All Questions
Tagged with cosmology experimental-physics
62
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What are the key pieces of cosmological evidence if you want to compare the success of dark matter versus quantised inertia?
Quantised Inertia is a controversial fringe theory that is claimed to be an alternative explanation of, for example, galactic motion.
The consensus explanation for why the outer stars in galaxies ...
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-2
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2
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153
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Is Young Earth universe distinguishable from non-creationist one? [closed]
While talking today about some religious beliefs I was struck by the next question:
So what if some super-natural being forks our universe 6,000 years
ago, i.e. creates the exact same copy of ...
- 141
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Tianqin project vs LISA
How does Tianqin space-based gravitational wave detector compare to LISA? Will it be able to detect gravitational waves from e.g. inflation (considering possible upgrades)?
- 2,726
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Estimate of neutrino masses from the values of $\Delta m_{21}^2$ and $\Delta m_{13}^2$ only!
The blog here says that
The measured mass differences between the eigenstates are $\Delta m_{21}^2=7.5\times 10^{-5} {\rm eV}^2$ and $\Delta m_{13}^2=2.5\times 10^{-3} {\rm eV}^2$, suggesting that ...
- 26.8k
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4
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Does the unobservable universe exist in the present?
Is our observation about universe limited due to the incapacity of telescopes to look further or is it just because we look too further into the future, so the "unobservable" universe hasn't been ...
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Is light actually faster than what our present measurements tell us?
It is well established that the light speed in a perfect vacuum is roughly $3\times 10^8 \:\rm m/s$. But it is also known that outer space is not a perfect vacuum, but a hard vacuum. So, is the speed ...
user182521
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1
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212
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Precision in cosmological constant
The observed cosmological constant, what is its precision? How precise do we know is it not a fluke or misinterpretation of cosmological data?
- 6,611
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Are physicists still ignorant of the existence of real singularities?
(1) Is the gravitational singularity (or space-time singularity) the same as the black hole singularity?
(2) The wikipedia page says
Physicists are undecided whether the prediction of ...
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133
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How is the primordial abundance of Lithium measured?
I was reading about the "Lithium problem" and I came across this Physics SE post: Discrepancy problem in lithium?
The answer mentioned
On the other hand, measurements of the $\rm Li$ abundance ...
user191954
6
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Sterile (4th) neutrino and cosmological bound
Recent results by MicroBoone seems to give support to old LSND experiment in favor of a fourth neutrino (sterile). How does it fit with the current cosmological bound for neutrinos?
- 6,611
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Experimental constraints on dark matter pressure?
The $\Lambda$CDM model assumes collisionless dark matter, so that its pressure $P=0$. But what are the best experimental constraints on $P$? I guess on $P/\rho$ in fact…
user175150
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125
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Is quantum theory useful to describe the whole cosmos? [closed]
We often say that QFT describes the nature on a fundamental level. However this is indeed a very complicated theory for which the calculations related to the interaction of just a few particles simply ...
user56963
1
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0
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125
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Fisher Forecasting For EUCLID Experiment Help [closed]
I'm trying to recreate the results of this paper https://arxiv.org/abs/1607.08016
to obtain the constraints for the matter density and hubble constant h.
However every time I try to create there ...
- 179
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0
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137
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Experimental test for a universal scale closed timelike curve?
So recently, in chat, I was interested in about what if our universe contains only one CTC (thus making it unlike the Gödel metric, van Stockum dust where there can be more than one CTCs found) and ...
- 935
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591
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To what accuracy do we know the value of the cosmological constant?
The Wikipedia article just says that the cosmological constant
"is measured to be on the order of $10^{−52} \text{ m}^{−2}$," but the only citation goes all the way back to 2004. What is $\Lambda$'s ...
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