A research probe is planned for the nearest black hole — a region of spacetime whose gravity traps even light. After a hundred years of flight, the spacecraft will enter orbit around the mysterious object to answer a key question: are we looking at a black hole or a neutron star — the ultra-dense remnant of a massive star, compressed to nuclear densities? A black hole has no surface, only a bottomless gravitational pit, while a neutron star has a solid crust of matter where a teaspoon weighs billions of tons.

The answer will come from the probe's trajectory. The curved spacetime around a black hole, according to Einstein's general relativity, dictates a specific path — orbits here obey strict equations, as if the massive body falls into a funnel, leaving only a gravitational wake. A neutron star affects motion differently: its solid surface and complex magnetic field perturb the trajectory in other ways. It's like a boat in a whirlpool: the funnel of a black hole sucks differently than an underwater mountain — a neutron star, which offers something to 'grip'.

The nearest known candidate is Gaia BH1, located 1560 light-years away. To reach the target within a century, the probe would need a speed of about 5% of the speed of light — a figure unattainable with current propulsion systems. And its signal, carrying the answer, would take another 1560 years to travel back, so the answer will be seen only by distant descendants, for whom it will be a message from the past.