The true context of science. It is just a model, get over it.

[dad]

Orbital mechanics and gravitational red shift. The orbits of the stars around it indicate that it's a relatively small and extremely dense massive object, and the light coming from its vicinity is red-shifted, indicating a very strong gravitational field, and it is a powerful emitter of radio waves; all characteristics of black holes.

So we have some stars orbiting an area that tell us the orbit distances are not very great. They go round and round something (we call a black hole). Apparently you think this confirms the mass for the stars in some way that affirms the distances cosmology places on the galaxy.

Seems to me that all we really see happening there is some stars (that could be molecular sized for all we know with a tiny mass) have an orbit. Something somehow is causing the stars to remain in their orbits. We assume it is gravity, and gravity exactly as we are familiar with here on in the earth and solar system areas. We also assume that the only thing out there in the unknown distant universe that could cause light to shift would be either gravity or recessional movement (or movement of some sort, such as blue shift which is moving toward us).

Seems to me that if, for example, the stars were the size of earth satellites, and the 'black hole' had the gravitational strength of earth, and the 'galaxy was actually only say, 3 light years away, that we would also see redhifted light and orbits for the stars that were 'fast' and not of great distances? So how does this tell us precisely how great the gravity is, or how far away the stars are?

We should remember this also I suppose, ..

"In cosmology, we can't quite do this, but we can do something analogous. By studying the redshift of light from a distant spiral galaxy, we can determine how rapidly different parts of the galaxy are moving toward or away from us. This lets us construct what's called a "rotation curve" - a plot giving the relationship between orbital speed and distance from the galactic center for the stars and gas that make up the galaxy. This plot lets us map out the distribution of matter in the galaxy.

For a given galaxy, we can compare the rotation curve we actually measure to the rotation curve we would expect to get if the galaxy contained no dark matter at all - in other words, if the visible matter was the only matter in the galaxy. It turns out that these two curves don't agree! "
Orbital Mechanics and Dark Matter

Redshift is apparently also used for cosmic distances. I think they believe space itself is expanding and causing the shift.


"In cosmological redshift, the wavelength at which the radiation is originally emitted is lengthened as it travels through (expanding) space. Cosmological redshift results from the expansion of space itself and not from the motion of an individual body.

For example, in a distant binary system it is theoretically possible to measure both a Doppler shift and a cosmological redshift. The Doppler shift would be determined by the motions of the individual stars in the binary – whether they were approaching or receding at the time the photons were emitted. The cosmological redshift would be determined by how far away the system was when the photons were emitted. "

Cosmological Redshift | COSMOS

It seems that the interpretation of what redshift is out in deep space rests on the idea that space is what they think space is! I seem to recall some folks admitting they do not really even know what space is?

 

[dad]

Noah is a fictional character. When are you proposing the he (didn't) live?

He is in the records of Israel/Scripture and was a contemporary with Abraham. You think Abraham is fictional also? Try to use language properly, fictional is not something you just chose to ignore and deny inside your head.

 

[dad]

The distance is ~ 8000 kpc. And it is irrelevant to measuring its mass, for the hard of thinking. As FB points out, we only need the orbital parameters of the stars around it. And Kepler's third law. Piece of cake.

M(bh) = (4 x pi^2 x a^3)/(G x P^2)

Where;
a = semi-major axis
G = gravitational constant
P = the orbital period

Do the maths. Comes out as ~ 4m solar masses. Gravitational redshift proves that it is a massive object.

We know that G is the same out there...because..?

We know that the time involved in orbits is the same out there as the time we are familiar with here in the solar system area,..... because..?

Also, in Kepler's third law I see radius is involved.

Can you explain how the length of any part of any orbit of any star is known here, without knowing any distances?

 

[dad]

Yep. When people don't have God, then they need some other 'god', some substitute, and that's about a million different things, often money or glamour or the body, ideologies, etc., but sometimes a kind of science fantasy or ideology. Beware that making up a new physics and then being faithful to it instead of merely testing it to find out if it works can itself be elevating one's theory into a special level of adoration.

