Big freeze
There’s a disturbing, and disturbingly possible, alternative endgame. The Higgs boson is the particle that gives other fundamental particles mass, and so is in some sense a guarantor of the universe’s stability. But the Higgs bosondiscovered at CERN in 2012 is strangely light, suggesting that the universe it builds is an unstable “false vacuum” state, teetering on the brink of ruin. A quantum fluctuation could at any moment conjure up a bubble of true vacuum. In that case the universe would eat itself from the inside out at the speed of light – faster than we would ever know. Daniel Cossins
There’s a disturbing, and disturbingly possible, alternative endgame. The Higgs boson is the particle that gives other fundamental particles mass, and so is in some sense a guarantor of the universe’s stability. But the Higgs bosondiscovered at CERN in 2012 is strangely light, suggesting that the universe it builds is an unstable “false vacuum” state, teetering on the brink of ruin. A quantum fluctuation could at any moment conjure up a bubble of true vacuum. In that case the universe would eat itself from the inside out at the speed of light – faster than we would ever know. Daniel Cossins
Big rip
Dark energy has made its presence felt only in the past few billion years, so it might be growing stronger over time. If so, the universe is bound for a more dramatic fate than a freeze. A surging dark energy would slowly tear apart galaxies and stars, and eventually space-time itself. Recent calculations indicate that the earliest this “big rip” could happen is 2.8 billion years from now, well before our sun is due to burn out. Most cosmologists think the solar system is safe, however. A big rip, if it ever happens, is most likely to be tens of billions of years in the future.
Dark energy has made its presence felt only in the past few billion years, so it might be growing stronger over time. If so, the universe is bound for a more dramatic fate than a freeze. A surging dark energy would slowly tear apart galaxies and stars, and eventually space-time itself. Recent calculations indicate that the earliest this “big rip” could happen is 2.8 billion years from now, well before our sun is due to burn out. Most cosmologists think the solar system is safe, however. A big rip, if it ever happens, is most likely to be tens of billions of years in the future.
Big crunch
In the 1990s, observations of distant supernovae indicated that the universe’s expansion has been gathering pace over the past few billion years. “Dark energy” is held responsible for that, but no one knows what it is. If it is unchanging, as most cosmologists assume, the cosmic ballooning will continue unabated and the universe will eventually become so thinly stretched that no galaxy, star or even particle is in contact with or even in sight of another. No new stars will form, and existing ones will burn out. As its temperature drops ever closer to absolute zero, this flaccid universe will go out in a cold, dark whimper.
In the 1990s, observations of distant supernovae indicated that the universe’s expansion has been gathering pace over the past few billion years. “Dark energy” is held responsible for that, but no one knows what it is. If it is unchanging, as most cosmologists assume, the cosmic ballooning will continue unabated and the universe will eventually become so thinly stretched that no galaxy, star or even particle is in contact with or even in sight of another. No new stars will form, and existing ones will burn out. As its temperature drops ever closer to absolute zero, this flaccid universe will go out in a cold, dark whimper.
Big slurp
If dark energy should for any reason weaken – perhaps even turn negative – gravity would finally prevail over its repellent phantom nemesis. The universe would crank into reverse gear, and begin shrinking again, right down to the same sort of pinprick of infinite density in which it started. The big bang universe will be bookended with a big crunch. Although that would be bad news for anything in the cosmos, it might not be bad for the cosmos itself: some models suggest it could rebound in a “big bounce” that would create another universe, starting the cycle all over again.
No comments:
Post a Comment