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Decade of Planetary and Earth Science as seen on The Frontiers Decade

q What is the approximate age of earth?

A Scientists believe that the Earth (and the Sun and the other planets in the solar system) is about 4.6 billion years old. This is really quite old! 4.6 billion is a VERY big number. For instance, if you started counting now and counted up as fast as you can without stopping for food or sleep or even a glass of water, it would take you about 44 years just to count to 4.6 billion!
Sue Barns
Life's Big Questions, October 1994

q At this point, what do you know about the composition of the rocks and soil on Mars?

A The first analysis of Martian soils took place over 20 years ago by Viking. Then the Pathfinder mission landed on Mars in 1997. Do you remember the vehicle called Sojourner which roamed the Martian surface and analyzed rocks called Scoobie Doo and Barnacle Bill? We have found that the rocks analyzed by Pathfinder contain a lot of an element called silicon. It has been suggested that rocks with high amounts of silicon are probably andesites. One way andesites can form is when liquid, hot rock-material from the mantle intrudes deep within the crust. Crystals rich in iron and magnesium also form but are separated from the melt, leaving a more silicon-rich melt that erupts onto the surface. This composition is very different from the Martian meteorites we have studied; the meteorites are composed of relatively low silicon and are high in iron and magnesium. The meteorites are believed to have formed by partial melting of the upper mantle of Mars; the melt rises up through the crust and solidifies at or near the surface. Both of these types of rocks formed at high temperatures. However, not all of the Martian rocks are believed to have formed at high temperatures. Some rocks appear to have layers like those in terrestrial sedimentary rocks, which formed by the deposition of smaller rocks in water. Some of the Sojourner images show rocks which appear to be rounded suggesting erosional activity by water on Mars. There are carbonates (carbon-containing rocks) in some of the Martian meteorites. Carbonates in Martian meteorite ALH84001 are believed to have formed at low temperatures with water and possibly bacteria, too. Therefore, there are several different types of rocks from Mars, some formed at high temperatures and some believed to have formed at low temperatures. Of course we have analyzed only a very small number of rocks from Mars. To get the complete story of how the planet formed, how much water was there, if bacteria existed or still exists on Mars, we need to bring back rocks and examine them with more sophisticated types of equipment that we have here on Earth. I believe that if we plan well (plus a bit of luck) that we may get samples back from Mars as early as 2008. If you are really interested, then study hard and you will be prepared to help us discover new and exciting information about the red planet!
Kathie Thomas Keprta
Journey to Mars, November 1998

q Hello, Andrew Thomas! We are studying about space flight in school and have a few questions: How does it feel to be weightless? How long did it take you to adapt to the feeling of weightlessness on Mir and then readjust when you came back to Earth?

A Weightlessness is a wonderful feeling and great sense of freedom. It does take a few days to adjust to it, but after a while it starts to feel like a very natural way to be. Since I was gone for so long (20 weeks), it did take some time to readjust back to Earth's gravity. It was a few days before my balance was restored, and a few weeks before my muscles were back to normal. The first time I stood up was a bizarre sensation and I had legs that felt unbelievably heavy and required a seemingly huge effort to move. And curiously the soles of my feet were very tender as I had not walked on them for 20 weeks.
Andrew Thomas
Journey to Mars, November 1998

q Do you want to travel to Mars and why?

A To my thinking, the idea of stepping foot on, and visiting another planet would be one of the most extraordinary adventures that anyone could possibly do. Just imagine what it would be like. . .every thing you saw and experienced, and all the sights would be those of another world.
Andrew Thomas
Journey to Mars, November 1998

q On your story, Alan Alda tried out three different kinds of exercise machines. I am wondering which one seems most effective and what type of exercise machine(s) you think will eventually be used for astronauts who go to Mars.

A As of now, we really do not know exactly what kind of exercise machines will be most effective in space to prevent the deconditioning effects of microgravity in a long-duration mission - such as a mission to Mars. The three kinds of exercise machines shown on the program were:
(1) the lower body negative pressure treadmill,
(2) the upper body positive pressure treadmill, and
(3) the human powered (bicycle) centrifuge.

All three machines provide a way to exercise the large antigravity muscles of the lower limbs and to stimulate the cardiovascular system. Both treadmill machines also provide contact and impact forces when the foot leaves and contacts the treadmill, thereby possibly providing additional stimulation to the bones that normally would support the weight of the person under normal gravity conditions. The human powered centrifuge generates a centrifugal force that can simulate the pull of gravity on the internal organs and the heart-brain blood column. This stimulation may be extremely effective in maintaining normal cardiovascular functioning for astronauts in space, but we do not yet have any data on this. We expect that some of the machines that were shown on the Scientific American Frontiers program will be tested on the International Space Station when it becomes operational as a test bed, and that the techniques that prove to be the most effective over a long mission duration will be the ones that will be used on a mission to Mars.
Malcolm Cohen
Journey to Mars, November 1998

q I'd like to know more about the system you developed to make fuel on Mars. What goes into the system, what chemical reactions occur and what is the final product?

A There are a number of ways to run the system. One way is to have hydrogen (taken from Earth) and carbon dioxide (taken from the Martian atmosphere) go in, and react to form methane and water. We then store the methane to use as fuel, and electrolyze the water, which makes oxygen (oxydizer needed to burn the fuel) and hydrogen, which is recycled back into the machine to react again. The net product of this cycle is thus methane and oxygen.

