Exoplanets, E.T. and Geek

One of my favorite things about astronomy is the existence of other planets and the possibility of extraterrestrial life (E.T.). I geek out to scifi shows and love the wide girth of imagination that comes with what other species might look like and how we would interact with them. I admit I sometimes wonder what it would be like to be in a position like Jodie Foster’s in Contact, or John Crichton from Farscape.  To find out that there are other life forms out there, to see just how wonderfully diverse our universe can be would truly be a mind-altering experience.

So this segment is about planets: Exoplanets (planets that revolve around different stars) and planets within our very own solar system, namely Mars. There is a lot of cool information and implications to the information we find on Mars. The existence of water in the form of ice was established early in our planetary exploration of the red planet. We have had quite a few landers on Mars and the reason for this is because the answers we uncover beg more questions. Finding water on Mars led to questions like: So is there life? Where is it? And if none exists: What happened? The What happened? is a very deep question. There are a lot of fascinating geological formations that lead many scientists to believe that Mars met with some catastrophic events.  Giant volcanoes, deep impact craters, and large crevices that dwarf anything we see on Earth dot the surface of the red planet and as scientists we LOVE to ask questions and find out more.

The current lander, Curiosity, has a few objectives NASA is hoping to accomplish. For life related research Curiosity will do experiments to gain a more detailed inventory of organic carbon atoms (a sign of life past or present), an inventory of life-building chemicals (carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur), and looking for features that would indicate some sort of biological process (http://mars.jpl.nasa.gov/msl/mission/science/objectives/). This vague experiment includes taking samples and exposing them to certain temperatures and radiation and then looking for the release of certain gases or signs of absorption. These tests are pretty standard since our past experiments have usually been inconclusive and with the advancement of technology, we can get more accurate and reliable readings.

Curiosity will also be doing geological studies. Using a high-powered laser it will drill into rock to take samples from deep inside these rocks. Much like on Earth when we dig through the layers of the surface and discover different compositions, drilling into the rock will give NASA a better idea of how these rocks were formed, were they volcanic? Are they Martian in nature or remnants from a meteorite?

Curiosity will also observe how the seasons change on Mars. During the Mars winter, the polar caps grow with the freezing of CO2 molecules, but in the summer these melt off showing a layer of permafrost.

                If nothing else however, Curiosity is practice. Practice for how we explore another planet remotely, and for landing large payloads onto the surface. Curiosity is paving the way for us to send a manned mission to Mars, complete with buildings and facilities for teams to live and work in. How awesome is that? This could happen in the near future, the colonization of Mars! It’s exciting when you consider that it is another small step towards deep space exploration for humanity. A chance for us to really interact with the universe around us in a big way!

                Mars is just the beginning, and as we learn how to explore other planets our search for life will continue to grow.  Currently there are over 3,000 exoplanets that we have observed from our small corner of the universe (http://planetquest.jpl.nasa.gov/).  As this number climbs our chances of finding life on another planet grows.

                In 1961 Dr. Frank Drake presented a formula that considers factors that would affect our chances of finding intelligent life in the Milky Way galaxy. This formula is known as the Drake Equation and has been largely accepted by the scientific community.  The equation looks like this:

N = Rⁿ × f_p × n_e × f_l × f_i × f_c × L

Where:

 

N = the number of civilization with detectable electromagnetic (EM) emissions in the Milky Way.	Rn = the rate of formation of stars suited for developing intelligent life.
fp = the fraction of those stars with planets	ne = The number of planets/ solar system with suitable life conditions.
fl = the fraction of those planets where life actually appears.	fi = the fraction of life bearing planets that have intelligent life.
fc = the fraction of civilizations that developed technology that emits EM waves detectable in space.	L = The length of time such civilizations release detectable signals into space.

 

We don’t have a lot of detailed data to plug into this equation, however. We are beginning to get some very rough estimates about what fraction of stars have planetary systems (f_p), but we are still in the early stages of knowing how many planets exist in the solar system. Planets with suitable life conditions (n_e) has turned out to be hard to find. Many of the exoplanets we have discovered are gas giants or “super Earth.” These planets are incredibly large and often times appear to have atmospheres not suitable for life.

Aside from size there is also the issue of the Circumstellar Habitable Zone (CHZ). This is the zone in which a planet would have to orbit around its parent star in order to have life-sustaining conditions. This zone varies depending on the type of star a planet orbits, but it is a such a relatively narrow margin that even though we have observed many exoplanets we have yet to find one in the CHZ of its star.

Ironically many of the other variables we won’t have answers to until we actually start finding life on other planets, but for now the more variables that we can fill in with actual numbers, the better our estimates will be. Astronomers are working hard to get more accurate numbers. One big way this is happening is with the JamesWebb Space Telescope (JWST). Built to be larger than the Hubble and with more light-gathering power, the JWST will work largely in the infrared so that it can pierce the vale of dust clouds that block our view of much of our galaxy. It will also have visual capabilities and be capable or more detailed pictures than the Hubble.

NASA is working on several other technologies to improve our planet-detecting capabilities. And as the next couple of years pass we will discover more and more fascinating solar systems and planets. In the mean time we practice our space travel and planetary exploration in our back yard, trying to unlock, at least in part, the stencil for life and planetary formation in an attempt to be prepared for whatever we might find out there.