Starship Asterisk*

http://en.wikipedia.org/wiki/MAGIC_%28telescope%29 wrote:

[b][color=#0000FF]MAGIC is sensitive to cosmic gamma rays with energies between 50 GeV and 30 TeV due to its large mirror; other ground-based gamma-ray telescopes typically observe gamma energies above 200-300 GeV. Satellite-based detectors detect gamma-rays in the energy range from keV up to several GeV.[/color][/b]

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<<MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov Telescopes) is a system of two Imaging Atmospheric Cherenkov telescopes situated at the Roque de los Muchachos Observatory on La Palma, one of the Canary Islands, at about 2200 m above sea level. MAGIC detects particle showers released by gamma rays, using the Cherenkov radiation, i.e., faint light radiated by the charged particles in the showers. With a diameter of 17 meters for the reflecting surface, it is the largest in the world.

The first telescope was built in 2004 and operated for five years in standalone mode. A second MAGIC telescope (MAGIC-II), at a distance of 85 m from the first one, started taking data in July 2009. Together they integrate the MAGIC telescope stereoscopic system.

The goals of the telescope are to detect and study primarily photons coming from:

• Accretion of black holes in Active Galactic Nuclei
  
  Supernova remnants, due to their interest as sources of cosmic rays.
  
  Other galactic sources such as pulsar wind nebulae or X-ray binaries.
  
  Unidentified EGRET or Fermi sources
  
  Gamma ray bursts
  
  Annihilation of Dark matter

MAGIC has found pulsed gamma-rays at energies higher than 25 GeV coming from the Crab Pulsar. The presence of such high energies indicates that the gamma-ray source is far out in the pulsar's magnetosphere, in contradiction with many models.

MAGIC detected very high energy cosmic rays from the quasar 3C 279, which is 5 billion light years from Earth. This doubles the previous record distance from which very high energy cosmic rays have been detected. The signal indicated that the universe is more transparent than previously thought based on data from optical and infrared telescopes.

MAGIC did not observe cosmic rays resulting from dark matter decays in the dwarf galaxy Draco. This strengthens the known constraints on dark matter models.

A much more controversial observation is an energy dependence in the speed of light of cosmic rays coming from a short burst of the blazar Markarian 501 on July 9, 2005. Photons with energies between 1.2 and 10 TeV arrived 4 minutes after those in a band between .25 and .6 TeV. The average delay was .030±.012 seconds per GeV of energy of the photon. If the relation between the space velocity of a photon and its energy is linear, then this translates into the fractional difference in the speed of light being equal to minus the photon's energy divided by 2×10¹⁷GeV.>>

Uwe wrote: Still my question: Why can't I receive the videos? I'm located in Germany, using Firefox 9 with Flash 11. Someone got an idea what's going wrong? Please.
Thank you.

florid_snow wrote:
El Cielo Canarias is translated "Canary Skies" in the opening title. But the word "cielo" reminds me of the English word "ceiling" which has connotations of a roof, or enclosure. "Le ciel" is the French word for the sky. I know in English we can say either "the sky" or "the heavens" recalling our ancient (and current) mythological beliefs, but to say "the ceiling" to refer to the sky would probably draw funny looks.

Does anyone else think it's neat that language records our previous mistaken beliefs, and that the meaning can change and the silly belief discarded without changing the word?

Wester's wrote:
Ceiling [OF. celle, fr. L. cella; akin to celare to hide, and E. hell, helm, conceal. Cf. Hall.]
The covering which overlays the inner roof of a building, or the timbers which form the top of a room.
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Cellar [OE. celer, OF. celier, F. celier, fr. L. cellarium a receptacle for food, pantry. See Cell.] A room or rooms under a building, and usually below the surface of the ground, where provisions and other stores are kept.
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Sky [OE. skie a cloud, Icel. sk; akin to Sw. & Dan. sky; cf. AS. sca, scwa, shadow, Icel. skuggi; probably from the same root as E. scum. &root. See Scum, and cf. Hide skin, Obscure.]

florid_snow wrote:El Cielo Canarias is translated "Canary Skies" in the opening title. But the word "cielo" reminds me of the English word "ceiling" which has connotations of a roof, or enclosure. "Le ciel" is the French word for the sky. I know in English we can say either "the sky" or "the heavens" recalling our ancient (and current) mythological beliefs, but to say "the ceiling" to refer to the sky would probably draw funny looks.

Does anyone else think it's neat that language records our previous mistaken beliefs, and that the meaning can change and the silly belief discarded without changing the word? Getting the religious connotation out of the word "disaster" certainly hasn't been a disaster

agulesin wrote:
Why is it that some people have to attack others beliefs at every opportunity? If you don't believe in certain things, don't try to prevent others or call them "silly". Never forget this: However "ancient" and "unfashionable" death may appear, no-one has managed to avoid it even in these days of technology and medicine...

agulesin wrote:

florid_snow wrote:El Cielo Canarias is translated "Canary Skies" in the opening title. But the word "cielo" reminds me of the English word "ceiling" which has connotations of a roof, or enclosure. "Le ciel" is the French word for the sky. I know in English we can say either "the sky" or "the heavens" recalling our ancient (and current) mythological beliefs, but to say "the ceiling" to refer to the sky would probably draw funny looks.

Does anyone else think it's neat that language records our previous mistaken beliefs, and that the meaning can change and the silly belief discarded without changing the word? Getting the religious connotation out of the word "disaster" certainly hasn't been a disaster :)

Why is it that some people have to attack others beliefs at every opportunity? If you don't believe in certain things, don't try to prevent others or call them "silly". Never forget this: However "ancient" and "unfashionable" death may appear, no-one has managed to avoid it even in these days of technology and medicine...

FloridaMike wrote:@Flash: WHADAYA mean telling people that "bad stars" don't cause disasters? Can you prove they don't? ;)

Chris Peterson wrote:

FloridaMike wrote:
@Flash: WHADAYA mean telling people that "bad stars" don't cause disasters? Can you prove they don't?

If you're a civilization within a few tens of light years of a star that decides to supernova, "disaster" takes on a very literal meaning!

carolh wrote:I have had APOD as my home page for some time but today I am changing that. The music for today's video (very loud and I personally found it annoying) took over my computer. Even if I muted the video, every time I changed pages it started playing again and I was unable to find where it was playing so unable to turn it off or even mute it. I have moved my home page to another site. I'll just check in from time to time to see your interesting pictures. Bye.

Boomer12k wrote:Not to be controversial, but some religious texts still have the sky as a "dome" over the Earth. That would be a flat Earth at that. There are many astronomical illusions based on perspective. Myth busted. Scientists can be just as dogmatic in their opinion. Anybody remember Fred Hoyle? Conclusions in Science can be wrong too...Ptolemy sure was. Hooray for Copernicus and Galileo.