That’s No Planet. Detecting Transiting Megastructures

One of the easiest ways to find exoplanets is using the transit method. It relies upon monitoring the brightness of a star which will then dim as a planet passes in front of it. It is of course possible that other objects could pass between us and a star; perhaps binary planets, tidally distorted planets, exocomets and, ready for it…. alien megastructures! A transit simulator has been created by a team of researchers and it can predict the brightness change from different transiting objects, even Dyson Swarms in construction. 

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There’s Another, More Boring Explanation for those Dyson Sphere Candidate Stars

WISE images of dust-obscured galaxies

Dyson Spheres have been a tantalising digression in the hunt for alien intelligence. Just recently seven stars have been identified as potential candidates with most of their radiation given off in the infrared wavelengths. Potentially this is the signature of heat from a matrix of spacecraft around the star but alas, a new paper has another slightly less exciting explanation; dust obscured galaxies. 

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Some Intelligent Civilizations Will Be Trapped on their Worlds

With thousands of exoplanets discovered so far, astronomers are learning how different planets can be. What if intelligent alien civilizations arise on extremely different habitable worlds? Some civilizations could develop space exploration technologies, but others would be trapped underwater, under ice, or in enormous gravity wells. How could they escape? Image Credit: DALL-E

Evolution has produced a wondrously diverse variety of lifeforms here on Earth. It just so happens that talking primates with opposable thumbs rose to the top and are building a spacefaring civilization. And we’re land-dwellers. But what about other planets? If the dominant species on an ocean world builds a technological civilization of some sort, would they be able to escape their ocean home and explore space?

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We Could Snoop on Extraterrestrial Communications Networks

The Atacama Large Millimeter/submillimeter Array (ALMA). Credit: C. Padilla, NRAO/AUI/NSF

The conditions for life throughout the Universe are so plentiful that it seems reasonable to presume there must be extra-terrestrial civilizations in the galaxy. But if that’s true, where are they? The Search for Extra-terrestrial Intelligence (SETI) program and others have long sought to find signals from these civilizations, but so far there has been nothing conclusive. Part of the challenge is that we don’t know what the nature of an alien signal might be. It’s a bit like finding a needle in a haystack when you don’t know what the needle looks like. Fortunately, any alien civilization would still be bound by the same physical laws we are, and we can use that to consider what might be possible. One way to better our odds of finding something would be to focus not on a direct signal from a single world, but the broader echos of an interstellar network of signals.

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Can Alien Civilizations Detect Humanity?

Is anyone out there? A new study examines how likely it is that an advanced ETI can "see" us. Image Credit: Jon Hrubesch

One of the fascinating things about being a human in this age is that we can do more than wonder about other life and other civilizations. We can actually look for them, although there are obvious limitations to our search. But what’s equally fascinating is that we can wonder if others can see us.

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First Contact Could Turn Out Well for Humanity

Illustration of a radio telescope listening for signals from an alien civilization. Credit: Zayna Sheikh, Breakthrough Listen

You’ve heard this story before. An advanced alien race comes to Earth. They offer peace and prosperity, but they hold a dark secret. One that could destroy humanity. That dark secret has varied over the years, from stealing our water, books on culinary advice, or communism, but the result is always the same. First contact with advanced extraterrestrials goes very badly for us. But in reality, how bad could it be? That’s the question a new study examines using game theory and Hobbesian philosophy.

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Could We Find Aliens Terraforming Other Worlds?

Artist's conception of a terraformed Mars. Credit: Ittiz/Wikimedia Commons

The first early humans to use fire had no inkling of what it would lead to.

Fire was one of our first technologies, and humans have been making changes to their environments since the advent of controlled fire hundreds of thousands of years ago. Fast forward to current times, and our modern technological and global civilization is changing the Earth’s entire biosphere. From carbon emissions that acidify the oceans and weaken the shells of marine life to microplastics that find their way into organisms’ bloodstreams, our technology is intersecting, or combining, with the biosphere.

This has spawned a useful word: biotechnosphere.

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Is Anyone Planning for Diplomacy with an Extraterrestrial Civilization?

Artist impression of an alien civilization. Image credit: CfA

Imagine we detect an interstellar object entering our Solar System. At first, astronomers think it’s just another natural interloper like Oumuamua or comet Borisov. We’re warming up to the idea of visitors from other parts of the galaxy, though they’ve been inanimate so far.

But then, what if it becomes clear that something’s different about this visitor? What if it moves unnaturally or somehow behaves purposefully? What if it takes up a stable orbit somewhere? What if, as we gather more evidence, it becomes clear that it’s a probe of some sort sent to us intentionally? What if it communicates with us?

Suddenly, as if thrust into a science fiction plot, humanity is in a totally different situation. What do we do?

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