No Naked Singularity After Black Hole Collision

Black holes cannot be naked... the event horizon will always be there to cover them up...

Black holes cannot be naked... the event horizon will always be there to cover them up...

You can manipulate a black hole as much as you like but you’ll never get rid of its event horizon, a new study suggests. This may sound a little odd, the event horizon is what makes the black hole, well… black. However, in the centre of a black hole, hidden deep inside the event horizon, is a singularity. A singularity is a mathematical consequence, it is also a point in space where the laws of physics do not apply. Mathematics also predicts that singularities can exist without an associated event horizon, but this means that we’d be able to physically see a black hole’s singularity. This theoretical entity is known as a “naked singularity” and physicists are at a loss to explain what one would look like.

Like any good physics experiment, an international team from the US, Germany, Portugal and Mexico have decided to simulate the most extreme situation possible in the aim of stripping a pair of black holes of their event horizons. They did this by constructing an energetic collision between two black holes travelling close to the speed of light, crashing head-on. Here’s what they discovered…
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Meet Sagittarius A*, Our Very Own Supermassive Black Hole

Yearly location of stars within 0.2 parsecs from Sagittarius A* orbiting the common, compact radio source (A. Ghez)

Yearly location of stars within 0.2 parsecs from Sagittarius A* orbiting the common, compact radio source (A. Ghez)

We are told there is a supermassive black hole living in the centre of our galaxy. Apparently, supermassive black holes can be found in the centre of most galactic nuclei, and all the stars within the surrounding galactic disk will orbit around it. But how do we know there is a huge black hole in the centre of the Milky Way? What evidence is there? It turns out there is quite a lot, actually.

In a recent review of the subject, the radio emissions observed since the 1950′s are examined. However, probably the most striking piece of evidence is the figure to the left. Of course, we know black holes exert a massive gravitational pull on local space, and by observing the centre of our galaxy, we find there is a huge gravitational influence over a compact cluster of stars, all orbiting a common point, reaching orbital velocities of 5000 km/s…
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New Exotic Particle May Explain Milky Way Gamma-Ray Phenomenon

Chandra observation of Cassiopeia A, a young supernova remnant in our galaxy - a prominent source of high-energy particles (NASA/CXC/MIT/UMass Amherst/M. D. Stage et al.)

Chandra observation of Cassiopeia A, a young supernova remnant in our galaxy - a prominant source of high-energy particles (NASA/CXC/MIT/UMass Amherst/M. D. Stage et al.)

There is something strange happening in the core of the Milky Way. A space observatory measuring the energy and distribution of gamma-rays in the cosmos has made an unexpected (and perplexing) discovery. It would seem there is a very high proportion of gamma-ray photons emanating from our galactic core with a very distinctive signature; they have a precise energy of 511 keV (8×10-14 Joules), and there’s a lot of them. So what could possibly be producing these 511 keV gamma-rays? It turns out, 511 keV is a magic number; it is the exact rest mass energy of a positron (the antimatter particle of the electron). So this is fairly conclusive evidence that positrons are dying (i.e. annihilating) in vast numbers in our galactic nuclei. Still, this is of little help to astrophysicists as there is no known mechanism for producing such high numbers of annihilating positrons. Ideas have been put forward, but there’s a new possibility, involving some new particle physics and some lateral thinking…
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Recoiling Supermassive Black Holes and Stellar Flares

Simulation of black holes colliding. In a word, awesome (Max Planck Group)

Astrophysicists love to simulate huge collisions, and they don’t get much bigger than this. From the discoverers of the first ever observed black hole collision back in April, new observational characteristics have been researched and Max Planck astrophysicists believe that after two supermassive black holes (SMBHs) have collided, they recoil and drag flaring stars with them. By looking out for anomalous X-ray flares in intergalactic space, or off-galactic nuclei locations, repelled black holes may be spotted powering their way into deep space at velocities of up to 4000 kms-1
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Are Primordial Black Holes Antimatter Factories?

