acceleration
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Cosmology Demystified
That has got to be the single strangest post title I’ve ever written. Of all the whacky branches of science out there, cosmology almost takes the cake — second only, I think, to the downright trippy world of quantum mechanics.…
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The Universe: A Timeline of Discovery
Aaaaand she’s back! Sorry for the delay — school had me burnt out! Consider this: humanity has existed for just a few thousand years, and for most of that time, our existence has been constrained to one little blue mote…
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Cosmology: How Do We Know?
Have you ever wondered how the heck astronomers think we know anything about cosmology? It’s a truly mind-blowing field of study, full of whacky concepts like the shape of empty space, the expansion of the universe, and dark energy. More…
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The Proof in the Afterglow
In 1915, Einstein published his theory of general relativity. This theory predicts that, since gravity works by bending space-time, it also determines the shape of space — and the shape of the universe as a whole. In 1929, Edwin Hubble…
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Geometry is Destiny…or is it?
Cosmologists used to think that gravity alone determined the shape of the universe, and that shape, in turn, determined its future. But that raised a lot of problems. Gravity works by curving space-time, so it can also force the fabric…
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The Discovery of Dark Energy
In 1998, astronomers made an extraordinary discovery. Contrary to expectation, the expansion of the universe is accelerating. Astronomers wondered at first if their measurements were wrong; further measurements confirmed the results. And then confirmation of the expansion came in the…
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Should Expanding Space be Slowing Down?
Einstein’s theory of general relativity holds that matter curves the fabric of space-time. That’s how gravity works. In turn, that gravity shapes the fabric of the universe. Depending on how much mass is in the universe, gravitation can curve the…
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Einstein: General Relativity
Albert Einstein may have been the genius among physicists, but like all others before his time, he stood on the shoulders of giants. Einstein did not propose that the sun was the center of the solar system; that idea was…
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Einstein: Special Relativity
Albert Einstein’s name literally sends shivers down my spine. This is the man who discovered physics as we know it. This is the man who filled in the gaps where even Newton’s laws of motion went wrong and expanded our…
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Newton and Gravity
So, the moon stays in orbit around the Earth, right? Yeah, I thought so. But why? The moon’s orbit is not a straight line, which means it’s accelerated motion (using the physics definition, which is absolutely any change in speed or…
