Are There Bugs Out There? NASA's Search for Extraterrestrial Life

Dr. John Delano

Distinguished Teaching Professor in the Department of Earth and Atmospheric Sciences at the University at Albany,

Associate Director of the New York Center for Studies on the Origin of Life

This is the recap of a talk given at the June 9, 2002 CDHS monthly meeting.

The number of stars in the universe is estimated to be 1022 (10,000,000,000,000,000,000,000), which is about equal to the number of grains of sand on all beaches and deserts on Earth. The number of planets out there will be an even bigger number. Is anybody out there? Dr. John Delano, Chairman SUNY Dept of Earth and Atmospheric Sciences, tells us that NASA is asking this and other fundamental questions about the origin and distribution of life in the Universe. It is likely that within the next 10 years some of the most profound questions of humanity will be answered. But, of course, these questions will lead to new ones. The reason we can look forward to these exciting headline-grabbers is because of the plans and goals NASA defined for itself which are beginning to pay off.

As an example of changing scientific view of the universe, Dr Delano related the ideas of Yuri Miller. In the 1950's, he suggested that the earth's early atmosphere was very different than the present one (nitrogen, molecular oxygen) and resembled the atmosphere of Jupiter (hydrogen, methane, ammonia, etc). He experimented with adding lightning to a flask filled with these gasses. The result was a cloud of over 20 amino acids and other building blocks of early life (needed for proteins and DNA to form). However, the current thinking is that the type of atmosphere Miller suggested did not exist on Earth. As Dr. Delano reminded us throughout the talk, science is not finding "the truth;" it is a process of seeking better and better approximations to "the truth."

Where did the molecules of early life come from? There are several suggestions:

Meteorites - they are loaded with carbon and have amino acids.
Comets - NASA will land on one in the future and analyze it. (They are loaded with Formaldehyde and Hydrogen Cyanide which are parts of the bases of DNA)

We used to assume that the sun was the basis of all life on earth. We now know that this in an incomplete statement. Although complex life depends on the sun, not all life does. The creatures closest to the origin of life are organisms which thrive in hot places (some in temperatures in excess of 100 degrees centigrade) but don't need the sun. What these life forms require comes from a reaction of sulfuric acid and molecular hydrogen and water, which are naturally occurring components where these creatures live deep in the oceans. Planets in interstellar space could also have this kind of microbial life which depends on radioactive heat rather than a star.

"The earth revolves around the sun" is another incomplete statement which science has fine-tuned. We now know the earth actually revolves around the center of mass of the solar system (sun and its planets) which is outside the sun. The sun itself revolves around this center of mass also.

NASA is looking for life on:

Mars - a lot of water/ice below the surface of Mars. We have 15 pieces of Mars which have fallen to earth. It has been proposed that some of these might have fossilized bacteria on it but the current evidence for this is weak.
Satellites around Jupiter - Europa is an ice-covered object the size of our moon which has a 60-mile-deep ocean under a 6-mile layer of ice. Based on images of the ice, it is believed the ocean is saltwater. NASA may, within 10 years, send a spacecraft to Europa which will crash through to the ocean like a spear at 30 km per second carrying robotic submersibles to look for microbial life.
Planets - The closest star is 4 light years away. Less than 5 years ago we knew of no planets around stars, but now we know of 85 to 100, all based on ground observation. Delano predicts that in 5 years we may know of 5,000. NASA is planning to go above Earth's atmosphere with spacecraft and start looking at 40 million solar-like stars that are within 100 light years of Earth. NASA knows that there are other planets with stars by studying the way the stars revolve. Even though we can't see the planets, the irregular movement or "wobble" a star displays is an indication of its rotation about the center of mass of its sun-planetary system. By measuring the light of these wobbling stars, NASA can determine the speed, the period of revolution, and the mass of the planets. The more complicated the revolutions (the observed "wobble"), the more planets there are. It is estimated that 10% of stars have planets but this figure could increase. Eventually, NASA would like to launch a terrestrial planet finder (est. 2015) into solar orbit to look at the planets that have been found (with the right type of orbits and stars) and study their atmospheres. Oxygen-rich atmospheres would be a sign of life.

Thoughts from the Q&A session:

In response to a question about his views concerning how religion feels threatened by his type of research, Dr. Delano stated that we can't know the grand scheme of things. We will make mistakes and we will continue to explore. God is a subject not threatened or touchable by science and science is not a threat to faith unless religion chooses to stand in its way.

Extermination event: NASA is funding studies of this. Some objects have come quite near us, but they do not predict anything as a threat for at least 200 years. However, there are probably objects that have not yet been detected.

The book Rare Earth suggests that there may be an abundance of planets with suns and life on them, but the life will be principally microbial. It would be rare to find complex (multi-cell) life like us because we depend on a narrow range of temperature, etc. Our moon is debris from the earth when it was hit by an object. The moon affects earth's orbit in ways that are conducive to our type of life. If a planet didn't have a moon, it would be unlikely to sustain life other than microbial.

Most planets are about 2 billion years older than earth. It is possible that they have already had life come and go.

Go to top of page

Send website comments to webmaster@humanistsociety.org

Return to CDHS Home