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---------------------------- 2603 - UNIVERSE - shape of the Universe?
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- Our Universe is in good shape but, is our universe really geometrically flat. A team of cosmologists are now reporting that our latest measurements show that the Universe is curved. There's far more to the story than one simple measurement.
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- The surface of the Earth is curved. We know this because the rules of geometry that you learned in high school don't always apply. For example, parallel lines don't always stay parallel on the Earth: lines of longitude intersect at the north and south poles, something that can never happen on a flat plain.
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- And if you were to draw a triangle connecting three cities on the Earth, you would find that the angles inside that triangle add up to more than 180 degrees; again this does not occur doing that on a flat plain.
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- Astronomers are very curious about the ultimate curvature of the universe: how do parallel lines and triangles behave on the very largest scales? They care because the shape of the universe is intimately connected to its fate. Einstein's theory of general relativity, which we use to understand the cosmos, tells us that the contents of space-time affect its shape, and the shape tells the contents how to move.
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- A geometrically flat universe will just keep on expanding forever, while a "closed" one will eventually pull back in on itself, leading to the reverse of the Big Bang, something called the Big Crunch.
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- To test the geometry of space-time, we need to look at all sorts of distant sources and determine if the light from those sources has undergone any major deviations in its path to us. Light beams should stay on a straight line for billions of years. Astronomers can use distant probes to "smooth over" tiny little bumps and wiggles like those caused by galaxies and black holes, and look at the true, underlying geometry of the universe.
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- The cosmic microwave background (CMB)is a bath of light soaking the universe, left over from when our cosmos was only 380,000 years old. That light has spent the past 13.8 billion years coming towards at light speed to us. Are these in straight lines or curved lines? We should be able to study features in the CMB to test our universe for flatness, that is straight lines.
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- The Planck satellite was the latest effort to map the CMB across the whole sky. Planck was measuring the CMB to the greatest level of precision yet. Its most recent data released in 2018.
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- The bare, raw, naked data of the CMB as recorded by Planck, seems to indicate that our universe might be closed. The measurement isn't significant enough to be considered ironclad, but it's still suggestive. This is intriguing because everything we know through our theory of the Big Bang suggests that instead our universe should be very, very flat, that is open, not closed.
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- Taking the Planck data hinting at a curved universe in isolation, we have two possible options:
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-------------------------- Planck is telling the truth, and the universe just might be curved.
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-------------------------- Planck is lying to us, and either something in the instrument itself or some other astronomical source (for example, pesky interstellar dust) is making the universe look curved, but it really is flat.
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- The Planck Collaboration itself did a lot of analysis and checking, and came to the conclusion that our universe is really flat, but that some other contaminant is nudging the data to make it look curved.
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- Or, Planck is not a liar, and the universe is indeed curved. What's the answer?
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- The Planck team took a straightforward approach. The researchers combined the data from the Planck satellite with data from other observations, mixed them all together (in a statistical way) and asked the combined data set about the curvature of the universe. The answer? No curvature at all; we live in a flat universe.
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- Some astronomers believe that the Planck data by itself is telling the truth about the curved universe. So when they go to mix in the other probes, they find a tension, because the other eyewitnesses tell us that we live in a flat universe. This is the current controversy over a possible "crisis" in cosmology. Note: this crisis is different than the one regarding potential differences in the expansion rate of the universe.
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- So is Planck lying to us or not? The Planck Collaboration says yes. Other astronomers , even members of the Planck Collaboration, say no. While a curved universe seems very unlikely, only more data and more digging in will settle this controversy. Which do you believe?
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-------------------- Index of other Reviews available upon request. Yes, it is a big topic:
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- 2585 - ATOMS - massless particles control the Universe? Massless particles are the smallest particles that we can think of. What could they possible have to do with astronomy? These massless particles are completely stable they do not lose their energy decaying into pairs of less massive particles. Because all their energy is kinetic, they always travel at the speed of light. Traveling at the speed of light don't actually age. A photon is actually not aging relative to us. It is timeless.
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- 2577 - UNIVERSE - What is the universe made of? Beyond-the-Standard-Model theories have not yet successfully predicted any new experimental phenomenon or any experimental discrepancy. After five decades, far from requiring an upgrade, the Standard Model is worthy of celebration as the Absolutely Amazing Theory of Almost Everything.
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- 2579 -UNIVERSE - how its age was determined? Once you figure out that the Universe is expanding, all you need to do is measure the expansion rate today and use the laws of physics to determine how the expansion rate must have changed over time. Then you calculate how long it would take to get back to the Big Bang where it all started. This is a high school physics problem once these measurements are made.
