{"id":1427,"date":"2018-01-14T23:46:55","date_gmt":"2018-01-14T21:46:55","guid":{"rendered":"http:\/\/www.xairforces.com\/?p=1427"},"modified":"2018-01-15T13:17:08","modified_gmt":"2018-01-15T11:17:08","slug":"are-aliens-plentiful-but-were-just-missing-them","status":"publish","type":"post","link":"https:\/\/www.xairforces.com\/?p=1427","title":{"rendered":"Are Aliens Plentiful, But We’re Just Missing Them?"},"content":{"rendered":"
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\"A<\/a>

A modified alien planet might exhibit unique electromagnetic signals, but that might not be the best way to find them. (Photo by Ryan Somma \/ flickr)<\/p><\/div>\n

A little over 80 years ago, humanity first began broadcasting radio and television signals with enough power that they should leave Earth’s atmosphere and progress deep into interstellar space. If someone living in a distant star system were keeping a vigilant eye out for these signals, they would not only be able to pick them up, but immediately identify them as created by an intelligent species. In 1960, Frank Drake first proposed searching for such signals from other star systems by using large radio dishes, giving rise to SETI: the Search for Extra-Terrestrial Intelligence. Yet over the past half-century, we’ve developed far more efficient ways to communicate across the globe than with broadcast radio and TV signals. Does searching for aliens in the electromagnetic spectrum even make sense anymore?<\/strong><\/p>\n

This question, of course, is extraordinarily speculative, but gives us a chance to look at our own technological progress, and to consider how that might play out elsewhere in the Universe. After all, if someone from a culture that was versed only in smoke signals and drum beats found themselves deep inside the heart of a forest, they might conclude that there was no intelligent life around. Yet if you gave them a cellphone, there’s a good chance they could get reception from right where they stood! Our conclusions may be as biased as the methods we apply.<\/p>\n

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\"\"An artistic representation of Ben Franklin’s electricity-harnessing experiments. (Public domain image)<\/small><\/div>\n<\/div>\n

The mechanism of electricity only began to be understood in the late 18th century, with the work of Ben Franklin. The power of electricity only began to be harnessed to run electric circuits and other powered devices during the 19th century, and the phenomena associated with classical electromagnetism only became understood through the latter half of that century. The first transmissions of electromagnetic signals for communication didn\u2019t take place until 1895, and the power of radio broadcasts to extend far out into interplanetary and interstellar space wasn\u2019t achieved until the 1930s.<\/p>\n

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\"\"This image, current in 2011 (and now 7 years out of date), shows the reach of humanity’s radio signals in space. A light year is a long distance, but the stars in our galaxy are tens of thousands of light years away, on average. (Abstruse Goose)<\/small><\/div>\n<\/div>\n

The speed of light is quite a limiting thing as well: if our radio signals have been traveling through interstellar space for 80 years, that means that only civilizations within 80 light years of us would have had an opportunity to receive those signals, and that only civilizations within 40\u00a0light years would have had the opportunity to receive those signals and send something back to us that we would\u2019ve received by now. If the Fermi Paradox is the question of \u201cwhere is everyone,\u201d the answer is, \u201cnot within 40 light years of us,\u201d which doesn\u2019t tell us very much about intelligent life in the Universe at all.<\/p>\n

While there might be hundreds of billions of stars within our galaxy alone, and around two trillion\u00a0galaxies in the observable Universe, there are less than 1,000 stars within 40 light years of Earth.<\/p>\n

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\"\"Inductiveload \/ Wikimedia Commons<\/small><\/div>\n
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There are a few dozen stars within 14 light years of Earth; that number rises up to only about 1000 after 40 light years, which is close to the maximum round-trip time of a light signal sent from Earth by humans capable of reaching out into the Universe.<\/strong><\/p>\n<\/div>\n<\/div>\n<\/div>\n

And to make matters worse, electromagnetic signals going out from Earth into interstellar space are decreasing, not increasing. Television and radio broadcasts are increasingly being run through cables or via satellite, not from transmission towers here on Earth. By time another century passes, it\u2019s very likely that the signals we sent out (and hence, began looking for) during the 20th century will cease to be emitted from Earth altogether. Perhaps an alien civilization, making note of these observations when the signals do arrive, would draw the conclusion that this blue, watery planet orbiting our star in the great distance actually achieved intelligent, technologically advance life for a short while, and then wiped ourselves out as the signals gradually stopped.<\/p>\n

Or, perhaps, drawing conclusions from what is or isn’t present in any form of electromagnetic signal is altogether wrongheaded.<\/p>\n

