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Black holes smaller than atoms pass unnoticed through planet, study suggests.

Like cosmic ghosts, miniature black holes may be zipping harmlessly through Earth on a daily basis, a new study suggests.
The new theory rebuts doomsday scenarios in which powerful atom-smashing machines such as the Large Hadron Collider spawn black holes that swallow the planet.
Instead, the study authors think that tiny black holes would behave very differently from their larger brethren in deep space, called astrophysical or stellar-mass black holes.

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Planetary scientists have claimed that a number of miniature black holes pass through the Earth almost everyday, but without causing any damage to our planet.
And, unlike the larger black holes -- formed by the collapse of giant stars -- that swallow everything even light, past a certain point, the mini black holes would instead hold objects in an orbit, say the scientists.
According to the research, led by Aaron P VanDevender from Halcyon Molecular in California, and J Pace VanDevender from Sandia National Laboratories in New Mexico, the orbiting effect is similar to the way electrons orbit a nucleus without collapsing inwards.

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Mini black holes
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Title: Structure and Mass Absorption of Hypothetical Terrestrial Black Holes
Authors: A. P. VanDevender, J. Pace VanDevender

The prospect of mini black holes, either primordial or in planned experiments at the Large Hadron Collider, interacting with the earth motivate us to examine how they may be detected and the scope of their impact on the earth. We propose that the more massive of these objects may gravitationally bind matter without significant absorption. Since the wave functions of gravitationally bound atoms orbiting a black hole are analogous to those of electrons around a nucleus, we call such an object the Gravitationally Equivalent of an Atom (GEA). Mini black holes are expected to lose mass through quantum evaporation, which has become well accepted on purely theoretical grounds. Since all attempts to directly observe x-rays from an evaporating black hole have failed, we examine the possibility of the inverse test: search for extant mini black holes by looking for emissions from matter bound in a GEA. If quantum evaporation does not occur, then miniature black holes left over from the early universe may be stable, contribute to dark matter, and in principle be detectable through emissions associated with the bound matter. We show that small black holes-with masses below ~10 kg-can bind matter without readily absorbing it into the black hole but the emissions are too weak to be detected from earth.

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Microscopic black holes
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Search for microscopic black hole signatures at the Large Hadron Collider

The CMS experiment at CERN's Large Hadron Collider (LHC) has completed a search for microscopic black holes produced in high-energy proton-proton collisions. No evidence for their production was found and their production has been excluded up to a black hole mass of 3.5-4.5 TeV (1012 electron volts) in a variety of theoretical models.
Microscopic black holes are predicted to exist in some theoretical models that attempt to unify General Relativity and Quantum Mechanics by postulating the existence of extra "curled-up" dimensions, in addition to the three familiar spatial dimensions. At the high energies of the Large Hadron Collider, such theories predict that particles may collide "closely enough" to be sensitive to these postulated extra dimensions. In such a case, the colliding particles could interact gravitationally with strengths similar to those of the other three fundamental forces - the Electromagnetic, Weak and Strong interactions. The two colliding particles might then form a microscopic black hole.

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Title: Do microscopic stable black holes contribute to dark matter?
Authors: P. Suranyi, C. Vaz, L.C.R. Wijewardhana

We investigate some of the experimental, observational and theoretical consequences of hypothetical stable black holes in the mass range between the electro-weak scale and the Planck mass, 2.4 x 10^{15} TeV. For the purpose of calculations we use Lovelock black holes in odd dimensions. If such black holes exist they contribute to dark matter. We show that the passage of the black holes through matter and the collision of black holes have a well defined experimental signature. Depending on their cross section and energy they also accumulate in stars and influence their development.

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Dartmouth researchers propose new way to reproduce a black hole
Despite their popularity in the science fiction genre, there is much to be learned about black holes, the mysterious regions in space once thought to be absent of light. In a paper published in the August 20 issue of Physical Review Letters, the flagship journal of the American Physical Society, Dartmouth researchers propose a new way of creating a reproduction black hole in the laboratory on a much-tinier scale than their celestial counterparts.
The new method to create a tiny quantum sized black hole would allow researchers to better understand what physicist Stephen Hawking proposed more than 35 years ago: black holes are not totally void of activity; they emit photons, which is now known as Hawking radiation.

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Title: On the Possibility of Catastrophic Black Hole Growth in the Warped Brane-World Scenario at the LHC
Authors: Roberto Casadio, Sergio Fabi, Benjamin Harms

In this paper we present the results of our analysis of the growth and decay of black holes possibly produced at the Large Hadron Collider, based on our previous study of black holes in the context of the warped brane-world scenario. The black hole mass accretion and decay is obtained as a function of time, and the maximum black hole mass is obtained as a function of a critical mass parameter. The latter occurs in our expression for the luminosity and is related to the size of extra-dimensional corrections to Newton's law of gravitation. Based on this analysis, we argue against the possibility of catastrophic black hole growth at the LHC.

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Black hole simulator to search for evidence of extra dimensions in space at the world-famous Large Hadron Collider
A team of theoretical and experimental physicists, with participants from Case Western Reserve University, have designed a new black hole simulator called BlackMax to search for evidence that extra dimensions might exist in the universe.
Information about BlackMax's creation has been published in Physical Review Letters in the article, "BlackMax: A Black-Hole Event Generator with Rotation, Recoil, Split Branes and Brane Tension."

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A black hole has been made in the laboratory. Its not, needless to say, a collapsed star with super-strong gravity, like the black holes thought to exist in deep space. Rather its a kind of toy black hole made from light and completely harmless, its creators say.
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The idea of using analogous systems to create black holes was first proposed by William Unruh of the University of British Columbia in 1981. He imagined fish trying to swim upstream away from a waterfall, which represents a black hole. Beyond a certain point close to the waterfall, the current becomes so strong like an event horizon that fish cannot swim fast enough to escape.
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If we ever make black holes on Earth, they might be much stranger objects than the star-swallowing monsters known to exist in space. According to a new theory, any black hole that pops out of the Large Hadron Collider under construction in Switzerland might be surrounded by a black ring forming a microscopic "black Saturn".
A black hole and a black ring can co-exist, in theory, as long as they are set spinning, say Henriette Elvang of MIT in Cambridge, US, and Pau Figueras of the University of Barcelona in Spain.

"If you just had a ring, it would collapse. It's essential that it rotates to keep balanced" - Henriette Elvang.

Just like the central black hole, the ring would be defined by its event horizon, a boundary beyond which nothing can escape the object's gravity. The ring could be thin like a rubber band or fat like a doughnut, and the rotation would flatten it "like a doughnut that you have squashed".

The spinning ring would also drag space-time around with it, making the central black hole spin as well.
The black Saturn can only exist in a space with four dimensions, rather than the three we inhabit. In 3D, a black ring is impossible, so there are no big black saturns out there for astronomers to spot but at a microscopic level, they might really exist.

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