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Mark_Wallace wrote: The ridiculous fame-grabbing explanation that was chosen is the wrong one.
I don't think many people would deny that it could be the wrong one...
Mark_Wallace wrote: How is it that they can tell us about the entire construction of stellar systems and the universe, and all the dynamics of supernovae, just by looking at microscopically tiny blobs of light (or radio data),
Well (as I'm sure you know) what actually happens is someone formulates a theory and observations support it or otherwise.
Mark_Wallace wrote: We've discovered 500 stars with planets by looking at tiny wibbles in 10-pixel-groupings in two photos taken a week apart! ... What?
For Example, the regular dimming of a star's light together with evidence of a perceived 'wobble' (detected by changing dopler shift) could be caused by something other than a planet orbiting - but these are real, repeatable measurements and the theory fits.
Similarly with supernovae - there's a theory, the maths holds together and observations support the theory. sure, they could be caused by aliens' wars, time travelling weebles or bad spaceship drivers - but there's little reason to discount the theory until either a better theory comes along, or observations show the theory to be wrong.
PooperPig - Coming Soon
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_Maxxx_ wrote: Well (as I'm sure you know) what actually happens is someone formulates a theory and observations support it or otherwise.
Indeed, but what troubles me is that the observations are of such tiny amounts of light/radio waves, that have traveled God knows how far and through God knows what (e.g. if it travels through a tiny patch of blue dust, in the billions of miles between here and its source, it becomes more yellow), so grand assumptions simply cannot be made.
But grand observations are made, nonetheless, and compounded with further grand assumptions, then backed up with numbers that are tailored to fit, until we have a model of the universe that makes very little sense, and is constantly being challenged by observations that are "more accurate" because they are backed up by three photons more than the previous observations.
And nowhere along the way does anyone admit that it's all guesswork -- they call it "great, new discoveries", rather than admit it's all guesses.
We need more data, not more guesses. Guessing is easy, but getting it right requires more than 2000 photons per month.
_Maxxx_ wrote: For Example, the regular dimming of a star's light together with evidence of a perceived 'wobble' (detected by changing dopler shift) could be caused by something other than a planet orbiting - but these are real, repeatable measurements and the theory fits.
But so would a thousand simpler theories -- i.e. plain ol' boring dust or temperature gradients could far more easily be proven to be the cause of wibbles.
But that wouldn't make people famous or get them big research grants, would it?
And when a few more quanta of the EMS arrive, which should easily prove that something else is the case, they'll just "massage" their Grand Unprovable Theories to make them fit the new data.
I wanna be a eunuchs developer! Pass me a bread knife!
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Quote: tiny amounts of light
The Hubble Ultra-Deep Field Image, a study of galaxies as old as 13.5 billion years at distances up to 60,000 light years was a composite of 288 exposures of approximately 20 minutes. Many degrees of magnitude more than 2000 photons collected in considerably less than a month I would suggest!
I am not a number. I am a ... no, wait!
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But that's not what we're talking about.
We're talking about the (was it five or six?) novae at Extreme ranges that were used to cobble together the ridiculous "dark energy" theory.
60,000 light years is just down the road.
I wanna be a eunuchs developer! Pass me a bread knife!
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Afzaal Ahmad Zeeshan wrote: Physics, needs abnormal people, who are able to imagine the world in an unusual way.
I have to disagree with that.
IMO, Physics needs people who can see the bleeding obvious without getting bogged down by ideas that sort-of work but don't.
I wanna be a eunuchs developer! Pass me a bread knife!
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It doesn't matter what 'shape' space/time takes in the slightest. The flat rubber sheet is, after all, a huge abstraction for the purposes of demonstrating the displacement theory of gravity. What 'dark energy' is supposed to explain is not expansion per se but the perceived acceleration of that expansion against all logic if you accept the standard cosmological model. Personally I can't help thinking that if you have to start making up stuff to fill in the gaps in your model than it's probably time to bin the model but then my living doesn't come from grants for research in theoretical physics!
