söndag 29 juni 2008

Svensk medias rapportering av LHC

Letade i våra stora tidningar om de nämner något om LHC. Jodå. Ganska utförligt dessutom. Åtminståne i DN och SVD

DN
SVD

Söker man i Sydsvenskan får man Linköpings Hockey Club istället :-)

Till min förvåning näms LHC även i aftonbladet. Artikeln avslutas på ett trevligt sätt "Väck lusten, naturvetenskap är kul!"
Inget i expressen eller gp...


PS Missa inte Max Tegmarks sommarprogram i P1. Han pratar mycket om parallella universa. Här finns hans program i mp3 DS

http://intressant.se/intressant

söndag 22 juni 2008

LHC är säker enligt CERN

Universe Today rapportera om att CERN återigen har gått utmed hur säker LHC är.

  • Microscopic black holes (not very likely): Although it would be pretty cool if micro-black holes were generated, the report concludes that this event will be unlikely, although theoretically possible. If a micro-black hole was produced by an LHC collision, it is very likely that it would evaporate very quickly (via Hawking Radiation), making it difficult for any observation attempt. If a micro-black hole was produced but it didn't evaporate (which isn't possible, in theory), depending on its charge, it would behave differently. Charged, the micro-black hole could interact with matter and get stopped as it tries to pass through the Earth. Un-charged, the micro-black hole will pass straight through the Earth and into space (as it will be weakly interacting) or simply hang around inside our planet. We know collisions between cosmic rays and the Earth's atmosphere happen naturally, often at higher energies than the LHC. Therefore, if micro-black holes are possible, the only option would be that they evaporate very quickly.. Besides, even if they were stable, they cannot suck in any matter and grow because they will have minimal gravitational influence over matter. Boring really…
  • Strangelets (practically impossible): This hypothetical "strange matter" (containing up, down and strange quarks) could theoretically change ordinary matter into strange matter in a thousand-millionth of a second. This possibility was raised in 2000 before the opening of the Relativistic Heavy Ion Collider (RHIC) in the US. This collider uses heavier particles than most of the LHC tests and therefore more likely to produce stranglets. In fact some of its experiments are set up to detect this strange matter. No stranglets have been found in eight years; not only that, but the chain reaction theorized (turning the world into a clump of strangeness) has no experimental foundation. Stranglets do not exist, and the LHC will not produce them.
  • Vacuum bubbles (practically impossible): Perhaps the Universe is not in its most stable configuration. Perturbations generated by the LHC could push it into a more stable state (a vacuum bubble), destroying the Universe as we know it. Not very likely. Again, collisions of higher energies happen throughout the cosmos, let alone in our own atmosphere, we're still here, our Universe is still here (or is it?).
  • Magnetic monopoles (practically impossible): Hypothetical particles with a single magnetic pole, either north or south. If they could exist, they might mess around with protons possibly causing them to spontaneously decay. There is no reason to suspect they can exist, and even if they did, they could not be produced by the LHC as they are too heavy. Again, cosmic rays come to the rescue; as the high energy natural particle hit the atmosphere, their collisional energy is higher than the LHC. No magnetic monopoles, not end of the world.77

Inga svarta hål när LHC kör igång (NyTeknik)

måndag 16 juni 2008

Utan Einstein skulle en GPS visa fel på 10 km!

Nästa gång du använder en GPS, tänk på Einstein och 50th Space Wing på Schriever Air Force Base.

Varför?

Einstein kom på att tid och rum påverkas av mycket höga hastigheter och gravitation. Då GPS satelitarna rör sig ganska snabbt över jorden blir effekterna så stora att Einsteins relativitetsteori måste tas hänsyn till.

Under en dag blir effekterna så stora att GPS:en skulle visa fel på ca 10 km om man struntade i Einsteins ca 100 år gamla upptäckt.

Flygbasen då? Jo det är här och ingen annanstans som de ca 20 GPS satelliterna övervakas.

För en utförlig beräkning se denna länk:
Time dilation in GPS (pdf)

torsdag 5 juni 2008

Missa inte www.teacherondemand.se

www.teacherondemand.se kan du titta på pedagogiska videomanulaer och filmer från grundskola, gymnasie och högskolenivå.
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