The technology is speculative -- and the costs astronomical -- but an astrophysicist suggests we're not far from sending the world's smallest spacecraft to achieve the biggest mission in modern physics.
(CN) -- In a vision that bridges science fiction and cutting-edge astrophysics, a researcher is proposing an 80-year mission to chase down a hidden black hole lurking in our cosmic backyard -- using miniature spacecraft propelled by powerful lasers.
If successful, the journey could unlock secrets of gravity, space-time and the universe itself, but it'll require patience: Even if prices fall enough to make the project feasible and technological developments advance enough to locate a nearby black hole, the first data might not arrive until the next century.
In a paper published Thursday in the Cell Press journal iScience, astrophysicist and black hole expert Cosimo Bambi proposes revolutionary gram-scale nanocrafts designed to reach relativistic speeds using breakthrough propulsion and miniaturization.
Powered by lasers based on Earth, each tiny spacecraft would feature a 1-gram microchip-like payload containing a computer processor for navigation, data collection and communication; tiny ion drives or photon thrusters for minor trajectory adjustments; miniaturized sensors like atomic clocks and spectrometers to test general relativity and an ultra-thin reflective light sail composed of metamaterials like silicon nitride or graphene.
Inspired by a research and engineering initiative known as Breakthrough Starshot, Bambi believes laser arrays can target the sail for around 17 minutes and accelerate the craft to as much as 90% of light speed. Although the closest known black hole is roughly 1,560 light years away, estimates suggest undiscovered black holes may exist within 25 light years of Earth.
"There have been new techniques to discover black holes," Bambi said in a statement. "I think it's reasonable to expect we could find a nearby one within the next decade."
At that distance, if Bambi's nanocraft were launched today, they could reach a targeted black hole by the year 2100 or sooner. Once there, testing could be performed to verify space-time geometry predictions by tracking the orbits of the tiny spaceships. Theoretically, researchers would even be able to test the black hole's event horizon by observing signal behavior as a nanocraft approaches.
Bambi, of Fudan University in China, believes it would take another 10 to 15 years for the data collected to be returned to Earth. While highly speculative today, he says the mission is feasible with future technology. It promises groundbreaking insights into black holes and fundamental physics, despite the multi-decade timeline and technical hurdles.
"We don't have the technology now," Bambi said. "But in 20 or 30 years, we might."
Among the hang-ups with today's technology are limited laser propulsion, light sail durability and an unknown ability to communicate over interstellar distances. There's also the issue of finding a feasible black hole. Precise detection of a nearby target would require intense observations of gravitational waves or microlensing, a gravitational phenomenon that occurs when a massive object like a star, black hole, or planet passes in front of a distant light source like a background star, bending and amplifying its light due to Einstein's theory of general relativity.
There's also the issue of cost. Bambi pegs initial estimates of $1 trillion, just for the laser array. But in his mind, the investment would be worth the discoveries.
"It may sound really crazy, and in a sense closer to science fiction," he said. "But people said we'd never detect gravitational waves because they're too weak. We did -- 100 years later. People thought we'd never observe the shadows of black holes. Now, 50 years later, we have images of two."