Would magn. pole reversal actually mess up electronic equipment?

I listen to the expanding Universe people but can't figure out how we are going to bang into Andromeda.

I have a theory of gravity. Its not being pulled but being pushed by black energy .

greg

I think of it as a big cheese ball, and a black hole places matter "outside" the bubble.

After all, where does all that matter go that they swallow up?

Once enough of it ends up outside the bubble, it will collapse the bubble, in a time frame quick enough that we may not see it coming.

"Entropy is a myth." I used to say that a lot.

No - they still have differing orbital periods, even though they move at about the same velocity, because those further out have further to travel to make one orbit.

Sylvia.

Which means that you obviously did NOT read the page.

What a dope you are.

The graph appears to be correct, and is consistent with the page on the Milky Way.

The text is wrong in describing the graph as showing that the the velocity is a constant function of radius, since the graph clearly shows that the velocity is simply a constant. I have made the required correction.

Sylvia.

I think you have the roles of reality and theory reversed. The universe behaves in some way. It is not constrained by theory. The role of theory is to model the behaviour of the universe. On reasonably local scales, theories involving force, mass and acceleration provide accurate predictions of the behaviour of matter. But that's as far as it goes. If the large scale Universe is found to be behaving in a way that is inconsistent with the theory, then the theory has to be modified. You can't argue that the Universe must take some form because the present theoretical model requires it.

Sylvia.

Big Bang was a derogatory term invented by the Steady State Cosmologist Fred Hoyle to disparage the new theory where the universe had a point in time where its entire radius was miniscule.

Although it is possible that universes look big and long lived when you are inside them they could just be quantum fluctuations in some other larger object. It isn't a scientific theory unless you can test the hyposthesis. Some multiverse proposals do make testable predictions.

The distances are far greater than that. Exponential inflation has made a very large universe, we can only hope to see a fraction of it, and to a very good approximation it looks similar in all directions. And amazingly smooth at the furthest extremes in the CMB wavelengths.

Not quite. Open universes expand forever and matter still has a finite velocity at infinity, and closed or bound ones it reaches zero and moves in again at some period - cyclic if you allow it to rebound.

Or some force to be repelling it which is how the field equations represent dark energy (not a term I like).

If the universe outside our visible horizon is as uniform and smooth as it looks from the microwave background then it is difficult to see how this would work. It might explain our peculiar velocity relative to the CMB if there was something massive accelerating us in the very early universe but is presently beyond beyond our observable horizon.

NB Cosmological expansion of space itself at large distances is not limited by the SR restriction of being less than c. This means there are or could be parts of our universe moving away so fast that they can never be reached even at the speed of light.

You cannot have uniform shells of external matter accelerating things towards them Gauss's Theorem prohibits that entirely.

It is called gravity. Our local cluster is gravitationally bound. It is no more surprising than finding the solar system with the odd comet hitting Jupiter. The heavyweights mop up the smaller stragglers and if you wait long enough either settle into a nice mutual orbit or collide. Galaxy collisions are fairly rare but very pretty.

Like atoms galaxies are mostly open space so they pass through each other but drag stars and gas into complex patterns.

You seem to be using the word "wall" in a non-standard way. Observations of galaxy distributions have put some pretty tight constraints on what is possible.

The string theorists might just be right - the distribution is suggestive - although it can also be simulated with conventional theory

- Durham University have a super computer doing exactly this. Some of the more interesting simulations are online at:

Regards, Martin Brown

They travel a LOT faster. D'oh.

Jeez, any 13 year old watching natgeo can remember that episode.

I was wondering why most things rotate inline bunched up, around the axis in the same direction. What starts this process ?

greg

What?

If you mean the rotation of galaxies, it's the compression of a ball of gas with a small amount of initial angular momentum. Size goes down, speed goes up, L stays constant.

The extreme case is a black hole, which can rotate very fast indeed (think inertial frame dragging).

Tim

Not necessarily. When we run across anomalies between predicted and observed, the choice usually comes down to "our understanding of gravity is incomplete" or "there's something else out there."

Observations of perturbations in the orbit of Mercury, for example, pretty much had the smart money betting on the "something else" theory (Vulcan) but the right answer turned out to be "incomplete understanding of gravity" (GR).

Some discussion (and a pretty picture) over at

although there's still quite a lot of room for legitimate "Yes, but ..." refutations.

The problem with a better idea is that it is necessarily limited.

There's a big army of people working out justifications and explanations and just-so stories that fit the current accepted theory. If you are one person you cannot hope to read all of that, much less respond to it. But if you create an alternative theory, all by yourself, then all takes is say five people trying to poke holes in your ideas and you probably can't keep up with them. Five of them can ask questions faster than you can answer them, and if you try to show that the current theory does not solve those questions they can repeat the standard assertions without necessarily understanding them, and you cannot possibly discuss the issues in enough depth with them to resolve the issues.

Being a single person who proposes an alternative is a little bit like being a single person who wants to defeat the Fifth Panzer Group. As Gisli pointed out, "Nothing prevails against numbers.". But the time you might have a chance is when the consensus is that the current explanation cannot explain the facts.

Still, you have an interesting question. If the shifted light indicates that the known universe is accelerating away in all directions, so the velocity is larger the greater the distance, how can that be explained?

One possible explanation is that the universe is not accelerating in all directions but that for some reason light gets slowly red-shifted as it travels. Or perhaps atoms used to emit light that was red-shifted compared to the light they emit now.

I see no obvious way to test these ideas. You can't keep light bouncing in a physics lab for a few thousand years to see if it gets red-shifted. The next best thing would be to see how well they fit together with other things to provide a seamless whole. If it all fits together in an elegant simple pattern then people will think that it's so beautiful it has to be true. But how could one person or a few people fit one of these ideas into the framework of modern physics, a structure so complicated that no single person can begin to understand it all?

How could anyone possibly tell whether something is a better idea, until it became the standard model that most physicists agree on?

the same direction.

Huge gasses and huge masses getting slammed outward at near the speed of light (beginning of 'time and space and matter')... as gravity begins to make them clump and glom together on their way outward, they swing past each other and set up "spins".

Make some fresh tea after heating the water up 'real good' in the microwave so it makes a nice foam and then stir it, and then perturb the flow such that it still spins but not quite perfect, then observe the bubbles.

It is all in the tea... life imitates life.

Chaos rules as far as the universe goes. Weather simulators do a fine job with it, and that link the guy posted this morning has some REALLY COOL videos on it.

The non-capitalized, and Capitalized version here tells it all.

That it is, in a nutshell. :-P A BIG nutshell

I agree with you... there is another 'somewhere' 'out there'.

In other words, we are dragging something along with us, OR IT is dragging us along with it.

De Mattre De Durkness. (not from any given language, consider it to have come from Blade Runner) :-)