Another way to run the machine is to use a different catalyst (copper on alumina instead of ruthenium on alumina) which will cause the hydrogen and carbon dioxide to react to make carbon monoxide and water. The water is electrolyzed to produce oxygen and hydrogen, as before. The carbon monoxide is reacted with more hydrogen in a second (copper on zinc oxide) reactor to make methanol. The net product of this cycle is thus methanol and oxygen.
Robert Zubrin
Journey to Mars, November 1998

q Why are we trying to colonize Mars when we haven't even tried to colonize the moon? And why Mars instead of another planet?

A The reason why we should try to colonize Mars first is because Mars, unlike the Moon, possesses all the resources needed to support life and civilization. The Moon has very little water, Mars has amounts that could fill oceans. Mars has carbon and nitrogen, the Moon does not. Mars has a 24 hour day, which is what plants need to grow, but the Moon has 2 weeks of light followed by 2 weeks of dark. Mars has an atmosphere, the Moon doesn't. In every respect but distance, Mars is a better target for colonization than the Moon. If we compare the Moon and Mars to possible destinations in Earth's past age of exploration, the Moon is like Greenland - close to Europe but barren of resources. Mars is like North America - further away but much richer in resources and thus a place where a new civilization could really be built.
Robert Zubrin
Journey to Mars, November 1998

q In your scientific opinion, could aliens really exist? And have there been any events that indicate any REAL evidence of alien life in the solar system?

A With "jillions" of stars in the vast universe, it would seem probably that there are many others with planets and that some of these would have intelligent life. It is for this reason that the SETI Institute employs giant radio telescopes to "listen" for signals from distant civilizations. Most probably such ET civilizations would use radio signals to search for and locate other intelligent life before sending a craft to this planet.

However, suppose than an ET civilization beamed a radio message toward earth some 2,000 years ago--some 1,900 years before we first invented radio. When they got no response, they may well have concluded: "There's no intelligent life on that planet" and have beamed their radio messages in other directions. Then, perhaps 1,000 years ago they decided to try again--again with no response from us. They may have given up for good, or perhaps they plan to try again but last year they engaged in nuclear was and destroyed all life on their planet.

There are some UFOlogists who claim the government knows that we have ET visitors but are keeping it secret because they fear the public would panic, that Wall Street would crash, and that our traditional religions would suffer. I have far more confidence in the American public --and the peoples of our planet.

To the best of my knowledge, there is no scientifically credible evidence or events that would indicate ET life in our solar system or elsewhere in the vast universe. However, hope persists and research continues via giant radio telescopes and sensitive radio receivers by the respected SETI institute.
Philip Klass
Beyond Science?, November 1997

q Do you think volcanologists will ever be able to predict eruptions perfectly? Do you think we will ever have technology to prevent volcanoes from erupting?

A I don't think we will be able to predict eruptions. That is the only thing we can say for sure. Volcanoes are incredibly, complex natural systems, and there all sorts of effects which interplay to control the eruption rate, the gas bubble content and so on. The physics of these interplaying effects is largely unknown. The best we can do is to monitor intensively, observe, follow all the changes and when necessary give a wide margin of error. Some things are fairly obvious though and although we can't say a certain event will happen at 10:35 tomorrow morning, we can say that it is likely to happen very soon. If it does happen these areas will be affected and if you are in that area when it occurs you will be killed. The areas that have been threatened by pyroclastic flows here have always been obvious and so there haven't been any surprises when large flows have developed and destroyed new areas.

I don't think we can prevent volcanoes from erupting. Lava flows can be diverted to an extent, mud flows can be controlled. For explosions you need to get under a strong roof. For ashfall you need to wear a mask so you don't inhale the dust. For pyroclastic flows and surges, you can do nothing really, other than make sure that you are not close to the volcano.
Rick Herd
Science in Paradise, October, 1998

q Is Surtsey the first time you've had a chance to study how plants colonize "new" land? What is the most surprising thing you have learned there?

A No, we have also been studying plant colonization on eroded land on the mainland of Iceland. Although there are many similarities between the conditions on eroded land and Surtsey (unstable and low nutrient content of soils), they also differ greatly. On eroded land the distance to the nearest seed sources is only few hundred meters but Surtsey is an isolated island and therefore the plants have to overcome that barrier to colonize the island.

There are several surprising things we have learned from our studies. We find it very interesting to follow how effective the Sea Sandworth (Honkenia peploides) has been in colonizing the island, in spite of the harsh conditions like the abrasion from wind blown material and the low soil nitrogen content. This species is by far the most successful colonist on Surtsey and has now spread over the whole island.

Quite surprising for us is also the fact that the vascular plants are the dominant colonists on Surtsey, but not the lichens or mosses which usually dominate young lava fields in southern Iceland. The main reason for the low cover of mosses and lichens compared to vascular plants might be the drifting sand and ash. These plants are known to be very sensitive to accumulation and abrasion by wind born material. It is also possible that the colonization by these plants is retarded in some way by surface characteristics of the lava fields.

We also find it very interesting to see how the sea gulls have affected plant succession on the island. In the gull colony, which started forming on the island in 1986, there has been a great increase in the number and cover of vascular plants, probably due to increased dispersal to the island and fertilization by the birds.
Sigurdur Magnusson
Nordic Sagas, January 1998

q Can you tell us how you are going to use the information you are learning by studying new life on the newly formed island of Surtsey?

A The results from Surtsey can be used in several ways. The information can help us to predict how natural plant succession will proceed in other places under similar circumstances, e.g., on new lava fields, on eroded land or following retreat of glaciers. Also, the information on the succession in Surtsey is very important as it can be used to make better restoration plans for severely disturbed areas which are of similar character as Surtsey.
Sigurdur Magnusson
Nordic Sagas, January 1998


Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
now a part of Verizon Communications Inc.