Search This Blog

Sunday, 19 April 2015

Searching for a galactic empire?

In search of Galactic Empires

When people look for evidence of an alien intelligence at work they're usually looking for something like Earth,  maybe a bit more advanced, maybe a lot more and spread across several worlds or even several star systems. What no one,  as far as I know,  has looked for before is an alien supercivilisation- a civilisation that controls a whole galaxy.

Until now.

Above: Why absorb the power of a whole galaxy? I refer you to Emporor Palpatine in the last moments of this clip for the answer. Courtesy of ... erm.... Disney?

This might sound like the brain child of someone who has been watching too many Star Trek episodes, or who has the Star Wars theme tune playing on a loop in the back of their mind all the time (it's not me, I promise). But it's actually from a team of serious astronomers who've set up a low key scheme called Glimpsing Heat from Alien Technologies (G-HAT). And there is a logic behind this: If you calculate how long it would take to set up a galactic empire... well it's looong in human terms. But compared to the life of most stars, or galaxies, or the universe itself, it's a short span of time (a few million years or so for a really determined race).

True, lots of races might not be interested in that kind of aggressive expansion, lots might be too primitive, might be too energy efficient, or might take steps to conceal themselves from whatever the interstellar equivalent of boogymen are. But if even a handful decided to go the route of 'colonise and dominate' across a whole galaxy we should be able to spot them.
To go into a bit more depth here's a talk (erm, well, a  full hour long lecture) on why that is from the big brains at Oxford University:

Above:This is really worth the time to watch - robot butlers lead to destroying the planet Mercury, and then conquering the whole galaxy. With gigantic rail guns. Seriously, Bond villains have nothing on real world physicists. And we could start doing this today.

The reason why we think we should detect any super civilisations is that there's a law of physics that says any energy using machine will give out heat (it's called the 2nd law of thermodynamics). Assuming that we're right about this law, and as far as we can tell we are, a civilisation spanning a whole galaxy should put out a lot of heat. What's more, such a civilisation would probably use the most obvious sources of power to power their empire ; their galaxies stars themselves, so they'd probably be collecting a significant fraction of their galaxies star light with solar panels - and eventually that energy would get re-radiated as heat too. By the way, the term for covering a sun in collectors to absorb all it's power is 'Dyson structure' or 'Dyson sphere' - it's industrilisation gone insanely large scale.

Above: Fraser Cain, editor of Universe Today websoite, gives us a quicker run down on what a Dyson sphere is. 

And, yes, they turn up in Star Trek:

Above: The starship Enterprise encounters a Dyson Sphere. Later on they find Scotty trapped in a transporter beam, and a technobabble off between him and Geordi Laforge results in a deadly spacetime rip.
The overall effect would be to make the whole galaxy dimmer in the visible light frequencies, and brighter in the infra red, and this is something that the the WISE space telescope might be able to pick up - so GHAT has been combing through its data, looking for any suspect object that might fit the description.

The GHAT team have found a hundred thousand galaxies that definitely aren't heavily modified in this way. That has left just 50 that might - and only might as a theoretical possibility - be evidence of an alien super civilisation using between 50% and 85% of their galactic energy output, and ultimately re-radiating it as heat. These will be followed up by searching for previous studies that can identify them as natural infra red emitters. Several of these objects are newly discovered, and in the team recommend that they be followed up by investigations from both SETI and more conventional astrophysics, because they look interesting even if they're not signs of super space aliens.

Elsewhere in the universe:

Another bit of Ceres related coolness from the image processing gurus at

This back and forth rocking animation of Ceres north pole was put together by the talented Toma B, and helps us to pick out surface details a bit more easily.

Procyon probe has a target (with a Moon) selected: The Procyon probe isn't about space exploration as much as how small a working interplanetary craft can be: It's barely bigger than a big pillow, and is testing an experimental, super lightweight, ion drive and thruster system.

Above: One of the probes experimental, ultra small, thrusters. Courtesy of JAXA
The probes only sensor is a telescope, and when it was launched it didn't even have a destination.... but now it does! It's going to an asteroid called 2000  DP107, which was the first asteroid ever discovered to have it's own moon.
Above: The Procyon micro satellite - one edge is about as long as a larg-ish laptop. If it hadn't gone into space it would have made a very interesting table ornament - it'd be a conversation starter, especially when you mentioned what it cost.... Courtesy of JAXA

Elsewhere on the internet:

Edge of space balloon to explore how cosmic rays damage computers

New dark matter hunter starts this autumn

Dark matter mapped by cosmic shear

New Horizons gets first colour snaps of Pluto 

The Batman Vs Superman trailer is out:

Latest Star Wars trailer is out:

No comments:

Post a Comment