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- 2574 - UNIVERSE - who made the Universe? Where did the universe come from? How did it get here? There must have been some earlier, pre-existing form of reality that can explain our situation. - We can continue this line of questioning as far back as we want, to even before the Big Bang, until science has nothing left to say, and all we have is the grand abyss of the unknown
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- 2572 - UNIVERSE - size and age determined?
- 2569 - What is the fate of the universe?
- 2551 - Exploring the age and size of the universe?
- 2552 - Studying the birth of the universe?
- 2553 - Is the Universe homogeneous?
- 2504 - Measuring the universe from the biggest to the smallest?
- 2524 - What is the structure of the universe?
- 2536 - Explaining the universe is explaining the impossible?
- 2449 - Strange universe is expanding forever?
- 2459 - Measuring the universe?
- 2476 - Determining the age of the universe?
- 2478 - What is the shape of he universe?
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- 2447 - UNIVERSE - how did it all happen? 13.8 billion years ago the universe started as the Big Bang when space itself rapidly began expanding. At the time the observable universe, which included enough materials to build at least 2 trillion galaxies, fit into a space less than a centimeter across. Today the observable universe is 93 billion light-years across and still expanding.
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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?
- 2412 - Comprehending the expanding Universe?
- 2394 - Wrap your mind around the Universe?
- 2364 - Universal beauty in symmetry?
- 2349 - Why the night sky is dark and the universe is leaving us?
- 2348 - The Universe from start to finish. 13 pages.
- 2347 - The Island Universe?
- 2335 - The Universe almost did not happen?
- 2334 - How is it expanding?
- 2328 - Born from the Universe?
- 2312 - How fast is it expanding?
- 2292 - Accelerating the universe from unknown force?
- 2253 - Expanding universe, how can it be flat? What is beyond the edge?
- 2263 - The universe as we know it?
- 2262 - How fast is it expanding?
- 2230 - The story beginning to end. The age of the universe from the expansion rate.?
- 2202 - The structure of the universe?
- 2196 - Discovering the age of he universe?
- 2195 - How are Cepheid’s used in the calculation of the age of the universe?
- 2194 - How the Universe was born?
- 2193 - What is the universe expanding in to?
- 2192 - The universe as we know it?
- 2177 - The universe by the numbers? Mass, density, diameter?
- 2167 - Planck satellite measures the cosmic microwave background?
- 2166 - History of the universe from picoseconds to years, birth to now. 17 pages.
- 2121 - An expanding Universe.
- 2104 - Laws of the universe.
- 2102 - Age of the Universe?
- 2086 - Puzzles in astronomy?
- 2083 - Pressed for time?
- 2075 - Too weird to ponder?
- 2072 - The age of the universe?
- 2066 - Extremes in the universe?
- 2031 - The observable universe?
- 2027 - Lists more reviews about the universe you live in?
- 2016 - Birth of the universe?
- 2008 - The universe almost did not happen?
- 1991 - What are the odds you are able to read this?
- 1836 - An expanding universe?
- 1821 - Describing the universe in math . This review list 15 more reviews.
- 1782 - Telescopes looking back in time?
- 1759 - Why is the universe expanding?
- 1701 - The expanding universe?
- 1672 - Beginning the universe? Astronomy looks for answers.
- 1665 - How the universe started?
- 1634 - The universe started out in the realm of particle physics.
- 1627 - Is the universe really expanding?
- 1584 - Universe lifetimes?
- 1583 - Simulating the expanding universe?
- 1563 - How old is the universe?
- 1523 - Turn the sky into a 3D map back to the beginning?
- 1493 - Puzzles in astronomy?
- 1471 - Our strange universe?
- 1469 - How we thing the universe began?
- 1421 - The size of the universe smallest to biggest?
- 1314 - Could the astronomer’s math be wrong?
- 1311 - Is the universe spinning?
- 1307 - How will the universe end?
- 1294 - How the universe was formed?
- 1285 - How the universe was born?
- 1275 - The universe is born in billion year steps?
- 1268 - How to explain the universe?
- 1227 - Does the expanding universe violate the law of conservation of energy?
- 1225 - Is the universe really a computer?
- 1146 - Why did the universe turn dark, then light up again?
- 842 - Pressed for time?
- 342 - The whole shebang. A book review.
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- Send me the number to receive a copy.
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- February 3, 2020 2603
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--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
--- to: ------ jamesdetrick@comcast.net ------ “Jim Detrick” -----------
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--------------------- Monday, February 3, 2020 --------------------
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