Originally Posted by Metryq
That's an assumption that lead to Dark Matter—matter that is completely undetectable, except by its gravitational effect on galaxy structure. And then it doesn't create any lensing effects. (Can you say "ad hoc"? More like ad hoc ptui.)
I realize plasma cosmology is on very tenuous ground, also, but no worse than the theory that gravity drives the entire universe.
Do these Hubble results say whether or not the Magellanic Clouds will be involved? 'Cause I might want to move to my vacation house there until this collision thing is over with.
Not a great believer of Dark matter - currently I think it's a fudge to preserve Einstein's equations. Of course it may be true and there are vast numbers of exotic particles floating about around us not interacting very much, but my current belief would be that general relativity is wrong in some fundamental manner - (no idea what it is of course, so I'm not much help, but if I were to put a bet on it, I'd say it's something to do with black holes and singularities...)
However I'm reasonably confident that bodies with mass are attracted to each other in this universe one way or another; beliefs gained through personal experience and experimental data. And I don't need dark matter to predict that some galaxies being in close proximity to others will, if the conditions are right, move towards each other.
Of course given current experimental data, gravity really doesn't have a say in this universe, given that it appears that the rate of expansion appears to be increasing. Which gives rise to my next bugbear, the great fudge of 'Dark Energy'. Again the assumption is that General relativity can't be wrong!
BTW, what's 'plasma cosmology'? Genuinely interested* Also what does "ad hoc ptui" mean. The Scottish state school education system did not touch upon the classical languages,at least when I was going through it
* note: I'm not a complete believer of the current scientific orthodoxy, and in some cases reject it - so please don't think I'm deliberately 'toeing the party line' or deliberately opposing your remarks. I studied Physics to PhD level - although as you can probably see from my verbose, long and no doubt dull reply on the Kepler
thread, bog standard QM was my speciality.