Age of Universe vs Furthest Object
Discussion
pointedstarman said:
and it does set me thinking about how much we really know and how much we just make up to fit what we see.
well we have the scientific method- ie you form a hyporthesis (and a null-hypothesis) you take lots of measurements and find out if there is any validity to your hypothesis based on you see. Problem is that for a LOT of advanced physics very very few people can really actually grasp just what the hell is going on- i know i can't, and so i have to use an analogy to get even tye simplest idea of what the hell is going on out there.
One crucial step in much advanced physics is to abandon the desire to be able to "visualise" what's going on, or for it to follow some rules of "common sense".
A couple of examples:
Space-time is defined in 4-dimensions (3 spatial and 1 time) which makes it impossible to visualise but doesn't mean the theories don't work (see footnote).
Quantum physics states that a quantum particle (an electron for example) explores every possible path between two points, rather than following a particular route - as shown by electron-interference patterns (footnote again).
Bear in mind that when something is observed that doesn't fit the current best-fit theory there might be many ways of explaining that behaviour. However, any explanation of the new observation also has to explain the pre-existing behaviour that was described by the original theory. Often it is a case of the new theory being a generalisation of the existing theory with extra terms that only become significant in extreme cases.
A couple of examples:
Space-time is defined in 4-dimensions (3 spatial and 1 time) which makes it impossible to visualise but doesn't mean the theories don't work (see footnote).
Quantum physics states that a quantum particle (an electron for example) explores every possible path between two points, rather than following a particular route - as shown by electron-interference patterns (footnote again).
Bear in mind that when something is observed that doesn't fit the current best-fit theory there might be many ways of explaining that behaviour. However, any explanation of the new observation also has to explain the pre-existing behaviour that was described by the original theory. Often it is a case of the new theory being a generalisation of the existing theory with extra terms that only become significant in extreme cases.
A theory "working" means that it can be used to make predictions and these predictions are confirmed by experiment. It doesn't mean that it can easily be explained by a journalist in an article.
ewenm said:
One crucial step in much advanced physics is to abandon the desire to be able to "visualise" what's going on, or for it to follow some rules of "common sense".
Absolutely - the rubber sheet visualisation for the effect of gravity on space is useful to a point but I certainly can't visualise what this "looks like" in 3d because that's just not possible... it doesn't "look" like anything!It's simply using something we can easily understand to demonstrate something we can't. The dimension of up/down stands in for a phenomenon, gravity, that works in 3D all on its own. Shed a dimension and then we can start to understand it.
We are simple creatures designed to cope in 3D, and our brains only to receive and interpret 3D signals. Anything else is, you could say literally, beyond our comprehension. The fact we can't visualise it in our simple cave-dwelling minds, does not mean that it cannot exist.
We are simple creatures designed to cope in 3D, and our brains only to receive and interpret 3D signals. Anything else is, you could say literally, beyond our comprehension. The fact we can't visualise it in our simple cave-dwelling minds, does not mean that it cannot exist.
carmonk said:
I wasn't referring to your post, rather the process that results in these kind of threads.
1) I saw something on TV
2) I didn't understand it
3) Therefore these so-called scientists are just making stuff up
Wrong actually. Have some education and an interest in astronomy. Regularly in the garden with my Celestron NGT looking at stuff and using my imagination - bit of a prerequisite otherwise you're largely looking at dots and smudges.1) I saw something on TV
2) I didn't understand it
3) Therefore these so-called scientists are just making stuff up
Never figured out the age v distance thing though have heard about effects of 'stretched' space time as I'm able to use the web. I just figure there's one or two PHers who may be able to make things a bit clearer.
A little ignorance or a lack of a Phd in physics (though the OH has a BSc in physics and doesn't understand it which makes me feel better) nevertheless allows one to exercise a little scepticism.
Edited by pointedstarman on Wednesday 14th March 18:24
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