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?

It's a very strong statement that there can be no such thing as an infinitely long piece of string. I don't see why it would be impossible to describe such a thing in an infinite universe.

Starting to roll my eyes here. I am saying the same thing again and again. I do not rule out that a piece of string (or the universe) might be infinite. I am saying it is unproven. That there is not currently sufficient evidence to say an infinite piece of string exists.

But what if they were numbers, as @DadDadDad suggested? That might make it easier for you.

And this... I do not have a problem with the concept of infinity. Numbers go on forever because we made them up; we can always add one more. But the universe is either physically infinite, or it is not. Whether or not I can imagine infinity is neither here nor there, and neither visions of onions nor numbers have a thing to do with it.

I would say there still isn’t anywhere near enough evidence to say whether the universe is infinite. Yes, the Friedman equations and Big Bang work well, good explanation by the RevSpooner, but like most models they will be an oversimplification, and one day will be improved and refined. Just like Einstein did to Newton. The view among observational cosmologists, at least the ones I know, is that it is unknown and we are many steps back from knowing.

Yes.

Every single thing that exists on our planet is made up of atoms that have come from stars.

If you look at pictures of the a Milky Way, our solar system is a tiny indiscernible dot on one arm of a spray of stars.

There are millions of galaxies in the universe.

Starting to roll my eyes here. I am saying the same thing again and again. I do not rule out that a piece of string (or the universe) might be infinite. I am saying it is unproven. That there is not currently sufficient evidence to say an infinite piece of string exists.

The thing is, @AStudyinPink, you've fairly consistently made claims stronger than the position of scepticism you say you hold.

Mon 25-Jan-21 10:19:05: And thus, since nobody can explain that paradox, we know... nothing.

Mon 25-Jan-21 13:48:54: But until I hear something sensible in words I will assume you are all very confused.

Mon 25-Jan-21 15:50:31: It should be possible to describe what you are thinking about in human language.

And in the last post of mine, to which you responded, I quoted you describing something of infinite length as "a fallacy". All of those are stronger than mere scepticism. Some of them appear to be statements about what you will and will not accept as possible, rather than a statement of doubt. Perhaps it's just your language, but you come across as rather more than sceptical.

They are not stronger than scepticism. It is a fallacy to try to defend the argument of an infinite universe by referring to an idea (that of an infinite piece of strong). One is imaginary, illustrative, only; the other is a claim about a physical reality.

I have been very clear that my position is one of doubt, not denial. If you’re going to try to pretend otherwise, I can only assume it is because you have been overreaching in your arguments, and now you want to pretend I have made a more positive argument so that yours looks less silly.

*string

I know this is a bit of a derail but I actually love the way on Mumsnet people can be arguing over astrophysics. All those sneery people out there who put this forum down as a bunch of bored housewives fighting about bottle Vs breastfeeding. They haven't a clue.

Long live discussions like this.

@peapotter - looking at Siegel's Wikipedia page he trained as a cosmologist, so it's not surprising the article on cosmology is pretty solid. Perhaps he isn't so hot on the (rather subtle and complex) physics of black hole interiors, and he certainly doesn't say anything wrong about them that hasn't been said wrong a thousand times before.

wellthatsunusual

True! Only works if people don’t report others for ‘trolling’ when they’re just expressing their opinion, though.

It is a fallacy to try to defend the argument of an infinite universe by referring to an idea (that of an infinite piece of strong).
I think it was intended to make you wonder if you understood infinity as well as you think you do if you dismiss the notion of an expanding infinite space as "not making sense".

I have been very clear that my position is one of doubt, not denial.

You have certainly consistently stated that. But if you don't see that dismissing all cosmologists as "confused" and insisting that descriptions of the evolution of the universe must be reducible to every day concepts is stronger than doubt, (or at least accept that what you've written can be read that way) I think I shall leave the argument there.

I think it was intended to make you wonder if you understood infinity as well as you think you do if you dismiss the notion of an expanding infinite space as "not making sense".

And again, I think I do understand it. I would question (again) why anyone thinks they can support the existence of a physical infinity (a universe) by reference to an imaginary one (numbers).

You have certainly consistently stated that. But if you don't see that dismissing all cosmologists as "confused" and insisting that descriptions of the evolution of the universe must be reducible to every day concepts is stronger than doubt...

Insisting that descriptions of the universe contain sufficient logic to make basic sense before I believe them is just rationality.

@AStudyinPink there's a phrase " mathematics is applied philosophy, physics is applied mathematics, chemistry is applied physics, biology is applied chemistry, psychology is applied biology, and philosophy is applied psychology".

I'm an engineer and rely on the same maths and physics that predict an infinite universe to keep planes flying. Euler is my hero.

Daftasabroom

None of that makes any difference to my position, but thanks for sharing.

Just read the whole thread and this is my summary of it:

Mathematician: The Earth is a 'sphere'.
Flat earther: That doesn't make sense, we would fall off.
Mathematician: That is where gravity comes in.
Flat earther: Prove it!
Mathematician: Ok let me talk you through the Maths.
Flat earther: F**k maths, explain it to me in English!
Mathematician: Well, gravity pulls you toward the centre of the Earth.
Flat earther: What nonsense, I cant see anything pulling me down.
Mathematician: You cant see gravity, its an 'invisible' force.
Flat earther: Pull the other one, next you will be saying the Earth goes around the sun.
Mathematician: Ummmm!
Flat earther: Therefore its impossible for the Earth to be 'round' until you explain gravity in English in a way that I find acceptable!
Mathematician: Walks away slowly.

