One Ivy League Astronomer says humans could achieve fuel-free interstellar travel by harvesting energy from binary black holes in a brand new method dubbed the ‘Halo Drive.’
Theoretically, said David Kipping, an astronomer at Columbia University, aliens could already be using that technology without our knowledge.
The Halo Drive method of propelling a spacecraft would work by utilizing ‘gravitational mirrors’ – a region of a black holes that swallows up matter and shoots it back out in exactly the same direction – to absorb the holes’ energy.
The Halo Drive theory uses black hole energy to propel space crafts beyond the speed of light. Artist’s impression of a black hole is pictured
‘The search for intelligence amongst the cosmos is often guided by considering the possible activities of hypothetical advanced civilizations and the associated technosignatures that would result,’ said Kipping in a study published in the journal AirXiv.
‘Along these lines, this work has considered how an advanced civilization might utilize the light sailing concept to conduct relativistic and extremely efficient propulsion.’
Scientists have observed that when photons enter a gravitational mirror and are subsequently shot back out, they not only gain velocity from their journey, they also retain some of the kinetic energy from the visit.
Kipping says using those returned photons, which are called ‘boomerang photons,’ interstellar travelers could theoretically use the harvested energy to travel at a velocity 133 percent greater than the black hole.
This method of harvesting energy from black holes would not only avoid having to tread dangerously close to the gravitational void – astronauts have tapped black holes as a type of slingshot to help propel objects into space for ages – they would also be extremely hard to detect.
‘A civilization could exploit black holes as galactic way points but would be difficult to detect remotely, except for an elevated binary merger rate and excess binary eccentricity,’ said Kipping.
As a result, Kipping said, a civilization that has the means to travel close enough to a black hole could theoretically be deploying this type of method of interstellar transit without our knowledge.
Another major benefit of the Halo Drive over other proposed forms of interstellar travel, posits Kipping, would be shedding the need for a massive fuel source.
While other theoretical forms of travel require a spacecraft to accelerate to what is called ‘relativistic speed’ – a speed comparable to the speed of light – the Halo Drive would subvert the need for any prior energy other than the light harvested from a black hole.
WHAT’S INSIDE A BLACK HOLE?
Black holes are strange objects in the universe that get their name from the fact that nothing can escape their gravity, not even light.
If you venture too close and cross the so-called event horizon, the point from which no light can escape, you will also be trapped or destroyed.
For small black holes, you would never survive such a close approach anyway.
The tidal forces close to the event horizon are enough to stretch any matter until it’s just a string of atoms, in a process physicists call ‘spaghettification’.
But for large black holes, like the supermassive objects at the cores of galaxies like the Milky Way, which weigh tens of millions if not billions of times the mass of a star, crossing the event horizon would be uneventful.
Because it should be possible to survive the transition from our world to the black hole world, physicists and mathematicians have long wondered what that world would look like.
They have turned to Einstein’s equations of general relativity to predict the world inside a black hole.
These equations work well until an observer reaches the centre or singularity, where, in theoretical calculations, the curvature of space-time becomes infinite.