Mildly interesting facts

[seikopath]

Mate. How can your measure the universe. No one has a ruler that big.

[Groundrush]

Mate. How can your measure the universe. No one has a ruler that big.

You can bounce radio waves of objects in our solar system to get very accurate measurements, parallax measurements will get you up to about 100 light years, then you're into main sequence fitting which relates the apparent brightness of known types of star to the distance. But to get the really big distances, you need to use Cepheid variable stars which pulsate with a rate very accurately associated to their brightness and by measuring their apparent brightness you can get distance. You can also use supernovas since their brightness is calculable. But you're right, we don't have a ruler that big and a lot of this is open to error, possibly a very big error.

[EchoSevenNine]

You can bounce radio waves of objects in our solar system to get very accurate measurements, parallax measurements will get you up to about 100 light years, then you're into main sequence fitting which relates the apparent brightness of known types of star to the distance. But to get the really big distances, you need to use Cepheid variable stars which pulsate with a rate very accurately associated to their brightness and by measuring their apparent brightness you can get distance. You can also use supernovas since their brightness is calculable. But you're right, we don't have a ruler that big and a lot of this is open to error, possibly a very big error.

I'd just like to add to this by saying that the Universe is really big.

Like, a million football pitches big.

[seikopath]

You can bounce radio waves of objects in our solar system to get very accurate measurements, parallax measurements will get you up to about 100 light years, then you're into main sequence fitting which relates the apparent brightness of known types of star to the distance. But to get the really big distances, you need to use Cepheid variable stars which pulsate with a rate very accurately associated to their brightness and by measuring their apparent brightness you can get distance. You can also use supernovas since their brightness is calculable. But you're right, we don't have a ruler that big and a lot of this is open to error, possibly a very big error.

Also, what do you mean by universe?
If you are just measuring one universe, how do you know that there are not multiple universes in existence?

[Groundrush]

Also, what do you mean by universe?
If you are just measuring one universe, how do you know that there are not multiple universes in existence?

Some people define the universe as the universal set, the set of all things, all of space and time and everything contained therein. If there are multiple universes it's utterly irrelevant to us since we can't, thus far, interact with or know anything about them in any way whatsoever.

[Raffe]

Some people define the universe as the universal set, the set of all things, all of space and time and everything contained therein. If there are multiple universes it's utterly irrelevant to us since we can't, thus far, interact with or know anything about them in any way whatsoever.

= 42.

[Mr Curta]

You may think it's a long way down the road to the chemist's, but that's just peanuts to space.
Thanks DA

[Griswold]

Mate. How can your measure the universe. No one has a ruler that big.

You can't as it is continuously expanding.

[hogthrob]

"Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it." Terry Pratchett


The 'speed of dark' is a thing. Hopefully someone with a better understanding of physics will be along shortly to explain.

[oldoakknives]

Also, what do you mean by universe?
If you are just measuring one universe, how do you know that there are not multiple universes in existence?

What about the eyeballs in the sky?



ook

[seikopath]

You can't as it is continuously expanding.

Thats like saying you can't measure a tree or the height of a child

[seikopath]

Some people define the universe as the universal set, the set of all things, all of space and time and everything contained therein. If there are multiple universes it's utterly irrelevant to us since we can't, thus far, interact with or know anything about them in any way whatsoever.

I agree with your definition, but i don't think something like that is necessarily measurable by beings like us, however much we would like to think so...

[Dave+63]

You can bounce radio waves of objects in our solar system to get very accurate measurements, parallax measurements will get you up to about 100 light years, then you're into main sequence fitting which relates the apparent brightness of known types of star to the distance. But to get the really big distances, you need to use Cepheid variable stars which pulsate with a rate very accurately associated to their brightness and by measuring their apparent brightness you can get distance. You can also use supernovas since their brightness is calculable. But you're right, we don't have a ruler that big and a lot of this is open to error, possibly a very big error.

So it’s a guess then!

[Parabola]

Gary Numan is two weeks older than Gary Oldman

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[Groundrush]

So it’s a guess then!

No, it's a measurement in the same way you might measure the height of a tree by measuring your own height and the length of the shadows cast by you and the tree, just a whole lot bigger.

[seikopath]

Gary Numan is two weeks older than Gary Oldman

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I like that one

[Dave+63]

No, it's a measurement in the same way you might measure the height of a tree by measuring your own height and the length of the shadows cast by you and the tree, just a whole lot bigger.

Sorry, should have put a smiley in the end. I wasn’t being serious.

[Groundrush]

I agree with your definition, but i don't think something like that is necessarily measurable by beings like us, however much we would like to think so...

Luckily I'm talking about the observable universe which can be measured using the methods described above.

[seikopath]

Luckily I'm talking about the observable universe which can be measured using the methods described above.

So you are presuming that all of the universe is observable then?

[Groundrush]

So you are presuming that all of the universe is observable then?