I am weary when unbelievers make up things or limit God or creation to the physics they know. I also realize God made up physics, and all other nature sets that will exist or did exist.

 

[ianw16]

We know that G is the same out there...because..?

We know that the time involved in orbits is the same out there as the time we are familiar with here in the solar system area,..... because..?

Also, in Kepler's third law I see radius is involved.

Can you explain how the length of any part of any orbit of any star is known here, without knowing any distances?

Because there is no scientific reason to believe otherwise, nor evidence to support such nonsense. And gravitational redshift is a part of General Relativity, which has been proven correct time and again. To get rid of laws founded by Newton, Kepler and Einstein you are going to need one hell of a theory. You appear to have nothing.

 

[ianw16]

We know that G is the same out there...because..?

We know that the time involved in orbits is the same out there as the time we are familiar with here in the solar system area,..... because..?

Also, in Kepler's third law I see radius is involved.

Can you explain how the length of any part of any orbit of any star is known here, without knowing any distances?

We do know the distance. We also know the velocity of the stars. And the period. Therefore you can work out r. Simples.

 

[ianw16]

He is in the records of Israel/Scripture and was a contemporary with Abraham. You think Abraham is fictional also? Try to use language properly, fictional is not something you just chose to ignore and deny inside your head.

So when did he live?

https://www.quora.com/How-do-we-know-the-story-of-Noahs-Ark-is-not-fictional

 

[ianw16]

So we have some stars orbiting an area that tell us the orbit distances are not very great. They go round and round something (we call a black hole). Apparently you think this confirms the mass for the stars in some way that affirms the distances cosmology places on the galaxy.

Seems to me that all we really see happening there is some stars (that could be molecular sized for all we know with a tiny mass) have an orbit. Something somehow is causing the stars to remain in their orbits. We assume it is gravity, and gravity exactly as we are familiar with here on in the earth and solar system areas. We also assume that the only thing out there in the unknown distant universe that could cause light to shift would be either gravity or recessional movement (or movement of some sort, such as blue shift which is moving toward us).

Seems to me that if, for example, the stars were the size of earth satellites, and the 'black hole' had the gravitational strength of earth, and the 'galaxy was actually only say, 3 light years away, that we would also see redhifted light and orbits for the stars that were 'fast' and not of great distances? So how does this tell us precisely how great the gravity is, or how far away the stars are?

We should remember this also I suppose, ..

"In cosmology, we can't quite do this, but we can do something analogous. By studying the redshift of light from a distant spiral galaxy, we can determine how rapidly different parts of the galaxy are moving toward or away from us. This lets us construct what's called a "rotation curve" - a plot giving the relationship between orbital speed and distance from the galactic center for the stars and gas that make up the galaxy. This plot lets us map out the distribution of matter in the galaxy.

For a given galaxy, we can compare the rotation curve we actually measure to the rotation curve we would expect to get if the galaxy contained no dark matter at all - in other words, if the visible matter was the only matter in the galaxy. It turns out that these two curves don't agree! "
Orbital Mechanics and Dark Matter

Redshift is apparently also used for cosmic distances. I think they believe space itself is expanding and causing the shift.


"In cosmological redshift, the wavelength at which the radiation is originally emitted is lengthened as it travels through (expanding) space. Cosmological redshift results from the expansion of space itself and not from the motion of an individual body.

For example, in a distant binary system it is theoretically possible to measure both a Doppler shift and a cosmological redshift. The Doppler shift would be determined by the motions of the individual stars in the binary – whether they were approaching or receding at the time the photons were emitted. The cosmological redshift would be determined by how far away the system was when the photons were emitted. "

Cosmological Redshift | COSMOS

It seems that the interpretation of what redshift is out in deep space rests on the idea that space is what they think space is! I seem to recall some folks admitting they do not really even know what space is?

