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Vampire Selfie: A Curious Case of an Absent Reflection

Top view of a person standing in an elevator while facing the door. (a) Rays originating from a point (O) on an object, reflected from a plane surface, form a virtual image at the apparent point of origin (I) of the reflected rays. (b) Rays originating from a point on an object, reflected from many irregularly oriented small facets, cannot be traced back to an apparent common point of origin, so no image forms. (c) If many points (O1, O2, O3, etc.) along the object are approximately the same color and shape, then the randomly reflected rays from these various points can appear to have a common origin (I) and form an image.

Top view of a person standing in an elevator while facing the door. (a) Rays originating from a point (O) on an object, reflected from a plane surface, form a virtual image at the apparent point of origin (I) of the reflected rays. (b) Rays originating from a point on an object, reflected from many irregularly oriented small facets, cannot be traced back to an apparent common point of origin, so no image forms. (c) If many points (O1, O2, O3, etc.) along the object are approximately the same color and shape, then the randomly reflected rays from these various points can appear to have a common origin (I) and form an image.

Joshua M. Grossman
During a recent ride in an elevator, I was startled by an observation. Once the door closed, the features on the back wall of the elevator were evident in a reflection on the door; however, my own reflection appeared absent . How could that be? What physics caused this curious phenomenon? The elevator had wooden molding, including horizontal strips that ran all the way around the back and sides . These horizontal strips were what showed up most clearly in the reflection. The door’s surface was brushed metal with the brush marks all running vertically. Therein lay the solution…
…Read more at scitation.aip.org

Video

A “Star Wars” laser bullet – this is what it really looks like

Action-packed science-fiction movies often feature colourful laser bolts. But what would a real laser missile look like during flight, if we could only make it out? How would it illuminate its surroundings? The answers lie in a film made at the Laser Centre of the Institute of Physical Chemistry of the Polish Academy of Sciences in cooperation with the Faculty of Physics at the University of Warsaw. Continue reading A “Star Wars” laser bullet – this is what it really looks like

Big Black Holes Can Block New Stars

Elliptical galaxy NGC 1132, as seen by NASA’s Chandra X-Ray Observatory; the blue/purple in the image is the X-ray glow from hot, diffuse gas that is not forming into stars. (Credit: NASA, ESA, M. West (ESO, Chile), and CXC/Penn State University/G. Garmire, et al.

Elliptical galaxy NGC 1132, as seen by NASA’s Chandra X-Ray Observatory; the blue/purple in the image is the X-ray glow from hot, diffuse gas that is not forming into stars. (Credit: NASA, ESA, M. West (ESO, Chile), and CXC/Penn State University/G. Garmire, et al.

Massive black holes spewing out radio-frequency-emitting particles at near-light speed can block formation of new stars in aging galaxies, a study has found.
The research provides crucial new evidence that it is these jets of “radio-frequency feedback” streaming from mature galaxies’ central black holes that prevent hot free gas from cooling and collapsing into baby stars. Continue reading Big Black Holes Can Block New Stars

POLARBEAR seeks cosmic answers in microwave polarization

The Huan Tran Telescope in the Atacama Desert of Chile. The POLARBEAR microwave bolometers are mounted on the telescope to study the polarization of light from a period 380,000 years after the Big Bang. Credit: POLARBEAR consortium

The Huan Tran Telescope in the Atacama Desert of Chile. The POLARBEAR microwave bolometers are mounted on the telescope to study the polarization of light from a period 380,000 years after the Big Bang. Credit: POLARBEAR consortium

An international team of physicists has measured a subtle characteristic in the polarization of the cosmic microwave background radiation that will allow them to map the large-scale structure of the universe, determine the masses of neutrinos and perhaps uncover some of the mysteries of dark matter and dark energy. Continue reading POLARBEAR seeks cosmic answers in microwave polarization

Video

Timelapse over Europe

This timelapse video shows two passes over Europe taken by ESA astronaut Alexander Gerst as he flew overhead on the International Space Station at around 400 km altitude.

The International Space Station travels at 28 800 km/h meaning that it only takes 90 minutes to circle Earth completely. Each orbit the Station moves around 2200 km to the West in relation to 90 minutes before.

Astronauts often use normal consumer digital cameras to take pictures of Earth through Europe’s observatory module Cupola in their spare time. Setting the camera to take an image every few seconds and then playing the images back quickly create this timelapse effect.

Alexander worked as a geophysicist and volcanologist before he was chosen as an ESA astronaut in 2009. His Blue Dot mission includes an extensive scientific programme of experiments in physical science, biology, and human physiology as well as radiation research and technology demonstrations. All experiments chosen make use of the out-of-this-world laboratory to improve life on Earth or prepare for further human exploration of our Solar System.

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Experimental Realization of Quantum Artificial Intelligence

quantum11Li Zhaokai, Liu Xiaomei, Xu Nanyang, Du jiangfeng
Machines are possible to have some artificial intelligence like human beings owing to particular algorithms or software.
Such machines could learn knowledge from what people taught them and do works according to the knowledge.
In practical learning cases, the data is often extremely complicated and large, thus classical learning machines often need huge computational resources. Quantum machine learning algorithm, on the other hand, could be exponentially faster than classical machines using quantum parallelism.
Here, we demonstrate a quantum machine learning algorithm on a four-qubit NMR test bench to solve an optical character recognition problem, also known as the handwriting recognition.
The quantum machine learns standard character fonts and then recognize handwritten characters from a set with two candidates.
To our best knowledge, this is the first artificial intelligence realized on a quantum processor.
Due to the widespreading importance of artificial intelligence and its tremendous consuming of computational resources, quantum speedup would be extremely attractive against the challenges from the Big Data…..
Read more at http://arxiv.org/pdf/1410.1054v1.pdf

Read also: First Demonstration Of Artificial Intelligence On A Quantum Computer