spacetime

Tag archives for spacetime

“Einstein’s Greatest Blunder” was REALLY a blunder!

Posted by Ethan on May 17, 2013
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Image credit: Galaxy cluster ACT-CL J0102−4915, courtesy of ESO/SOAR.

“Anyone who has never made a mistake has never tried anything new.” -Albert Einstein Back when Einstein first proposed his theory of General Relativity, his revolutionary picture of the Universe was met with a mix of curiosity, awe, and intense skepticism. It isn’t every day that your most cherished of all physical theories — the…

Putting Einstein to the Test

Posted by Ethan on May 1, 2013
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Image credit: European Southern Observatory / J. Antoniadis, MPIfR.

“The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will…

Inflation, Dark Energy, and the Physics of Spacetime

Posted by Ethan on April 12, 2013
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Image credit: NASA / Chandra X-ray Observatory.

“Orbiting Earth in spaceship, I saw how beautiful our planet is. People, let us preserve and increase beauty, not destroy it!” -Yuri Gagarin Fifty-two years ago today, the first human being left Earth, and we began our journey into outer space. But back in 1961, we didn’t really know how far outer space stretched, or…

How Big is Our Observable Universe?

Posted by Ethan on March 1, 2013
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Image credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team.

“The mind, once expanded to the dimensions of larger ideas, never returns to its original size.” -Oliver Wendell Holmes When General Relativity supplanted Newton’s work as our theory of how gravity works in the Universe, it didn’t just change how we view how masses attract, it gave us a new understanding of what the questions where…

Energy Conservation and an Expanding Universe

Posted by Ethan on April 11, 2008
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So, what’s the deal with this one? startswithabang.com reader Scott Stuart asks the following question: I was reading “The First Three Minutes” last night and came across an interesting section about blackbody radiation and energy density. The author states that as the universe expands, the number of photons running around (in the CMB, for example)…