“The final stage in the life of a star,” observes physicist Carlo Rovelli in Seven Brief Lessons on Physics, “where the quantum fluctuations of space-time balance the weight of matter, is what is known as a ‘Planck star’. If the sun were to stop burning and to form a black hole, the event horizon would measure about six kilometers in diameter. The black hole’s event horizon is not a physical barrier, but simply the boundary where the black hole’s gravitational field becomes so intense that the escape velocity exceeds the speed of light. Nothing, not even light, can escape the event horizon.
Starting up in 2024, the enhanced Advanced LIGO Plus detector of gravitational waves will embed the Heisenberg uncertainty principle to improve the machine’s ability to detect ripples in spacetime. One of the foundations of quantum theory, the Heisenberg principle states that it’s impossible to precisely measure certain properties, such as the position and momentum of an object, at the same time.