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Tension over Hubble Constant Continues

17 points by Hooke 7y ago

deleted 7y ago
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dimator 7y ago
Great video on the topic: https://youtu.be/R30ratQanWw https://youtu.be/R30ratQanWw In addition to standard candles and CMB, another method of measuring the Hubble constant is mentioned, using gravitational waves.
- regnerba 7y ago
  Thank you for sharing that. Was a really good watch.
th0ma5 7y ago
If the universe is increasingly expanding... Am I? Are my protons getting farther apart or are the sub atomic particles in me getting larger? Or are you all and other celestial bodies just moving away from me? :P
- scarmig 7y ago
  If the Hubble constant is increasing, as the article points out is consistent with existing evidence, then yes, all distances are getting "larger." In fact, the observable universe would be getting smaller and smaller. At some point it would become so small that the electrons in your atoms couldn't see either each other or the nucleus of the atom; then, the nucleons couldn't see each other; and finally, even the subatomic particles making up the protons and neutrons couldn't see each other. Since they wouldn't interact with each other, everything just falls apart at some point. Look up the Big Rip, one possible fate of the universe.
- ymolodtsov 7y ago
  No they’re not. At least, not yet. The accelerated expansion of the universe is driven by the “dark energy” (whatever this is) and although it prevails at very large distances it’s easily cancelled by gravity, meaning any gravitationally bound structures stay the same. As time goes, everything outside of the Virgo supercluster we live in will start flying away from us at the speed faster than the speed of light (that’s fine, no violation of special relativity) but the supercluster should remain the same. But if the cosmological constant responsible for the dark energy is not actually a constant but is increasing it might go to the point where dark energy becomes stronger than the gravity on the smaller scales.
jobigoud 7y ago
Can we stop calling it the Hubble Constant? The Hubble Parameter is a much better term. It's not meant to be constant in time, only in space. It is continually decreasing over time, even in a Universe in accelerated expansion (unless the expansion is exponentially accelerating which is not the case).

17 points by Hooke 7y ago

deleted 7y ago

[deleted]

Great video on the topic: https://youtu.be/R30ratQanWw https://youtu.be/R30ratQanWw In addition to standard candles and CMB, another method of measuring the Hubble constant is mentioned, using gravitational waves.

regnerba 7y ago
Thank you for sharing that. Was a really good watch.

th0ma5 7y ago

If the universe is increasingly expanding... Am I? Are my protons getting farther apart or are the sub atomic particles in me getting larger? Or are you all and other celestial bodies just moving away from me? :P

scarmig 7y ago
If the Hubble constant is increasing, as the article points out is consistent with existing evidence, then yes, all distances are getting "larger." In fact, the observable universe would be getting smaller and smaller. At some point it would become so small that the electrons in your atoms couldn't see either each other or the nucleus of the atom; then, the nucleons couldn't see each other; and finally, even the subatomic particles making up the protons and neutrons couldn't see each other. Since they wouldn't interact with each other, everything just falls apart at some point. Look up the Big Rip, one possible fate of the universe.
ymolodtsov 7y ago
No they’re not. At least, not yet. The accelerated expansion of the universe is driven by the “dark energy” (whatever this is) and although it prevails at very large distances it’s easily cancelled by gravity, meaning any gravitationally bound structures stay the same. As time goes, everything outside of the Virgo supercluster we live in will start flying away from us at the speed faster than the speed of light (that’s fine, no violation of special relativity) but the supercluster should remain the same. But if the cosmological constant responsible for the dark energy is not actually a constant but is increasing it might go to the point where dark energy becomes stronger than the gravity on the smaller scales.

jobigoud 7y ago

Can we stop calling it the Hubble Constant? The Hubble Parameter is a much better term. It's not meant to be constant in time, only in space. It is continually decreasing over time, even in a Universe in accelerated expansion (unless the expansion is exponentially accelerating which is not the case).