Frank Robert
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Sometimes, likely too often, I am slow on the uptake.I was just putting your explanation 'to the test', with the result being that I ultimately find that I still know a thing or two in science (which admittedly, I also had to learn).
Ok .. so learning, in that case, still leads to knowledge .. (and therefore, excludes a learner from 'never ultimately knowing' something).
Cats kill for fun. I love cats, but I'm a realist. Mine stays inside. We have magnificent rainbow lorikeets, that are a delight to see. I see beauty, the cat sees lunch.
What you know deep down; I am not an animal.What do you mean by "internal perspective"?
Your skepticism is based solely on personal incredulity.I do not make the mistake of assuming that I can through a mechanism of observation. Determine the rate of expansion of the universe.
If you think that science can know that expansion rate, then that is your choice. I remain deeply skeptical. In fact, all of man's observations are from one point in space time. If you believe you can rely on just having one reference point, then fine, accept the theories.
I would much prefer observations from reference points outside of our solar system. Outside of our galaxy. To avoid a mind stretching extrapolation from the limited data. No wonder there are different values in the Hubble constant.
:sjastro said:LIGO responded to my following question.
sjastro said:
Congratulations on this significant discovery.
Has this discovery broken the mass-redshift degeneracy allowing the calculation of the redshift of GW170817?
If so how does it compare to the redshift of NGC4993?
Christopher Berry LIGO said:
Not directly, but you could if you are willing to assume a neutron star mass.
Since (i) we get masses consistent with known neutron stars, and (ii) we overlap with the distance estimates for NGC 4993, you’d end up with a redshift consistent with that of the galaxy. For precise numbers you’d need to factor in the peculiar velocity of the binary.
So why do they call it the Hubble constant? Why don't they call it the Hubble variable?Your skepticism is based solely on personal incredulity.
The Hubble constant is a misnomer as it is a time dependent parameter.
It is only called a constant as a snapshot of the current cosmological time of the universe.
When observers are separated in space-time in the universe they will all measure a different Hubble constant relative to our frame of reference as they are in our past light cone in a different cosmological time.
So apart for the obvious problems of making measurements outside our galaxy which can be compared it will only prove the Hubble constant is not a constant.
In order not to be dependent on a single method for determining the Hubble constant, scientists have come up with different independent methods for calculating distances.
There are distance measurements based on photometry of Cepheid variables, type Ia supernovae etc.
Distances are also calculated from the size of the acoustic rings in the cosmic radiation background.
In this forum a few years ago I posed a question to LIGO whether redshift of gravitational waves can be determined and ultimately used as a distance measurement to calculate Hubble’s constant.
They went ahead and did it.
It is still very early days for this technique.
Even though each method produces a different rate of expansion what is not in question as confirmed by the measurements themselves is the expansion of the universe.
The Hubble value is constant now, our present cosmological time; cosmologists refer to this as a time slice which is an instantaneous snapshot of the universe.So why do they call it the Hubble constant? Why don't they call it the Hubble variable?
Will there ever be a way of determining the Hubble constant exactly?
What happens if the different schools in astronomy cannot be reconciled, what then?
I'd ask God why he was a deceiver.I'm convinced that's a privilege reserved for Jesus, when He comes back.They may not cling to it anymore; but I believe they will switch their tactics to God being a deceiver.
For example, what if Jesus comes back and takes you back in time to observe the Creation Week firsthand?
What then?
Here is a more detailed explanation why the Hubble constant is not a constant.The Hubble value is constant now, our present cosmological time; cosmologists refer to this as a time slice which is an instantaneous snapshot of the universe.
The rest of your questions require a crystal ball to answer.
From your article.Here is a more detailed explanation why the Hubble constant is not a constant.
Sorry, Astronomy Fans, The Hubble Constant Isn't A Constant At All
And if He asks, "What gives you that idea?"I'd ask God why he was a deceiver.
I'd ask him to be polite. You don't answer a question with a question, that's a form of avoidance. An all-knowing god would know what gave me that idea.And if He asks, "What gives you that idea?"
You would say ...
From your article.
Friedmann realized that if you assumed that the Universe was, on the largest scales, both isotropic (meaning it was the same no matter which direction you looked in) and homogeneous (meaning it had the same density no matter where you were located), then one can derive two unique equations — the Friedmann equations — that govern the Universe.
What happens if the universe is not isotropic and homogeneous.
How could one ever know this assumption is valid?
A cosmological model whether it is the Big Bang, Steady State, or Static Universe is a mathematical model.From your article.
Friedmann realized that if you assumed that the Universe was, on the largest scales, both isotropic (meaning it was the same no matter which direction you looked in) and homogeneous (meaning it had the same density no matter where you were located), then one can derive two unique equations — the Friedmann equations — that govern the Universe.
What happens if the universe is not isotropic and homogeneous.
How could one ever know this assumption is valid?
Abstract
Observations of neutron-star mergers with distinct messengers, including gravitational waves and electromagnetic signals, can be used to study the behavior of matter denser than an atomic nucleus and to measure the expansion rate of the Universe as quantified by the Hubble constant. We performed a joint analysis of the gravitational-wave event GW170817 with its electromagnetic counterparts AT2017gfo and GRB170817A, and the gravitational-wave event GW190425, both originating from neutron-star mergers. We combined these with previous measurements of pulsars using x-ray and radio observations, and nuclear-theory computations using chiral effective field theory, to constrain the neutron-star equation of state. We found that the radius of a 1.4–solar mass neutron star is 11.75 km +0.86/-0.81 km at 90% confidence and the Hubble constant is 66.2 +4.4/-4.2 at 1σ uncertainty.
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