Seeking Life’s Source on the Cheap
Over the years, Congress has shot down a number of the grander projects that scientists sought to study cosmic questions. These included a half-trillion-dollar manned mission to Mars, proposed by President George Bush in 1989 to look for life on the Red Planet, and the $11-billion superconducting supercollider, intended to study Big Bang physics but rejected in 1993. Rightly, perhaps, the projects were dismissed as expensive dreams of grown-ups playing with fancy toys.
Still, it’s impressive to see what scientists have done of late with modest tools that taxpayer dollars helped them build. Particularly striking are two discoveries reported in this week’s edition of the journal Science that could help answer what is arguably the most overarching question of all: How did the chemistry of rocks and minerals give rise to the cellular biochemistry of life as we know it?
In the first discovery, UCLA geophysicists used recent data from the Galileo space probe to produce compelling evidence of a salt water ocean beneath the icy surface of Europa, one of Jupiter’s many moons.
The second came from researchers at the Carnegie Institution of Washington, D.C., who used a powerful machine to generate high pressures and temperatures that mimicked conditions presumed to have been present when the Earth formed as a planet.
Working with pressures 20 times those of today’s atmosphere and a temperature of 482 Fahrenheit--more than twice the boiling point of water--the Carnegie scientists created a crucial component of life: the chemical pyruvate, which is the fuel for a universal energy-producing process known as the citric acid cycle.
Both the UCLA and the Carnegie experiments are efforts to develop an alternative to the prevailing “broth” theory of life, which holds that the first cells grew slowly in a “pre-biotic” soup of various chemicals. The alternative “iron-sulfur world theory” hypothesizes that life instead began quickly when hydrothermal vents catalyzed chemical reactions in Earth’s oceans.
Whether life emerged similarly on the moon Europa is still just a matter of speculation. The only way to confirm it, NASA says, would be to land a submarine-like probe on Europa and use its thrusters to burrow through the icy crust--just the sort of megabucks project that Congress is reluctant to fund.
In the meantime, though, the UCLA discovery, along with the Carnegie research, has bolstered the argument of those who believe that life may have developed in seemingly inhospitable circumstances both on Earth and Europa and confirmed that scientists, with or without fancy toys, aren’t about to flinch from cosmic questions.
