Showing posts with label martin rees. Show all posts
Showing posts with label martin rees. Show all posts

Monday, April 10, 2023

DALL-E

The Multiverse: Our Universe Is Suspiciously Unlikely to Exist—Unless It Is One of Many Although we can confidently trace cosmic history back to one second after the Big Bang, what happened before is harder to gauge. Our accelerators simply can’t produce enough energy to replicate the extreme conditions that prevailed in the first nanosecond. ..........

it’s in that first tiny fraction of a second that the key features of our universe were imprinted.

........ The conditions of the universe can be described through its “fundamental constants”—fixed quantities in nature, such as the gravitational constant (called G) or the speed of light (called C). There are about 30 of these representing the sizes and strengths of parameters such as particle masses, forces, or the universe’s expansion. But our theories don’t explain what values these constants should have. Instead, we have to measure them and plug their values into our equations to accurately describe nature. ........ The values of the constants are in the range that allows complex systems such as stars, planets, carbon, and ultimately humans to evolve. Physicists have discovered that if we tweaked some of these parameters by just a few percent, it would render our universe lifeless. ....... like on the ocean, there’s a horizon that we can’t see beyond. And just as we don’t think the ocean stops just beyond our horizon, we expect galaxies beyond the limit of our observable universe ........ If they stretched far enough, then everything we could ever imagine happening may be repeated over and over. Far beyond the horizon, we could all have avatars. ....... The theory of inflation, which suggests that the early universe underwent a period when it doubled in size every trillionth of a trillionth of a trillionth of a second has genuine observational support. It accounts for why the universe is so large and smooth, except for fluctuations and ripples that are the “seeds” for galaxy formation. ........ under some specific but plausible assumptions about the uncertain physics at this ancient era, there would be an “eternal” production of Big Bangs—each giving rise to a new universe. ......... The “laws of nature” may therefore, in this still grander perspective, be local by-laws governing our own cosmic patch. ........ you could imagine universes that are even more friendly to life than our own. Most “tweakings” of the physical constants, however, would render a universe stillborn. ........ First we had the Copernican realization that the Earth wasn’t the center of the solar system—it revolves around the sun. Then we realized that there are zillions of planetary systems in our galaxy, and that there are zillions of galaxies in our observable universe.......... Critics sometimes argue that the multiverse is unscientific because we can’t ever observe other universes. But I disagree. We can’t observe the interior of black holes, but we believe what physicist Roger Penrose says about what happens there—his theory has gained credibility by agreeing with many things we can observe. ......... About 15 years ago, I was on a panel at Stanford where we were asked how seriously we took the multiverse concept—on the scale “would you bet your goldfish, your dog, or your life” on it. I said I was nearly at the dog level. Linde said he’d almost bet his life. Later, on being told this, physicist Steven Weinberg said he’d “happily bet Martin Rees’ dog and Andrei Linde’s life.” ........ Indeed, we can’t even be sure we’d understand the answer—just as quantum theory is too difficult for monkeys. ..... But it’s no reason to dismiss the multiverse as unscientific. .

Martin Rees: The multiverse: our universe is suspiciously unlikely to exist – unless it is one of many

“For the scientist who has lived by his faith in the power of reason, the story ends like a bad dream. He has scaled the mountain of ignorance; he is about to conquer the highest peak; as he pulls himself over the final rock, he is greeted by a band of theologians who have been sitting there for centuries.”



use incredibly bright colors of all kinds to say farewell to anger

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