Researchers say stardust origin of life
18 June 2004
DARMSTADT – All life on this planet had its origins in stardust which probably brought the microscopic building blocks of life through trackless space to Earth billions of years ago, according to a team of German physicists.
The researchers at the Darmstadt research laboratory of Dr Franz R. Krueger and the Max Planck Institute for Aeronomics in Katlengurg-Lindau said they had found traces of molecular enzymes in the tail of a comet encountered by the American Stardust probe.
The NASA probe has an onboard Cometary and Interstellar Dust Analyser (CIDA), a mass spectrometer that has been collecting information from interstellar dust particles since 1999.
The scientists said they found evidence of a co-enzyme similar to pyrroloquinoline-quinone (PQQ) that is a pre-requisite for life as we know it.
“PQQ-like co-enzymes occur in all life forms aside from archaeobacteria,” said Jochen Kissel of the Robert Koch Institute. “It is a vital link in the chain of life on Earth.”
Writing in the journal Science, co-researcher Krueger, head of a private physics lab in Darmstadt, said he is convinced that it was the arrival of PQQ-laden stardust on Earth 3.6 billion years ago that spawned life on the otherwise lifeless planet.
For years scientists were puzzled by the sudden appearance of PQQ co-enzymes. The question was where the genetic makeup of PQQ co-enzymes, so necessary for life, came from if the Earth had no life able to produce such a genetic makeup.
“It is the age-old question of which came first, the chicken or the egg,” Krueger said. “The enzymes that start the process can only come into existence themselves if a genetic code already exists.”
Combined with water and other factors, the co-enzymes could have spawned life in the early seas of Earth.
“The PQQ-like co-enzymes themselves come into being with the aid of cosmic rays from existing molecules on the surface of mineral particles,” Kissel said.
Krueger is part of the team that developed the spectrometer aboard the NASA probe which gathers dust particles streaking through space at the speed of 20 km per second.
“To this day about 4,000 tons of interstellar dust falls to Earth each year,” Krueger said, “most of it vaporizing in the atmosphere.”
Subject: German news