A black hole, artist impression (NASA)

A black hole, artist impression (NASA)

Could small, primordial black holes be efficient antimatter generators? It is well known that cool planetary bodies, surrounded by equal numbers of protons and electrons in thermal equilibrium, will eventually become positively charged. Why? Because electrons, with their low mass, have a higher velocity than the larger protons. Although they undergo the same gravitational acceleration, electrons are able to attain “escape velocity” more readily as the more massive protons get stuck in the gravitational well. The result? The planet has a net positive charge as more electrons, than proton escape into space.

Primordial black holes are thought to exist in our Universe (left-overs from the Big Bang), and although they may be small, they may influence ionized cosmic clouds in the same way, more electrons escape than protons left behind. However, should a threshold be reached, the extreme gravitational force surrounding the black hole could set up a powerful electrostatic field, kick-starting a strange quantum phenomenon that generates the electron’s anti-matter partner (the positron) from the vacuum of space…
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Supermassive Black Holes are Not Fussy Eaters

The core of M81 (Chandra/NASA)

By combining observations from a multitude of observatories, all looking at spiral galaxy M81, astronomers have taken a very close and intimate look at a supermassive black hole’s feeding habits. As supermassive black holes (of tens of millions of solar masses) and stellar black holes (of a few solar masses) exist in entirely different environments, astrophysicists were uncertain as to what supermassive black holes feed on. Stellar black holes eat away at the gas from companion stars, creating an accretion disk, generating a range of emissions as stellar gas falls into the disk. But where do supermassive black holes get their food? It turns out they feed off gas in the central region of galactic cores, generating similar emissions as their smaller stellar cousins. What’s more, this finding supports Einstein’s theory that all black holes, regardless of mass, share the same characteristics…
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The Case of the Supermassive Black Hole, the Infrared Object and Perceived Accuracy of Science

There is a trend in astronomical observations to label strange and exotic objects with superlative names. Take “supermassive” black holes for instance. Yes they are more massive than intermediate black holes, bigger than stellar black holes, and in a whole different league to theoretical micro-black holes. But is the label “supermassive” an accurate description? Is it even scientific?

After reading a very interesting article written by Michael Gmirkin on “Incorrect Assumptions in Astrophysics“, I began to relate his investigation into the use of terms to describe astronomical phenomena with very expressive names. Terms like “super-massive”, “ultra-luminous”, and “beyond-bright” are mentioned by Gmirkin, perhaps leading astronomers to incorrect conclusions. Whilst this may be perceived as an issue amongst scientists, what if the media or non-specialist individuals misinterpret the meaning of these grand statements? Could it lead to public misunderstanding of the science, possibly even causing worry when a scientist describes a particle accelerator collision as “recreating the conditions of the Big Bang”?
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Supermassive Black Hole Flare Lights Up Mysterious Molecular Torus

Artists impression of a light echo from the surrounding torus of a supermassive black hole (Max Planck Institute)

Theoretically, supermassive black holes that occupy the centre of galaxies (including our own) are surrounded by a vast cloud of gas. Depending on the angle you are viewing this molecular torus will obscure the supermassive black hole’s bright accretion disk. Until now, this vast doughnut of matter has never been observed, but with the help of the supermassive black hole accretion disk and a dying star, there’s a possibility that the molecular torus will not only be observed, but also mapped…
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LHC Worries are Based on Fear of the Unknown, not Science

The construction of the LHC is nearing completion, exciting or worrying? (AP)

I’ve heard some crazy talk in my time, but the fear surrounding the Large Hadron Collider (LHC) at CERN has really surprised me. On writing a story last month that a guy in Hawaii (with a scant background in physics) was trying to pass a lawsuit to put a stop to the construction of the LHC, I realised the pressures physicists at the cutting edge of science are under. Physicists the world over have defended the science behind the LHC, and although some of the products from high energy particle collisions are as yet unknown, there is an infinitesimal chance that a black hole will swallow Earth… (I actually want a black hole to be created, the scientific implications will be revolutionary.)
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Astroengine.com Roundup and Opinion

It’s been a while since I last posted as I’ve been flying from the US to the UK and have only just gotten my office up and running. That’s not to say I haven’t been writing. On the Universe Today, I’ve posted quite a few articles ranging from quite an elaborate April Fools story (but not quite as elaborate as Virgin and Google’s Virgle prank), to a black hole hiding in the middle of Omega Centauri, to rocks rolling around on Mars… here’s a round up of the most interesting…
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