Theoretical physicists may have solved the "impossible" mystery of universe's accelerating expansion

danielravennest

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So someone finally decided calling the issue dark energy was basically the equivalent of balancing an equation by writing 'and then a miracle happens'?
We see galaxies by the light that their stars and gas clouds give off. We estimated the mass of those galaxies by how much light they produced. Then we measured the doppler shift across the width of those galaxies to find out how fast they were rotating. Turns out the rotation was faster than the indicated mass could hold together. The galaxies would be flying apart. So astronomers assumed there had to be more mass there. Since it wasn't giving off light we could see, it got called "Dark Matter". Ever since, we have been trying to figure out what it is made of.

Certain supernovae are a predictable brightness. So when they happen in a distant galaxy, that tells us how far away the galaxy is. The general red-shift also tells us how far the galaxy is under the Big Bang theory. The farther the galaxy, the faster it is moving away from us. Gravity, acting over the life of the Universe, should be slowing down the expansion. The supernovae data was telling us the opposite, that they are speeding up. In general physics some kind of energy is needed to speed things up. But the kind of energy speeding up the Universe isn't showing up in our particle accelerators or telescopes. So they called it "Dark Energy" because we can't see it.

They always knew their basic assumptions could be wrong. Dark Matter and Dark Energy could be neither matter nor energy, but new physics that broke how we assumed the Universe worked. But until we found an answer, the names stuck as a placeholder, because we had to call them something in order to talk about the mass and velocity discrepancies we see.
 

Kara Spengler

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We see galaxies by the light that their stars and gas clouds give off. We estimated the mass of those galaxies by how much light they produced. Then we measured the doppler shift across the width of those galaxies to find out how fast they were rotating. Turns out the rotation was faster than the indicated mass could hold together. The galaxies would be flying apart. So astronomers assumed there had to be more mass there. Since it wasn't giving off light we could see, it got called "Dark Matter". Ever since, we have been trying to figure out what it is made of.

Certain supernovae are a predictable brightness. So when they happen in a distant galaxy, that tells us how far away the galaxy is. The general red-shift also tells us how far the galaxy is under the Big Bang theory. The farther the galaxy, the faster it is moving away from us. Gravity, acting over the life of the Universe, should be slowing down the expansion. The supernovae data was telling us the opposite, that they are speeding up. In general physics some kind of energy is needed to speed things up. But the kind of energy speeding up the Universe isn't showing up in our particle accelerators or telescopes. So they called it "Dark Energy" because we can't see it.

They always knew their basic assumptions could be wrong. Dark Matter and Dark Energy could be neither matter nor energy, but new physics that broke how we assumed the Universe worked. But until we found an answer, the names stuck as a placeholder, because we had to call them something in order to talk about the mass and velocity discrepancies we see.
Right. Although while using the terms dark matter and dark energy is intellectually honest it always struck me as a bit of a cop out. While they started as just a placeholder people could just ignore that status and pretend the series of ???? they pointed to did not exist.
 
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