So now arises the question that most people that let their minds float off into the infinite folds of the blanket of possibility often find themselves confronting: is there extraterrestrial life in the universe?
In finding myself wondering this same question and pondering different possibilities as well, I became quite interested when I recently came across a poster on campus here at UND that was in fact titled “Life in the Universe.” The poster was for a lecture by Dr. Lawrence Rudnick from the University of Minnesota. The title of the lecture and the buitiful cluster of solar systems picture behind it were easily enough to provoke me to come. The lecture was very interesting and pointed out a lot of different things I think should be mentioned. The rest of this post will consist of different ideas, facts, and methods about space exploration and potential life in the universe.
What are the requirements for life? In other words, what do scientists and astronomers look for on other planets in order for them to conclude that there could be life there whether it is microbial life or intelligent life.
-The obvious necessity for life, as we know it, is water. Many planets that we know of actually have water on them. As far as we know however, life forms must have water in the liquid form or be able to change the water to liquid form in order to use it in natural processes. Our bodies at birth are made up of about 78% water and his water needs to be in liquid form, obviously, otherwise many of our essential life processes would not work and we would not receive the proper nutrients to all of our body parts. So, this is why astronomers and scientists team up and search for life on potential life-bearing planets.
– It should also be noted that astronomers have found many planets and even moons with water on them, including Mars and Jupiter’s moon, Europa. However Europa is nearly a solid sheet of ice on the surface. The interesting thing is that scientists speculate that there is a vast ocean of liquid water underneath this surface due to the constant tug and pull of this moon orbiting around Jupiter. This strain causes the underlayer of the surface to be liquid while the outer layer is ice since that atmoshphere of the planet provids very cold temperatures. Possible exploration of this moon in the future is very possible and scientists are eager to determine what this vast ocean contains. Also, Mars at one point in time did have liquid water on it but over time it has lost its atmosphere and now there only exists on polar cap of ice on Mars. This spot can be seen as a large white circle on the end of top of the planet surrounding by a sea of red.
-Another requirement scientists consider for life to be possible is the distance of a planet to that planet’s sun. This distance needs to be close to 1 AU. An AU (astronomical unit) is a unit of measurement used in situations where the mile it too small and the light-year is too large. It is set as the distance from Earth to our sun. I do not know exactly how leniant this distance is in order for scientists to consider life but it should be near 1 AU. This distance is crucial because a given temperature range and amount of light and heat is believed to be need to sustain life. This AU distance is believed to be that distance. This makes sense because if a planet is too close to the sun, temperatures may be too hot and not only will the life forms burn but the liquid water will also turn to gaseous water. If the planet is too far the opposite is obvious.
-Along with temperature, the nature of the planet’s atmosphere is also considered. However, it is easiest for scientists and astronomers to assess all of the now possible 494 planets that we have discovered as of 2 weeks ago as having potential to sustain life or not by deciding if they have liquid water present on them, but more so how close they are to the sun. Even a very distant solar system can be sized up easily by this criteria with a good telescope. However another criteria that scientists keep in mind is the size of the planet, because a planet needs to be of a certain size unless it possesses other unique properties, to be able to create a large enough amount of pressure (near 1 atmoshpere) on its surface. 1 atmoshpere is the amount of pressure of the earth’s atmosphere on a particle at sea level on the earth. This value is necessary so that the planet can actually keep its atmosphere. As stated before this is what occurred on Mars. The planet is too small and it lost its atmosphere, by that its liquid water, and then by that its ability to carry life. Not only pressure of the atmosphere are necessary to know but other facts as well such as amount of elements, relative temperature ranges, how acidic or basic the atmosphere is (For instance acid rain on earth is a large contributor to weakening trees and plants to death. it also has a negative effect on fish and other aquatic life forms as well.). Earth is a very “mild” planet. This means that for instance on a scale of 0 to 100 where 0 is zeroand 100 maximum, the average temperature, atmospheric pressure, amount of oxygen relative to other gaseous elements, acidic/basic compounds, and on and on of all other properties of the earth would be at a value of about 50 +- (plus or minus) 10 for different catergories, relative to all the other planets we know of so far.
So with all of these criterion, and the technology we have today for finding other planets, what is the likelihood that we will soon find a planet with the possibility of sustaining life? Who knows? However, at the exponential rate that we are making new astronomical discoveries, I would speculate that the day we find this planet is coming soon. And by soon I mean within the next decade. How cool is that?
Note: Dr. Rudnick said that when he was first starting to teach I believe in 1987 or so, there was one other confirmed planet outside of our solar system. He also said that soon after that, that one planet was decided to actually not be a planet and that it was a mistake. So in about 30 years or so, technology has provided us with the ability to discover nearly 500 neighboring planets outside of our own solar system! And most of these planets have not even been searched for the criterion listed above necessary to posses life!
Space on Cyberspace 