Giant telescope could eavesdrop on alien TV

<body leftmargin="0" bgcolor="#000060" text="#FFFFFF" link="#FFFF00" vlink="#FF9900"> <b> <p class="MsoNormal"><font size="4" face="Arial">Giant telescope could eavesdrop on alien TV</font></p> </b> <p class="MsoNormal"><font face="Arial"><font size="1">Posted Dec. 28, 2004<br> Special to World Science staff</font> <b> <font size="2" face="Arial"><br> <br> </font> </b> </font> <b> <font face="Arial" size="2">An enormous new telescope will be able to pick up television and radio signals from extraterrestrial civilizations, if they’re fairly nearby, scientists say.</font> </p> <p class="MsoNormal"><font face="Arial" size="2">Telescopes designed to detect signals from life outside our planet already exist, but aren’t considered powerful to detect such transmissions. Instead, they can probably only detect signals from beings that are purposely trying to send signals across outer space. This probably precludes the possibility of detecting many civilizations that, like ours, aren’t sending signals like that.</font></p> <p class="MsoNormal"><font face="Arial" size="2">We do, however, watch TV and listen to radio. These activities leak signals into space that could theoretically reveal our presence to aliens. The new telescope, called the Square Kilometer Array (SKA), would be designed to detect these types of signals from the aliens themselves, if they’re close enough.</font></p> <p class="MsoNormal"><font face="Arial" size="2">SKA could detect such transmissions up to a distance of roughly 10 light-years, the distance that light travels in 10 years, according to researchers. This means it would cover an area of about 1 percent the size of our Milky Way galaxy – a modest area in astronomical terms, but still comprising more than a billion stars, and any planets orbiting them. Depending on the estimates one uses of how many planets exist per star, the detection area might cover between 200 million and 500 million planets.</font></p> <p class="MsoNormal"><font face="Arial" size="2">“Rather than searching for deliberate transmissions, the SKA will be able to search for incidental transmissions or ‘leakage,’” wrote <span style="mso-bidi-font-size:10.0pt">Joseph Lazio of the Naval Research Laboratory in Washington, DC, in a recent paper for the SKA project. “</span>The same improved sensitivity will expand the volume of the Galaxy that can be explored for intentional beacons by a factor of 1000.”</font></p> <p class="MsoNormal"><font face="Arial" size="2">It might seem surprising that a telescope could pick up television and radio transmissions. It could because such transmissions are made of light, just like starlight – except their light is invisible. Visible light is only that light whose waves are within a certain range of sizes detectable by our eyes.</font></p> <p class="MsoNormal"><font face="Arial" size="2">The SKA – whose construction is scheduled to start in 2012 – would have one square kilometer (247 acres) of area for detecting these transmissions, as well as other types of light. This is 30 times as much as the biggest existing telescopes.</font></p> <p class="MsoNormal"><font face="Arial" size="2">The types of waves used for TV are about a million times longer, from crest to crest, than those used for visible light. This “long-wavelength” light requires a correspondingly larger type of telescope to detect, called a radio telescope. But radio telescopes are easier to build in some respects than regular ones: they don’t need smooth, mirrored surfaces to collect light, as long-wavelength light isn’t scrambled by bumpy surfaces the way short-wavelength light is.</font></p> <p class="MsoNormal"><font face="Arial" size="2">Another peculiarity of a radio telescope is that it often consists of an array of smaller telescopes, or reflectors that look like satellite dishes. This is one possible design for the SKA, according to researchers.</font></p> <p class="MsoNormal"><font face="Arial" size="2">An international consortium of 15 countries, including Australia, China, India, the United States and 10 European countries, has been planning SKA for half a decade. Scientists for the project recently conducted a review and revision of its goals, including a more detailed assessment of its potential for detecting extraterrestrial life. They published the findings in the December issue of the research journal <i>New Astronomy Reviews.<o:p> </o:p> </i></font></p> <p class="MsoNormal"><font face="Arial" size="2">The SKA could do far more than pick up TV transmissions, scientists say: it also will peer at the most distant reaches of the universe with unprecedented accuracy in the longer wavelengths, allowing it to study the origins of the earliest galaxies ever formed.</font></p> <p class="MsoNormal"><font face="Arial" size="2">It will also examine the formation of planetary systems to determine how life may evolve, according to Lazio.</font></p> <p class="MsoNormal"><font face="Arial" size="2">Scientists have already detected, floating among the stars, organic molecules crucial for life. The SKA could help answer whether these same molecules make it onto forming planets to spark the process of life. It could do so by scouring planetary systems in every stage of development to find out whether these organic molecules leave characteristic marks in the light that reaches us.</font></p> <font face="Arial" size="2"><span style="mso-bidi-font-size: 12.0pt; mso-fareast-font-family: Times New Roman; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">SKA will also reveal the physical features of these emerging planetary systems in unprecedented detail, scientists say. “The SKA may be the only instrument capable of imaging the inner regions of disks where Earth-like planets might be forming,” according to the SKA Website.</span></font> <p><font face="Arial" size="2">* * *</font></p> <p><font face="Arial" size="2">Send us a <a href="mailto:editor@world-science.net">comment</a> on this story</font> </b> </p> </body>