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-------------------------- 2447 - UNIVERSE - how did it all happen?
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- Until 1929, the origins of the universe were shrouded entirely in myth and theory. But that year Edwin Hubble discovered something very important about the universe. The whole thing is expanding. Everything we could see in our galaxy appeared stationary. A new model was needed.
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- Hubble made his discovery by measuring the redshift, which is the shift toward longer, red wavelengths of light seen in very distant galaxies. The farther away the object, the more pronounced the amount of redshift. Hubble found that redshift increased linearly with distance in far-off galaxies, indicating that the universe isn't stationary. It's expanding, everywhere, all at once.
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- Hubble was able to calculate the rate of this expansion, a figure known as the Hubble Constant. It was this discovery that allowed scientists to extrapolate back and theorize that the universe was once packed into a tiny point. They called the first moment of its expansion the Big Bang.
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- The Hubble Constant, “Ho”, has the universe expanding 49,306 miles per hour faster for every million lightyears distance.
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- In 1964, Arno Penzias and Robert Wilson, researchers at Bell Telephone Laboratories, were working on building a new radio receiver in New Jersey. Their antenna kept picking up a strange buzzing that seemed to come from everywhere, all the time. They thought it might be pigeons in the equipment, but removing the nests did nothing. Neither did their other attempts to reduce interference. Finally, they realized they were picking up something real coming to them from outer space.
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- What they'd detected was the first light of the universe, the cosmic microwave background radiation. This radiation dates back to about 380,000 years after the Big Bang, when the universe finally cooled enough for photons of light could travel freely.
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- The discovery gave support to the Big Bang theory and to the notion that the universe expanded faster than the speed of light in its first instant. The cosmic background is quite uniform, suggesting a smooth expansion of everything at once from a small point.
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- The cosmic microwave background opened a window into the origins of the universe. In 1989, NASA launched a satellite called the Cosmic Background Explorer (COBE), which measured tiny variations in the background radiation.
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- The result was a baby picture of the universe showing some of the first density variations in the expanding universe. These minuscule variations gave rise to the pattern of galaxies and empty space, the cosmic web of galaxies, that we see in the universe today.
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- The cosmic microwave background enabled researchers to find the origin for inflation, the massive, faster-than-light expansion that occurred at the Big Bang.
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- In 2016, physicists announced that they had detected a particular kind of polarization, or directionality, in some of the cosmic microwave background. This polarization is known as "B-modes." The B-mode polarization was the first-ever direct evidence of gravitational waves from the Big Bang.
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- Gravitational waves are created when massive objects in space speed up or slow down. The waves were ever discovered coming from the collision of two black holes. The B-modes provide a new way to directly probe the early universe's expansion.
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- In 2017, scientists detected gravitational waves from the collision of two neutron stars. They measured the time it took the waves to travel from the stars to Earth.
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- One of the strangest discoveries in physics is that the universe is not only expanding, it's expanding at an accelerating rate.
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- The discovery dates back to 1998, when physicists announced the results of several long-running projects that measured particularly heavy supernovas called Type Ia supernovas. The results revealed weaker-than-expected light from the most distant of these supernovas. This weak light showed that space itself is expanding: Everything in the universe is gradually getting farther away from everything else.
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- Scientists call the driver of this expansion "dark energy," a mysterious engine that could make up about 68% of all the energy in the universe. This dark energy seems to be crucial to making theories of the beginning of the universe fit observations that are being conducted today.
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- Results from the Hubble Telescope have deepened the puzzle of the expanding universe. The measurements from the space telescope show that the universe's expansion is 9% faster than expected from previous observations. For galaxies, every 3.3 million light-years' distance from Earth translates to an additional 46 miles per second faster than earlier calculations predicted.
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- Why does this matter for the origins of the universe? Because physicists must be missing something. According to NASA, there may have been three separate dark energy "bursts" during the Big Bang and shortly thereafter. Those bursts set the stage for what we see today.
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- The first might have started the initial expansion; a second may have happened much faster, acting like a heavy foot pressed on the universe's gas pedal, causing the universe to expand faster than previously believed. A final dark energy burst may explain the accelerating expansion of the universe today.
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- Astronomers are measuring the faint light from galaxies as far away as 11 billion light-years, which will allow researchers to see any changes in the universe's acceleration over time. They are studying the echoes of disturbances in the 400,000-year-old universe, created in the dense soup of particles that made up everything right after the Big Bang.
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- There is more to discover to explain the mysteries of expansion and the dark energy that is driving it. Stay tuned, your education is incomplete.
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- To learn more see Reviews :
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- 2439 - UNIVERSE - discovering the expansion? One of the biggest scientific surprises in astronomy was the recent discovery that space itself is expanding. And, expanding the Universe at an ever increase rate. Distant galaxies recede from us and from one another more quickly than the nearby ones, as though the fabric of space itself is being stretched by some dark form of energy.
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- 2432 - UNIVERSE - expanding space. If you were born when the Universe was ten times its current age, our local group of galaxies would merge into one and would be the only galaxy you could see in the Universe for trillions of light years.
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- - 2419 - and - 2393 - Age of the Universe
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- 2412 - Comprehending the expanding Universe.
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- 2394 - Wrap your mind around the Universe.
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- 2348 - The Universe from start to finish. 13 pages.
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- 2347 - The Island Universe
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- 2335 - The Universe almost did not happen.
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- 2334 - How is it expanding?
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- 2262 - How fast is it expanding? List 21 more reviews about the Universe.
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- September 30, 2019 2447
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--------------------- Wednesday, October 2, 2019 --------------------
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