Black holes are the universe’s Energizer Bunnies. They are the most efficient “machines” for transforming matter into energy through their intense gravitational pull.
For example, the early universe was ablaze with untold supermassive black holes pouring out prodigious amounts of energy from the cores of galaxies. 11 billion years ago the black holes did the heavy lifting by reheating the universe and therefore inhibiting new generations of stars to form in some small galaxies.
As I mentioned in a previous blog, far-advanced technological civilizations might be highly motivated to manufacture their own mini-black holes as the ultimate power sources capable of Herculean feats.
Ironically, mini-black holes would radiate extraordinary amounts of energy quickly because they are so small. They might be the preferred “engine” for propelling a starship at near-light-speed. In fact, the signature of an extraterrestrial starship plying the galaxy may be detectable from Earth.
“Black hole drives” are common in science fiction. In Arthur C. Clarke’s 1975 novel Imperial Earth they power interplanetary cruise ships.
Making a black hole would be no easy task, but a century ago neither would the idea of extracting vast quantities electricity from radioactive ore.
A super-civilization could build black holes for numerous mega-engineering projects and to support the energy needs of a ballooning population. Interstellar travel and colonization would be a natural spinoff.
A number of far-advanced alien civilizations might converge on black hole propulsion as the only logical choice. Matter-antimatter propulsion requires even more exorbitant energy production simply to manufacture antimatter. Safely storing it is problematic without risking a titanic explosion should the magnetic containment vessel leak.
But a black hole is much tamer by comparison. You can’t afford to lose it or collide with it, but it just sits there, sucks up matter and doesn’t explode.
In a scenario proposed by Louis Crane and Shawn Westmoreland of Kansas State University several years ago, a power-hungry super-civilization uses robots to fabricate immense solar cell arrays with the collecting area of Arizona. Placed very close to their star, the arrays would store up energy to power a spherical cluster of gamma-ray lasers. The laser beams would converge to pack so much energy into a shell of photons that it collapses under gravity to create a black hole singularity.
The black hole would weigh about a million tons have an event horizon only one one-thousandth the size of a proton. According to Stephen Hawking it would release a furious hot dose of gamma rays, particles and antiparticles. For galactic core black holes, the amount of Hawking radiation produced is small, but mini-black holes should quickly convert mass into a huge amount of energy. The price tag is that the black hole evaporates away over decades or centuries. The Hawking radiation carries away mass from the black hole until it vanishes.
A black hole stardrive would direct this radiation into a particle beam jet that would be ejected at nearly the speed of light, providing the impulse to propel the vehicle.
Today’s gamma-ray telescopes might be able to pick up the exhaust from a black hole starship, but the particle beam may be so narrow that a chance alignment with our observatories would be rare.
The stardrive engine would also emit gravitational waves, but current gravitational wave detectors are working at wavelengths that are too long for what would be produced by a mini-black hole. A specialized gravitational wave telescope would have to be built just to look for artificial black holes and exotic natural phenomena.
Imagine the shock and awe of picking up such a signal from deep space. It would be reminiscent of the scene from Tom Clancy’s 1984 novel, The Hunt For Red October where a Navy submarine’s sonar engineer picks up the long-wavelength throbbing of a stealthy magnetohydrodynamic “caterpillar drive” on an advanced Soviet sub.
In the ultimate bootstrapping, a far advanced civilization may fabricate a cluster of black holes to power a machine to crank out even more black holes. Fed on dust or water or even empty beer cans (swapping Doc Brown’s Mr. Fusion for Mr. Black Hole) the black hole duplicator would make the civilization “unimaginably rich” according to the researchers. “The extraterrestrial could settle the galaxy at will,” they assert.
Image credits: NASA, DOE