that life could have come to Earth from space — a notion called panspermia — since the 1870s, when Lord Kelvin suggested microbes could have ridden here on a comet or meteor. Others have suggested tiny organisms could cross the galaxy embedded in dust grains, which could be nudged from one planetary system to another by the slight pressure of stars’ radiation.
However, most astrobiologists think that same radiation spells a death sentence for delicate microbes.
“That essentially kills panspermia in the classical sense,” said astrobiologist Rocco Mancinelli of the SETI Institute in Mountain View, California.
But maybe not, says astronomer Paul Wesson, a visiting researcher at the Herzberg Institute of Astrophysics in Canada. In an upcoming paper in Space Science Reviews, Wesson argues that even if the actual microbes are dead on arrival, the information they carry could allow life to rise from the charred remains, an idea he calls necropanspermia.
“The vast majority of organisms reach a new home in the Milky Way in a technically dead state,” Wesson wrote. “Resurrection may, however, be possible.”
The key lies in how much genetic information survives the trip, Wesson says. An organism’s genetic information is encoded in the sequence of nucleotides in their DNA. This information can be measured in bits in the same way as computer processes. Bacteria like E. coli, for example, carry about 6 million bits of information in their DNA.
Random chemical processes couldn’t produce enough information to run even a simple cell. Over 500 million years, random molecular shuffling would produce only 194 bits of information, Wesson says.
