AIBU to question the popular belief that there are more stars in the sky than grains of sand on earth?

[Tryingtryingandtrying]

How can this possibly be true? Tbh I'd question if there were more stars than grains of sand on my local beach? I've read a bit around it and still is impossible for me to comprehend. Any other facts or theories that just don't make sense to you?

I find the infinite part v expanding difficult

Is the universe still expanding? How is it infinite

Oh and into what but obvs no one will know that one

@AStudyinPink

If they don't make sense ... well that's your sense that is fucked, not the universe.

That’s not only impolite, it’s silly. I don’t think either is ‘fucked’. I think, like any sensible person, I only have a responsibility to believe what has been clearly explained.

(I read a lot of AIBU which can be ... robust ...)_

So if you can't understand it, it isn't real. It isn't true ?

No one has ever successfully explained Boris Johnson to me. Yet still he moves.

->

@AStudyinPink

The idea that the Universe needs your belief to exist is an interesting philosophical idea.

Interesting. Who said that?

I did. Just now.

So if you can't understand it, it isn't real. It isn't true ?

For a scientist, you are struggling here. I have not said what I do not understand isn’t true. I have said I will not accept something to be true until I understand what it is supposed to mean. Which is, I hope, the position of any rational person.

I did. Just now

Apropos of nothing, because I didn’t.

[quote TheReluctantPhoenix]@BobbinThreadbare123

It is called cerenkov radiation when electrons break the ‘light barrier’ in a medium. It shows as a ghostly blue glow in nuclear reactors.[/quote]
Thanks, Phoenix. At the risk of sounding like a know-it-all, I work as a nuclear phycisist and I've got a degree and a PhD in it. Cerenkov radiation is very pretty though!

There are infinitely more stars in space than there are grains of sand on earth - infinity starts getting a bit weird when you start trying to do sums with it...!

Space also gets very odd when you start trying to reckon it's size in terms that make sense :-)

We visited a dark skies night in Keilder Forest a couple of years ago (those were the days, eh?) one of the many wonderful things we saw through a simple reflecting telescope that just blew my mind was Andromeda. It looked like a small fuzzy ball. But it's the nearest major galaxy to us here in the Milky Way. It's a bit bigger, and is about 2.5m light years away give or take. Makes you realise how tiny we are.

With this argument going on, I thought I would bring the Wisdom of Carl to the forum:

@MarshaBradyo

I find the infinite part v expanding difficult

Is the universe still expanding? How is it infinite

Oh and into what but obvs no one will know that one

Infinity is expanding is how I try and see it.

And what it's expanding into isn't conceived until the universe has expensed into it. Is how I try and think of that

It should be possible to describe what you are thinking about in human language.

Mathematics IS a 'human language'. It may or may not be one you're capable of learning, but it is a perfectly valid form of human communication. It's often a lot clearer than words, which differ between different nations.

I write a lot of code - a lot of my thinking when I'm doing it really isn't verbal at all. The output may be visual or numeric and conveys clear meaning.

Mathematics IS a 'human language'. It may or may not be one you're capable of learning, but it is a perfectly valid form of human communication. It's often a lot clearer than words, which differ between different nations.

And yet still, if you are using it to describe physical properties of physical realities, it is meaningless unless you know what you are describing. And if you know, and you want others to believe it, you’ll have to find a way to explain it in physical terms: what does ‘infinite’ mean? What does ‘expanding’ mean?

And obviously you don’t have to do that (nobody has to do anything) but I don’t have to believe it either.

I write a lot of code - a lot of my thinking when I'm doing it really isn't verbal at all. The output may be visual or numeric and conveys clear meaning.

But it IS communicable in English. You are doing something to something to make it do something else. If someone said to you, “What are you doing?” you would be able to tell them.

This is different. This is “I can only communicate this to you in a way that doesn’t make sense, but I expect you to believe it anyway.”

The flaw is either in the science, or in the communication of the science. It’s not in the minds of those who ask for an explanation that makes basic sense.

Anyway, I’m going to leave it there because it’s a de-railing of the actual thread.

And yet still, if you are using it to describe physical properties of physical realities, it is meaningless unless you know what you are describing

Is that not the same for any language?

But it IS communicable in English. You are doing something to something to make it do something else. If someone said to you, “What are you doing?” you would be able to tell them.

It probably wouldn't be comprehensible to someone who wasn't familiar with that area, other than at the same descriptive type of level you don't 'believe'. 🤷‍♀️

unmarkedbythat

Well, sure, but when a reality is shared across languages, it should be translatable. And that is the case here, since these are concepts that exist in English: space, matter, infinity, expanding etc.

It doesn’t make sense to say, “Space (which means the same as nothing) is both infinite and expanding into more nothing”. If the words aren’t adequate to the descriptive task, make new ones; don’t just make a word salad and then suggest the problem is with everyone else!

