Hawking's Quest

For years, I have waited for Stephen Hawking to get the Noble prize in physics based on his theory predicting "that black holes are not totally black, but emit a steady stream of radiation." a notion that cannot be proven experimentally given the fact "no-one has been able to detect a black-hole signal because it would be so faint compared with the universe's background radiation."


Using analogues to show how Hawking Radiation would work has become a boomlet in research as it appears Hawking is right but proof must be in hand in order for justice to be served. "Because Hawking radiation is currently impossible to observe for real black holes, physicists have recently been looking to black hole analogues in the lab that can mimic the behaviour of their astrophysical counterparts. One type of analogue employs lasers to simulate an event horizon, because intense light can alter a medium's refractive index, which governs light propagation speed. In simple terms, shining a powerful laser through glass creates a refractive index peak: any other photons in front this peak can travel forward, while those behind and trying to travel forward are slowed to a halt – they are trapped, as in a real black hole."

Other experiments using different tech corroborates Hawking's theory in spades. "There is a mathematical analogy between the propagation of fields in a general relativistic space-time and long (shallow water) surface waves on moving water. Hawking argued that black holes emit thermal radiation via a quantum spontaneous emission. Similar arguments predict the same effect near wave horizons in fluid flow. By placing a streamlined obstacle into an open channel flow we create a region of high velocity over the obstacle that can include wave horizons."

In english, the Cnadian researchers created a white hole using water as the medium to show how the event horizon would work as a barrier forever separating the inside from the outside of the white hole save for the tunneling effect subatomic particles exhibit in certain circumstances based on quantum mechanics. Interesting enough, an outrageously cool article from Wired shows how we can create a white hole in the kitchen sink intuitively showing how these exotic things work.

"That ring of water in your kitchen sink is actually a model white hole. For the first time, scientists have shown experimentally that liquid flowing from a tap embodies the same physics as the time-reversed equivalent of black holes.

When a stream of tap water hits the flat surface of the sink, it spreads out into a thin disc bounded by a raised lip, called the hydraulic jump. Physicists’ puzzlement with this jump dates back to Lord Rayleigh in 1914. More recently, physicists have suggested that, if the water waves inside the disc move faster than the waves outside, the jump could serve as an analogue event horizon. Water can approach the ring from outside, but it can’t get in."

Circular Hydraulic Jump

As per the Canadian researchers findings regarding white holes, this research further substantiates the fact Hawking's notions are correct, Black Holes are not totally black.

"We provide an experimental demonstration that the circular hydraulic jump represents a hydrodynamic white hole or gravitational fountain (the time-reverse of a black hole) by measuring the angle of the Mach cone created by an object in the “supersonic” inner flow region. We emphasise the general character of this gravitational analogy by showing theoretically that the white hole horizon constitutes a stationary and spatial saddle-node bifurcation within dynamical-systems theory. Some perspectives are outlined on the usefulness of the circular jump as an experimentally viable white hole model for analogue gravity, in particular with respect to the ongoing debate on the robustness of Hawking radiation."

It's time for Hawking to get the prize, don't you think?