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Way Cool Scientist!

Questions mark the beginning of every space science journey. So if you've ever wondered why, where, what, who or how — click the "Ask A Question" button below to find out from the Athena Mission scientists. Read on to discover what other kids have found out!


1) How long will the rovers stay on Mars? And how long will it be before we start sending rovers to other planets?

Unless, sometime in the future, when humans visit Mars on such a regular basis that some people just decide to live there, and a rover is sent back to Earth to reside in a museum, the Mars Exploration Rovers will in all likelihood stay on Mars. I rather expect they'll end up as museum exhibits there. Regarding sending rovers to other worlds besides Mars, that has already happened! The Soviet Union, now the Russian Federation and a bunch of other countries like Ukraine, Georgia, etc., sent rovers to the Moon and successfully operated them there for several months at a time. These rovers were called Lunakod. I'm sure rovers and humans will again explore the Moon during the next hundred years.

I don't see rovers operating at the red hot temperatures of the surface of Venus; it's easier to fly a balloon in the cooler altitudes of that planet's atmosphere, as has already been done in a joint Soviet-French mission. Some imaginative scientists have come up with the idea of dropping a sampling device on a long "rope" from a balloon and hauling it up to retrieve samples to be analyzed in an automatic lab in the gondola of the balloon flying in the cool venusian air (which is mostly CO2).

Rovers could be used on Mercury, of course it can get pretty hot there, and on the surfaces of the moons of Jupiter and Saturn. Taking into account the economics of space exploration (and I mean money), it is most likely that rovers will next be operated on asteroids. In fact there was a plan for a joint US-Japan rover mission but the rover got canceled for lack of dollars. I think for the foreseeable future Mars and again the Moon will be the targets for rover missions.

2) Do you think that NASA 25 years ago passed up finding life for a soil sample from Viking 1 & 2?

No! Actually, I wish that instead of "test-strip" life search instruments (that is what I call them), we had sent instruments to better analyze the rocks and soil before we tried to test for the presence of life. The life search instruments gave either outright negative results or ambiguous results better explained by something other than life. After which the instruments just sat there! They weren't much use in understanding Mars, unlike the cameras and other instruments. Part of a life search instrument, a mass spectrometer, did tell us about the composition of the atmosphere. There is a class of instruments that can do double duty, namely tell us about Mars as a world, and detect evidence regarding life if it ever existed on Mars or did and is still there. These kinds of instruments inquire into the molecular structure of minerals and substances involved in life equally well. They allow searching for the effects of water in ancient times or more recently, and water is a necessity if life is to exist. Although I'm more optimistic than some scientists about using instruments on Mars to search for evidence regarding the question of life having been or still being there, I think bringing samples from Mars to Earth is a very good thing to do. When this is done it is very important to select the samples very carefully, with instruments of course, and to bring back as wide a variety in location and character as possible. This can happen over the next 15 years or so using robotic missions with rovers. Twenty or thirty years from now, hopefully humans will be employed in the search as well.

3) Is Pluto the coldest planet in the universe?

Pluto is one of the coldest places in the solar system, but you have to remember that its orbit brings it a bit closer to the sun than the orbit of Neptune does at certain times. In fact, the position of Pluto over the past few years has been closer to the Sun than parts of the orbit of Neptune. Pluto as a planet is the subject of controversy with one school of thought saying it really isn't a body like the other eight "planets". In a way I have to tend to agree with that, mainly on the basis that the word "planet" just means "wanderer" in ancient Greek. Jupiter and Saturn are very different kinds of cosmic bodies, perhaps more like the Sun because of composition and the way they were formed, than like the Earth, Mars, Venus, or Mercury (I tend to think of bodies you can walk or rove upon as "worlds"). We now know there are Pluto-like bodies farther out in the Solar System so they would be colder by simply receiving less sunlight. Astronomers also have good reason to think there are bodies, call them planets, that are independent of stars and traveling alone through interstellar space. These objects would get very cold only being illuminated by starlight. In fact their temperatures could approach the temperature of the Universe which is about 2.7 Kelvin or 2.7 above absolute zero. Pluto, with a temperature ten times higher would be a relatively warm place in comparison.

4) What are your thoughts about life on Mars?

First off, the reason I'm so thrilled to be involved in the Mars Exploration Rover missions is because the information we already have on Mars, and what we are beginning to understand about life on Earth and its origins and capabilities for survival, argues strongly for doing the kind of effort underway to try to answer the Life and Mars question. Consider this - what we know about the Moon indicates spending any level of effort on the question of life and that body would only lead us to a negative result. Mars is quite a different situation, in fact what we already know compels us to address the question. Water quite probably played a role on the world in the ancient past, and perhaps even more recently (maybe even now). That alone is sufficient to give cause for formal speculation ("theories"). The picture emerging for Mars and the Earth, particularly the first billion years, suggests conditions on both worlds may have been similar enough for at least a sufficient period early on, for life to come into existence on Mars as it did on Earth. Indeed, even though I am formally trained as an astronomer and chemist, I got into this adventure from the standpoint of searching Mars for fossil evidence of life. Not Martian dinosaurs, but rather microbes, the smallest forms of life like the bacteria and archea which presently exist on Earth, and have done so for billions of years. To do this we have to learn if the right kinds of minerals for retaining ancient fossils even exist on Mars. For almost fifteen years now, I've been learning about the oldest evidence for life on Earth, now going back some 3.5 billion years and perhaps even earlier. I've learned, thanks to some really smart friends and practical experience, that in order to create a fossil of a microbe, the mineral texture must be just right and the rock very tough to survive billions of years against erosion forces. I've been engaged in studying hot springs in places like Yellowstone National Park, and have examined material brought up from the volcanic environments deep in the oceans. You can bet that I will keep an eye out for evidence of similar things as we move across Mars. All those volcanos, and strong suggestions of water on Mars demands my attention, and of my MER colleagues in that regard. We need to find good places to go to in the future to pick up samples for transport to laboratories on earth, and to get as much experience in doing so.