Size Of The Universe

[Turtle]

Hi Turtle,

 

I suppose I didn't go into enough detail in my earlier post.

 

Beryllium is used to dope lenses and the Gunter Nimtz experiments prisms were heavily doped. As Beryllium, according to the BB theory, was produced after initial Hydrogen, Helium and Lithium production at a relatively fixed period after the BB could not the structure of these short lived clouds, when light waves passing through them were collected over large distances, actually behave like doped lensing structures? i.e. in both the micro and the macro.

 

The most distant galaxies that have been imaged are irregular and not oval or circular in shape so there is potential for optical vortex/laser structures.

 

http://en.wikipedia..../Optical_vortex

http://wwwrsphysse.a...esearch/vortex/

 

i don't know. :shrug: however the fact that "they" are imaging distant galaxies tells me "they" know what they are doing. :smart:

[CraigD]

This idea that the Universe is "expanding". Where does it come from? Isn't it only from prisms[?]

Prisms show a "redshift" in the light from a galaxy. Which apparently means the galaxy is moving further away.

No, evidence for an expanding visible universe doesn’t come only from prisms.

 

Let’s introduce some key concepts and practical examples:

 

Redshift and blueshift are the two kinds of EM radiation (which includes visible and invisible light, including radio) frequency spectrum shift. They indicate merely that light known to have had a specific frequency (or inversely, wavelength) at their source have a different one at their receiver. We now know that this can have several different causes. The most common, and longest known (for about 170 years), is due to the source moving toward or away from the receiver. This kind is called Doppler shift.

 

What an astronomer does when they want to measure whether a star is moving toward or away from an instrument – its radial motion – is measure its light’s frequency spectrum. Starlight consists of a mixture of different frequency light. A frequency spectrum shows its intensity at various frequencies.

 

An instrument that separates light into its different component frequencies and measures them is called a spectrograph. They can be made using any optical device that refracts of diffracts (bends) light, because the angle by which light of different frequency bends is different, and precisely describable. The first spectrometer, made by Isaac Newton around 1700, used a glass prism, but other methods are possible, and nowadays, more common. A single thin slit in an opaque material works, as do diffraction gratings consisting of many opaque and transparent lines. Most present day, professional-grade spectrographs use high-precision diffraction gratings and more-or-less the same light recording components found in high-quality digital cameras, though the most extreme astronomy uses specialized, super-sensitive components.

 

The key point here is that light frequency spectrum shift is a real thing. Various kinds of devices can be made and used to measure it, but it exists whether it’s measured or not. In principle, a person with a really good eye for color might be able to have a rough sense of it by comparing similar stars with different motion, of optical photographs of stars at different times, but I’ve never met such a person – we humans tend to have a poor, subjective awareness of fine differences in color.

 

Back to how an astronomer measures the radial motion of a star: Once they have a graph of its frequency spectrum, they look for characteristic sharp “line” – high and low intensities at narrow frequency ranges – that are known to be produces by specific elements and compounds in stars. They find that the entire spectrum must be “shifted” some fixed ratio by multiplying each frequency by a single value, customarily called a z factor (technically [imath]z = \frac{f_{emitted}}{f_{observed}} -1[/imath]). Simply multiplying this z factor by the speed of light gives, when the velocity is small, a good approximation of the radial velocity of the star (an exact formula for any velocity is known, and not much more complicated).

 

This technique can be used on not just on individual, nearby stars, but distant and large collections of distant one, such as whole or parts of other galaxies. When this was done systematically, beginning in the 1920s, the scientific world got a big, shocking surprise.

 

To appreciate the feel of this scientific shock, you have to know some astronomy history many folk don’t, and which at least I found shocking when I first read it:

Prior to the 1920s, few astronomers believed there were any galaxies other than our own Milky Way, or that the universe consisted of more than our Milky Way galaxy, or was more than about 100,000 light years in radius. That there were lots of objects in the sky that didn’t seem to be stars, planets, or comets bad been known for over a century – by 1775 Charles Messier had published a catalog of nearly 50 of them, primarily so that comet hunters wouldn’t waste time thinking they were comets – but it wasn’t ‘til about 1917 that serious speculation that these objects might be distant galaxies began making the rounds among astronomers. By 1930, largely due a several “super telescopes” of that era and folk like Edwin Hubble, nearly all astronomers agreed that the Milky Way is just one of a great many galaxies in the visible universe, and that the universe appeared – though perhaps erroneously, due to some misapplication of known physics – to be expanding.

 

By 1930, astronomers agreed that the visible universe was at least several 1,000,000 light years in radius. Many proposed it was effectively infinite. Many, including Hubble, tried to find models in which it wasn’t expanding, and thus hadn’t had any sort of “big bang” scenario in its recent past. These arguments have been going on for about the past 80 years, leading to the present day consensus that the universe started in a Big Bang about 13,700,000,000 years ago, and we can see light from objects that are about 46,000,000,000 light years distant.

 

Those last quantities deserve careful scrutiny. By best current theory, the universe we see is over 3 time larger than can be explained by the matter in it having moved apart in a normal manner. This is where the theory of a different kind of expansion, the expansion of space itself, comes from.

 

Researching the above, I found this expert article on the history of scientific understanding of the astronomical universe a good one.