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?

waitbutwhy.com/2014/05/fermi-paradox.html

Fascinating

Well there is less and less sand everyday.
It’s a resource we are using at a ever increasing rate faster than it can replace itself.
We are literally running out of sand.

We (humans) use about 50 billion tonnes of sand every year. We use it to make concrete, glass, in manufacturing, to make whole bloody islands.

I was listening to the Infinite Monkey Cage podcast in which they talked about how, if humans are still around in several million years the universe will have expanded to such an extent that the stars will all be out of view and we'll think we're all alone.

That blew my mind.

If you go somewhere without much light pollution then you will see the sky filled with stars so thick it looks like milk to tiny pin points and that’s just the tiny wee bit of our own galaxy that we can see from our place out on the arm.

We can’t imagine how many stars there truely is because we have ruined it for ourselves and can only see the very brightest.

You can go faster than light if you change the medium you're travelling in, but in a vacuum it's generally agreed that Einstein was right about c. I think there might be some mix up in an earlier post between 'spooky action at a distance' ie quantum entanglement and FTL travel...

To answer the OP, a grain of sand weighs, typically, 7 x 10-8 kg. So 1 kg of sand contains about 14 billion (109) grains. There are supposed to be 700 trillion m3 of sand on the earth's beaches, and sand weighs 1,600 kg per cubic metre, so there's a total of 1.12 x 10 18 grains of sand on earth

The estimate of the number of stars varies, but seems to about 1 x 10 ^23, based on that there are 100,000 more stars than grains of sand.

(probably out a bit on some of these sums as it's very early!)

@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.

@Ifailed,

But that is not the quote! There are definitely more stars than grains of sand on beaches. But what about the rice an floor?

I agree with those that can accept everything except where the fuck the universe is expanding into. It my tiny mind it can not expand into nothing, for if it can expand into it then its something, but what something?

Oh and big bang, fine. But how did it start, what was there in the very begining, what was nothing, that has nothing in..... I just can't cope with that thought

I promise that it's not a dodgy link and its safe to click, you'll probably enjoy having a play with the scale of the universe.

If the implications of the double slit experiment blow your mind, try the delayed-choice quantum eraser experiment for size. In this variation of the double slit experiment, the outcome appears to be determined by a second event that hasn't yet happened. Check it out here:

What does a finite universe expand into exactly?

Nothing. There isn't anything outside of the universe - the problem people have with understanding this is that our brains can't grasp the concept of "nothing" existing. We have to use a word to describe it, and a word is something. If you have no money, you have zero. Zero is a thing. It exists.

Complicating the idea that there is nothing outside of the universe is the theory that there are other universes too. It's just they don't exist anywhere in relation to our universe, at least not in dimensional terms we understand (height, length, time etc).

In essence: there is nothing outside of the universe, our universe is expanding into that nothingness, and other universes exist in parallel to our own but not in the traditional dimensions of length/depth/height/time.

Thinking about the sheer vastness of the universe is a head hurter indeed. Planet earth is tiny - a mere dot.

Nothing. There isn't anything outside of the universe - the problem people have with understanding this is that our brains can't grasp the concept of "nothing" existing.

My brain can grasp that concept. Most of the ‘universe’ we are aware of is a vacuum, ie nothing. So how does ‘nothing’ expand into ‘nothing’? What makes it finite if it is nothing growing into nothing?

@AStudyinPink

Nothing. There isn't anything outside of the universe - the problem people have with understanding this is that our brains can't grasp the concept of "nothing" existing.

My brain can grasp that concept. Most of the ‘universe’ we are aware of is a vacuum, ie nothing. So how does ‘nothing’ expand into ‘nothing’? What makes it finite if it is nothing growing into nothing?

Space itself is expanding.

Space itself is expanding.

But the same questions stands: expanding into what? If it has a current ‘finite’ amount, there must be something separating the nothing we are describing expanding from the nothing into which it is expanding. And that means - in any case - that we must add the ‘nothing’ ‘outside’ the ‘known’ universe to the ‘nothing’ into which it is expanding, the entire becoming what is ‘known’.

And thus, since nobody can explain that paradox, we know... nothing.

OP, if you ever get the chance to go somewhere with no light pollution, do it! The night sky is just incredible and awe inspiring. Every human should experience it.

Head blown

• But the same questions stands: expanding into what? If it has a current ‘finite’ amount, there must be something separating the nothing we are describing expanding from the nothing into which it is expanding. And that means - in any case - that we must add the ‘nothing’ ‘outside’ the ‘known’ universe to the ‘nothing’ into which it is expanding, the entire becoming what is ‘known’.

No, you're missing the point. There is absolutely nothing, versus space filled mainly by vacuum which is an absence of matter but is still space. In a similar way, there was no 'before' ahead of the Big Bang - that was the start of space-time for this universe.

It's best not to try to think about it too hard, I reckon. My DD pretty much got it when we were reading a dorling kindersley book about space when she was about 4.

No, you're missing the point. There is absolutely nothing, versus space filled mainly by vacuum which is an absence of matter but is still space

I don’t think I am missing the point. I think you are saying something that makes no sense and you don’t understand any more than I.

I find that a good way to approach the question of what happened before the Big Bang is to ask "What is north of the North Pole?"

The universe is not infinite. But there are infinite universes

Yes to the first part, but the second is theory, not fact. And not a theory accepted by all even working in the subject.

This is how flat earthers start out..

I don’t think I am missing the point. I think you are saying something that makes no sense and you don’t understand any more than I.

Lots of things about physics don't make intuitive sense. How can a photon be both a wave and a particle at the same time? To our intuition that seems impossible, but all observation says that is exactly how photons behave and we can explain this perfectly with maths even if we can't imagine it.

Likewise we can perfectly well describe the expansion of the universe mathematically without needing a medium for the universe to expand into, even if we can't imagine what that is actually like.

There is no reason that the physical laws of the universe should be constrained by what we can imagine, anymore than they should be constrained by what a chimp or an orang utan can imagine. We are just glorified apes after all.

I love the idea of infinite universes. Every choice you make affects the universe. I like to think somewhere in another universe I'm a top scientist. Or stinking rich living on my own private island. Or I have marmite in the cupboard so I can have marmite on toast right now. I love the idea that I've done everything conceivable somewhere in the universe! Go me!