Size and age of universe

Astronomers admit that parallax is not accurate beyond 300
light-years. Empirically speaking no one is required to commit himself to a universe greater in size than 600 light-years in diameter. Any claims to
something larger are simply not conclusive, since it with all the anomalies
associated with measuring distance by a star’s redshift, ther is no indisputable yardstick to measure the universe.
Not true. Cepheid variables and type 1A supernovas provide good yard sticks throughout the Milky Way (100,000 light years) and out to nearby galaxies eg M31/Andromeda.
 

Maalox

War Hero
Not true. Cepheid variables and type 1A supernovas provide good yard sticks throughout the Milky Way (100,000 light years) and out to nearby galaxies eg M31/Andromeda.

"Other methods of determining parallax include: Photometric parallaxes, which are found by estimating a star’s absolute magnitude (M) based on a spectral classification, and comparing that with its apparent magnitude (m). Statistical parallaxes could perhaps extend to 500 parsecs, but this only applies to groups of stars, not individual stars.

Overall, of the half dozen or so methods employed today to measure astral distances, none of them are indisputable (including distances measured by redshift, Cepheid variables, luminosity, color of stars, etc.). There is only one purely empirical method, parallax (and its attendant modifications such as Spectroscopic, Moving Cluster Method, and Statistical Method), but it is quite limited in its applicability, since it can accurately measure only a thousand or so stars. In effect, modern science is left without an irrefutable means to measure cosmological distances, and thus all the literature espousing that stars, galaxies or quasars are billions of light years away from Earth is an unproven scientific assertion.

Using Cepheid variables, for example, is certainly a question-begging venture, since Cepheids are too far away to be measured by parallax and, thus, depends on an unproven statistical method to measure distance.

Other methods such as Secular Parallax, Expansion Parallax, Kinematic Distance, Light Echo Distance, Baade-Wesselink Method, Expanding Photosphere Method, Main Sequence Fitting, RR Lyrae Distance and about a dozen or so other methods have been proposed for measuring star distances, each with their own problems and uncertainties".
 
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Today's (or fifty million year's ago's, depending on your thought processes) APOD.

Food for thought after a bottle of Pinot Noir.
 

Today's (or fifty million year's ago's, depending on your thought processes) APOD.

Food for thought after a bottle of Pinot Noir.
APOD is a must view every day. Todays picture with a type 1A supernova which appears to question the use of a 1A to determine distance as it is too bright for its alleged distance.
 

GreyArea

War Hero
"Scientists have announced tantalizing hints that the universe is actually relatively small, with a hall-of-mirrors illusion tricking us into thinking that space stretches on forever. Weeks and his colleagues, a team of astrophysicists in France, say the WMAP results suggest that the universe is not only small, but that space wraps back on itself in a bizarre way (Nature, vol. 425, p. 593). Effectively, the universe would be like a hall of mirrors, with the wraparound effect producing multiple images of everything
inside.” Spergel adds: “If we could prove that the universe was finite and small, that would be Earth-shattering. It would really change our view of the universe.” (
New Scientist Oct 11, 2003)

This is the actual article.


A 16 year old puff piece in the New Scientist does not constitute current thinking in the Astrophysics/Astronomy/Cosmology community.
 

GreyArea

War Hero
Here's something from the people who know about such things. It's a bit simple but should suffice for most of us.

 

GreyArea

War Hero
"Other methods of determining parallax include: Photometric parallaxes, which are found by estimating a star’s absolute magnitude (M) based on a spectral classification, and comparing that with its apparent magnitude (m). Statistical parallaxes could perhaps extend to 500 parsecs, but this only applies to groups of stars, not individual stars.

Overall, of the half dozen or so methods employed today to measure astral distances, none of them are indisputable (including distances measured by redshift, Cepheid variables, luminosity, color of stars, etc.). There is only one purely empirical method, parallax (and its attendant modifications such as Spectroscopic, Moving Cluster Method, and Statistical Method), but it is quite limited in its applicability, since it can accurately measure only a thousand or so stars. In effect, modern science is left without an irrefutable means to measure cosmological distances, and thus all the literature espousing that stars, galaxies or quasars are billions of light years away from Earth is an unproven scientific assertion.

Using Cepheid variables, for example, is certainly a question-begging venture, since Cepheids are too far away to be measured by parallax and, thus, depends on an unproven statistical method to measure distance.

Other methods such as Secular Parallax, Expansion Parallax, Kinematic Distance, Light Echo Distance, Baade-Wesselink Method, Expanding Photosphere Method, Main Sequence Fitting, RR Lyrae Distance and about a dozen or so other methods have been proposed for measuring star distances, each with their own problems and uncertainties".
Can I ask where you cut and pasted this from?
 

GreyArea

War Hero
For further information on the current Gaia mission measuring stellar distances within the Milky Way I refer M'learned friends to the following article in Wikipedia and from there you can link to the original sources via the hyperlinks at the bottom.
I've also provided the link to the ESA website in case you just want to have a look at the stunning pictures of the Milky Way galaxy released in the multimedia gallery


 
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A film that the scientists were interviewed for under false pretences and have said they do not agree with is not a great piece of evidence either.

Still, you're not making weird comments about jews or Israel so I suppose this is progress.
 
Good thing I read the subsequent comments after that piece of film without immediately posting, using the word 'sh*te', as that would be duplication. 'Tripe' hasn't been used yet, so I'll put it here.
 
I refer to that as "Doesn't matter". I theorise that it's all the crap that we don't need yet constantly surrounds us and gets in the way.

Awaits Nobel prize.
You mean like stuff put aside for recycling & shed animal hair?
 
I don't think I've seen that figure before. Where does it come from?
Incidentally, it would take 10 to the power of 86 peas to fill the observable universe (a tin or two on either side).
That’s a lot of theoretical peas.

Hard to find though as a common estimate of the number of molecules in the universe is only about 10^80 (^78-^82).

Just started reading a book on astrophysics by Neil deGrasse Tyson. Opens with the quote “The universe is under no obligation to make sense to you.”
 

ericferret

War Hero
My universe is 5 feet 6 inches, 140 pounds and about 65 years old.
All that planetary stuff is insignificant in comparison and of minor interest.
 

Wooden Wonder

War Hero
Given that the universe is L light years across, is T years old and has a mass M and the Big Bang occurred from a point source, where did the mass come from? And if it came through the point from somewhere else, where was ‘somewhere else’?

I can sort of understand the expansion, but I have never had/seen an explanation for the origin of the mass.
 
Given that the universe is L light years across, is T years old and has a mass M and the Big Bang occurred from a point source, where did the mass come from? And if it came through the point from somewhere else, where was ‘somewhere else’?

I can sort of understand the expansion, but I have never had/seen an explanation for the origin of the mass.
Nor are you ever likely to!

From Tyson:

“In the beginning, nearly fourteen billion years ago, all the space and all the matter and all the energy of the known universe was contained in a volume less than one-trillionth the size of the period that ends this sentence.​

Conditions were so hot, the basic forces of nature that collectively describe the universe were unified. Though still unknown how it came into existence, this sub-pinpoint-size cosmos could only expand. Rapidly. In what today we call the big bang.”​

Wondering about the where and why takes you into the realms of metaphysics, speculation, religion and philosophy.

The only way I can get my brain around the concept is that most of everything consists of nothing so it probably fitted in. And by not thinking about it.
 

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