Posts Tagged ‘aliens’

Allen Telescope Array

Allen Telescope Array

The Search for Extraterrestrial (meaning outside Earth) Intelligence (SETI) has been going on for 50 years and as you can probably guess, we have not found any aliens yet. Otherwise, we would have stopped looking. 🙂

It STARTED with an astronomer named Frank Drake. He thought, quite reasonably, that since we were using radio waves to communicate here on Earth, beings on OTHER planets around other stars might be doing the same thing. The thing about radio wave transmitters, especially the kinds used by broadcasting stations, is that they transmit radio waves in all directions, including into out space. And if there were anybody out there with a receiver, they could easily pick up those transmissions.

If we can do it, why couldn’t another, sufficiently ADVANCED civilization on another planet do the same? And so, SETI astronomers have been using radio telescopes to look for signals from other civilizations.

Where are they?

There are many reasons why we have not yet detected any aliens. They may not have developed the technology to use radio transmissions, or they may have developed other means of communication like lasers. There is a branch of SETI that looks for laser signals from aliens but this is a very difficult search. As you are probably aware a laser is a concentrated light beam. In order to detect it, the laser has to be pointed right at us.

Is it possible that we have not detected anything because there is nothing to detect? Yes, it is possible but highly improbable. As one character from one of my favorite movies of all time put it, “I’ll tell you one thing about the universe, though. The universe is a pretty BIG place. It’s bigger than anything anyone has ever dreamed of before. So if it’s just us… seems like an awful waste of space. Right?”

Will we ever find life outside our solar system?

I believe we will FIND life on planets outside our solar system before the next 50 years of SETI are up. It may not be intelligent life that SETI looks for but it will be life, most likely plant life. As I have posted before, we are looking for other Earth-like planets. Once we find a few, we can start studying them with better telescopes to find the composition, or makeup, of their atmosphere. If we detect oxygen in the planets’ atmosphere, we will know that there are at least plant-based life on those planets. And where there are plants, there are critters to munch on them. 🙂

You can help look for ET.

Due to advances in radio telescope technology, SETI astronomers are flooded with data they have not yet analyzed because they do not have the computing resources to do so. So, just like Galaxy Zoo, scientists are recruiting the help of people just like to you to help them sort through the data and see if we have received signals from outside Earth. The project, called SETI@Home allows anyone with a computer and an internet connection to download data from telescopes like the Allen Telescope Array pictured above and analyze it to see if CONTACT has been made. SETI is not just for professionals anymore; YOU could be the one who discovers ET!

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Well, Earth-like planets to be precise. What does that mean, you ask? You see, Earth is a very SPECIAL planet. Special in the sense that it is the only planet that we (currently) know of that can support life.

How does Earth support life?

For starters, Earth is right DISTANCE from our Sun, in what some call the Goldilocks Zone (also known as the habitable zone). It is the region where water can exist in a liquid form on the surface of a planet. Too much closer and the heat from the sun would boil away all the water. Too far, and there isn’t enough heat causing any water on the planet to freeze.

Earth is also a TERRESTRIAL planet, meaning that part of the surface is solid, i.e. made up of rocks and dirt. The Earth is also large enough to have a GRAVITY that can have an atmosphere, you know, the air we breathe. Without enough mass, the gravity would be too low to prevent the air from escaping out into space. You can read more about this in my book. 😉

Believe it or not, those are the pretty much all the things that are needed for a planet to support life. What about OXYGEN, you ask? Oxygen that we breathe is created by plants, which are a form of life. You would think, with these meager requirements, there are probably HUNDREDS, if not thousands, of planets that can support life.

The thing is, detecting other Earth-like planets is not an easy thing to do. Stars are really far away, and planet that may exist around those stars tend to be very TINY compared to the star they orbit. Our own Sun contains more that 99% of all the mass in our solar system. And our, habitable Earth is quite small compared to giants like Jupiter and Saturn.

Kepler Satellite

Kepler Satellite

Kepler, the planet hunter.

As you can imagine, looking for other Earth-like planets is not an easy task. However, a space mission launched in March of 2009 aims to do just that. Kepler, named after the astronomer, Johannes Kepler carries very POWERFUL cameras to catch a planet transiting its parent star. A transit is when the planet that we are looking is in between us and its parent star as the planet goes around the star. When the planet is between us and its star, the brightness of that star as seen by us is lower than when the planet is behind star. The animation below explains it better than I can write it.

Look at the sky on a clear night. What is the largest star you see? Imagine looking for a planet in front of that star. A tiny Earth-like planet around a star that already looks only like a dot from where we are. That is what Kepler is trying to do. At a lecture given by a Kepler mission scientist that I attended, she said that they expected to find about a 100 Earth-like planets in the tiny patch of the sky it will look at. Whether those planets will have ALIENS will be another matter.

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