Aditya MadanapalleDec 27, 2016 12:33:10 IST
A group of scientists are gearing up to send repeated messages to exoplanets, in an effort to elicit a response from alien civilisation. The organisation, known as Messaging Extraterrestrial Intelligence (METI) is a response to the decades long unsuccessful search for aliens by the Search for extraterrestrial intelligence (SETI) program, mostly funded by Nasa. While Seti passively listens to potential signals from space, Meti hopes to initiate contact by sending messages to planets that are likely to host alien life, using highly targeted lasers or radio signals.
While there have been previous attempts at contacting alien civilisations, none of them involve consistently and repeatedly sending the same message over and over again. The reason for this is that scientists like a series of consistent results, and one off intelligent signals are more likely to be dismissed as an error if it is not confirmed with repeated signals from the same source.
The first target planet is a small rocky planet in orbit around the closest star to the Sun, Proxima Centauri. The messages are expected to be sent for months, if not years, and the program intends to further expand to other planets, according to a report in Phys.org.
There are plenty of known earth like planets with a potential for supporting life. Earlier this year, the resurrected Kepler mission discovered 1284 new planets, the biggest batch of exoplanet discoveries. Earth like planets in habitable zones around planets are regularly discovered, there are rocky planets that are just the right distance from the sun, so that the terrestrial conditions have liquid water, but are not too hot. Earlier this year, MIT discovered three rocky exoplanets in the habitable zone around an ultracool dwarf star. The keywords here are rocky, which means earth like, and not a gas giant such as Jupiter or Saturn, and habitable, which means it is the right distance from the star.
The Drake Equation is an estimate of the number of planets that have a potential for life. The predicted numbers from the equation shows that alien life should be fairly common, but there is an eerie lack of evidence. We haven't seen confirmed signals, or an artifact, or trails of propellant. That there is no evidence despite maths showing that there should be plenty of life, is known as the Fermi Paradox. One possible explanation is the Rare Earth hypothesis, which says life as we know it on Earth is incredibly rare, but microbial life is common in the universe.
Since the number of planets known to have life is a sample set of one, it is difficult to derive statistical information on how common life is. In opposition to the Rare Earth theory is the possibility that the conditions for life on Earth are not the best they could be. Superhabitable planets could have conditions that are even more hospitable to life than on Earth, and we do not know how common or rare these kinds of planets are.
The problem is that the parts of the Drake Equation is not fully understood, and there are no hard numbers here. For example, every time a civilisation discovers radio signals, there is a spike in the discoverability of the civilisation, but the window of discovery may be two hundred years or less. Humans have moved on to using wires and fibres, which reduces the amount of signals that leak out into space, and thus reducing the chances of our civilisation being discovered through radio waves. Meti is working on better understanding of the Drake Equation, which could pave the way for a more fine tuned search for extra terrestrial life.
If Seti continues in the traditional way, with only passive listening instead of actively sending signals, it could be a while before we find evidence. A probabilitic analysis of the Fermi Paradox has allowed scientists to estimate how long it will be before we hear from alien civilizations. The analysis is based on a potential response from alien civilisation to the signals from earth that have leaked into space. The analysis shows that aliens are very unlikely to contact Earth before 1,500 years. Using targeted laser based signals, scientists believe that contact could be established in under a century.
The bigger issue here is the implications of initiating such a contact. An optimistic result for the exercise would be Proxima-b pings back with a hello, and the two civilizations start a radio conversation that spans decades, with a delay of around four years. Science and maths are expected to be universal languages, but the potential to exchange philosophy and art with alien civilisations is perhaps more exciting. The message is being figured out, as well as the appropriate language to use. There are complexities of using a language with an alien civilisation, a theme that was recently explored in the movie Arrival. Exposure to alien languages can potentially transform the way humans think, or at least influence human cognition.
That is however, the best case scenario. The worst case scenario is well, we just set up a homing signal calling out to all nearby civilisations that there is a resource rich planet right here waiting to be looted for resources. A nouveau elite planet ingenuously hoping to find benign life in the skies discovers to its horror that the extra terrestrials are not really as interested in art, language, philosophy, or unsolicited messages cluttering their inbox. Here is Douglas Vakoch, President of Meti, explaining why humans need to initiate direct contact with aliens.
There are some simple reasons to be cautious. We have no basis for taking an informed decision of how extra terrestrials might react to such signals. We have only recently discovered the capabilities for interstellar communications, and using transmission capabilities at this point of time to contact aliens would be the equivalent to putting a baby who has just learnt to talk on public radio. Although Seti has been going on for decades, there program is only expanding, with newer telescopes joining in the hunt, including the largest telescope in the World, the Five hundred meter Aperture Spherical Telescope (FAST) that began operations in China this year. Only a fraction of the skies have been scanned so far, and interpreting the signals is the largest distributed computing project on Earth.
Those not in support of sending messages directly to aliens include technology historian George Dyson, Hugo and Nebula award winning science fiction author David Brin, and CEO of SpaceX, Elon Musk. Scientists and industry leaders have stressed the need for caution before attempts are made to directly contact extra terrestrials, in a statement regarding Meti. It is better to listen than to shout, the statement says, and any signals should be a global effort, once there is a thorough discussion of the scientific, humanitarian and political implications.
Astrophysicist Stephen Hawking also says that humans should be careful of contacting aliens, and warns that the results could be similar to Columbus discovering America. A problem that Meti opposers have identified is the fallout of Seti being associated with Meti, by vocal opponents of Meti. This could mean that funding for Seti could dry out because people do not support Meti.
There are no current international regulations on transmitting signals to aliens. The Meti team is on track to send the signals by the end of 2018. Meti intends to seriously take forward the research in interplanetary and interspecies communications. Meti intends to be the leader in the field of interstellar message design, and tackle the issues of transmission of science, maths and aesthetics. The counter argument of the scientists who oppose Meti is that most of the research and investigation can go ahead, including building up the capabilities of interstellar communications, without actually jeopardising humans by initiating contact.
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