Official big Something And Doom Flamingo April 6 2023 Washington, DC Poster shirt

Official big Something And Doom Flamingo April 6 2023 Washington, DC Poster shirt

Ever watch a whirlpool? How about water going down a drain or even a Official big Something And Doom Flamingo April 6 2023 Washington, DC Poster shirt of cream swirled into your coffee? It sometimes looks like a spiral galaxy. And we once thought gravity was holding a galaxy together. If you watch a whirlpool carefully you will notice the outside orbits the center slowly and the closer to the middle you are the faster it spins. But this was a bit of a problem for galaxies because this would make the arms of the galaxy wind up tight. They would not last for millions of years. Earlier in the century, before computers, astronomer would hire dozens of women who were good at math to do calculations for them. One of them made an important discovery: the speed of the stars in the outer arms was way faster than it should be. The galaxy was spinning like a solid LP record album! According to the laws of gravity, which we know quite well, it shouldn’t behave like this…unless there was WAY more mass than we could see. And the issue of *dark matter* was born. Yes, there would be a lot of dust and gas and planets and small stars we couldn’t see. But all that is still not enough for the behavior we observe. It is a mystery we are still working on!

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Official big Something And Doom Flamingo April 6 2023 Washington, DC Poster shirt, Hoodie, Sweater, Vneck, Unisex and T-shirt

Best Official big Something And Doom Flamingo April 6 2023 Washington, DC Poster shirt

The description from Richard Muller quoted in the question is a simplification of reality meant to help people better visualize how the Official big Something And Doom Flamingo April 6 2023 Washington, DC Poster shirt of spacetime works. In reality the galaxies are moving through spacetime in a complex fashion, based on the combination of all the forces acting on them, primarily the gravity of nearby galaxies and galaxy clusters. In the case of the Milky Way and Andromeda, these two galaxies are part of a gravitationally bound cluster of galaxies, called the Local Group. The dominant force that determines the movements of objects within the cluster is the combined gravitation of all the mass in the cluster, and not the expansion of spacetime. In other words, the gravitational attraction that the Milky Way and Andromeda have for one another that is drawing them together is stronger than the expansion of spacetime between them that would otherwise push them apart, and thus attraction wins and the two galaxies are on a collision course. In the same vein, the gravitational force that holds the earth in orbit around the sun is stronger than the expansion of spacetime between the earth and the sun (the expansion of spacetime at that distance being very small), and so the earth’s distance from the sun is not increasing for that reason. Likewise you are not flying apart because the molecular bonds holding the atoms in your body together are stronger than the minuscule expansion of spacetime between them in your body. The Local Group as a whole, however, is moving away from other galaxies and galaxy clusters to which it is not gravitationally bound, due to the expansion of spacetime.

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