Imagine a spacecraft not heavier than a trombone, powered by pure light, spinning through the cosmos at dizzying speeds to probe the deepest secrets of the universe. This vision worthy of science fiction could well become reality in a few decades. Cosimo Bambi, astrophysicist specializing in black holes at Fudan University, has just published in Iscience a detailed plan for an extraordinary mission: send a probe to a black hole in order to test the very limits of physics.
A trip to the borders of the impossible
The audacity of the bambi project lies in its conceptual simplicity and its technical complexity. The idea is to exploit the technology of nanovaisseaux, miniaturized probes weighing barely a few grams and made up of a sophisticated micropuce attached to an ultra-light sail. These revolutionary devices would be propelled not by traditional fuels, but by laser beams of an incredible power led from Earth.
This photonic propulsion would make it possible to reach phenomenal speeds: about a third of the speed of light. To put this performance in perspective, our fastest current space probes caps a few tens of kilometers per second, or less than 0.01% of the speed of light. This extraordinary acceleration would make you possible what until then seemed impossible: an interstellar journey within a reasonable time on a human scale.
The quest for the neighboring black hole
Before going on a cosmic adventure, you still have to find the destination. Bambi believes that a black hole could hide only 20 to 25 light years from our solar system. This relative proximity is based on the current models of stellar evolution which predict the formation of these extreme objects during the collapse of massive stars.
However, finding a black hole is a major challenge. By definition, these gravitational monsters do not emit any light and remain practically invisible to conventional telescopes. Astronomers can only detect them indirectly, observing their influence on the surrounding stars or the distortions they print in the light that crosses them.
Fortunately, new detection techniques are emerging regularly. Bambi is optimistic: according to him, the discovery of a black hole in our galactic neighborhood could occur within a decade.
A natural laboratory at extreme conditions
Once the target is identified, the trip would take around 70 years at the speed of a third of that of light. The data collected would then take two additional decades to reach us, bringing the total duration of the mission to almost a century. A transgenerational project that challenges our usual conception of scientific research.
But the stake is worth the candle. Black holes represent the most extreme natural laboratories of the universe, where gravity reaches unimaginable intensities. Their direct study would make it possible to answer fundamental questions that tap the physicists: is the horizon of events really? Do the laws of physics remain valid in these limits? Does Einstein’s general theory of general relativity resist the test of the most hostile environments of the cosmos?
Although this represents a considerable challenge, the astrophysicist Cosimo Bambi maintains that an interstellar mission aimed at sending a tiny spaceship to the nearest black hole is not out of reach. Credit: Event Horizon Telescope Collaboration
Technological and financial obstacles
Bambi does not hide the extent of the challenges to be met. Currently, the lasers necessary for propulsion would cost approximately a thousand billion euros approximately. As for nanovisseaux technology capable of surviving the trip and collecting relevant data, it remains to be invented from scratch.
However, the Chinese astrophysicist keeps confidence in human ingenuity. He recalls that many prowess deemed impossible in the past have become reality: the detection of gravitational waves, long considered inaccessible because of their extreme weakness, or the direct observation of the shadow of black holes, recently carried out by the collaboration Event Horizon Telescope.
In 20 to 30 years, Bambi believes, costs could drop drastically, while the necessary technologies would reach their maturity. This mission of a century could then transform our understanding of the universe and once again repel the boundaries of human knowledge.
