Thursday, February 14, 2008

The Farthest Galaxy


The Rho Oph nebula, a star-forming region in our Milky Way photographed by the Spitzer Space Telescope. The oldest stars here are over 12 billion years old. Our galaxy must be extremely old. Using the Spitzer and Hubble Space Telescopes, astronomers have photographed one of the most distant galaxies ever. A1689-zD1 is about 13 billion light-years away, and must have formed when the Universe was about 700 million years old. Those numbers are approximations, for the speed of light has not always been the same.

Every galaxy ever observed contains at its centre a massive Black Hole. Galaxies have been found dating from barely half a billion years after the Big Bang. Their supermassive Black Holes are far too young to have formed from star collpase or mergers of smaller objects. They are very likely primordial, formed from quantum fluctuations shortly after the Big Bang. These tiny fluctuations grew large because of the Universe's rapid expansion. Size of a primordial Black Hole is limited by a horizon distance related to the speed of light. Supermassive primordial Black Holes are one more indication of a "c change" in physics.

Even with the evidence, it may take a while for physicists to accept the simple idea of a changing c. A physics education forces students to treat c as fixed, just like the Earth. This is a reasonable assumption to make if one's mind is small. When careers and dollars have been wagered on "dark energy," escaping the epicycles is dificult. To comprehend the wonder that is our Universe, we must accept change.

More exciting discoveries at the new Carnival of Space!

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6 Comments:

Blogger Kea said...

Heh, I was just reading about A1689-zD1 at really high redshift! So exciting.

8:29 AM  
Blogger mark said...

lovely photo too

8:35 AM  
Blogger nige said...

The outward force of a receding galaxy of mass m is F = mRH^2, which requires power P = dE/dt = Fv = m(H^3)(R^2), where E is energy. This comes from the normal Hubble recession v = HR which implies acceleration a = dv/dt = H(dR/dt) + R(dH/dt) = H(dR/dt) = Hv = RH^2.

For radius of universe R, the acceleration is just 6*10^{-10} ms^-2 or so, which (according to Smolin, TTWP, 1996) is about the same figure as the acceleration of the universe derived from Perlmutter's observations of receding supernovas in 1998. The prediction of acceleration = RH^2 = Hc = c/t where t is age of universe, based just on Hubble's law, was published in October 1996 via Electronics World.

It's weird that this is completely censored out of mainstream cosmology, when it is fact based. Nobody has even claimed that calculus doesn't apply to the Hubble law or that a recession with velocities increasing with distance is a kind of acceleration because distance is equivalent to time past, and any apparent variation of velocity with time gives rise to an apparent acceleration.

I think that the small size of the acceleration of the universe, only about 1 part in 10^10 of the acceleration due to gravity at Earth's surface, is the reason why it was ignored. It only becomes significant at the greatest distances, which is why it was only discovered in 1998.

I had tried with much energy to get the original research published somewhere appropriate, but had been brushed aside. At that time I was a part-time Open University student and tried to correspond to my physics professor there, Russell Stannard, but only received instead letters from Dr Bob Lambourne defending the status quo as then taught in the Open University's cosmology course. He had no comment to make on the prediction of cosmological acceleration.

Going back to the formula for the power needed to make a distant galaxy recede with the observed acceleration:

P = dE/dt = Fv = m(H^3)(R^2).

For a typical galaxy like the Milky Way, the mass is roughly m = 1.2*10^42 kg, the Hubble constant is about H = 2.1*10^{-18} s^{-1}, and R = c/H = 1.4*10^26 metres. It's interesting that the power in watts needed to accelerate each kilogram of the most distant masses away from us is 0.19 watts. For the 1.2*10^42 kg mass of a galaxy (ignoring relativistic mass increase), 2*10^41 watts is needed.

That's a lot of power. The simplest explanation for "dark energy" viewed this way as the cause of the acceleration is the graviton exchange radiation which causes gravity between masses which aren't relativistically receding.

For distances which are a large fraction of the effective radius of the universe (i.e. a large fraction of the horizon radius), masses are accelerating away from one another because they are exchanging gravitons with great force. The outward force of a receding piece of matter is accompanied, according to Newton's 3rd law, by a reaction force directed towards us, which from the available possibilities seems to be mediated through space by the spacetime fabric i.e. graviton radiation.

The mass of the Earth isn't accelerating away from us with any force; because its distance from us is only a trivial fraction of the radius of the universe, it's force away from us and the reaction force it sends towards us as gravitons is trivial (F = mRH^2). If the Earth is contributing in any significant way to quantum gravity interactions with us, it's only doing so by preventing some of the gravitons coming through the Earth to reach us (some of the fundamental particles in the Earth will get in the way of gravitons which will interact with them, and so there will be a reduced flux of gravitons coming from that direction).

The imbalance produced by the Earth's presence therefore causes us to get accelerated towards the Earth. The same gravitons which cause gravitational attraction by this shadowing mechanism also produce cosmological expansion by impacting on distant masses. A balloon inflates because of air molecules hitting each other and causing the gas to expand. The action of gravitons being exchanged between masses in the universe is similar.

It's conceivable that the mainstream Lambda-CDM model is an approximation if the role of the cosmological constant is that of gravitons on large scales, causing masses to accelerate away from one another due to the forceful exchange of gravitons. I.e., "dark energy" is the energy of the gravitational field, gravitons.

11:22 AM  
Blogger Parvulus said...

Hi, Louise. I've just posted the final version of my cosmological model (I renamed the previous to "beta".) In case you haven't bookmarked,

physicsdilettante.blogspot.com

Now it has complete consistency, including quantum theory. To make it close, I had to make a crucial assumption: that the movement of radial expansion of matter (my model proudly has a center) is not included in the law of conservation of energy. Anyway, the standard model based on general relativity does not even care about conservation of energy.

The equation that I reached in the final version is exactly yours.

You have the merit of having sparked this Big Bang in my mind.

4:22 PM  
Blogger L. Riofrio said...

It is a pleasure hearing from all of you as loyal followers of the blogs. Happy Galileo's birthday!

5:46 PM  
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5:30 AM  

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