SETI Should Consider Black Holes As Potential Targets


Contrary to Disney's vision, entering a black hole will not make you Satan 2.0, reigning over legions of the damned. Instead, the inside of a black hole is really dark and meaningless. Still it's not the destination but the journey. TopTrending posted a great little video on YouTube illustrating the increasingly bizarre effects from approaching a singularity.

As the video illustrates, the greatest phenomenon experienced is the time dilation as one approaches the point of no return, or event horizon. Outsiders will see the craft's descent slow 'til it stops, getting stuck like a fly in amber. Those travellers are effectively outside the universe's subjective timeline. For every one of their minutes, decades, centuries or millennia pass on the outside. This phenomenon has implications for the search for extraterrestrial life.

"Where is everybody?" is the central question of the Fermi Paradox. When we point our eyes and ears heavenwards, we are met with a profound silence. For half a century humanity has been combing the heavens for a signal affirming we aren't alone in the universe. The radio band holding the most promise for detecting life similar to our own lay between 1,420 and 1,666 megahertz. Also known as the "water hole", these frequencies correspond with the wavelengths of hydroxyl radicals (OH, 18cm) and hydrogen (H, 21cm) making up H20, a.k.a water. This part of the radio spectrum is relatively quiet, making it perfect for extraterrestrial eavesdropping and inspiring Dr. Bernard Oliver's quote "Where shall we meet our neighbors? At the water-hole, where species have always gathered."

Frustratingly this band, and others, has been too quiet. According to data from the Kepler observatory, there could be as many as 40 billion habitable worlds in our galaxy. Back in 2012 Thomas Hair and Andrew Hedman modelled the expansion of interstellar civilizations, concluding a civilization travelling at ΒΌ of 1% the speed of light could colonize the galaxy in 50 million years. [1] Based on this data, the skies should be alive with chatter.

Since faster-than-light travel isn't a theoretical possibility, yet, civilizations are stuck with slower-than-light ships. As they hop between star systems, those beings would be more likely to encounter empty tombworlds or planets full of primitives, rather than spacefaring peers. Bringing us back to black holes. Rather than wasting valuable time and resources hunting down other civilizations, most likely rising and falling during the journey; a species could wait for the rest of the universe to catch up inside a black hole.

The search for extraterrestrial life around black holes raises many questions. Where do we look? What do we look for? In 2014, NASA's the Nuclear Spectroscopic Telescope Array (NuSTAR) and Swift space observatory may have spotted a clue. Black holes are surrounded by coronas, made up of energetic particles moving at a fraction of the speed of light and emitting x-rays. NuSTAR and Swift observed the supermassive black hole Markarian 335's corona collapse inwards before being ejected, emitting an x-ray flare. [2] There is the outside possibility an event like this is intended as beacon to pique the curiosity of others to take a closer look at potential alien hideouts.

If that's the case, with apologies to Dr. Oliver, "Where shall we meet our neighbors? At a black hole, where species will gather in the far future."

You may also enjoy:

  1. Spatial dispersion of interstellar civilizations: a probabilistic site percolation model in three dimensions -
  2. Black Hole Has Major Flare -


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Martin J. Clemens's picture
Member since:
11 August 2013
Last activity:
1 week 2 days

You gloss over the one critical element of black hole physics, the one element that still, and likely will always stand in the way of any living thing entering, or more accurately, crossing the event horizon...that element being gravity.

Any living thing approaching a black hole will be crushed to subatomic size, thus stopping it from being a living thing before it can even get to threshold.

All of the suppositional "what if's" are fun, but all of them require a suspension of that one simple fact. So no, I highly doubt aliens are coming through black holes to visit us.