Posts tagged physics
A dirty thunderstorm (also, Volcanic lightning) is a weather phenomenon that occurs when lightning is produced in a volcanic plume. A study in the journal Science indicated that electrical charges are generated when rock fragments, ash, and ice particles in a volcanic plume collide and produce static charges, just as ice particles collide in regular thunderstorms.
(Source: spaceplasma, via rednightmare18)
Preparing NASA’s next solar satellite for launch
Orbital Sciences team members move the second half of the payload fairing before it is placed over NASA’s IRIS (Interface Region Imaging Spectrograph) spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit. The work is taking place in a hangar at Vandenberg Air Force Base, where IRIS is being prepared for launch on a Pegasus XL rocket.
Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere.
Image credit: NASA/Tony Vauclin
(Source: distant-traveller)
Black-body radiation
When astronomers refer to the temperature of a star, they are talking about the temperature of the gases in the photosphere, and they express those temperatures on the Kelvin temperature scale. On this scale, zero degrees Kelvin (written 0 K) is absolute zero (2273.2°C or 2459.7°F), the temperature at which an object contains no thermal energy that can be extracted. Water freezes at 273 K and boils at 373 K (at sea-level atmospheric pressure). The Kelvin temperature scale is useful in astronomy because it is based on absolute zero and consequently is related directly to the motion of the particles in an object.
Now you can understand why a hot object glows, or to put it another way, why a hot object emits photons, bundles of electromagnetic energy. The hotter an object is, the more motion there is among its particles. The agitated particles, including electrons, collide with each other, and when electrons accelerate—change their motion—part of the energy is carried away as electromagnetic radiation. The radiation emitted by a heated object is called black-body radiation, a name translated from a German term that refers to the way a perfectly opaque object would behave. A perfectly opaque object would be both a perfectly efficient absorber and a perfectly efficient emitter of radiation. At room temperature, such a perfect absorber and emitter would look black, but at higher temperatures it would glow at wavelengths visible to a human eye. That explains why in astronomy and physics contexts you will see the term black-body referring to objects that glow brightly.
Black-body radiation is quite common. In fact, it is responsible for the light emitted by an incandescent light bulb. Electricity flowing through the filament of the bulb heats it to high temperature, and it glows. You can also recognize the light emitted by hot lava as black-body radiation. Many objects in the sky, including the sun and other stars, primarily emit black-body radiation because they are mostly opaque.
Credit: Michael A. Seeds, Dana E. Backman
Gif credit: caucasianmale
In September 2012, hundreds of amateur and professional photographers had the rare opportunity to explore and photograph accelerators and detectors at particle physics laboratories around the world.
The top 39 photographs from the Photowalk, including the six winners of the jury and “people’s choice” competitions, are now viewable online.
“The worldwide opening of the physics laboratories for the Photowalk has been an excellent opportunity for showing the real places of physics research,” says Antonio Zoccoli, a member of the executive board at the Italian Institute for Nuclear Physics. “The Photowalk tells us that scientific research is a global enterprise, which brings together intelligence, resources and technologies from different countries toward a common goal.
“Photowalk winners show modern beauty of science”
Photos viewable here [x]
(via scinerds)
Metamaterial Flows Like Liquid, Returns to Shape
A bit reminiscent of the Terminator T-1000, a new material created by Cornell researchers is so soft that it can flow like a liquid and then, strangely, return to its original shape.
Rather than liquid metal, it is a hydrogel, a mesh of organic molecules with many small empty spaces that can absorb water like a sponge. It qualifies as a “metamaterial” with properties not found in nature and may be the first organic metamaterial with mechanical meta-properties.
Read more: http://www.laboratoryequipment.com/news/2012/12/metamaterial-flows-liquid-returns-shape
(via shychemist)
Aurora borealis over Høgtuva Mountain
The Earth’s magnetic field funnels particles from the solar wind over the polar regions. More than 80 kilometres above the ground, these collide with molecules in the atmosphere causing them to glow: green and pale red for oxygen and crimson for nitrogen
Credit: Tommy Eliassen/Royal Observatory
(Source: distant-traveller)
Photos from Dark Energy Camera in Chile
This photo from the new Dark Energy Camera, taken in September 2012, shows the barred spiral galaxy NGC 1365, in the Fornax cluster of galaxies, which lies about 60 million light years from Earth.
In physical cosmology and astronomy, dark energy is a hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe. Dark energy is the most accepted hypothesis to explain observations since the 1990s that indicate that the universe is expanding at an accelerating rate. In the standard model of cosmology, dark energy currently accounts for 73% of the total mass–energy of the universe.
(via expose-the-light)
The scanning single-electron transistor (SET) microscope head, seen through a viewport into the microscope vacuum chamber. The image shows the SET tip above a graphene sample. (Courtesy: Yacoby lab)
Graphene offers up another quantum surprise
Physicists in the US and Germany have discovered yet another surprising property of the “wonder material” graphene – it displays a fractional quantum Hall effect (FQHE) that is different to that seen in conventional materials. The finding will be important for studying correlations among relativistic particles and may even help in the development of quantum computers in the future.
The FQHE occurs when charge carriers like electrons are confined to a 2D plane, as in graphene, and are subjected to a perpendicular magnetic field in the Z-direction. If a current flows in the X-direction, a voltage – the Hall voltage – occurs in the Y-direction. At very low temperatures, this voltage is quantized in distinct steps or Hall states.
(Source: spaceplasma, via scinerds)
