Christmas quiz esp. for astronomers

[Bob LambParticipant @boblamb44747]

[Bob LambParticipant @boblamb44747]

I have three simple questions related to the universe which have been bothering me recently and I would love some of the astronomers amongst you to help me please.

1. If the universe is expanding – what is it expanding into?

2.If it all started with a Big Bang – who lit the fuse?

3. How does Rudolph manage to pull Santa's sleigh through the skies so fast at Christmas when, as far as I know, reindeer don't have wings?

I know it is a bit early but Happy Christmas.

Bob

[Neil WyattModerator @neilwyatt]

1 – It isn't. the universe has a fixed size, but everything in it is getting smaller and the speed of light is slowing down as it drians into a big black hole in the middle.

2 – See 1, you should be asking who pulled out the plug?

3 – These days he hitches a ride on the ISS.

[Steve PaveyParticipant @stevepavey65865]

Question 1 – it’s expanding into nothing. Nothing may not necessarily mean nothing, and Lawrence Krauss will explain this in one of his books.

Question 2 is malformed – it assumes there is a fuse to light, and also assumes a ‘who’. It could have been a ‘what’ or it could have occurred spontaneously, or it could have not occurred at all but be a continuation of a process that was already underway.

Question 3 – no idea, but then I also have no idea why my in-laws turn up on Boxing Day.

[Geoff TheasbyParticipant @geofftheasby]

1) It isn't expanding into nothing. Like builders expanding aerosol foam, it's overflowing from a parallel universe

2) Before all 'what' started?

3) It's reindeer because its too warm to snow.

Geoff

[pgk pgkParticipant @pgkpgk17461]

1)My wife can do the same thing. Some matters are better not questioned.

2)The beauty of the theory is that you can get something for nothing and has become a cultural icon of the west. It's even better than apparently antimatter can convert to matter and explains why bankers can lose billions and still afford to pay themselves a bonus.

3)Santa et al as imaginary beings have no mass and therefore the limits of light speed don't apply.

[Ian ParkinParticipant @ianparkin39383]

In the independent today

What shape is the universe?

The Universe is what is known as a hypersphere. A hypersphere is almost impossible to visualise, as it is a four-dimensional sphere – it alters with time. However, you can use the analogy of an onion to describe it quite well. Imagine the universe as it is now, this very instant, to be the outside layer of an onion. If you could look out into the universe as it is now, you would be looking around this shell. If you could look far enough, you would look right round it and see the back of your head.

But we cannot look at the universe at this very instant, because as we look out we are looking back in time. You can imagine that everything you are looking at that is at the same distance – say, five light years away – is on the same shell of the onion. The further away you look, the closer you are looking to the centre of the onion. These layers do not exist in this state any more (in terms of place or appearance) as they have moved (with the expansion of the Universe) since the light left them, but this is how we see them. You cannot travel from one side of the outer sphere (the universe as it is now) to the other side through the centre, as the centre is not just empty space; there is no space. You can travel only around the shell itself, as this is where the space exists. Well, we said it was hard to visualise.

[Ian S CParticipant @iansc]

I think the answer is "42". "Hitch Hikers Guide to the Galaxy".

Ian S C

[Cornish JackParticipant @cornishjack]

"What did Horace say, Winnie?" … for those old enough to remember

rgds

Bill

[pgk pgkParticipant @pgkpgk17461]

At this time of year in rural Wales when it comes to feeding the stock my wife is also like an onion of many many layers that alter with time and have no space between them – explains why she must be my universe and why it is impossible to travel between layers…and indeed why nothing I do gets past her.

[John FlackParticipant @johnflack59079]

Tried it with a spring onion…………..think the theory is flawed☃☃☃☃

[MWParticipant @mw27036]

You can't even observe how big the universe is, so, the best that they have are extremely loose estimates, which vary massively, but the only thing they can agree on is that it's bigger than we can observe, and they know that through theory.

Really, this is just a funny way of saying that they don't know at worst, and that it's still up in the air at best.

