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cryusakiscience:

What is Hawking Radiation in Black Holes?

                The universe if full of curiosities and conundrums; the pull of intrigue and the push of impossible conceptualizations can scare those away from the idea of virtual particles and black holes, as well as quantum mechanics. To some that is a pull in of itself, and it is to those this article is for. The first mental barrier that must be broken is the concept that the vacuum of space is empty. It is not; in fact it is playground for particle and their antiparticle twins to pop into existence seemingly from nowhere. This would seem to defy the simple concept of conservation of energy. The particles and photons can get away with this because they only exist on such small timescale that they can’t be observed directly. You can, however, observe the effect of their existence.

                This was done by putting two parallel plates close to one another. We’re talking so close that certain wavelengths of light cannot pop into existence within the space between because there is simply not enough room. The space outside the plates has plenty of room though. The insides now have less ‘virtual particles’ than the outside which means there is less pressure on the inside. Thus the two plates experience an attractive force that is not gravity. Things get weird if you vibrate one of the plates as this causes extra space to be created in the middle. Since all virtual particles must be created in pairs this extra space causes the pairs to get lost in the new world, if they can’t find each other then they can’t be destroyed so they become real photons.

                Aha! Conservation of energy seems to be broken, photons that were not there are now there. However this is not true, it took energy to move on the plates and the work done to make that plate against the outside pressure of virtual particles is what gives the energy to the virtual particles to become real photons. Energy is conserved. So now it’s time to come full circle back to Hawking Radiation in black holes and how this relates to virtual particles. You need to know that gravity is acceleration; neither is distinguishable from one another. If the earth pulled you at 9.8m/s or the earth was accelerating into you at a rate of 9.8m/s you would never know experimentally.

                A black hole with huge gravity does the part of the accelerated parallel plate. The two photons created near the event horizon will experience the pull of gravity by the black hole. The one being closer will be sucked into the event horizon while the other will not find the twin ever again. Thus it will drift off into space but it is forced into a real photon. Once again it sounds like you created energy from nothing, but counter intuitively the energy for that photon came from the mass of the black hole. So in the end a photon gets created near the event horizon of a black hole while the black hole loses mass.

                Given enough time a black hole will evaporate enough mass to stop being a black hole. It is good to note that this effect has never been directly observed. It is however one of my favourite theories of science since it requires so much realignment of what you thought was physically possible and capable. Just proof that no matter how creative you think you are, Mother Nature will always be one step ahead.

artandsciencejournal:

Cartographic Assemblages

Maps help us find our way in the world (or make us even more lost), but the concept of a map can also be applied when trying to organize together memories, identity, narrative and materiality.

Artist Lindsey Dunnagan explores the mapping of memories and identity in her series Mapping the Intangible, while in Mapping New Worlds, the artist focuses on manipulating topography, hinting at familiar places, but distorted in a way that the familiar becomes alien.

The materiality of Dunnagan’s work in Mapping the Intangible is significant because the watercolour is mixed with salt, allowing unexpected patterns to form, as if creating city limits, but also transform over time as the salt dries and flakes off. The artist focuses on locations that are familiar and important to her memories and identity, yet unrecognizable to the viewer because the maps juxtapose on one another, creating “false connections”, rather serving, as the artist states, “as an atlas of memory that informs identity”. The same kind of atlas, albeit abstract, can be found in Mapping New Worlds but rather than focusing just on identity and memory, the pieces in this series focus on “concepts of city development, communication, and abstracted” landscape. Familiar images such as cities and roads are obstructed by rivers or clouds, creating an almost mythological narrative of the geography.

Similar to Dunnagan’s work, is that of Scott W. Bradford’s, but rather than mapping out specific locations which focus on geography, Bradford pieces together various elements which map out a narrative through materiality. The artist states that he links “the materiality of the surface to the drawing itself, either metaphorically or in terms of the narrative” in order to emphasize that it is constructed; his maps are fiction. In both his series’ Blueshift and Journey to Nowhere, stories are being told.

Each piece maps out its own narrative, but when the series is presented as a whole, the works become a collection of stories, mapping out an overall narrative of materiality.

-Anna Paluch

astronomicalwonders:

The Fairy of the Eagle Nebula

The dust sculptures of the Eagle Nebula are evaporating. As powerful starlight whittles away these cool cosmic mountains, the statuesque pillars that remain might be imagined as mythical beasts. Pictured above is one of several striking dust pillars of the Eagle Nebula that might be described as a gigantic alien fairy. This fairy, however, is ten light years tall and spews radiation much hotter than common fire. The greater Eagle Nebula, M16, is actually a giant evaporating shell of gas and dust inside of which is a growing cavity filled with a spectacular stellar nursery currently forming an open cluster of stars. The above image in scientifically re-assigned colors was released in 2005 as part of the fifteenth anniversary celebration of the launch of the Hubble Space Telescope.


 Credit: The Hubble Heritage Team, (STScI/AURA), ESA, NASA

spaceplasma:

Gemini 4

The Gemini program was designed as a bridge between the Mercury and Apollo programs, primarily to test equipment and mission procedures in Earth orbit and to train astronauts and ground crews for future Apollo missions. The general objectives of the program included: long duration flights in excess of of the requirements of a lunar landing mission; rendezvous and docking of two vehicles in Earth orbit; the development of operational proficiency of both flight and ground crews; the conduct of experiments in space; extravehicular operations; active control of reentry flight path to achieve a precise landing point; and onboard orbital navigation. Each Gemini mission carried two astronauts into Earth orbit for periods ranging from 5 hours to 14 days. The program consisted of 10 crewed launches, 2 uncrewed launches, and 7 target vehicles, at a total cost of approximately 1,280 million dollars.

Gemini 4 was the second crewed mission of the Gemini series and carried James McDivitt and Edward White on a 4-day, 62-orbit, 98-hr flight from June 3 to June 7, 1965. The mission included the first American spacewalk. The objective of the mission was to test the performance of the astronauts and capsule and to evaluate work procedures, schedules, and flight planning for an extended length of time in space. Secondary objectives included demonstration of extravehicular activity in space, conduct stationkeeping and rendezvous maneuvers, evaluate spacecraft systems, demonstrate the capability to make significant in-plane and out-of-plane maneuvers and use of the maneuvering system as a backup reentry system, and conduct 11 experiments.

Credit: NASA/JSC/Arizona State University

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