Word salad. Show me a scientist that disagrees with the Sgr A* data. Believers in primitive superstition do not count.

 

[Halbhh]

I am weary when unbelievers make up things or limit God or creation to the physics they know. I also realize God made up physics, and all other nature sets that will exist or did exist.

We won't win any converts to Christ by telling them our science ideas. We might get a convert to a science idea that way, but not to Christ. Only the word of Christ can create saving faith (Romans 10:17). About God doing things impossible in physics, I take that as a basic normal thing. Even for situations where He might have He used physics instead of supernatural overturning of physics I still don't always presume He used physics. For instance, when the sun was made to "stand still", which could be done either physically (with amazing technology perhaps) or supernaturally; I tend to go with supernatural, unphysical --
A flat earth and an earth-centered universe Post #56

 

[Halbhh]

Can you explain how the length of any part of any orbit of any star is known here, without knowing any distances?

The way distances to stars are figured out begins with the laws of geometry for a triangle -- that when you know 1 side length and 2 angles in a triangle that fixes the other 2 side lengths.

We know the diameter of the Earth's orbit, and because if 2 observations of a nearby star are done 6 months apart in time, it will appear to shift against the background of more distant stars due to the different location of Earth in its orbit 6 months apart in time, then that angle of shift can then be used to obtain the distance to that nearby star. This is called "parallax" and it requires measuring it a few times to get it more accurate by subtracting out the constant motion of the star itself.

That's all geometry, trigonometry. No complex theory at all.

The math from high school is enough, if a person works at it -- those doing ok in those math classes who worked hard could do this parallax measurement of a nearby star with effort and time.

Next comes a certain kind of reliable star type called a Cepheid variable, which reliably will have a certain intrinsic brightness that is the same for any two alike Cepheids of the same mass. This means once we get the distance to a Cepheid with parallax, we then can figure out more distant Cepheids by their relative apprend brightness and their period of variation.

Fun Fact: The North Star -- Polaris -- is a Cepheid variable and close enough to us to measure it's parallax easily! (though Polaris isn't the best kind of Cepheid for making the cosmic distance ladder, it's still a fun thing that it's variable)

This step by step process can continue with type 1A supernovae, and thus astronomers can work out greater distances still. The step by step process is called the Cosmic Distance Ladder:
Cosmic distance ladder - Wikipedia

Even though there are margins of error in all these parts, even multiplied together the margins of error wouldn't change the rough magnitudes of cosmic distances. Andromeda galaxy light we receive in telescopes we know is over 2 million years old.

Because there is no scientific reason to believe otherwise, nor evidence to support such nonsense. And gravitational redshift is a part of General Relativity, which has been proven correct time and again. To get rid of laws founded by Newton, Kepler and Einstein you are going to need one hell of a theory. You appear to have nothing.

Sometimes some people have rather unique ideas, such as the ever present one here on this site about how magnetic fields are important in galaxies but with the imagined situation astronomers/astrophysicists intentionally ignore these important magnetic fields. That's a conspiracy theory, and I've often tried to help those imagining it realize science is a process of testing and discovery. Some tend to imagine it's more like a cabal it seems, or political, etc. I try not to get impatient with them, so sometimes I just have to leave after I've stated useful facts. ;-)

 

[Halbhh]

I sometimes point out some of the interest and effort to measure and understand galactic and system scale magnetic fields, for instance:

https://phys.org/news/2018-04-cosmic-magnetic-fields-astonishing.html
https://phys.org/news/2018-10-magnetic-fields-key-black-hole.html
https://phys.org/news/2009-10-galactic-magnetic-fields-boundaries-solar.html

and on and on.

