Ask the Expert

Q: Is there life on Mars?
Powers Ginsburg 4th Grade, Fresno, California

A: Currently, we have not detected any life on Mars. It is something we are very interested in knowing, however, and we are trying to find better and better ways to look for life (past or current) on Mars.

Q: If after the martian winter you can bring Phoenix back to life, what tests will you do on the martian soil?
Manchester 5th Grade, Fresno, California

A: We would primarily continue excavating the martian soil above the ice layer to see what the ice table looks like, and we would use our probe to measure the temperatures and water content in the topsoil.

Q: What does your team think the chances are that (even though it's not expected to do so) Phoenix could truly live up to its name and rise from the "ashes" of the martian winter and "phone home" and be ready to do more work? Do some team members feel more optimistic about that than others? What's your opinion? Thank you.
Anonymous

A: Most of the team members are not very optimistic that Phoenix will wake up when the sun shines on its solar panels again. The temperatures are so cold, and the temperature changes (expansion and contraction) tend to make things break on the spacecraft. In addition, when the carbon dioxide ice cap is formed at the lander's latitude, it could form by snowing, and the weight of that carbon dioxide snow could perhaps break the solar panels.

Q: If life is indicated by Phoenix, what precautions would be taken to assure that it isn't contamination from Earth?
Mike, Merritt Island, Florida

A: Phoenix did not have the capability to detect life. It only had the capability to detect organic (carbon-based) molecules. These molecules are the building blocks for life but also occur in non-life situations.

But we take great precautions to avoid bringing contamination from Earth. We clean our spacecraft very well and also heat-sterilize parts of it that interact with the martian soil. In addition, we took samples of spacecraft materials containing carbon and analyzed them to ensure that we wouldn't mistake any Earth contamination that may have been left (deceased) and interpret it as though it was from Mars.

Q: Are there any heat sources on Mars right now?
Jay (age 5), Wayne, Pennsylvania

A: We don't know if there are any active volcanoes right now. There are very large volcanoes present, but we haven't observed them erupting since we've started observing Mars (for about 50 years now).

Q: Is it possible that the things necessary to sustain life are different on other planets than they are on Earth?
Westview 8th Grade, Denver, Colorado

A: It may be possible, but life as we know it needs relatively moderate temperatures and water to live. So, places with those conditions are the first place to look. We know that, at a minimum, life needs an energy source of some sort.

Q: Given Mars' size and two wobbly moons, would life on Mars have evolved to look like us, or would it have been very different? Thank you.
Jack (age 8), Seattle, Washington

A: The lower gravity on Mars (due to its smaller size) may have enabled creatures to grow taller.

Q: Dr. Tamppari, Why does the quest for life outside Earth restrict itself to the narrow realm of carbon-based life forms, in which water is essential? Is it possible that alien life relies on another compound, one that we may not be familiar with? Is it possible that alien life could be so abstract that we are overlooking it? It seems that humans seek too much similarity in the quest for things outside the realm of what we currently understand. Do the same laws of physics, biology, genetics, math, etc. apply to alien worlds, and if the possibility exists that they do not, is the science community equipped to expand the search to include this possibility?
Respectfully submitted,
Ed Capowich, Canaan, Connecticut

A: As I understand it, the other element that easily combines, similar to carbon, is silicon. So, science fiction has sometimes proposed silicon-based life. I'm sure it's possible that our current understanding and techniques may overlook alien life. But we only understand what we know about life from our own experiences, so then we can devise ways to look for life as we understand it. It would be much harder to look for something unknown. How would we know when we've seen it?

Q: Your biography on this page says you're an expert in the martian atmosphere. Might the search for life on Mars continue in its atmosphere? Or is that just "pie in the sky"? Thanks.
Anonymous

A: My expertise is not in chemistry of the atmosphere, unfortunately. For life to exist solely in the atmosphere, it would have to be so small that atmospheric motions kept it aloft and gravity essentially never pulled it to the ground. I think looking on the surface is a much more likely place, but perhaps sometime in the future the atmosphere could be studied with this in mind as well.

Q: While I have the utmost respect for your quest of knowledge and find the exploration absolutely fascinating, I have some very basic questions: If you do find life on Mars, what does that mean to us? If there is life found on Mars, what's next? What is the expected value or payoff of the total cost? Thank you.
Kevin, Round Lake Beach, Illinois

A: If we found native life on Mars, either currently alive or extinct, it would mean that life didn't just arise on Earth. That would be a huge discovery to know that life can originate in multiple places. It has been thought that the Earth's temperature conditions, due to its distance from the sun, and its water content make it unique, and, like Goldilocks and the three bears, "just right" for life to occur. If that is not the case, then life may be originating all over the universe!

If we did find life on Mars, I'm sure there would be a lot more exploration of Mars than there is now. We would try to understand when and where it originated and how widespread that life is. I think a "life-on-Mars" discovery would be the biggest discovery of our lifetime, so the value would far outweigh the cost.

Q: Why not populate a sample of the martian soil with a known quantity of bacteria from Earth that could grow in subzero temp-pH 8.3-high perchlorate concentration and see after a time if the quantity of bacteria has increased or try to measure metabolites of bacterial growth? This would not answer the question about indigenous life on Mars but would demonstrate that conditions exist to support life. Your team has probably done this experiment, but if not this would be an interesting project.

The program was excellent. Happy New martian discoveries in 2009.
J.C. Sipio, M.D., Mount Laurel, New Jersey

A: It would be interesting to know what could grow in martian soil. However, it is too risky to do that just yet given that we are trying to understand if indigenous life ever existed on Mars. We are very careful to not contaminate Mars with any Earth microbes prior to a better understanding of the potential for extant life on Mars.

A related project, however, is one in which we are studying soils in the Antarctic Dry Valleys. This location is the best Earth analog to the location in which the Phoenix landed. We are trying to understand the similarities and differences between these soils and the water environment so that we can draw inferences as to what might live on Mars.

Q: I seriously question the identification of calcite by TEGA. Errors of identification will result if you do not know conditions inside furnace and you do not know the pressure conditions inside furnace. A mixed carbonate (Fe, Mg, Ca) will give various carbon dioxide releases. Prove it is calcite!
Everett Gibson, Houston, Texas

A: TEGA measures outlet and manifold pressures. In addition, we have an analog system at Johnson Space Center in which we run samples for comparison/calibration. We have a paper that is scheduled to be delivered to Science magazine later this month that will describe this story. We will also be discussing this at the Lunar and Planetary Science Conference in March—check here if you're interested: http://www.lpi.usra.edu/meetings/lpsc2009/

Q: Doctor, have you seen any credible evidence of "artifacts" that gives you some reasonable doubt as to whether an ancient civilization once inhabited Mars? Or are you convinced all the photos of "faces", "pyramids", and "statues" on Mars are merely tricks of light and shadow rather than intelligent constructions?
Michael, Las Vegas, Nevada

A: Personally, I am convinced that the putative "faces, pyramids, and statues" are only natural features on Mars. I have not seen any convincing evidence of ancient, intelligent civilizations on Mars. Instead, the Mars program will be attempting to look for evidence of microbial life, now or in the past.