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\"\"NASA’s Earth Observatory\/NOAA\/DOD<\/small><\/div>\n
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The Earth at night emits electromagnetic signals, but it would take a telescope of incredible resolution to create an image like this from light years away.<\/strong><\/p>\n<\/div>\n<\/div>\n<\/div>\n

If we were to look at Earth from a nearby distance in visible light, there would be no doubts about the fact of whether or not it\u2019s inhabited: the great glow of cities at night is unmistakably a sign of our activity. Yet this light pollution is relatively new, and is something we\u2019re finally learning how to manage and control if we put the effort (i.e., time, money, manpower and resources) into it. There\u2019s no reason not to be optimistic that by the end of the 21st or 22nd centuries, the Earth at night will look no different than it did for billions of years: dark, except for the occasional aurora, lightning storm or erupting volcano.<\/p>\n

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\"\"United States Air Force photo by Senior Airman Joshua Strang<\/small><\/div>\n
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The aurora borealis is one such transient feature that can be seen from space… or across the interstellar distances.<\/strong><\/p>\n<\/div>\n<\/div>\n<\/div>\n

But if we\u00a0weren\u2019t\u00a0looking for electromagnetic signals, what would we look at? Indeed, everything in the known Universe is limited by the speed of light, and any signal created on another world would necessitate that we be able to observe it. These signals?\u2014?in terms of what could reach us?\u2014?fall into four categories:<\/p>\n

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  1. Electromagnetic signals, which include\u00a0any form of light\u00a0of any wavelength that would indicate the presence of intelligent life.<\/li>\n
  2. Gravitational wave signals, which, if there is one unique to intelligent life, would be detectable with sensitive enough equipment anywhere in the Universe.<\/li>\n
  3. Neutrino signals, which?\u2014?although incredibly low in flux at great distances?\u2014?would have an unmistakable signature dependent on the reaction that created them.<\/li>\n
  4. And finally, actual, macroscopic space probes, either robotic, computerized, free-floating or inhabited, which made its way towards Earth.<\/li>\n<\/ol>\n

    How remarkable that our science-fiction imaginations focus almost exclusively on the fourth possibility, which is by far the\u00a0least\u00a0likely!<\/p>\n

    \n
    \"\"flickr user plaits<\/small><\/div>\n
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    A representation of an alien invasion. This is not an actual extraterrestrial.<\/strong><\/p>\n<\/div>\n<\/div>\n<\/div>\n

    When you think about the vast distances between the stars, how many stars there are with potentially habitable planets (or potentially habitable moons), and how much it takes, in terms of resources, to physically send a space probe from one planet around one star to another planet around another star, it seems literally crazy to consider that method to be a good plan. Far more likely, you\u2019d think, it would be smart to build the right type of detector, to survey all the various regions of the sky, and seek out the signals that could unambiguously show us the presence of intelligent life.<\/p>\n

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    \"\"PZmaps \/ Wikimedia Commons<\/small><\/div>\n
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    Long-term average precipitation by month (mm\/day and in\/day), based on 1961-1990 data, which affects the H2O concentration and therefore the emission spectrum of Earth.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

    In the electromagnetic spectrum, we know what our living world does in response to the seasons. With winters and summers, there are seasonal (and hence, orbital) changes in what electromagnetic signals our planet emits. As the seasons change, so do the colors on various parts of our planet. With a large enough telescope (or array of telescopes), perhaps the individual signs of our civilization could be seen: cities, satellites, airplanes and more. But perhaps the best thing we could look for is alterations of the natural environment, consistent with something that only an intelligent civilization would create.<\/p>\n

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    \"\"Ittiz \/ Wikimedia Commons<\/small><\/div>\n
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    An artist’s impression of an ammonia world with an advanced stage of life on it. Yet we must be careful to rule out any natural signals that could mimic what we observe before we conclude in favor of aliens.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

    We haven\u2019t yet done these things, but perhaps large-scale modifications of a planet would be the exact thing we should be looking for, and should be the large-scale projects we\u2019d aspire towards. Remember, any civilization that we find is unlikely to be in their technological infancy like we are. If they survive it and thrive through it, we\u2019ll likely encounter them in a state tens or hundreds of thousands of years more advanced than we are. (And if that doesn\u2019t boggle your mind, consider how much more advanced we are than we were just a few hundred years ago!) But this brings up two other possibilities, too.<\/p>\n

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    \"\"ESA \/ NASA and the LISA collaboration<\/small><\/div>\n
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    For the past 2+ years, gravitational waves have been detected on Earth, from merging neutron stars and merging black holes. By building a gravitational wave observatory in space, we may be able to reach the sensitivities necessary to detect a deliberate alien signal.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

