Friday , August 19 2022

Halo Drive: Lasers and black holes can launch ships to the speed of light


Future spacecraft could use black holes as powerful star launchers for exploring stars.

A new study predicts the release of laser beams that would bend around the black hole and returned with additional energy to move the spacecraft to the speed of light. Astronomers could seek signs that alien civilizations use such a "halo drive", as the study calls it, seeing whether black hole pairs are more often merged than expected.

David Kipping, an astrophysicist at the University of Columbia in New York, came up with the idea of ​​driving aureole through what he calls "gamer thinking."

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"Sometimes in a computer game you find" exploitation, "a hack that allows you to do something overridden otherwise banned by the rules of the game," said Kipping "In this case, the game is a physical world, and I have tried to think about exploits that would allow civilization to achieve a relativistic flight back and forth through the galaxy without huge energy costs that could be naively assumed."

The key challenge for using rockets to fly through space is this which they carry with them has a mass. Long journeys require a lot of fuel, which makes the rockets heavy, which in turn requires more fuel, making the missiles even harder, and so on. This problem exponentially worsens that the rocket is bigger.

However, instead of carrying propulsion propulsion, a spaceship equipped with sails similar to mirrors could rely on lasers to push them out. $ 100 million Breakthrough Starshot Initiative, announced in 2016, plans to use powerful lasers for the propulsion of spacecraft to Alpha Centauri, the closest star system in our country, up to 20 percent of the speed of light.

The space ship that launches Breakthrough Starshot is the size of a microchip only. In order to accelerate larger spaceships to relativistic speeds – to a significant part of the speed of light – Kipping sought gravity assistance.

The spaceship now uses "slave maneuvers" on a regular basis, in which body gravity, such as a planet or a month, casts vessels into space and increases their speed. In 1963, the famous physicist Freeman Dison suggested that spaceships of any size can rely on maneuvers of slings around compact pairs of white dwarfs or neutron stars to fly at relativistic speeds. (Dison came up with an idea of ​​what became known as a Dison sphere, a megastructure that unites the star to capture as much energy as possible for the supply of advanced civilization.)

However, the "Dione Sling" risks damaging the aircraft with extreme gravity forces and dangerous radiation from these dead star pairs. Instead, Kipping suggests that gravity can help space ships by increasing the energy of laser beams fired on the edges of the black holes.

The black hole has a gravitational field so strong that nothing can escape them when it comes close enough, not even light. Their gravitational fields can also distort the path of photons of light that do not fall into the holes.

In 1993, physicist Mark Stukki suggested that a black hole could, in principle, behave like a "gravity mirror" so that the gravity of the black hole could accelerate the photon around him so that he returns to his source. Kipping calculated that if the black hole moves towards the photon source, the "boomerang photon" will separate the black hole energy.

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Using what he called a "halo drive" – ​​named after the ring of light, he would create around a black hole – Kipping discovered that even spaceships with the mass of Jupiter can achieve relativistic speeds. "Civilization could use black holes as galactic points," he wrote study accepted by the Journal of the British Interplanetari Societe and detailed online February 28 in the arKsiv preprint server.

The faster the black hole moves, the more energy the halo can get out of it. As such, Kipping mainly focused on the use of black hole pairs that spiraled one before the other before merging.

Astronomers could seek signs that extraterrestrial civilizations use pairs of black holes to travel with such a motor. For example, halo discs would effectively steal energy from such binary black hole systems, increasing the rates by which black hole pairs merged above what could be expected naturally, Kipping said.

His findings are based on incentives from pairs of black holes circling one another at relativistic speeds. Although estimated to be 10 million pairs of black holes in the Milky Way, Kipping noted that few of those who probably circled around relativistic speeds for a long time would quickly merged.

Nevertheless, he noticed that isolated, black holes swinging can start and hail at relativistic speeds, "and we already know a number of examples of relativistic, rotating supermassive black holes."

The main disadvantage of the halo drive would be "to travel to the nearest black hole," Kipping said. "It's worth paying off a one-way toll for driving the highway system. You need to pay some energy to get to the nearest access point, but after that, you can drive for free as long as you want."

The halo drive works only in the immediate vicinity of the black hole, at a distance of about five to fifty times the diameter of the black hole. "That's why you must first travel to the nearest black hole [why you] I can not do it simply through the light years of the universe, Kipping said. We must still first have the means to travel to nearby stars to drive the highway system.

"If we want to achieve a relativistic flight, huge energy levels are needed regardless of the drive system you are using," he added. One way to get around is to use astronomical objects as a source of energy, as they have literally astronomical levels of energy inside them. In this case, a binary black hole is essentially a huge battery waiting to be taped. The idea is to work with nature, not against it. "

Kipping is now exploring ways to use other astronomical systems for a relativistic flight. Such techniques "may not be as efficient or as fast as a halo-powered approach, but these systems have the deepest energy reserves needed for these trips," Kipping said.

Follow Charles K. Choi on Twitter @ ckchoi. Follow us on Twitter @ Spacedotcom and at Facebook.

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