* Astronomy

Blobrana · L

RE: Artificial black holes

Blobrana · L

Title: Ultrarelativistic Particle Collisions
Authors: Matthew W. Choptuik and Frans Pretorius

We present results from numerical solution of the Einstein field equations describing the head-on collision of two solitons boosted to ultrarelativistic energies. We show, for the first time, that at sufficiently high energies the collision leads to black hole formation, consistent with hoop-conjecture arguments. This implies that the nonlinear gravitational interaction between the kinetic energy of the solitons causes gravitational collapse, and that arguments for black hole formation in super-Planck scale particle collisions are robust.

Read more

Blobrana · L

Nobel physicist designing 'toy' black hole for research

Eric Cornell, one of three winners of the 2001 Nobel Prize for Physics, said that he was in the process of developing a 'toy' black hole. This would help in a better understanding of theories around the space body. In 1915, Albert Einstein first published the general theory of relativity. Among the astrophysical implications of that theory is the presence, in space, of regions that distort space and time, allowing nothing, not even light, to escape. The black hole was posited as the end-state for massive stars.
Read more

Blobrana · L

Title: X-ray astronomy in the laboratory with a miniature compact object produced by laser-driven implosion
Authors: Shinsuke Fujioka, Hideaki Takabe, Norimasa Yamamoto, David Salzmann, Feilu Wang, Hiroaki Nishimura, Yutong Li, Quanli Dong, Shoujun Wang, Yi Zhang, Yong-Joo Rhee, Yong-Woo Lee, Jae-Min Han4, Minoru Tanabe, Takashi Fujiwara, Yuto Nakabayashi, Gang Zhao, Jie Zhang and Kunioki Mima

X-ray spectroscopy is an important tool for understanding the extreme photoionisation processes that drive the behaviour of non-thermal equilibrium plasmas in compact astrophysical objects such as black holes. Even so, the distance of these objects from the Earth and the inability to control or accurately ascertain the conditions that govern their behaviour makes it difficult to interpret the origin of the features in astronomical X-ray measurements. Here, we describe an experiment that uses the implosion driven by a 0.3 TW, 4 kJ laser system6 to produce a 0.5 keV blackbody radiator that mimics the conditions that exist in the neighbourhood of a black hole.

Source

Blobrana · L

Title: Plasma astrophysics: How to see a black hole
Authors: R. Paul Drake

One way to collect data about black holes is to analyse the X-rays emitted from the surrounding plasmas heated to extreme temperatures by the flux of photons flowing into them. The use of intense lasers to recreate these conditions in the lab provides a potentially valuable tool for understanding what these data mean.

Read more

Blobrana · L

Researchers create portable black hole
Physicists have created a black hole for light that can fit in your coat pocket. Their device, which measures just 22 centimetres across, can suck up microwave light and convert it into heat.
The hole is the latest clever device to use 'metamaterials', specially engineered materials that can bend light in unusual ways.

Read more

Blobrana · L

Title: An electromagnetic black hole made of metamaterials
Authors: Qiang Cheng, Tie Jun Cui

Traditionally, a black hole is a region of space with huge gravitational field in the means of general relativity, which absorbs everything hitting it including the light. In general relativity, the presence of matter-energy densities results in the motion of matter propagating in a curved spacetime1, which is similar to the electromagnetic-wave propagation in a curved space and in an inhomogeneous metamaterial2. Hence one can simulate the black hole using electromagnetic fields and metamaterials. In a recent theoretical work, an optical black hole has been proposed based on metamaterials, in which the numerical simulations showed a highly efficient light absorption3. Here we report the first experimental demonstration of electromagnetic black hole in the microwave frequencies. The proposed black hole is composed of non-resonant and resonant metamaterial structures, which can absorb electromagnetic waves efficiently coming from all directions due to the local control of electromagnetic fields. Hence the electromagnetic black hole could be used as the thermal emitting source and to harvest the solar light.

Read more (2144kb, PDF)

Blobrana · L

Scientists propose lab-grade black holes
One day, scientists may create the ultimate tempest in a teapot - an artificial black hole in a millimetre-long gadget. Such laboratory-grade black holes may illuminate enigmatic physical properties of their wild galactic counterparts, all from the safety of a lab bench, a study to appear in Physical Review Letters suggests.

"For black holes, we just don't understand the physics at all" - physicist William Unruh of the University of British Columbia in Vancouver, Canada, who was not involved in the new study.

Read more