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.
While 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.
No comments:
Post a Comment