But my guess is that in spite of the clear ongoing effort in astrophysics to better understand more about large scale magnetic fields, that still some will continue to tell us "astronomers are ignoring 99% of the Universe" or other such conspiracy theory views of that kind. I mean if I spent hours tracking down instances and pointing out counterexamples to people on the internet, it might make a small dent in this conspiracy theory. Maybe. But I wouldn't be surprised if a few days later I just heard it again from a new person.

 

[FrumiousBandersnatch]

So we have some stars orbiting an area that tell us the orbit distances are not very great. They go round and round something (we call a black hole). Apparently you think this confirms the mass for the stars in some way that affirms the distances cosmology places on the galaxy.

Seems to me that all we really see happening there is some stars (that could be molecular sized for all we know with a tiny mass) have an orbit. Something somehow is causing the stars to remain in their orbits. We assume it is gravity, and gravity exactly as we are familiar with here on in the earth and solar system areas. We also assume that the only thing out there in the unknown distant universe that could cause light to shift would be either gravity or recessional movement (or movement of some sort, such as blue shift which is moving toward us).

Seems to me that if, for example, the stars were the size of earth satellites, and the 'black hole' had the gravitational strength of earth, and the 'galaxy was actually only say, 3 light years away, that we would also see redhifted light and orbits for the stars that were 'fast' and not of great distances? So how does this tell us precisely how great the gravity is, or how far away the stars are?

We should remember this also I suppose, ..

"In cosmology, we can't quite do this, but we can do something analogous. By studying the redshift of light from a distant spiral galaxy, we can determine how rapidly different parts of the galaxy are moving toward or away from us. This lets us construct what's called a "rotation curve" - a plot giving the relationship between orbital speed and distance from the galactic center for the stars and gas that make up the galaxy. This plot lets us map out the distribution of matter in the galaxy.

For a given galaxy, we can compare the rotation curve we actually measure to the rotation curve we would expect to get if the galaxy contained no dark matter at all - in other words, if the visible matter was the only matter in the galaxy. It turns out that these two curves don't agree! "
Orbital Mechanics and Dark Matter

Redshift is apparently also used for cosmic distances. I think they believe space itself is expanding and causing the shift.


"In cosmological redshift, the wavelength at which the radiation is originally emitted is lengthened as it travels through (expanding) space. Cosmological redshift results from the expansion of space itself and not from the motion of an individual body.

For example, in a distant binary system it is theoretically possible to measure both a Doppler shift and a cosmological redshift. The Doppler shift would be determined by the motions of the individual stars in the binary – whether they were approaching or receding at the time the photons were emitted. The cosmological redshift would be determined by how far away the system was when the photons were emitted. "

Cosmological Redshift | COSMOS

It seems that the interpretation of what redshift is out in deep space rests on the idea that space is what they think space is! I seem to recall some folks admitting they do not really even know what space is?

Yes; I suppose it all sounds very dubious when you don't really have the foggiest idea about it.

 

[dad]

Because there is no scientific reason to believe otherwise, nor evidence to support such nonsense.

So there is no evidence to support your claims of an identical space and time in far space, and it is purely a matter of belief. That's all we needed you to admit here. Your opinion of the Creator, or believers is of no consequence here.

And gravitational redshift is a part of General Relativity, which has been proven correct time and again.

So, ignorance is pleaded again. OK. You would need to show that space and time are the same way out there, to achieve any correlation with GR. Merely seeing shifted light when something gets near something else does not tell us GR did it! That tells us only that if gravity were the same and space, that we also would expect that a redshift would occur under those conditions.

Tell us, does the redshifted light we see here tell us that a star is of a certain size, or if space and time is the same there!?

You see unless gravity and time and space were all identical at all points in the universe (?) GR itself, of course would be relative!

To get rid of laws founded by Newton, Kepler and Einstein you are going to need one hell of a theory. You appear to have nothing.

Hey, I don't need to get rid of the 20 MPH speed limit in Hicksville USA (if there were such a thing) to travel almost as fast as I like on the Autobahn in Germany!