I did wonder to myself the other day if the explanation could simply be that as inflation increases, and the distance between masses increases along with it, gravitational drag is reduced, ie. the brakes are taken off, but then I figured if I'd thought of that there's probably a couple of thousand papers out there telling me why it's rubbish. Sometimes it's easier to sleep at night just knowing what you don't know.
I am not a number. I am a ... no, wait!
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Yes, but it's all based on "observations" of a handful of supernovae seeming to cool faster than expected, and an assumption based on that that they're moving further away quicker than was previously assumed.
Me, I reckon that since we don't know precisely the dynamics of supernovae, something else is happening either to make them cool faster than anticipated, or to block/absorb some of the heat, again making them appear to cool faster than anticipated.
Something like an expanding cloud of dust that's recently been fused into higher-order atoms and molecules would likely have that kind of effect -- but what are the chances of something like that conveniently surrounding a supernova, eh?
Nah, it's much more likely that some idiot needed to publish something radical quickly, or lose his research grant there's some mysterious "dark" thingummy that's at back of it all.
I wanna be a eunuchs developer! Pass me a bread knife!
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When peer reviewed papers are, erm, peer reviewed that's exactly the sort of question that gets asked.
And just to be picky, they're not 'moving away more quickly' they, and everything else, is expanding so, while the novae are getting further away, they are also getting larger.
the analogy of the 'raisins in dough' so often used is only legitimate if raisins also expand in the oven.
PooperPig - Coming Soon
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Maxxx wrote: if raisins also expand in the oven
Which of course they do, absorbing moisture from the mix.
I am not a number. I am a ... no, wait!
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Weeeellllll that depends on how dry they are, how moist the dough and how long you cook for, and what is the cosmological constant...
PooperPig - Coming Soon
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_Maxxx_ wrote: they, and everything else, is expanding so, while the novae are getting further away, they are also getting larger.
I think you might have misunderstood something you read, there.
Nothing's getting bigger (well, novae get bigger because they're explosions), it's all just moving apart. It's the universe that's expanding, not the suns, planets, and teaspoons.
I wanna be a eunuchs developer! Pass me a bread knife!
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you're right. I was wrong!
damn - I'm as confused as when I found that the Hubble constant isn't!
PooperPig - Coming Soon
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Not your fault.
There's so much written on the topic using such poorly crafted language that it's not surprising that people get wrong ideas.
I wanna be a eunuchs developer! Pass me a bread knife!
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Some sorta "dark energy" is driving some posters here.
... such stuff as dreams are made on
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It seems that when these ideas are presented above, it is assumed that the ball(s) are attracted by a force below the rubber surface. I might say that it is in the center of that expanding rubber "balloon". Now here is an interesting clue. It has been discovered that not just the universe is expanding, the expansion is accelerating. The balls or mass-objects are not attracted to anything, it is the moving rubber surface that is accelerating toward the mass-objects(balls). If the expansion of the universe was just at a constant rate, there would be no gravity. It all runs on dark energy. It's just a thought. No, I didn't do the math.
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ronDW wrote: it is assumed that the ball(s) are attracted by a force below the rubber surface
Nah, it's just an analogy that, although it uses three dimensions to demonstrate the movement of smaller objects, only demonstrates the effect in two-dimensions.
ronDW wrote: It has been discovered that not just the universe is expanding, the expansion is accelerating
It really hasn't been "discovered"; it's been huge-leap-of-silly-supposition assumed, based on virtually zero data.
ronDW wrote: If the expansion of the universe was just at a constant rate, there would be no gravity
This is true. Coulomb's Law (known only as the Inverse-square law, in the US, because Coulomb wasn't American) wouldn't have it otherwise.
ronDW wrote: I didn't do the math
Nor did I, but Physics isn't about Maths; it just uses it to confirm observations.
