Looking and Listening for Life on Mars (and Elsewhere)
Saturday, August 18, 2012
The Mars rover Curiosity's mission on the Red Planet has many thinking about what it will find... and what might be out there. Image: NASA.
However, for a long time humankind has been asking the question whether life exists off the Earth. While scientists were most likely thinking about microbes, a few bold individuals were thinking about life a lot higher up on the evolutionary scale — intelligent life. How can we detect it?
Within the last few years our home galaxy, the Milky Way, doubled in size. I didn’t notice anything unusual. Did you? Well, it didn’t just suddenly get bigger. The expansion was the result of the diligent research of many astronomers and astrophysicists whose observations and calculations compelled us to accept that the Milky Way was actually much larger than originally thought. In fact, the estimated number of stars went from 200 billion to 400 billion. That doubling of star systems most certainly increased the number of possible planets contained in the Milky Way as well.
GET THE LATEST BREAKING NEWS HERE -- SIGN UP FOR GOLOCAL FREE DAILY EBLASTWhile many planets (777 to date) have been discovered orbiting distant suns, many of these planets are gas giants, some even more massive than Jupiter. However, finding an earth-sized planet is like finding the proverbial needle in a haystack. Aiding in that effort is the Kepler spacecraft, launched back in March 2009. Its primary mission is to search for Earth-sized planets residing within a planetary system in the habitable or “Goldilocks” zone. This location ensures that the planet is neither too hot nor too cold, but just right for liquid water to flow on the planet’s surface. And water is essential for life as we know it to exist.
At this time, a total of 775 planets have been discovered and confirmed by many search projects, including Kepler. Kepler has discovered an additional possible 2,326 candidates at last count, has discovered and confirmed at least one earth-sized planet in the Goldilocks zone, and has discovered about ten new such candidates waiting to be confirmed.
Now that we know that exoplanets exist where liquid water may be present, are any of these worlds inhabited by sentient beings capable of transmitting a deliberate signal that we earthlings can detect?
There have been several major projects looking for such signals over the decades. Nothing has been detected so far. Vast amounts of radio signals are collected at specific frequencies, and this data must be processed to detect any signal. Much computing time is required for this analysis, so the data is not analyzed in real time; rather it is stored for processing later.
An important SETI (Search for Extra-terrestrial Intelligence) project that you can participate in celebrated its 13th anniversary back in May. It’s the SETI@home project. This ambitious program uses the Arecibo radio telescope in Puerto Rico to collect the radio signals to analyze. When the project first started, researchers thought it would take years and costly computer time to process all the collected signals. Then, someone got an absolutely brilliant idea. Where can one find lots of smaller computers sitting idle most of the time? Home computers!!!! So began the idea of “distributed processing,” and the SETI@home project was born in May 1999.
The signal data captured at Arecibo is stored at the University of California at Berkeley. A computer program there “chops up” segments of the data into units 107 seconds each. Computer users at home can download free software that not only contains a nice screen-saver, but also provides the number-crunching processing program required to perform a detailed analysis of the downloaded data.
(The computer analysis is too complex to present here. When you decide to visit the SETI@home website you can click on all the links that describe the screen-saver display characteristics and what they represent. Also you’ll find information on the various calculations performed on the data to detect any potential signal.)
Once a unit has been processed, the program will signal the user to login to the website and transmit the results and get another unit of data (or the program can automatically dial the website, send the processed data and retrieve another “work unit”). Downloading a unit used to take me a couple of minutes on a dial-up connection. With any broadband connection it is instantaneous. Processing the data is another story. On a two-year old Dell Inspiron Pentium 5, 2.27 GHZ computer it takes an average of about 5 hours to complete the analysis with whatever other applications I have running at the time. The SETI tech folks estimate a computer processes anywhere from 2.4 to 3.8 trillion operations per unit.
There are several options you can choose. You can set it to run only when your machine is idle (like a regular screen-saver), or you can have the calculations always running, and the screen-saver will still kick-in when the machine has been idle for a set time. It’s really simple to do, and it’s really important.
Millions of computer users around the world have analyzed SETI data in this manner. Researchers promise that the user whose computer detects a true signal will get a co-discovery credit. Since the inception of SETI@home the researchers have processed the initial acquisition of signal data, and are now re-analyzing signals that showed “potential.” Some require re-observation to determine whether we have kindred spirits out there amongst the 400 billion stars of the Milky Way.
And now that we are discovering potentially habitable planets, I’m sure SETI is targeting those systems in the hope of detecting the telltale signals of an intelligent civilization.
Several years ago the original SETI@home platform was replaced by a more ambitious program called BOINC (Berkeley Open Infrastructure for Network Computing). It has been developed as a distributive processing application that can be adapted to any scientific discipline. The SETI@home project now runs under the BOINC platform.
In addition, if SETI isn’t to your liking, there are other projects which now benefit from the enhanced architecture that BOINC provides. Think about it. Climate and global warming models require enormous computing power. So does cancer research. You can select which projects you wish to support and play a big role in lending your computer’s idle time to scientific endeavors.
Please visit the SETI@home website at setiathome.berkeley.edu and follow the directions provided in the “Get Started” section and soon you will be contributing to mankind’s search for the ultimate discovery. Maybe your computer will detect that signal from an alien intelligence. You, and the entire human race, will never be the same.
Don’t forget you can sample the local neighborhood of our galaxy with optical telescopes at Seagrave Memorial Observatory on Peeptoad Road in North Scituate every clear Saturday night. Check the web-site www.theskyscrapers.org for open/close notices and for starting times as we move into the summer months. Admission is free. Ladd Observatory in Providence is scheduled to re-open on Tuesday, September 4. Please don’t forget about Frosty Drew Observatory in Charlestown. The darkest skies in Rhode Island are available to stargazers every clear Friday night.
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