Black holes not black at all?

black holeLet’s start with the beginning, shall we ? A black hole is a region of space in which the gravitational field is so powerful that nothing, not even light, can escape its pull after having fallen past its event horizon. That means that electromagnetic radiation (e.g. visible light) is unable to break away from the attraction of these massive objects. Hence the name. They were first described by Einstein’s general theory of relativity, which he developed in 1916.

But now, a team of international scientists have used flowing water to simulate a black hole, testing Stephen Hawking’s theory that black holes are not black after all. While I fully understand and appreciate what Stephen Hawking has done for science, many of his theories are… not always as good as many people think. The media has a player a role here too. The researchers, led by Professor Ulf Leonhardt at the University of St Andrews and Dr Germain Rousseaux at the University of Nice, used a water channel to create analogues of black holes, simulating event horizons.

An event horizon is a boundary in spacetime, an area surrounding a black hole, beyond which events cannot affect an outside observer.The scientists sent waves against the current, varied the water speed and the wavelength, and filmed the waves with video cameras. They made observations for several months and wanted to see whether the waves show signs of Stephen Hawking’s famous prediction that the event horizon creates particles and anti-particles. Professor Ulf Leonhardt, from the School of Physics and Astronomy, explained,

“It is probably impossible to observe the Hawking radiation of black holes in space, but something like the radiation of black holes can be seen on Earth, even in something as simple as flowing water.”

The team showed that even something as simple as water can bring out conclusions about things as complex as black holes. Professor Leonhardt continued,

“Flowing water does not create anti-particles, but it may create anti-waves. Normal waves heave up and down in the direction they move, whereas anti-waves do the opposite.

“We definitely have observed these negative-frequency waves. These waves were tiny, but they were still significantly stronger than expected. However, our experiment does not completely agree with theory and so much work remains to be done to understand exactly what happens at the event horizon for water waves.”

Here’s a small video showing those phenomenae, and the rest can be seen here.

6 thoughts on “Black holes not black at all?

  1. Sile this Millennium

    Another order idea ,castigat ridendo mores *( manners by laughing at them)what you say this evolution :
    ” The Vatican’s chief astronomer says there is no conflict between believing in God and in the possibility of “extraterrestrial brothers” perhaps more evolved than humans.

    “In my opinion this possibility (of life on other planets) exists,” said Rev. Jose Gabriel Funes, a 45-year-old Jesuit priest who is head of the Vatican Observatory and a scientific adviser to Pope Benedict.(…)”
    [By Philip Pullella
    VATICAN CITY (Reuters) -]
    I read this just now and I put in my Blog now….

  2. Ryan

    I like the fact that this really cool sounding research is going on. But I don’t understand why the story about an experiment that has almost nothing to do with black holes is full of information about black holes. I think maybe these researchers are trying to create hype and publicity.

  3. Julian Banks

    Actually, it’s not as far-fetched as you would think trying to model this behavior with water. I actually found it to be quite clever, taking advantage of wave-particle duality and capitalizing on the fundamental similarities of matter. The “anti-waves” were a really cool analogue to anti-matter/particles and in the quantum mechanics portion of my chemistry class, water was again used to demonstrate some of the properties of quantum mechanics. In fact, if we are to learn more about events beyond our scope and reach, it is paramount that we are able to scale down and model these processes (or in this case phenomenon) in the lab using available materials. I think I may look more into this for a potential thesis project! Thanks Andrei!

  4. kris acly

    I have a therey that black holes are not black holes at all and that the gravity one finds there stops at the event herison that the particals are not destroied but fused in to differnt forms of energy and then focased out werd via radiation. if my thery is right then the galixy is actuly a large storm were the gasses are brought in to the center and compressed only to be elimently changed and rechaneld on a subatomik lvl gravity and sentrifical force feed the beast energy but when the mass becomes to dence matter must reform in to vapers of its self its just my thery no science to prove it yet but if there was such a thing as black holes why would there be an event herisen at all once an object is put in to motion it stays in motion and eaven light can not escape this law

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