Michael W

[Neil WyattModerator @neilwyatt]

The worst bit is discovering these two well-accepted propositions about the universe.

1) The size of the visible universe is considerably bigger than 4.5 billion light years or even 2 x 4.5 billion light years – because you have to had on a whole series of confusing extras…

2) The big band isn't thought to be a point, it just looks that way. The 'big bang ' singularity may have been huge or even infinite(!) and ever since is continuing to expand so it has no 'outer edge'.

I will now go and lie down for a bit…

[Geoff TheasbyParticipant @geofftheasby]

OTOH, Mr Parkin, we surmise that a body loses energy if it goes from one layer to the next nearer the centre, and absorbs energy if it jumps from one layer to the next higher. This explains why the centre is dark and the outside is light. Or is that an atom?

Anyway, everything is in hyperspace, because they exist in time, thus in four dimensions. We see them as they were, not as they are 'now'.

Geoff

[Bob LambParticipant @boblamb44747]

Just got back from shopping and I thought all would be revealed. However, having read the answers, I feel like going back to bed for a light year or two as my brain hurts a lot!

Onions I can cope with but Neil's idea of pulling the plug out scares me – how long have we got before the swamp drains?

Ian S C comes the nearest to something I can understand – I thought Santa would have been powered by the infinite improbability drive connected to Rudolph.

Bob

[SillyOldDufferModerator @sillyoldduffer]

Re Question 3, I hear Santa's not coming this year:

[Gordon WParticipant @gordonw]

That's where all the bitcoin will be found.

[MWParticipant @mw27036]

Posted by Geoff Theasby on 15/12/2017 12:51:39:

Anyway, everything is in hyperspace, because they exist in time, thus in four dimensions. We see them as they were, not as they are 'now'.

Geoff

Also, the solar system and the galaxy itself isn't a static object, as we move around the sun, the entire solar system is also travelling through space, So we're never occupying exactly the same place that we were in the past. To say you have "travelled" through your life, isn't just a metaphor it's really true.

So we can surmise that to travel through time also means travelling through space, so you better make sure your time machine is set right or else it's going to be very dark and cold and empty outside!

Michael W

[vintagengineerParticipant @vintagengineer]

It cannot be of a fixed size as if it was a fixed size it would have an edge, therefore if it had an edge then there would be something else the other side of the edge!

[Geoff TheasbyParticipant @geofftheasby]

That's why I think the following is the definitive proof of the inherent flaw in the Flat Earth theory – if it really WAS flat, the cats would have pushed everything off the edge by now!

Geoff

[Ed DuffnerParticipant @edduffner79357]

Posted by Cornish Jack on 15/12/2017 11:26:57:

"What did Horace say, Winnie?" … for those old enough to remember

rgds

Bill

My Mother used to say that now and again. Always wondered where it came from

Ed.

[Ed DuffnerParticipant @edduffner79357]

1. I think the universe itself is infinite so cannot expand or shrink, however the objects within it, according to celebrity physicists are moving further apart relative to each other. The big crash at the other end of the time scale has probably already happened and we'll witness that in a few billions years time.

2. Higgs – He had the force with him!

3. Reindeer walk on dark matter.

[Mick B1Participant @mickb1]

1. It only expands into itself, to match its new size.

2. Some would say that was about the only thing left for a god to do, and the only time for it to do so…

3. The ISS is nowhere near good enough. Santa needs a FTL hyperdrive, plus a Stasis Field out of a Larry Niven story, to have any hope of getting around a billion-odd kids in a night. Even at 1 second per child, it'd take him nearly 32 years.

[Danny M2ZParticipant @dannym2z]

Santa moves by quantum mechanics, thus the probability is that he is everywhere and nowhere at any given time.

The given time seems to be less than a nanosecond after midnight in Dec 25th with allowance given due to the earth's rotation.

If you want to upset your younger relatives, try telling them that it's not so!

I would like to know however, why could he not deliver the kids bikes readily assembled?

* Danny M *

[Geoff TheasbyParticipant @geofftheasby]

He's too busy with the IKEA stuff!

Geoff

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