This is a collection of thoughts and ideas which form a cloud that strives to find sufficient structure to convey the value contained in it.
Wednesday, February 27, 2013
Tuesday, February 26, 2013
Monday, February 25, 2013
Saturday, February 16, 2013
Thursday, February 14, 2013
Sunday, February 10, 2013
Friday, February 8, 2013
Standardmodell der Elementarteilchenphysik
Das Standardmodell der Elementarteilchenphysik beschreibt erfolgreich die grundlegendsten Elemente der Materie und ihre Wechselwirkungen.
Obwohl wir die Elementarteilchen, und wie sich deren Kräfte auswirken, sehr gut verstehen, bleiben aber dennoch einige Rätsel offen, welche bislang noch nicht mit dem Standardmodell erklärt werden:
- Die wichtigste Herausforderung ist es, die Gravitation als eine der vier Grundkräfte (Elektromagnetische Wechselwirkung, Schwache Wechselwirkung, Starke Wechselwirkung, Gravitation) in das Standardmodell der Elementarteilchenphysik zu integrieren.
Die Energie des Teilchenbeschleunigers LHC ist jedoch noch immer viel zu niedrig, um die Fragen der Quantengravitation letztlich zu beantworten, denn es müssten hierzu die Größenordnungen der Planck-Länge (10-35m) experimentell untersucht werden können.
- Eine weitere Herausforderung ist es, die Art und Weise zu verstehen, wie die Masse der Elementarteilchen entsteht. Der Wert der Masse eines Teilchens gibt an, wie viel Energie das Teilchen im Ruhezustand besitzt. Die Experimentalphysik hat die Masse der Elementarteilchen zwar gemessen, aber die einfachen Regeln der Physik erklären bislang nicht, woher diese Massen kommen.
Es wird vermutet, dass in der Frühzeit des Universums ein Phasenübergang (vergleichbar "dampfförmig-flüssig" bei der Kondensation von Wasser) stattgefunden hat, den die Physiker Higgs-Mechanismus nennen. Während ursprünglich die Teilchen keine Masse hatten und mit Lichtgeschwindigkeit umherflogen, erhielten sie dann - während dieses Phasenübergangs der mit dem Higgs-Feld in Zusammenhang steht - ihre Masse und bewegten sich nun langsamer. Der experimentelle Nachweis des Higgs-Teilchens belegt die Existenz des Higgs-Mechanismus ("Phasenübergangs").
- Während der Higgs-Mechanismus erklärt, wie Elementarteilchen ihre Masse erhalten, beschäftigt sich das Hierarchieproblem der Elementarteilchenphysik mit der Frage, warum diese Massen so sind, wie sie von der Experimentalphysik gemessen werden. Durch Kombination von Quantenmechanik und spezieller Relativitätstheorie lassen sich Teilchenmassen theoretisch herleiten, aber das Problem dabei ist, dass diese Berechnungen Werte ergeben, die um das 10-Trillionen-fache (Faktor 1016) größer sind, als die experimentellen Messungen der Teilchenmassen ergeben. Es ist daher wahrscheinlich, dass es noch eine umfassendere Theorie geben muss, die das Hierarchieproblem löst. Es wäre z.B. denkbar, dass der Raum mehr als die drei von uns wahrgenommenen Dimensionen (Höhe, Breite, Tiefe) umfasst. Die experimentelle Entdeckung von Kaluza-Klein-Teilchen durch das LHC könnte solche zusätzlichen, höheren Dimensionen beweisen.
Tuesday, February 5, 2013
Galileo Galilei
Prior to Galilei (1564–1642) all natural sciences were based only on direct observations and pure thinking. He changed the methodology of observations by using tools like a telescope or microscope and he also created artificial situations in experiments to investigate certain phenomena (e.g. using an inclined plane to simulate and measure the speed of falling objects).
In 1611 the scholars of the church decided to accepted the fact that indirect measuring methods, like observations made by using a telescope, produce valid results.
Galilei's most significant observations with the telescope were confirming the Copernican helio-centric concept and hence challenged the church:
Galileo Galilei therefore came to the conclusion, that the earth could not be the centre of the universe. Later he withdrew from supporting the new copernican model to escape a more severe punishment from the inquisition. In 1633 he was sentenced to house arrest in which he remained for the rest of his life.
Galileo allegedly muttered the rebellious phrase "And yet it moves", but there is no evidence that he actually said this or anything similar. It might have been Giordano Bruno who said these words when being burned at the stick as a heretic in February 1600.
Galilei's experiments around motion and gravity together with the work of Johannes Kepler (1571–1630, three Kepler's laws) and René Descartes (1596–1650) formed the basis for the laws of classical mechanics, for which Isaac Newton (1642–1726) is renowned.
(For further information refer to Wikipedia, Wikiquote or this article in a German online magazine.)
In 1611 the scholars of the church decided to accepted the fact that indirect measuring methods, like observations made by using a telescope, produce valid results.
Galilei's most significant observations with the telescope were confirming the Copernican helio-centric concept and hence challenged the church:
- The discovery that moons orbit Jupiter, which meant that a moving planet (Jupiter) can have satellites moving around it. This made it plausible that also the Earth (which was obviously orbited by our moon) could actually move as well. Prior to this discovery a steady earth was assumed as the only possible option to explain the fixed orbit of our moon around the earth. Those observations were only explained later by Newton's law of universal gravitation.
- The discovery of hills and valleys on the moon. Prior to these findings all of heaven was assumed unchangeable and of ideal divine nature. Comets and meteors were assumed local weather phenomena on Earth (that's were the word Meteorology has got it's origin from). The observation of topography on the moon's surface questioned the dichotomy between earthly and heavenly objects, meaning earth was not unique, but a celestial object like any other.
- The most important discoveries were the phases of venus. Galilei saw that Venus displayed phases, just like the Moon, and that the phases of Venus were only understandable if Venus orbited the Sun. The observed phases were, in fact, impossible in a Ptolemic geocentric system.
Galileo Galilei therefore came to the conclusion, that the earth could not be the centre of the universe. Later he withdrew from supporting the new copernican model to escape a more severe punishment from the inquisition. In 1633 he was sentenced to house arrest in which he remained for the rest of his life.
Galileo allegedly muttered the rebellious phrase "And yet it moves", but there is no evidence that he actually said this or anything similar. It might have been Giordano Bruno who said these words when being burned at the stick as a heretic in February 1600.
Galilei's experiments around motion and gravity together with the work of Johannes Kepler (1571–1630, three Kepler's laws) and René Descartes (1596–1650) formed the basis for the laws of classical mechanics, for which Isaac Newton (1642–1726) is renowned.
(For further information refer to Wikipedia, Wikiquote or this article in a German online magazine.)
Monday, February 4, 2013
Scale of Planets and Stars
Video
Smaller than Earth
Smaller than Jupiter
Smaller than Sun
Smaller than Arcturus
(on this scale Jupiter is approx. the size of 1 pixel and the Earth is invisible)
(on this scale Jupiter is approx. the size of 1 pixel and the Earth is invisible)
Smaller than Antares
(on this scale our Sun is approx. the size of 1 pixel and all planets are invisible)
Antares is a red supergiant and the brightest star in the constellation Scorpius.
Betelgeuse is a red supergiant and the second-brightest star in the constellation of Orion (top hand).
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