Scientist: Jupiter radiation could mean life on Europa

January 28, 2000
Web posted at: 4:53 PM EST (2153 GMT)

From staff reports

PALO ALTO, California -- A vast subterranean sea underneath one of Jupiter's moons could host living microorganisms similar in size and complexity to bacteria found on Earth, according to an article in the journal Nature this week.

Despite having a frozen surface, Europa could possibly produce sources of energy for basic chemical reactions needed for life, thanks to billions of charged particles that constantly rain down from Jupiter, theorizes Stanford University professor Christopher Chyba in the report.

The evidence is strong that beneath Europa's frozen exterior of ice lies an ocean of liquid water, one of the essential ingredients for all living organisms.

And a relentless bombardment of radiation "should produce organic and oxidant molecules sufficient to fuel a substantial Europan biosphere," Chyba writes.

Sunlight would not provide enough energy to sustain life on Europa since its ocean appears to lie beneath an ice layer "too thick to permit photosynthesis," said Chyba, as quoted by the Stanford University News Service.

A more likely source of energy, he concludes, may come from fast-moving, charged particles that pound Europa from the atmosphere of Jupiter.

	 IMAGE GALLERY
The latest Io images

	 MESSAGE BOARD
Stargazing


Jupiter has the strongest magnetic field of any planet, Chyba says, more than 10 times stronger than Earth's. When protons, electrons and other particles from space get trapped in Jupiter's magnetosphere, they are accelerated to extremely high velocities.

Europa's orbital path around Jupiter lies deep within this powerful magnetic field, so it receives a continuous barrage of electrified particles or ions.

According to Chyba, when these ions slam into the icy surface of the moon, chemical reactions are likely to occur, transforming frozen molecules of water and carbon dioxide into new organic compounds such as formaldehyde.

It turns out that one of the most common bacteria on Earth, Hyphomicrobium, survives on formaldehyde as its sole source of carbon, and Chyba believes that similar formaldehyde-feeding microbes could be alive and swimming in Europa's subsurface.

In addition to his Stanford post, Chyba works for the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California.