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The Universe


dont_do_it_doug.

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A mother takes her son to the doctor's and tells him she's really worried. "All he does is lock himself in the bathroom all hours of the day and night and he is just getting paler and paler. The doctor asks the boy what he is doing. "Reflecting on the universe" the boy answers. The doctor diagnoses him as having an over-developed albedo.

Edited by MakemineVanilla
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filament.jpg?w=300&h=225

 

Every point of light on this map is a supercluster. Mind boggling!

 

 

Even the Milky Way and her satellites are not alone, they are part of what we call the Local Group. Comprised of three major galaxies and dozens of satellites on our scale the local group is the size of a football pitch. Within these 10 millions lightyears lie trillions of stars, the largest galaxy is our nearest neighbour called Andromeda which itself contains well over 1 trillion stars. I always think fondly of Andromeda, as a child I had a book about the universe and I remember becoming upset because it told me that in 4 to 5 billion years the Milky Way and Andromeda are going to crash. Count to five……I’ll give you time to do it……we are now 600 kilometres closer! We are on a collision course with each other, on our scale Andromeda is 25 metres from us (2 and a bit buses) and its racing towards us at a rate of 5 billionths of a metre every year. Granted that doesnt scare me any more, but it’s going to be a titanic display!

crash.jpg?w=300&h=225

In billions of years to come somebody will be voiding their no claims bonus...

Our Local Group may seem huge but it is tiny compared to some of the other groups nearby. 65 million light years away the Virgo Cluster is home to over 1 thousand galaxies! When we look at the Virgo Cluster now we’re seeing it as it was when the dinosaurs were walking the Earth, from the entirety of that point until now those photons have been serenely flying through space until one day after aeons of travel they land in our telescopes to tell us a tale from the deep past. The Virgo Cluster is so huge that we use it to name our local supercluster. Yes our Local Group is just a small part of a bigger group. The Virgo Supercluster contains at least 100 galaxy clusters and on our scale where the Milky way is a metre across and the Earth just half an atom wide it is over a kilometre wide. That’s about the same scale as an ant standing next to a car

Now I know this is beginning to sound repetitive but even our supercluster is just a tiny dot. When we look out beyond our supercluster we see that there are many, many more. Superclusters litter our universe forming truly colossal structures. They bunch together forming filaments (chains billions of lightyears long) and Great Walls formed from giant webs. This is our home. This is our universe. At this size our scale collapses again, with the Milky Way 1 metre wide some of these filaments would be tens of kilometres long!

filament.jpg?w=300&h=225

One of the universe's 'Great Walls' made from filaments of superclusters

This is the observable universe, countless stars in hundreds of billions of galaxies. We are but a tiny part of this but it’s all out there! The numbers are horrible and the distances incomprehensible but I hope my analogy has helped. I was planning on taking this further and explaining just how small things in our universe can be but I found this brilliant animation that paints a picture worth a thousand blog posts. Its awesome, its unimaginably big, and its where we live.

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Big Bang isn't a description of a particular 'bang', it's just a term given to the start of the set of events that the start of the Universe has grown from, there's also nothing that would say that time never was in existence before the Big Bang, just that the time our Universe feels hadn't started. However there could be other dimensions of time that we are unaware of just as there are more than one dimensions of our known physical universe

"Big bang" is a sound bite taken out of context. A bit like happens to football managers. Hoyle was dismissing the idea when he used this term. The "primeval atom" model did not describe an explosion, but an inflation. It's modern usage is incorrect and leads to people making false assumptions about its nature.

 

Time is a dimension of our universe as such it is completely contained within our universe. It has a starting point. We don't yet know if it has an end point. I think you have a category error in your understanding of dimensions. Time-like dimensions are bound by the universe in exactly the same way as space-like dimensions. The most promising unified model describing our universe postulates an 11 dimensional membrane. It is far from complete and is not yet robust enough to be testable. It may be that more dimensions are required especially as we still have nothing describing how inflation is accelerating.

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The expansion of the universe boggles me.

To think that it is expanding, but theoretically is unable to Expand INTO a space is just... It just bakes my noodle.

It's not expanding, it's inflating. :)

 

Think of points on the surface of a balloon. Now inflate the balloon. The points haven't moved relative to each other, but are now further apart. Inflation is like that, but all of the space-like dimensions are inflating, not just an arbitrary boundary. It's not the outside edge getting bigger, it's everything

 

When our brains evolved to help us become better apes it didn't equip us for modelling things so far outside of our experience. This is why it's hard to get your head around it. You have to stop trying to put it in the context of other things that you know.

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Big Bang isn't a description of a particular 'bang', it's just a term given to the start of the set of events that the start of the Universe has grown from, there's also nothing that would say that time never was in existence before the Big Bang, just that the time our Universe feels hadn't started. However there could be other dimensions of time that we are unaware of just as there are more than one dimensions of our known physical universe

 

 

Time is a dimension of our universe as such it is completely contained within our universe. It has a starting point. We don't yet know if it has an end point. I think you have a category error in your understanding of dimensions. Time-like dimensions are bound by the universe in exactly the same way as space-like dimensions.

 

There is a argument that time is not a dimension as usually accepted, but instead that time exists completely independent from space, with time as the quantity used to measure change (i.e., photon motion) in space.

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Big Bang isn't a description of a particular 'bang', it's just a term given to the start of the set of events that the start of the Universe has grown from, there's also nothing that would say that time never was in existence before the Big Bang, just that the time our Universe feels hadn't started. However there could be other dimensions of time that we are unaware of just as there are more than one dimensions of our known physical universe

 

 

Time is a dimension of our universe as such it is completely contained within our universe. It has a starting point. We don't yet know if it has an end point. I think you have a category error in your understanding of dimensions. Time-like dimensions are bound by the universe in exactly the same way as space-like dimensions.

 

There is a argument that time is not a dimension as usually accepted, but instead that time exists completely independent from space, with time as the quantity used to measure change (i.e., photon motion) in space.

General relativity shows us that time is only fixed within an observer's reference frame. There is no "absolute time". If you can back up that argument, there's at least a Nobel prize in there for you.

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The expansion of the universe boggles me.

To think that it is expanding, but theoretically is unable to Expand INTO a space is just... It just bakes my noodle.

It's not expanding, it's inflating. :)

 

Think of points on the surface of a balloon. Now inflate the balloon. The points haven't moved relative to each other, but are now further apart. Inflation is like that, but all of the space-like dimensions are inflating, not just an arbitrary boundary. It's not the outside edge getting bigger, it's everything

 

When our brains evolved to help us become better apes it didn't equip us for modelling things so far outside of our experience. This is why it's hard to get your head around it. You have to stop trying to put it in the context of other things that you know.

Beautifully eloquent analogy.

Thank you.

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