    Perhaps \u2014 as our gravitational wave technology becomes set to detect the first signals from the Universe \u2014 we\u2019ll discover that there are subtle effects that lend themselves to detection across the cosmos. Perhaps there\u2019s something to be said for a world with tens of thousands of satellites orbiting it, something unique that a gravitational wave detector could spot? We haven\u2019t worked it out in great detail because this field is in its infancy and not yet developed to the point where it could detect such a small signal. But these signals don\u2019t degrade the way electromagnetic ones do, nor is there anything that shields them. Perhaps this new branch of astronomy will be the way to go, hundreds of years from now. But my money\u2019s on the third options, if you want an out-of-the-box thought.<\/p>\n

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    \"\"Centro Atomico Bariloche, via Pieck Dar\u00edo<\/small><\/div>\n
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    Reactor nuclear experimental RA-6 (Republica Argentina 6), en marcha, showing the characteristic Cherenkov radiation from the faster-than-light-in-water particles emitted. The reactions also produce copious amounts of antineutrinos.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

    What\u2019s likely to be the power source for a sufficiently advanced civilization?\u00a0Perhaps it\u2019s nuclear power, most likely\u00a0fusion power<\/a>, and most likely a specific type of fusion that\u2019s proven to be efficient, abundant, different from what occurs in the cores of stars, and that emits a very, very specific neutrino (or antineutrino) signature as a by-product. And those neutrinos should come with a very specific, explicit signature as far its\u00a0energy spectrum goes: one that isn\u2019t produced by any natural process.<\/p>\n

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    \"\"IceCube collaboration \/ NSF \/ University of Wisconsin<\/small><\/div>\n
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    There are many natural neutrino signatures produced by stars and other processes in the Universe. But note the unique and unambiguous signal that comes from reactor antineutrinos. The cutoff in energy is key to identifying this signal.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

    If we can predict what that signature is, understand it, build a detector for it and measure it, we can find a fusion-powered civilization anywhere, and not have to worry about whether they\u2019re broadcasting or not. So long as they\u2019re making power, we can find them. With SETI focusing solely on electromagnetic signatures, we\u00a0may, at present, be looking for the cosmic equivalent of smoke signals in a cellphone-filled world. But this\u00a0likely won\u2019t be the case for long. As our technology continues to advance, our knowledge of what to look for will advance along with it. And perhaps someday \u2014 perhaps even someday soon \u2014 the Universe may have the most pleasant surprise of all in store for us: the news that we aren\u2019t alone, after all.<\/p>\n<\/div>\n

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    Astrophysicist and author Ethan Siegel is the founder and primary writer of Starts With A Bang! His books,\u00a0Treknology<\/a>\u00a0and\u00a0Beyond The Galaxy<\/a>, are available wherever books are sold.<\/em><\/p>\n<\/div>\n


    \nSource:\u00a0<\/em><\/strong>Ethan Siegel<\/span>\u00a0,\u00a0<\/small>Contributor (    forbes.com<\/a>) – JAN 12, 2018<\/small><\/span><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

    A little over 80 years ago, humanity first began broadcasting radio and television signals with enough power that they should leave Earth’s atmosphere and progress deep into interstellar space. If someone living in a...<\/p>\n","protected":false},"author":1,"featured_media":1428,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"footnotes":""},"categories":[36,33,7,28,25,1663,1667,1668,1669,1664,23,1666,6,177,18],"tags":[1624,1621,1643,1653,1627,1647,1638,1641,1652,1649,1626,1617,1620,1645,1630,1640,1619,1629,1639,1623,1637,1642,1635,1622,1618,1633,1634,1636,1656,1644,1650,1646,1616,1655,1654,1648,1631,1625,346,1651,1628,1632],"aioseo_notices":[],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.xairforces.com\/index.php?rest_route=\/wp\/v2\/posts\/1427"}],"collection":[{"href":"https:\/\/www.xairforces.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.xairforces.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.xairforces.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.xairforces.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1427"}],"version-history":[{"count":3,"href":"https:\/\/www.xairforces.com\/index.php?rest_route=\/wp\/v2\/posts\/1427\/revisions"}],"predecessor-version":[{"id":1431,"href":"https:\/\/www.xairforces.com\/index.php?rest_route=\/wp\/v2\/posts\/1427\/revisions\/1431"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.xairforces.com\/index.php?rest_route=\/wp\/v2\/media\/1428"}],"wp:attachment":[{"href":"https:\/\/www.xairforces.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1427"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.xairforces.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1427"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.xairforces.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1427"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}