{"id":11963,"date":"2024-06-06T22:00:00","date_gmt":"2024-06-06T22:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=11963"},"modified":"2024-05-28T18:52:27","modified_gmt":"2024-05-28T18:52:27","slug":"dyson-spheres-astronomers-report-potential-candidates-for-alien-megastructures-heres-what-to-make-of-it","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/dyson-spheres-astronomers-report-potential-candidates-for-alien-megastructures-heres-what-to-make-of-it\/","title":{"rendered":"Dyson spheres: astronomers report potential candidates for alien megastructures \u2013 here\u2019s what to make of it"},"content":{"rendered":"\n
\n\n Simon Goodwin<\/a>, University of Sheffield<\/a><\/em><\/span>\n\n

There are three ways to look for evidence of alien technological civilisations. One is to look out for deliberate attempts by them to communicate their existence, for example, through radio broadcasts<\/a>. Another is to look for evidence of them visiting the Solar System<\/a>. And a third option is to look for signs of large-scale engineering projects in space.<\/p>\n\n

A team of astronomers have taken the third approach by searching through recent astronomical survey data to identify seven candidates for alien megastructures<\/a>, known as Dyson spheres, \u201cdeserving of further analysis\u201d. <\/p>\n\n

This is a detailed study looking for \u201coddballs\u201d among stars \u2013 objects that might be alien megastructures. However, the authors are careful not to make any overblown claims. The seven objects, all located within 1,000 light-years of Earth, are \u201cM-dwarfs\u201d \u2014 a class of stars that are smaller and less bright than the Sun. <\/p>\n\n

Dyson spheres were first proposed by the physicist Freeman Dyson in 1960<\/a> as a way for an advanced civilisation to harness a star\u2019s power. Consisting of floating power collectors, factories and habitats, they\u2019d take up more and more space until they eventually surrounded almost the entire star like a sphere. <\/p>\n\n

What Dyson realised is that these megastructures would have an observable signature. Dyson\u2019s signature (which the team searched for in the recent study) is a significant excess of infrared radiation. That\u2019s because megastructures would absorb visible light given off by the star, but they wouldn\u2019t be able to harness it all. Instead, they\u2019d have to \u201cdump\u201d excess energy as infrared light with a much longer wavelength. <\/p>\n\n

Unfortunately, such light can also be a signature of a lot of other things, such as a disc of gas and dust, or discs of comets and other debris. But the seven promising candidates aren\u2019t obliviously due to a disc, as they weren\u2019t good fits to disc models.<\/p>\n\n

It is worth noting there is another signature of Dyson sphere: that visible light from the star dips as the megastructure passes in front of it. Such a signature has been found before. There was a lot of excitement about Tabby\u2019s star, or Kic 8462852<\/a>, which showed many really unusual dips in its light that could be due to an alien megastructure. <\/p>\n\n

\n \"Image\n
\n Tabby\u2019s Star in infrared (left) and ultraviolet (right)<\/span>\n wikipedia<\/span><\/span>\n <\/figcaption>\n <\/figure>\n\n

It almost certainly isn\u2019t an alien megastructure. A variety of natural explanations have been proposed, such as clouds of comets passing through a dust cloud. But it is an odd observation. An obvious follow up on the seven candidates would be to look for this signature as well.<\/p>\n\n

The case against Dyson spheres<\/h2>\n\n

Dyson spheres may well not even exist, however. I think they are unlikely to be there. That\u2019s not to say they couldn\u2019t exist, rather that any civilisation capable of building them would probably not need to (unless it was some mega art project).<\/p>\n\n

Dyson\u2019s reasoning for considering such megastructures assumed that advanced civilisations would have vast power requirements. Around the same time, astronomer Nikolai Kardashev proposed a scale<\/a> on which to rate the advancement of civilisations, which was based almost entirely on their power consumption. <\/p>\n\n

In the 1960s, this sort of made sense. Looking back over history, humanity had just kept exponentially increasing its power use as technology advanced and the number of people increased, so they just extrapolated this ever-expanding need into the future.<\/p>\n\n

However, our global energy use<\/a> has started to grow much more slowly over the past 50 years, and especially over the last decade. What\u2019s more, Dyson and Kardashev never specified what these vast levels of power would be used for, they just (fairly reasonably) assumed they\u2019d be needed to do whatever it is that advanced alien civilisations do. <\/p>\n\n

But, as we now look ahead to future technologies we see efficiency, miniaturisation and nanotechnologies promise vastly lower power use (the performance per watt of pretty much all technologies is constantly improving).<\/p>\n\n

A quick calculation reveals that, if we wanted to collect 10% of the Sun\u2019s energy at the distance the Earth is from the Sun, we\u2019d need a surface area equal to 1 billion Earths. And if we had a super-advanced technology that could make the megastructure only 10km thick, that\u2019d mean we\u2019d need about a million Earths worth of material to build them from.<\/p>\n\n

A significant problem is that our Solar System only contains about 100 Earths worth of solid material, so our advanced alien civilisation would need to dismantle all the planets in 10,000 planetary systems and transport it to the star to build their Dyson sphere. To do it with the material available in a single system, each part of the megastructure could only be one metre thick. <\/p>\n\n

This is assuming they use all the elements available in a planetary system. If they needed, say, lots of carbon to make their structures, then we\u2019re looking at dismantling millions of planetary systems to get hold of it. Now, I\u2019m not saying a super-advanced alien civilisation couldn\u2019t do this, but it is one hell of a job. <\/p>\n\n

I\u2019d also strongly suspect that by the time a civilisation got to the point of having the ability to build a Dyson sphere, they\u2019d have a better way of getting the power than using a star, if they really needed it (I have no idea how, but they are a super-advanced civilisation). <\/p>\n\n

Maybe I\u2019m wrong, but it can\u2019t hurt to look.\"The<\/p>\n\n

Simon Goodwin<\/a>, Professor of Theoretical Astrophysics, University of Sheffield<\/a><\/em><\/span><\/p>\n\n

This article is republished from The Conversation<\/a> under a Creative Commons license. Read the original article<\/a>.<\/p>\n<\/div>\n\n","protected":false},"excerpt":{"rendered":"Simon Goodwin, University of Sheffield There are three ways to look for evidence of alien technological civilisations. One…\n","protected":false},"author":840,"featured_media":11965,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","fifu_image_url":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/e\/e1\/Dyson_sphere.png","fifu_image_alt":"","footnotes":""},"categories":[15,14],"tags":[1182,1356,1416,1159,75,474],"class_list":{"0":"post-11963","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-engineering","8":"category-space","9":"tag-dyson-sphere","10":"tag-energy","11":"tag-future","12":"tag-futurism","13":"tag-star","14":"tag-the-conversation","15":"cs-entry","16":"cs-video-wrap"},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/11963","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/users\/840"}],"replies":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/comments?post=11963"}],"version-history":[{"count":1,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/11963\/revisions"}],"predecessor-version":[{"id":11964,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/11963\/revisions\/11964"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/media\/11965"}],"wp:attachment":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/media?parent=11963"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/categories?post=11963"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/tags?post=11963"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}