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As a result of the close-down of the UK by the British Government last night, we have made all the Buy/Sell areas read-only until we open back up again, so please have a look at the announcement linked here.

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Beardie

A strange world full of odd facts

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52 minutes ago, Pete in Lincs said:

If I can get this sofa up to warp factor eight then I'll see you there.


Now what?

 

Trevor

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On ‎12‎/‎3‎/‎2019 at 7:07 PM, Max Headroom said:

It’s a common (local) myth that you are allowed to shoot at Welsh people within the walls of Chester during the hours of darkness.

 

Whether or not it was ever true, it isn’t now!

 

 

What, not even with a longbow?  No point going, now, is there?

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On 12/3/2019 at 8:53 AM, Tony C said:

Another UK Law - No person shall, in the course of a business, import into England, potatoes which he knows, or has reasonable cause to suspect, are from Poland.

So it would be perfectly OK to do so for recreational or private reasons then?

Perhaps a potato collector or hobbyist would also be safe from the ravages of importation beauracracy!

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The expansion of the universe is not the same as things rushing away from each other at speeds faster than light. It is spacetime that is growing so the speed of light is still constant. The maths that explains this is quite complex however, so don't ask me to quote it...

 

The two examples of 2/3 light speed ships is also dependent on your frame of reference.

An isolated 3rd party will see each vehicle moving at 2/3rd light

However, observers on each ship will be under the effects of Relativistic Time Dilation calculated using the Lorenttz transfrmation:

 

6d4475fbd112aad0bedebebac14a4fa6b220de74

 

So if you are going at 0.5C (ie half the speed of light, time will be slowed by about 15%, however if you are travelling at 0.99C you will experience time slowed by about 700%, ie you will age one year while a stationary observer will age 7 years. 

 

The calculation which shows the relative speed between the two vehicles is not to simply add the speeds together, you need to pass it through the other equations derived from Special Relativity as not only is time dilated by space is also affected, so the closing speed observed by each vehicle will be totally different from that of a stationary observer.

 

One of the most difficult things to get your head around when dealing with Special Relativity is that there is NO fixed point of observation - every observation is relative, hence it name!

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41 minutes ago, Kallisti said:

The expansion of the universe is not....

6d4475fbd112aad0bedebebac14a4fa6b220de74

........................
.........So if you are going at 0.5C.......

Be honest. You've been at the bottle, haven't you 🥺🤭🤭🤭

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The phrase “If life gives you lemons, make lemonade” is founded on nonsense. We were never given lemons. They, like most of the citrus fruits we know and use, are a cultured hybrid that people needed to develop.

 

A more correct version would be “If life gives you bitter orange(sour orange) and citron, make lemons then make lemonade”

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And if you have tracks you are probably either a treadhead, a train fan  or some kind of junkie...

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Just reading 'The Fabric of the Cosmos' by Brian Greene and have come across something new to me and I'm interested to hear from the experts @LostCosmonauts @Kallisti etc. if this is still Current thinking. It is in regard of Alan Guth's Cosmic Inflation theory. It states in the book that models indicate that, in the very earliest moments of the Big Bang the universe expanded to such an incredible size that the visible universe (all the billions of years of it that we can see) would only be a very small fraction of the overall space and that there are regions of space whose light won't reach this region for such a long time that the Sun will have burnt out before it happens. Truly it makes one feel altogether, infinitesimally small. 

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1 hour ago, Beardie said:

Just reading 'The Fabric of the Cosmos' by Brian Greene and have come across something new to me and I'm interested to hear from the experts @LostCosmonauts @Kallisti etc. if this is still Current thinking. It is in regard of Alan Guth's Cosmic Inflation theory. It states in the book that models indicate that, in the very earliest moments of the Big Bang the universe expanded to such an incredible size that the visible universe (all the billions of years of it that we can see) would only be a very small fraction of the overall space and that there are regions of space whose light won't reach this region for such a long time that the Sun will have burnt out before it happens. Truly it makes one feel altogether, infinitesimally small. 

It’s actually weirder than that. There are regions of the Universe from which the light will never reach Earth. The expansion of space-time is greater than the speed of light so those regions are forever cut off from us. We can see galaxies that are about 13.7 billion light years away at the edge of the visible Universe. However, those objects have been moving since the light we now see left them and it’s been estimated that they would now be about 40 billion light years away.

Furthermore, the expansion is accelerating so over time less and less of the Universe will be visible. Eventually, the only thing we would see from Earth would be our own galaxy if that isn’t so far in the future that there would be no stars left shining to see.