 

[dad]

We do know the distance. We also know the velocity of the stars. And the period. Therefore you can work out r. Simples.

Ah, bingo! You thought you knew distances...unless that were true all is lost for your case! I say you do not know them. Knowing distance depends on knowing time all the way there.

 

[dad]

So when did he live?

https://www.quora.com/How-do-we-know-the-story-of-Noahs-Ark-is-not-fictional

Abraham? They say he likely lived and was a young lad when Noah was still alive.

 

[dad]

Word salad. Show me a scientist that disagrees with the Sgr A* data. Believers in primitive superstition do not count.

No one cares what is believed. Show us a scientist that understands the data, and we can rake him or her over the coals here.

 

[dad]

We won't win any converts to Christ by telling them our science ideas. We might get a convert to a science idea that way, but not to Christ. Only the word of Christ can create saving faith (Romans 10:17). About God doing things impossible in physics, I take that as a basic normal thing. Even for situations where He might have He used physics instead of supernatural overturning of physics I still don't always presume He used physics. For instance, when the sun was made to "stand still", which could be done either physically (with amazing technology perhaps) or supernaturally; I tend to go with supernatural, unphysical --
A flat earth and an earth-centered universe Post #56

Maybe it is not all about winning converts in science forum discussions?! Maybe it should also be about telling the truth and warning kids against lies and anti bible gobblygook religion falsely called science?

The sun standing still was felt physically by those living in that little area or at least fighting in a little area one day.

Whatever God did made itself real in this physical world there.

 

[dad]

The way distances to stars are figured out begins with the laws of geometry for a triangle -- that when you know 1 side length and 2 angles in a triangle that fixes the other 2 side lengths.

No. You see we cannot separate time from space here that I am aware of. When we take a swath of the solar system maybe hundreds of millions of miles long, that represents more than just space. That is time and space. Unless space and time also existed identically all the way to a star, the drawing of lines to a star is useless and totally unable to render actual distances in space and time.
So it is absolutely NOT just all geometry, and trigonometry.

Next comes a certain kind of reliable star type called a Cepheid variable, which reliably will have a certain intrinsic brightness that is the same for any two alike Cepheids of the same mass

One rung of the cosmic distance ladder rests on the former ones you know.

Of course we also have time involved when we measure periods of luminosity! e also need space to be the same for luminosity to 'fall off' at the rate we are familiar with in the solar system area. Time would have to be the same for any period...example 100 days... to give meaning to the period as seen in earth time!

. This means once we get the distance to a Cepheid with parallax, we then can figure out more distant Cepheids by their relative apprend brightness and their period of variation.

No. It means the distance you got by parallax was wrong and other distances based on that (and added assumptions about space and time further away) are exponentially wrong!

Even though there are margins of error in all these parts, even multiplied together the margins of error wouldn't change the rough magnitudes of cosmic distances. Andromeda galaxy light we receive in telescopes we know is over 2 million years old.

Wrong. We are not talking about margins of error WITHIN the belief set of so called science! I am talking about their whole belief set being utterly wrong.

Sometimes some people have rather unique ideas, such as the ever present one here on this site about how magnetic fields are important in galaxies but with the imagined situation astronomers/astrophysicists intentionally ignore these important magnetic fields.

Sorry, never heard of that.

 

[dad]

Yes; I suppose it all sounds very dubious when you don't really have the foggiest idea about it.

That depends if the foggiest idea is defined by accepting the blind faith notions of distances and space and time that earth science has embraced.

The important thing is to realize that origin related sciences, such as cosmology are religion.

 

[FrumiousBandersnatch]

That depends if the foggiest idea is defined by accepting the blind faith notions of distances and space and time that earth science has embraced.

The important thing is to realize that origin related sciences, such as cosmology are religion.

I've explained more than once how our notions of distances and space and time are based on observation and inference, but it appears you still don't have the foggiest notion of this stuff.