Every day the search for planets beyond our solar system goes on. Different types of instruments are used. Telescopes, radio telescopes and space probes are the main tools. The interest in these planet finds seems to be increasing, ever since the first one was found. Maybe this is caused by the fact that most scientists don't believe that we will find life on our level in this solar system. The human race seems to be driven by the search for life outside of our world.

Kepler Probe
Photo Source: NASA

We have a probe called Kepler that is scheduled to launch in 2006 or 2007, depending upon what area of NASA you check. The probe is designed to be able to find planets in our galaxy that are even smaller than the earth. NASA says, "With this cutting-edge capability, Kepler may help us answer one of the most enduring questions humans have asked throughout history: Are there others like us in the universe?". Could it be that NASA already knows the answer to that question and Kepler really has a different purpose, the discovery of where this life is coming from? Many scientists that state, that they have seen incontrovertible proof of ufos might agree with this. But back to planet discovery. The very first planet outside the solar system was discovered by its gradational pull on its star. The presents of planets make the star they orbit wobble even if it is ever so slight. Kepler will use a different method to detect planets. It is called the transit method. When a planet passes in front of its star, or sun as it is commonly know, it will be detected. The planet will leave a signature that will allow us to determine its size and its orbit. This is called an indirect method of detection. After three transits of a planet NASA feels it will have enough information to official list the object as a planet.

We discovered in 2001 that a planet we found had sodium in its atmosphere. But that was not the important part of the discovery, the important part was we discovered that we can actually analyze the atmosphere of these distant worlds. Can you imagine this fact? We were able to look across vast distances that are many light years away, find planets, and tell what there atmospheres contained. This almost boggles the mind. We now have new methods for canceling out some of the light of a star so that we can reveal planets that orbit it, if they exist.

Canceling Out Star Light
Animation Source: NASA

NASA has employed another new technique to search for planets outside the solar system. They are now able to link several telescopes together, increasing their light gathering ability dramatically. "We're trying to measure the size of the hot material in the dust disc around DG Tau, where planets may form," said Dr. Rachel Akeson, leader of the study team and an astronomer at the Michelson Science Center at the California Institute of Technology in Pasadena. "Studies like this teach us more about how stars form, either alone or in pairs, and how planets eventually form in discs around stars."

Keck Interferometer observations
Photo Source: NASA

The process of linking telescopes together to increase the light gathering ability is called interferometry. Of course, because of the huge distances involved, the light from the planets and there sun may be reaching the earth after these planets and their suns have disappeared. An example of this is when a planet is 10 light years away. We see the light from ten years ago now but the planet and sun could have exploded after this light left them. If they exploded 4 years ago we would still be getting light showing them for the next six years. Ten light years distant - explosion 4 years ago = six years light travel time for the light from the explosion to reach us. The light received is adjusted and the distortion caused by the Earth's atmosphere is removed, leaving an image as good as one taken from space.

The question is what if we find a planet that is a candidate for life? We check its atmosphere and find it is similar to Earth's own. We next aim our radio antennas at it and we detect signals. Do we send a signal and try and contact it? This might be a good thing but it might also be a bad thing. Since radio waves travel at the speed of light it would would take us the same time for our signal to reach it that it takes for the planets light to reach us. Assuming that they could even understand that we were sending a radio signal they might be able to send one back if they were at least as advanced as we are. On the other hand if they were a lot more advanced they might decide we were some sort of galactic pest and want to get rid of us. There is a third scenario, we contact a distant planet, it has intelligent life, we have no way of reaching it and they have no way of reaching us and we exchange radio messages every ten or twenty years. Of course the planet could be friendly and advanced and share their technology with us thus releasing a warring tribal society into deep space to eventually start trouble.

NASA's Origins Program is seeking to find out the answers to the questions, where do we come from and are we alone? At least that is what they say. The methods of detection and the devices discussed above are part of this program. I am sure as this program progresses more avenues of detection will open up as new discoveries are made. Who knows, maybe even some future genius will figure out how to get every detail from light that has left a planet so that we might be able to get a close up picture of a society living on a distant planet.