Edited by VMA131Marine

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8 hours ago, Beardie said:

Just reading 'The Fabric of the Cosmos' by Brian Greene and have come across something new to me and I'm interested to hear from the experts @LostCosmonauts @Kallisti etc. if this is still Current thinking. It is in regard of Alan Guth's Cosmic Inflation theory. It states in the book that models indicate that, in the very earliest moments of the Big Bang the universe expanded to such an incredible size that the visible universe (all the billions of years of it that we can see) would only be a very small fraction of the overall space and that there are regions of space whose light won't reach this region for such a long time that the Sun will have burnt out before it happens. Truly it makes one feel altogether, infinitesimally small. 

@beardie Thanks, I was a lowly chemist and am a very very long way from being an expert on physics (or as my lecturers, PhD supervisor and various managers and coworkers would probably also add on chemistry) 

 

I did find revising for my undergraduate Physical chemistry quantum thermodynamics class easier after a couple of drinks when I was just just hazily drunk enough that it all seemed to start making sense and then tried as far as was possible (it was an early start) to replicate those experimental conditions for the exam. I can only advise that the Physics of the very small and very large is like playing pool and you’ll hit your stride somewhere between 2 and 3 drinks in. Just don’t have a 4th as you’ll run the risk of thinking playing the bongos and chasing women are good ideas and you’ll likely get mistaken for Richard Feynman. 

 

As far as I know inflation theory is a popular intellectual camp but it is all still being hotly debated https://www.forbes.com/sites/startswithabang/2017/09/28/is-the-inflationary-universe-a-scientific-theory-not-anymore/ and probably won’t be settled in either of our lifetimes. 

Edited by LostCosmonauts

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The inflationary theory certainly 'seems' to make sense to me. Before reading the book I was ignorant of the reasoning and concepts behind Alan Guths inflationary Universe theory and how it puts the 'bang' into the Big Bang using the Higgs field. Fascinating stuff but, at the same time, it really puts any arrogance about Earth being the centre of the universe into very sharp perspective.

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There are 15 full days left until Christmas day

more importantly; There are 12 full days left until the day my favourite #1 dottir comes home for her Christmas break

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10 hours ago, Black Knight said:

There are 12 full days left until the day my favourite #1 dottir comes home for her Christmas break

I hope that she's the only one that you have, otherwise the others are going to feel a bit miffed!

 

John.

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11 hours ago, Black Knight said:

There are 15 full days left until Christmas day

Oh.  Time to think about doing some Christmas shopping, then.

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15 hours ago, Black Knight said:

There are 15 full days left until Christmas day

 

So that's 14 days until the Tree has to go up and 17 days until it can come down!

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^you're keen, aren't you? In today's green, energy saving world, Mine will stay in the loft.

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So how do you know if the lights are switched on or not?

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18 hours ago, Black Knight said:

There are 15 full days left until Christmas day

more importantly; There are 12 full days left until the day my favourite #1 dottir comes home for her Christmas break

Ah, good: at last some figures I can get my head around.

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That is a very sharp point @Seahawk The 'big numbers' of our universe are so huge as to be incomprehensible to us puny humans. I think we struggle even when we get into the millions. We are horrified to hear a handful of people were killed or injured in an accident but we can't comprehend it when it comes to the millions who died of the Spanish Flu or the holocaust etc. The numbers are just outwith our personal sense of scale. We can visualise a hundred miles but who can really get their head round the distance just to reach our Moon let alone the other planets in our own backyard.

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Mindblowing fact for today.... I am sure everyone is aware of the microwave radiation that is key in theories of the early universe, originally discovered by Penzias and Wilson and which has since been mapped and turned into a rather fetching oval image in vivid, but fairly uniform colours. Well, according to my source 'The Fabric of the Cosmos' by Brian Greene (thanks again to @LostCosmonauts for the tip on the book), the absolutely tiny fluctuations in the temperatures tell us that, billions of years ago, when the universe was tiny it correlated very accurately with the predictions of cosmic inflation and basically tells us that our Universe owes everything it contains now to tiny quantum level 'wiggles' in the fabric of the young universe. It is thoroughly scary just how precisely tuned everything in the history of this universe had to be in order for it to exist in such a way that we, or anything, can exist. I get the feeling that a lot of scientists get somewhat 'itchy' and irritable when things have to be too precise for creation to be just 'close enough for jazz'. 

 

Found myself a nice expression for those I don't have a great deal of regard for in this book as well, credited to Fritz Zwicky. It is 'Spherical swines'(he didn't use the word 'swines' but I don't believe I am allowed to use the word he used here). The reasoning of this term is based on physical symmetry. A sphere is a sphere whatever way you look at it. 

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