I’m a final year physics student and I have really enjoyed this thread! I understand more than I realised. It’s also nice to see “asymptotically” being used correctly rather than as an unfortunate autocorrect error for “asymptomatically” on a covid thread

What a fascinating thread! (Apart from intentional derailing by some).
I saw a documentary long ago suggesting that maths is the language of the universe and maths might be interwoven in the fabric of the universe regardless of human existence and/or usage of it, whereas languages (English, Greek, Sanskrit etc) are a superficial construct made by and solely for humans and hence the majority of phenomena in space can be only explained by maths (and then relayed in layman’s terms to those less brainy of us who wish to know but fail at the language of the universe ).
What I am currently trying to embrace with my tiny brain is why Big bang couldn’t have been some gigantic black hole exploding? What if there is nothing fancy and si-fi out there, just good old infinite universe with very very occasional gigantic black holes that end up exploding with a bang and thus creating observable universe? And that it takes hundreds of billions of years for one to develop hence we haven’t observed any other big bang?

@newstart1337

Just read the whole thread and this is my summary of it:

Mathematician: The Earth is a 'sphere'.
Flat earther: That doesn't make sense, we would fall off.
Mathematician: That is where gravity comes in.
Flat earther: Prove it!
Mathematician: Ok let me talk you through the Maths.
Flat earther: F**k maths, explain it to me in English!
Mathematician: Well, gravity pulls you toward the centre of the Earth.
Flat earther: What nonsense, I cant see anything pulling me down.
Mathematician: You cant see gravity, its an 'invisible' force.
Flat earther: Pull the other one, next you will be saying the Earth goes around the sun.
Mathematician: Ummmm!
Flat earther: Therefore its impossible for the Earth to be 'round' until you explain gravity in English in a way that I find acceptable!
Mathematician: Walks away slowly.

If you'd realised that at the start, you could have taught 10 people who did want to learn with your time instead.

(Why conspiraloons cost ...)

More black hole stuff explained here. It’s pretty basic and simple compared to what some of the very clever ones on this thread know, but I enjoyed it, it made some of the theories nice and easy for my normal sized brain! Brian Cox, sorry if it’s already been posted.

@Burgersandfries

What a fascinating thread! (Apart from intentional derailing by some). I saw a documentary long ago suggesting that maths is the language of the universe and maths might be interwoven in the fabric of the universe regardless of human existence and/or usage of it, whereas languages (English, Greek, Sanskrit etc) are a superficial construct made by and solely for humans and hence the majority of phenomena in space can be only explained by maths (and then relayed in layman’s terms to those less brainy of us who wish to know but fail at the language of the universe ). What I am currently trying to embrace with my tiny brain is why Big bang couldn’t have been some gigantic black hole exploding? What if there is nothing fancy and si-fi out there, just good old infinite universe with very very occasional gigantic black holes that end up exploding with a bang and thus creating observable universe? And that it takes hundreds of billions of years for one to develop hence we haven’t observed any other big bang?

I love this idea. In fact once I had a very proud moment, one of the proudest of my life I was watching how the universe works on Discovery, and they said (something like) the only place relatively doesn’t work is in a singularity and at the time of the Big Bang. So I said to my husband oh maybe we are living in a black hole, and then five minutes later they were saying that that is actually a genuine theory! For about 30 seconds I felt like a theoretical physicist

That’s really interesting as well about maths being the language of the universe. Makes a lot of sense.

love this idea. In fact once I had a very proud moment, one of the proudest of my life grin I was watching how the universe works on Discovery, and they said (something like) the only place relatively doesn’t work is in a singularity and at the time of the Big Bang. So I said to my husband oh maybe we are living in a black hole, and then five minutes later they were saying that that is actually a genuine theory! For about 30 seconds I felt like a theoretical physicist grin

When I saw Prof. Brian Cox (with Robin Ince) on tour, he asked for questions at the end, and a young girl asked about the idea that this is all some sort of simulation (which is at least one episode of Monkey Cage). He took the question very seriously (as it's a thing in science) which seemed a great demonstration of science embracing, rather than rejecting and gave a long answer. Which (If I understood) is "we just don't know".

Loads of young faces at the gig - really cheered me up.

Ah I love Prof Brian Cox, for all his expertise and knowledge he never comes across as condescending even when explaining the most basic notions
Chocbeforecock that’s an exciting idea, isn’t it, that we could be living Inside the black hole!

@Burgersandfries

Ah I love Prof Brian Cox, for all his expertise and knowledge he never comes across as condescending even when explaining the most basic notions Chocbeforecock that’s an exciting idea, isn’t it, that we could be living Inside the black hole!

I have enormous amounts of time for anyone who tries to explain science to encourage kids to get into it. Especially from the traditionally under-represented demographics.

In my day, James Burke (not a scientist, but a great communicator) was The Man. "Connections", "The Real Thing" and "The Day The Universe Changed" all being played to transparent plastic on VHS growing up ....

I'd be interested to know what the big brains think of dark matter and dark energy. Many of our cosmological models rely on the existences of these things and the seem rather as hoc to me.

Took 8 year old DD to see Brian Cox live in 2019. She absolutely got all of it far better than I did. My dad - ex uni lecturer - said it was the best physics/astronomy lecture he’d ever seen.

@Eleganz

I'd be interested to know what the big brains think of dark matter and dark energy. Many of our cosmological models rely on the existences of these things and the seem rather as hoc to me.

If we know 0.01% of what there is to be known I'd be impressed.

Much more like 0.000001%

I heard a cosmologist once describe our knowledge of the universe as a town, on which at the outskirts we are looking for their car keys under a 100W lamp.