It probably wouldn't be comprehensible to someone who wasn't familiar with that area, other than at the same descriptive type of level you don't 'believe'. 🤷‍♀️

Of course it would. The purpose of writing the code would be communicable in English.

But anyway, I’m out. Clearly there are some very credulous people here!

@AStudyInPink - Unless Maths is describing something real, that can be articulated to an intelligent human, I’m not sure about it.

Of course it can be articulated to an intelligent human. How do you think I learned it? The problem is that mathematical models are far more than words. They tell you about the relationships between measurable quantities, and that is something that you simply cannot express precisely in words. The best that can be done is vague statements like "space is expanding", but without really explaining what we mean by "space", "expanding", or how you could tell or differentiate it from other models.

So why should you believe modern cosmological models? Basically because they make detailed predictions about what you will see if you point a telescope (and assorted other bits of kit) at the sky, and they haven't been wrong yet. However you explain it, Friedman's equations (published in 1922) predict that spectra of distant galaxies will show a redshift growing with distance. Redshifts like that were confirmed by Hubble (the man after whom the telescope is named) in 1929. Coupled with a bit more physics they predict that the sky should glow very faintly (what is now known as the Cosmic Microwave Background), which was confirmed (accidentally) by a couple of Marconi engineers, Penzias and Wilson.

There were alternative hypotheses put forward to explain these observations. The only one I'm familiar with is the "tired light" hypothesis, which said that light loses energy (becoming more red) as it travels. All specific proposals for that end up introducing some other effect (such as blurring of distant objects) that isn't seen.

Furthermore, Friedmann's equations are a specific form of the Einstein Field Equations. Those are thoroughly tested in other arenas (the behaviour of satellite clocks in the GPS is probably the most famous ongoing test, but there are many more) and have yet to make an incorrect prediction.

There are definitiely limitations to the model. If you "run it backwards" to look at how the universe started you get a singularity. We're still trying to work out what to do about that. The problem is actually that all our experiments match the model too well - we can't really get a handle on what's wrong with it if it keeps looking right!

I didn’t say I don’t believe ‘modern cosmological models’, SpeverendRooner. I said I don’t believe things that appear to make no sense until they are explained in a way that does make sense. And I understand (basically) that the observations made suggest that the space between galaxies is expanding. I don’t disbelieve that, although I maintain that it could be flawed (lots of things are). What I question is what has been suggested here: that the universe (and, by extension, the ‘space’ that makes up the universe) is both expanding and infinite. That’s not the same, and doesn’t make sense to me when I apply the basic meanings of those words.

Of course, if those words are being used incorrectly in that explanation and something else is meant, that’s fine. When someone can explain it in a way that makes sense to me, and use more accurate words, I’ll believe it. I can’t do otherwise.

The purpose of writing the code would be communicable in English.

Yes, to people in my team etc. No reason at all why it would need to be communicable to someone ignorant of the domain. And some parts of the 'English' description might often still be equations or diagrams.

We used to have a problem with tech writers wanting to include detailed explanations of concepts they didn't understand, but which the target audience of users would already be familiar with. A user manual doesn't need to cover the contents of a 3rd year undergrad degree.

Yes, to people in my team etc. No reason at all why it would need to be communicable to someone ignorant of the domain.

‘Need to be’ isn’t the issue. The point is simple: it could be communicated, in English, accurately. And if you can’t do that, don’t expect others to have confidence in it.

The argument ‘But you don’t need to know so I won’t bother to translate properly...’ is incompatible with any form of Science with any form of integrity whatsoever, as is the idea (simultaneously expressed here) that I don’t need to know it but should be content to believe it.

it could be communicated, in English, accurately.

Up to a point (honestly trying to do some of it in words would be ludicrous), but you might need to do a degree or two first to understand all the words.
It's weird to assume everything can be fully explained in layman's terms, except at a very high level.

Most of us don't really understand the mechanisms of life saving drugs, or what goes on inside your computer or tablet, or the engine of your car nowadays or even your washing machine, or your satnav. Would you mistrust your satnav just because you might not adequately understand relativity?

I know the conversation has moved on a bit but anyone who would like to be in awe of incredibly large numbers and different types of infinity should watch this:

It'll give a bit of perspective on the grains of sand thing.

Most of us don't really understand the mechanisms of life saving drugs, or what goes on inside your computer or tablet, or the engine of your car nowadays or even your washing machine, or your satnav. Would you mistrust your satnav just because you might not adequately understand relativity?

I am not saying I need to understand ‘how’ something works in order to believe that it does. I can observe that my satnav takes me from A to B.

What is being said here, on a basic level, makes no sense (and that has been admitted above) in the language in which it has been expressed. If someone said, “Take this drug, it will make you weightless”, you wouldn’t take it no matter how many degrees the person offering it to you had, because that doesn’t make sense. You would say, “What do you mean, ‘weightless’? As in, it would literally negate gravity?’ And when they said, ‘That’s the layman’s way of expressing what it does but it’s really good, honest!” you wouldn’t take it, would you?