Future spaceships could use black holes as powerful stepping stones to explore the stars.
A new study plans to fire laser beams which curve around a black hole and come back with added energy to propel a spacecraft near the speed of light. The astronomers could look for signs that alien civilizations are using such a "halo drive" as he studied, seeing if couples of blacks holes merge more often than expected.
Author of the study David Kipping, an astrophysicist at Columbia University in New York, came up with the idea of guiding the aura through what he calls "the mentality of the player".
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At the key challenge of using missiles to fly in space is that the propellant they carry has mass. Long journeys require a lot of fuel, which makes heavy rockets, which in turn require more fuel, making the missiles even heavier, and so on. The problem becomes exponentially worse the bigger the missile becomes.
Instead of carrying fuel for propulsion, however, the spacecraft equipped with mirrored sails could rely on lasers to push them & # 39; external. The $ 100 million initiative Breakthrough Starshot announced in 2016, plans to use powerful lasers to make ships swarm to Alpha Centauri, the star system closest to ours, up to 20% of the speed of light .  The spaceship Breakthrough Francisco Rush has plans to launch all & # 39; only about the size of a microchip. To speed up the largest spacecraft at relativistic speeds – a significant fraction of the speed of light – Kipping tried l & # 39; help of gravity.
Spaceships now regularly use "slingshot maneuvers", in which the gravity of a body, like a planet or moon, hurls ships across space and increases their speed. In 1963, the famous physicist Freeman Dyson suggested that spaceships of any size could count on sling maneuvers around compact pairs of white dwarfs or neutron stars to fly at relativistic speeds. (Dyson developed the notion of what became known as Dyson's a megastructure that encapsulates a star to capture as much energy as possible to power an advanced civilization.)
However, a Dyson sling "risks damaging a spacecraft through extreme gravitational forces and dangerous radiation from those pairs of dead stars. Instead, Kipping suggests that gravity could help spaceships by increasing the energy of laser beams fired at the edges of black holes.
The blacks holes possess gravitational fields so powerful that nothing can escape them once close enough, not even light. Their gravitational fields can also distort the paths of photons of light that do not fall into holes.
In 1993, physicist Mark Stuckey suggested that a black hole could, in principle, behave as a "gravitational mirror", since the gravity of the black hole could cleave a photon around so that it returned to its origin . Kipping calculated that if a black hole was moving toward the source of a photon, the "boomerang photon" would have taken part of & # 39; energy of the black hole.
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Using what he called a "halo driver" – called for the ring of light that would have created around a black hole – Kipping discovered that even spaceships with the mass of Jupiter could reach relativistic speeds. "A civilization could exploit black holes as galactic waypoints," a study wrote in accepted by the Journal of the British Interplanetary Society and detailed online February 28 in the prepress arthritic server.
The faster the black hole moves, the more energy can come from a halo disk. As such, Kipping focused mainly on & # 39; use of pairs of blacks holes that are hurled l & # 39; a to l & # 39; other before a merger.
The astronomers could look for signs that alien civilizations were exploiting pairs of blacks holes to travel with such an engine. For example, halo units would actually steal energy from such systems of binary black hole by increasing the rates at which pairs of black holes join above what one would expect to see naturally, has said Kipping.
His findings were based on upgrades of pairs of blacks holes orbiting l & # 39; s a & # 39; another at relativistic speeds. Although there are about 10 million pairs of black holes in the Milky Way, Kipping noted that some of them probably orbited at relativistic speeds for a long time, because they would unite rather quickly.
However, he observed that isolated and rotating black holes could also launch halo units at relativistic speeds "and we already know numerous examples of supermassive and relativistic black holes."
The main disadvantage of a halo is that "you have to go closer to the black hole," said Kipping. "It's like paying a one-time toll to drive the highway system: you have to pay a little energy to reach the nearest access point, but then you can go for free as long as you want."
L & # 39; halo unit works only in the vicinity of a black hole, a distance of about five to 50 times the diameter of the black hole. "This is why you must first bring to you closer to the black hole and [why you] can not do it simply through light years of space," said Kipping. "We still need a means to travel to nearby stars to drive the highway system.
" If we want to achieve a relativistic flight, it takes immense energy levels, no matter what propulsion system you use, "he added. to get around this is to use astronomical objects as a source of energy, since they literally possess astronomical levels of energy within them.In this case, the black-hole track is essentially a gigantic battery waiting for us to touch it The idea is to work with nature and not against it. "
Kipping is now studying ways to exploit other astronomical systems for relativistic flight. Such techniques" may not be as efficient or fast as l & # 39; halo-drive approach, but these systems possess the deep energy reserves necessary for these trips, "said Kipping