Alpha Centauri 2

Community => Recreation Commons => Destination: Alpha Centauri => Topic started by: Buster's Uncle on July 08, 2025, 01:21:28 pm

Title: New study claims the universe will start shrinking in 7 billion years
Post by: Buster's Uncle on July 08, 2025, 01:21:28 pm

New study claims the universe will start shrinking in 7 billion years
Joshua Hawkins
BGR (https://bgr.com/)
Mon, July 7, 2025 at 4:55 PM EDT
2 min read


(https://s.yimg.com/ny/api/res/1.2/2hh7NZVXcI18qItKoIYnPg--/YXBwaWQ9aGlnaGxhbmRlcjt3PTEyNDI7aD04Mjg7Y2Y9d2VicA--/https://media.zenfs.com/en/bgr_208/e67c61cf0667361b7e938087aa64d137)

How will the world end? While some, like Robert Frost, have waxed poetic about the end of life on Earth—fire or ice—others have been looking to science to solve the mystery. Even still, others have been looking at the bigger picture, trying to figure out when the entire universe will end. Now, a new study claims that the universe itself might start shrinking within the next 7 billion years, leading to what scientists call “the Big Crunch.”

The study was published by physicists from Cornell University, Shanghai Jiao Tong University, and several other institutions. Using data collected from many different astronomical surveys, including the Dark Energy Survey, the researchers have created a new model that predicts our universe will end with what scientists have long theorized will be a “Big Crunch.” The model suggests the universe will end roughly 33.3 billion years after the Big Bang.

Using that date, the researchers then began looking backward. So far, the universe is estimated to be around 13.8 billion years old. Based on that number and the model’s prediction of when the universe will end, we have roughly 20 billion years before the universe collapses in on itself. This study, and the theory of the “Big Crunch,” challenges long held assumptions that the universe will expand forever, eventually leading to a “Big Freeze.”

Instead, the researchers estimate that the universe will continue to expand for another 7 billion years. At that point, the universe will then begin contracting. Essentially, it will collapse in on itself until a single point remains, destroying everything. It’s an interesting and somewhat terrifying theory, even if we aren’t expecting it to happen in our lifetime.

One easy way to think about it is to imagine the universe as a massive rubber band. As the universe expands, the rubber band stretches. But then it eventually reaches a point where it can’t be stretched anymore, forcing the band to become stronger than its expansion force. This then causes everything to snap back together.

It’s a bit of a sad way for the universe to end, and I can’t imagine what it would actually look like if there was any way to see it taking place. Luckily, it’s not really something we have to worry about, and this research is far from actual confirmation that this is what will happen. For all we know, the theories could be incorrect, and the universe could indeed keep expanding forever.

https://www.yahoo.com/news/study-claims-universe-start-shrinking-205500396.html

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Chaps me, it does, when they write up cosmological models that predict Big Crunch and treat it like bad news.  Big Freeze is bad news; nothing forever after.  Big Crunch clearly implies pulsating universe and the possibility of life again; SOMEthing is better than nothing.  None of it's happening next week, anyway, y'know.

Title: Re: New study claims the universe will start shrinking in 7 billion years
Post by: Lorizael on July 08, 2025, 03:24:29 pm

Quote from: Buster's Uncle on July 08, 2025, 01:21:28 pm

Chaps me, it does, when they write up cosmological models that predict Big Crunch and treat it like bad news.  Big Freeze is bad news; nothing forever after.  Big Crunch clearly implies pulsating universe and the possibility of life again; SOMEthing is better than nothing.  None of it's happening next week, anyway, y'know.

Well, expanding to a big freeze is supposed to give us a much longer expected lifespan than this particular big crunch.

...

Doing a little digging here, this is very speculative stuff. Some results from dark energy surveys suggest the accelerating expansion of the universe might not be constant everywhere/when. Jumping on that, you can build a model where dark energy comes from a cosmological constant + some other variable thing. The variable thing they point to is an "ultra-light axion field," which is some dark matter candidate from string theory. This field, if it exists, has a cyclical nature to it, which translates to the variable part of dark energy sometimes being negative and sometimes being positive. When negative, you eventually get a shrinking universe instead of one with accelerating expansion.

The paper is a preprint on arXiv and I don't see any evidence it's been peer-reviewed, so I can't speak to whether the math and physics here are solid. (I understand the general thrust of it but not the heavy technical details.) But either way, it's built on a lot of ifs: if the dark energy survey results are real, if they imply a non-constant expansion factor, if there's an ultra-light axion field, if that field has a very particular set of parameters (the paper readily admits there are a lot of other numbers you can wiggle around to explain the dark energy survey numbers and they chose ones that give this result), etc. So, fun, interesting stuff, but definitely speculative.