Death of the universe?(3)
This dark matter is responsible for producing galaxies in a finite amount of time. If we had to rely on the gravity of atomic matter to produce galaxies, we wouldn't be anywhere, we wouldn't exist today to be able to ask these questions. Cause there's not enough time for gravity to have condensed the atomic matter that we know exists in the cosmos, So dark matter has to exist to give, to help this process out and speed it up.
Yet the universe continues to expand and isn't showing any signs of collapsing. This suggests the opposing force of dark energy could be stronger than dark matter. But it will take scientific detective work to find out. They look to one of the most violent forces in the universe for clues. We studying exploding stars to try to understand if they can tell us the rate at which the universe is expanding. These are explosions at the end of the lives of stars, not unlike our sun. The fuel that these stars have in their center is as, is spent. The star collapses, the outer part expands, and the star becomes something called a White Dwarf.
White Dwarf stars sometimes have other stars orbiting nearby. A companion star. A massive explosion could happen if the companion star's debris falls onto the White Dwarf causing a spectacular fireworks display in the cosmos. Scientists consider exploding stars, or supernovae, Their brief and bright explosions allow scientists to track the universe's expansion and give them a way to measure its speed. Essentially they are White Dwarf stars that become nuclear bombs. They explode with a certain brightness and certain length of time. It takes a certain amount of time for that brightness to dissipate. They are essentially standard candles Anyone of these will look the same no matter where it is in the universe.
Astronomers measure the distance and speed of these exploding stars by measuring the amount of red light they emit. The faster the star moves away from us, the redder its light appears. When we study the spectrum of a supernova, we get indicators of its chemical composition, we understand the velocities as the supernova shell expands following the initial explosion. And so there are a lot of physics that we can study about the individual events.
The Expansion rate of galaxies containing stars like supernovae can then be used to interpret how the rest of the universe is moving outward. We know this because we can compare the velocities of galaxies with their distances.This are the clues that lead astronomers to answer just how soon the universe will reverse direction and come back together in a Big Crunch or, This information might lead to an entirely different conclusion.
Dr.Ellis is looking at clues at the Keck observatory in Hawaii. While the telescope is on the top of a hugh volcano, he is in a viewing room on another part of the island. At the same time. John Reshar is at the California Institue of Technology in Pasadena, California evaluating the light from a distant galaxy that thr Keck Telescope captured in Hawaii. He's looking to see if any of the known elements coming from the galaxy are in the red spectrum and moving farther away.
We can interpret that as a velocity of how much the galaxy is moving away from us. We can really interpret how the entire universe is behaving, is expanding. Interpreting red shift is the cornerstone of the quest to pin down the fate of the universe. Clearer pictures of the universe that have only been possible in recent years have led cosmologists to conclude that the red shift of distant galaxies is greater than previously predicted. This is startling. Not only is the universe expanding, it's speeding up.
Nothing in the observable cosmos could account for an acclerating universe. And yet the data seem irrefutable. This has to mean that an invisible force is working against gravity. Cosmoslogists have come up with a name, dark energy.
Death of the universe?(1)
Death of the universe?(2)
Death of the universe?(4)
Death of the universe?(5)
Death of the universe?(6)
Death of the universe?(7 end)
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