Astronomy

Are we alone



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Are we Alone in the Universe?

Are we alone in the universe? Are there other Earth type planets supporting life, maybe even intelligent life? These questions might be answered when an Alien race lands on Earth and introduce their selves, but it is more likely that we will have to seek them out. If, they exist and are aware of us apparently it isn't their intention to make their selves known, at least not yet or to the general public.

For hundreds of years we have been aware of the planets in our solar system and wondered if our star system was unique and possibly the only one of its kind. With the recent discovery of other stars with planets the question of, are we alone in the universe has greater significance. Life as we know it requires a planet with an atmosphere and certain elements and conditions. Finding these planets and studying their make up has become one of the fastest growing fields in Astronomy.

The first planet outside our solar system was discovered in the mid 1990's. Since that first detection scientists have discovered hundreds of other planets rotating around other stars. These are called exoplanets. After discovery of their existence it raises many other questions such as, can they support life as we know it. One very important ingredient for a life sustaining planet is an atmosphere, so scientist immediately started searching for ways to identify the exoplanets with atmospheres, and if so what they may consist of.

Detecting atmospheres and the elements they are made of is tedious and expensive. The tools available to scientist for this type of detection are few and in extreme demand. Two of the most important tools for this work are the Hubble and Spitzer space telescopes. The Hubble is getting old and the Spitzer is running out of cryogen, which is the coolant that allows it to detect minute variations in temperature thousands of light years away. With these drawbacks scientist like Mercedes Lopez Morales of the Carnegie Institution. and her team has resorted to using land based telescopes. Last summer using the European Southern Observatory's Telescope, and Carnegie's Magellan-Baade telescope she and her team had very revealing breakthrough.

A faint exoplanet about 5,000 light years away called OGLE TR056b was their candidate for this intensive research, and it paid off. Acquiring accurate readings of the exoplanet's star's light (photons) and heat (infrared radiation), then comparing it to that given off by the exoplanet during its eclipse of its star. In simple terms it is like taking pictures of the sun with a candle burning in front of it, then comparing it to pictures without the candle in front. The candle doesn't produce enough light to be visible to the naked eye in front of the sun, but with very sensitive instruments the photos can be compared and analysis done that shows the difference without the candle. Using methods to detect small temperature variations using the light (photons) that OGLE TR056b and its star emit during an eclipse or as the exoplanet moves to the far side of its star they were able to come up with the following observations.

Lpez-Morales and her team took more than 600 images of OGLE TR056b with both telescopes. The planet is the hottest of any ever detected. The atmosphere is more than 4,400 degrees Fahrenheit and has little movement or cloud cover which was one of the requirements to get an accurate measurement, at least at that time. Planets such as these are referred to as hot Jupiters, because of the similarities in mass and gaseous make up.

Another hot Jupiter that has been found is HD 189733b. This planet is about 65 light years away and was discovered by Giovanna Tinetti from University College London, UK and her colleagues. It also has an atmosphere and was examined in much the same way as the previous planet discussed. Giovanna Tinetti and her colleagues used a device onboard the Hubble telescope called a Near Infrared Camera and Multi Object Spectrometer. The importance of this discovery was magnified (no pun intended) when this planet was discovered to have carbon dioxide.

The importance is that carbon dioxide, water, methane and oxygen/ozone are considered to be the four major markers (The Big Four) for an earth type or habitable planet. Although HD 189733b is to hot to support life it is important that we now know we can detect the possible ingredients of life on exoplanets. The only one of the Big Four that has not yet been found is oxygen/ozone. These essential elements of life should be able to be picked up relatively easily by the planned NASA Planet Finder. One of its many abilities is that it should be able to find smaller rocky worlds like our own. The possibility of finding a living planet will increase tremendously.

I hope that the NASA Planet Finder and other projects to explore the universe can continue to move forward at an accelerated pace. I am grateful for all the time and effort these noble scientist put in. I feel that one day their efforts will be truly recognized, when we find we are not alone in this vast universe. The human race may benefit greatly with the knowledge that life exist elsewhere.

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