Can't say I care to be honest. There seems little point in pondering the existence of things that are indistinguishable from their own non-existence. That way madness lies.

[SimonK]

So you are presuming that all of the universe is observable then?

I'm willing to bet that all of the observable universe is observable.

[seikopath]

Can't say I care to be honest. There seems little point in pondering the existence of things that are indistinguishable from their own non-existence. That way madness lies.

So that's analogous to saying that if the ocean was x deep, but only observable to the depth of x minus y,
then its ok to make statements like the ocean is only x minus y deep?

- - - Updated - - -

I'm willing to bet that all of the observable universe is observable.

But not to everyone all at the same time, surely?

[Groundrush]

So that's analogous to saying that if the ocean was x deep, but only observable to the depth of x minus y,
then its ok to make statements like the ocean is only x minus y deep?

Key word: observable.

Measuring the size of the observable universe is akin to asking how far you can see. Whether that be the size of the universe or the depth of the ocean, if you can only gain information up to a certain distance then what is beyond that is fundamentally not knowable and therefore it's pointless to waste time thinking about it.

[seikopath]

If you look at the biggest thing in the universe, the size of the universe itself (10^27 m).... Etc etc


.

But you didn't say that in your original statement.

You just said the universe is such and such a size.

You didn't mention that that size was merely the size of your ruler, and not the actual universe.


Another key word : Presumption.

[seikopath]

Key word: observable.

Measuring the size of the observable universe is akin to asking how far you can see. Whether that be the size of the universe or the depth of the ocean, if you can only gain information up to a certain distance then what is beyond that is not fundamentally not knowable and therefore it's pointless to waste time thinking about it.

So it's pointless to waste time thinking about things you cannot observe?

I've got a friend down the road who is a theoretical astronomer at Cambridge, she's going to be gutted.

[Groundrush]

I've got a friend down the road who is a theoretical astronomer at Cambridge, she's going to be gutted.

I think she'd probably understand.

I thought this thread was supposed to be mildly interesting, not mildly argumentative. I'm out.

[seikopath]

I think she'd probably understand.

I thought this thread was supposed to be mildly interesting, not mildly argumentative. I'm out.

Sorry geezer. Have a nice evening. Dave.

[Raffe]

Andy, you would argue with yourself if you were trapped alone in a lift. Have a nice day :)

He's not alone.

[subseastu]

Gary Numan is two weeks older than Gary Oldman

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The last thing I understood in this thread. Also pretty funny.

[SimonK]

There is a town in Missouri called Braggadocio.

[raptor]

Rarely two breasts are exactly the same


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[Kingstepper]

The last thing I understood in this thread. Also pretty funny.

Understand it but no idea who Gary Oldman is.

[seikopath]

Understand it but no idea who Gary Oldman is.

Are you serious?

Drexel in True Romance etc

[Kingstepper]

Are you serious?

Drexel in True Romance etc

Yes and that hasn't helped.

[seikopath]

Yes and that hasn't helped.

British actor who cracked Hollywood and also wrote and directed an autobiographical movie which was excellent, but I've forgotten the name of!

[Raffe]

Yes and that hasn't helped.

He played the guy who killed Matilda's family in Leon, the professional.

[Parabola]

Understand it but no idea who Gary Oldman is.

He played Churchill in Darkest Hour very recently

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[E_2_Right-Force]

You can fit the contents of one Olympic-sized swimming pool into one Olympic-sized swimming pool.

[PickleB]

Understand it but no idea who Gary Oldman is.

...or perhaps Sirius Black?

[Andyg]

You can fit the contents of one Olympic-sized swimming pool into one Olympic-sized swimming pool.

Only if they are the same depth

Gary Oldman was also a villian in the 5th Element

Gary Numan is actually Gary Webb.

[subseastu]

...or perhaps Sirius Black?

Excellent film. Wonder what pill he pops? Asking for a friend.

[Der Amf]

Blackcurrants are virtually unheard of in America

[Raffe]

Americans are virtually unheard of on Mars.

[SimonK]

Letzebuerg is virtually unheard of anywhere in the observable universe.

[Raffe]

Letzebuerg is virtually unheard of anywhere in the observable universe.

Certainly not in Paris, the 'Jardin du Luxembourg' is almost bigger than our entire country!

[Dave+63]

So you are presuming that all of the universe is observable then?

I thought we’d already covered that.see post 30.

[anz3001]

Mildly interesting? Some of this is confusing as hell!

[Mr Curta]

This sentence is false

[Jardine32]

British actor who cracked Hollywood and also wrote and directed an autobiographical movie which was excellent, but I've forgotten the name of!

Nil by mouth. Superb film.
J

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[Mikee]

Easily the most numerous creatures on earth are bacteria and most of these live in the sea (apart from possibly those living in deep rocks...)

Of those oceanic bacteria approximately half are killed by viruses (bacteriophages) every day.

Given that the Oceanic Bacteria make every other life form on earth basically a rounding error this means that every single day we are living in a colossal slaughter.