Life on Venus?

From: (Ken Edgett)
Subject: Life on Venus?
Date: Mon, 03 Mar 1997 10:49:04 -0700 (MST)

Dear Mars Educators,

With all the "life on Mars" discussions going on these days, its
only natural the folks also look at and talk about other Solar 
System objects as possible havens for life.  The most surprising
idea I have seen since the August 1996 "life on Mars" announcement
comes from my colleague David Grinspoon at UC Boulder.  He suggests
the possibility that VENUS had life!

Below is an article, he also has a forthcoming book about Venus that
you might want for the classroom.  The article comes from "Marsbugs:
The Electronic Exobilogy Newsletter," v. 4, n. 4, 26 February 1997.
You can subscribe to this newsletter by sending an email request to
Julian Hiscox,  This is a 
legitamate forum of exchange between exobiology scientists and 

The article below, about life on Venus, surely will provoke interesting
discussion among your students about the differences between Earth, Mars,
and the other planets.

Ken Edgett,
Arizona Mars K-12 Education Program


Forwarded from University of Colorado

Despite recent reports of possible fossils in Martian meteorites,
Venus, not Mars, may hold the most promise for harboring life
elsewhere in our solar system, according to a University of
Colorado at Boulder professor.

Some four billion years ago when the sun was 40 percent cooler
than today, Earth and Mars probably were frozen, said CU-Boulder
Assistant Professor David Grinspoon of the astrophysical and
planetary sciences department.  But Venus, closer to the sun, may
have had warm liquid oceans and a mild climate at the time.
"There is some reason to believe Venus may have been the best
haven for life in the early solar system," he said.

With 900 degree Fahrenheit surface temperatures and an atmosphere
permeated by carbon dioxide, chlorine and sulfuric acid clouds
today, Venus seems inhospitable to "our kind of life," he said.
"But we really don't know much about life -- its requirements,
it's differences and how to recognize it."

Humans on Earth "may have evolved from life forms provided by
Venus," Grinspoon said.  "Pieces of planets were blasting off of
each other all the time early in the evolution of the solar
system, and microbes from Venus could easily have wound up on

The standard scientific view is that life requires water and
carbon-based molecules, he said.  "We simply do not know if that
is the only chemical system that can make life, because the only
example of a biosphere we have is our own," said Grinspoon, who
has been studying the surface, atmosphere and clouds of Venus for
10 years through NASA-sponsored programs.

Grinspoon is the author of "Venus Revealed," published by
Addison-Wesley Publishing Co.  of Reading, Mass., this month.

In some ways, Venus may have a better environment for nurturing
life than Mars, he said.  Like Earth, Venus has a "chemically
lively surface and atmosphere" that could provide organisms with
energy and nutrients.

"In my view, what makes Earth special is its atmospheric cycles
that renew themselves like a garden tilling itself," he said.
"It could well be that kind of an environment on Venus is just as
important for life as carbon."

Because the surface and atmosphere of Venus are constantly
renewing themselves through volcanic activity, there is "more
potential for interesting chemical and even biochemical processes
on Venus than on Mars."

It's possible, he said, that Venus could have tiny microbes in
its cloud particles, or that some form of Venusian life could
have developed by using ultraviolet light much like Earth's
plants use sunlight to make food.

There could even be a non-carbon-based equivalent to lichens atop
Venus' five-mile-high volcanoes, perhaps feeding on sulfur gases,
he said.

The interactions of Earth's oceans, clouds, surface and biosphere
has led some scientists to support the Gaia theory that Earth
itself is a living system, he said.  "By constantly exhaling
sulfur gases that react with the clouds and surface minerals,
Venus could be considered in that Gaia realm."

Although NASA's 1989 Magellan probe opened a new window on the
planet using sophisticated radar mapping, there is still much to
learn about Venus, said Grinspoon.  One key is to keep an open
mind about chemical and perhaps biological processes that may be
occurring there and on other planets.

"Venus is the closest thing Earth has to a twin," he said.
"Studying Venus is how we learned about the problem with our
ozone layer, and it's a way for us to become wiser in taking care
of our own planet."

Excerpts and images from "Venus Revealed" can be accessed on the
World Wide Web at: