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Judi Lynn

(160,211 posts)
Mon Oct 22, 2018, 01:15 PM Oct 2018

Why We Need Cosmic Inflation

By Paul Sutter, Astrophysicist | October 22, 2018 07:25am ET

The Big Bang model is our most successful explanation for the history of the universe that we live in, and it's ridiculously easy to encapsulate its core framework in a single, T-shirtable sentence: A long time ago, our universe was a lot smaller. From this simple statement flows major testable predictions that have been verified by decades of observation. The expansion rate of the universe. The cosmic microwave background. The production of the lightest elements. The differences between near and far galaxies. All the juicy lines of evidence that makes cosmology a science.

But there are some issues. [The Universe: Big Bang to Now in 10 Easy Steps]

Eyes on the horizon
We can see a tremendous volume of raw space. Our observable universe is more than 90 billion light-years in diameter. And the farther out we look the deeper into the past we peer. Surrounding us is the cosmic microwave background, the leftover fossil light released when the universe was barely a newborn — only 270,000 years old, well over 13.8 billion years in the past.

That light comes to us from distant reaches of the cosmos, so distant that it's now inaccessible to us. And different sections of that background light are inaccessible to each other. In the wonderful jargon of physics, regions of the cosmic microwave background are not causally connected. In other words, for one chunk of the limits of our observable universe to communicate with another chunk in the past 13.8 billion years, they would have had to send signals faster than the speed of light.

More:
https://www.space.com/42202-why-we-need-cosmic-inflation.html?utm_source=notification

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Why We Need Cosmic Inflation (Original Post) Judi Lynn Oct 2018 OP
Wormholes! Space warps! Folds in the fabric of space! Nitram Oct 2018 #1
How can they know that the observable universe is 90 billion light years in diameter if its only cstanleytech Oct 2018 #2

cstanleytech

(26,080 posts)
2. How can they know that the observable universe is 90 billion light years in diameter if its only
Mon Oct 22, 2018, 02:55 PM
Oct 2018

13.x billion years old? I mean shouldn't the light from that distance (assuming they mean its a 45 billion light year bubble with the earth at the center) not be due here for another 31.x billion years?

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