And these guys didn't do the Maths, either. They used statistical analysis -- and real mathematicians don't like statistical analyses.
I wanna be a eunuchs developer! Pass me a bread knife!
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Maxxx wrote: we represent 'spacetime' as a flat sheet (usually black rubber with white grid lines)
That's just a projection onto a 2D surface so that the uneducated masses can go "oooh, I understand Einstein now" when they visit the science center.
In reality, it is the three dimensional space we live in that is curved. It looks straight because there's so little curvature created by the planets or even the sun. But it'll look a lot different near a black hole!
Marc
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OriginalGriff wrote: Or even a long way away from a galaxy!
Exactly!
Marc
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Marc Clifton wrote: That's just a projection onto a 2D surface so that the uneducated masses can go "oooh, I understand Einstein now" when they visit the science center.
Very true - but a convenient demonstration nonetheless.
Marc Clifton wrote: But it'll look a lot different near a black hole!
True - but in the sheet analogy the black hole is a vertical-sided well - so the demonstration model holds up quite well.
ripple the sheet and you get gravitational waves
stretch it - expansion of the universe (though have to stretch your balls too - which some may find a less than pleasant experience :grin
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You can create any concept you want: a big sphere or a chicken shaped multiverse. It is just a concept like space time.
Physics is not the science that was a thousand years ago. Instead of analyzing the real world, physicists try to "blow our mind" with some superstition theories about space-time. As a programmer, I do not believe them. Variable is not the same as an actual object, it is just a placeholder for a concept related to an actual object, so we can work with it.
tl,dr; Too much modern physics is just based on misunderstanding mathematical concepts and representing it as something great.
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Plamen Dragiyski wrote: It is just a concept like space time.
Well, I'd like to see the mathematics to support a chicken-shaped multiverse!
Plamen Dragiyski wrote: physicists try to "blow our mind" with some superstition theories about space-time.
Seriously?
Plamen Dragiyski wrote: As a programmer, I do not believe them.
What? That's like saying "As a programmer I don't believe in God" the two things are unrelated!
so are you seriously saying you don't believe in spacetime? Do you not believe that the rate of passage of time varies by the observer?
this effect is real, and measurable, and used IRL !
PooperPig - Coming Soon
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Maxxx:
Your extension of the "rubber sheet" metaphor is an valid way of visualizing the action of the cosmological constant. So I think that you're providing a useful analogy to explain its action, rather than suggesting an alternative.
My own position regarding dark energy is rather more revolutionary, and motivated by a far simpler proposition. Dark Energy cannot be moving at all speeds in all directions. Since it interacts with regular matter, it therefore establishes a preferred reference frame. Einstein's theories of special and general relativity go out the window.
So I think that physics has gone on a long detour since 1860, when the Michelson-Morley experiment was done. This was an experiment that sought for evidence of the "aluminiferous ether" - the medium in which light waves traveled - by measuring the change in the velocity of light as the earth circled the sun. It did not detect any change, and so physicists adopted the view that space was empty. But there's another explanation: the speed of sound does not vary as the earth circles the sun, because the air is entrained with the motion of the earth. Dark Energy must be entrained with matter and carried along with it as it moves. This allows a whole lot of interesting possibilities for explanation of general relativistic effects.
Brian
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If you want to learn more about Dark Matter and Dark Energy, read the book "Dark Side of the Universe" by Iain Nicolson. It's pretty technical and filled with charts and graphs but nothing the people in this forum couldn't comprehend. It's also a little dated - astronomy/cosmology have progressed as fast as computer hardware and software in the past 20 or 30 years (largely because of advances in computer hardware and software).
There are mountains of data that support the current theories of General Relativity, Dark Matter, Dark Energy and the existence of planets around other stars. Those theories have evolved as more data is gathered.
The community of astronomers and cosmologists is as dedicated, hard-working and objective as the community of coders/developers. No more and no less. Conspiracy theories about astronomy have about as much validity as conspiracy theories about the latest version of C++.
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