Is the universe expanding faster than expected

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Discussion Overview

The discussion centers on the implications of recent measurements suggesting that the universe is expanding faster than previously expected, specifically referencing the Hubble constant. Participants explore the accuracy of distance measurements, the potential consequences of this accelerated expansion, and the compatibility of these findings with existing cosmological models.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants question the accuracy of parallax measurements used in determining the expansion rate of the universe.
  • Others highlight a significant discrepancy between the locally measured Hubble constant and the value predicted by the Planck Collaboration, suggesting potential systematic errors or new features in cosmological models.
  • A participant seeks to understand the implications of a faster expanding universe.
  • There is a discussion on whether the new measurements will remain consistent with independent measurements, with some suggesting that inconsistency could lead to significant challenges in understanding fundamental physics.
  • Another participant argues that if the assumption of fixed fundamental laws is falsified, it would indicate a lack of understanding of the universe's evolution rather than a complete upheaval of current knowledge.
  • Questions are raised about the advantages and disadvantages of an expanding universe and its potential effects on cosmic structures.
  • One participant notes that a universe that does not expand would collapse, while an excessively fast expansion could prevent star formation.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the faster expansion rate and the reliability of measurements. There is no consensus on whether the findings represent a significant challenge to existing theories or merely indicate gaps in understanding.

Contextual Notes

Participants reference various assumptions regarding the fundamental laws of physics and the evolution of the universe, which remain unresolved in the discussion.

wolram
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Here they use information gathered form Cepheids, are these parallax measurements accurate?

From science daily.
Date:
June 2, 2016
Source:
Space Telescope Science Institute (STScI)
Summary:
Hubble Space Telescope astronomers have discovered that the universe is expanding 5-9% percent faster than expected. They made the discovery by refining the universe's current expansion rate to unprecedented accuracy, reducing the uncertainty to only 2.4%. The team made the refinements by developing innovative techniques that improved the precision of distance measurements to faraway galaxies. These measurements are fundamental to making more precise calculations of how fast the universe expands with time, a value called the Hubble constant.
 
Space news on Phys.org
You can read Adam Reiss et al.'s paper on the physics ArXiv here:Abstract A 2.4% Determination of the Local Value of the Hubble Constant and .pdf paper.

5. Discussion
Our primary fit of H0 = 73.00 ± 1.75 km s−1 Mpc−1 is 3.3 higher than the value of 66.93 ±0.62 kms−1Mpc−1 predicted by Planck Collaboration et al. (2016) based on CDM with 3 neutrino flavors having a mass of 0.06 eV and the Planck CMB data (TT,TE,EE+SIMlow; 3.1 for TT+SIMlow). Assuming the 3.3 difference is not a fluke (99.9% confidence), possible explanations include systematic errors in the local H0 or CMB measurements, or an unexpected feature in the cosmological model that connects them.
Garth
 
Hi. I'm trying to learn about this myself. What are the implications of a faster expanding universe?
 
Cosmologists now have to see if that value is still compatible with other, independent measurements. If yes, it helps to improve the precision of some parameters about the universe. If it is not consistent, it gets interesting.
 
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Interesting is probably sugar coating it, it gets downright ugly in a hurry. Scientists are habituated into assuming the fundamental laws of physics are fixed and unchanging, at least on times scales up to the age of the universe. If this assumption is falsified, everything we think we know about the universe is on shaky ground.
 
Chronos said:
If this assumption is falsified
It would not be. It would just mean we don't understand the evolution of the universe between the very early stages and the current day well enough.
 
What are some advantages and disadvantages of expanding universe ?
And how it can affect us
 
A universe that never expanded would gravitationally collapse, probably in less time than it took for Earth to form. A universe that expands too fast would dilute matter to the point that not even stars could form.
 
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