Universe

[JulianO]

There was a computer simulation i saw on tv...of course with Prof. Cox lol...but it involved inputing everything we know about gravity and mass (and obviously much more) into the computer simulation, then using that data to start a big bang type reaction.

The results, obviously speeded up thousands of times, created a view of the universe as we see it today.... as the simulation was happening the maths involved came to life, showing millions of particles gathering to gain mass...and as they did the gravity affected the other particles creating clusters of stars and galaxies....a short explanation of it...but it was pretty darn cool to watch.

Most probably the millenium simulation - something I work on indirectly.

Lots of video's of it here.

Millennium Simulation

That said...it was only a simulation, but it was a simulation that showed more or less accurate results which we can see with our own eyes and telescopes; all created with data collected from our current understanding of physics in the universe.

Right - and then the test is to see how well the simulation matches with reality, and what bits it can and can't explain.

[JulianO]

here is one thing though, theorists say the expansion of the universe is speeding up, sooooo, if there is an initial big bang, momentum says it should slow down? as energy dissipates and reduces the further you get away from from initial explosion?

It's not theorists that say the universe is speeding up, its observational astronomers. Originally they were trying to see how quickly it was slowing down, as that was the obvious result, and what they found surprised everyone.

If it is increasing, what could be pulling the universe faster away from the initial moment?

Other universes? Gravity, or gravities, must surely be pulling our universe outwards?

The current though is it is more of an internal push than an external pull.

Oh, and yes theories are based on experiments and tested concepts about what is known, but as we all know, we seem to always "discover" new theories all the time, and scientist alter there hypothesis' all the damned time, but at the truth of things, they are just best guessing as they don't know what we cannot comprehend/ cannot see as yet things that exist way out there.

I'd argue that what we discover is refinement, not replacement. This is quite different in some respects. Its not like they think the world is black one day and then white then next. Its like its black, but if you look really hard in one tiny corner, it a sort of dark grey, and in another place there is a little spot, but by and large it is all black.

Newtons law of gravity for instance, a very very very good approximation to everyday things. Its all you need to get to the moon, and the other planets, but actually its not 100% correct in all cases and all places. So Einstein revised it, but mostly you don't need his additions unless you are doing specialist things. I imagine someone will come along and revise his work eventually, and again you'll find Newtons laws are good for most case, Einsteins for specialist cases, and if you want to go live in a black hole, then you'll need need the revision.

I think Isaac Asimov said it best in his essay though, Asimov - The Relativity of Wrong.

[Doughzer]

But surely an internal push means the force creating the momentum to expand is increasing its own speed? For the speed to increase it must have greater pressure being forced upon it, so what is the explanation for a push, for if surely the Big Bang if thats what it was, was as far as we could say the greatest force ever on our universe what is increasing the speed if not a pull, of an even greater force?

Is the last 14 billion years a fraction of a split second that a bullet is fired from a rifle as is speeds up?

What is the arguement to say it is a push rather than a pull?

do we know in which direction from Earth was at the centre of the big bang? and surely if it is a push, then those objects closer to this direction would be catching us up as they get pushed first, unless as above the last 14 billion years is a fraction of a second as momentum increases?

And surely theorists can encompass astronomers too? as a collective they have together many theories?

[Grunthos]

The current thought is it is more of an internal push than an external pull.

I'm afraid your "metaphorical imagery" (of a subtle and beautiful subject) seems to have been taken literally....

I think Isaac Asimov said it best in his essay though, Asimov - The Relativity of Wrong.

+1

I hadn't seen this until now.

Asimov, as always, concise and erudite.

Thanks for posting.

[phat tony]

the belief is we are expanding from a central point and very quickly, but they also believe we are also orbiting around that central point. i do think you could be right with heading toward something, it might even be pulling us. i mentioned in here before about us being sucked into a total vacuum, so i see what your saying but i agree we are coming from a central point and we might be heading towards something. nothing is 100% fact, theory's change and the small amount of fact that makes them believable can also change. if we are comming from a central pint there is nothing to say we are not also being pushed or pulled in one derection, i think that the whole universe could be going in one derection but i also think it would be very hard to put any fact behind that theory as you would need a fixed or close to fixed point outside of the universe to judge if off. good topic

[Treeden]

here is one thing though, theorists say the expansion of the universe is speeding up, sooooo, if there is an initial big bang, momentum says it should slow down? as energy dissipates and reduces the further you get away from from initial explosion?

I may be wrong but I think the answer is that in space there is no resistance to motion until a force is applied to counter it. Energy is not dissipated with distance travelled.... well, not in those terms anyway.

If it is increasing, what could be pulling the universe faster away from the initial moment?

Other universes? Gravity, or gravities, must surely be pulling our universe outwards?

I believe (careful!) that the culprit is 'Dark Energy' and it isn't really pulling or pushing the way we understand those terms. It's a repulsive force and acts the opposite way that gravity works.

Apparently, the only reason dark energy is accelerating the expansion of the universe is because the universe is already expanding. If the universe suddenly stopped expanding and decided to start contracting, then dark energy would then accelerate this contraction.

[Vince1963]

This is all getting very interesting stuff... I love it when you come to realise how many different ideas and theories can be inter placed and generate new ideas with a mix of science and "personal theories" ( not to be mistaken with scientific theories). I really have enjoyed reading your posts, I have learned something.. And that's good right?. Thanks guys. Kind regards Vince

[JulianO]

I believe (careful!) that the culprit is 'Dark Energy' and it isn't really pulling or pushing the way we understand those terms. It's a repulsive force and acts the opposite way that gravity works.

Apparently, the only reason dark energy is accelerating the expansion of the universe is because the universe is already expanding. If the universe suddenly stopped expanding and decided to start contracting, then dark energy would then accelerate this contraction.

Dark energy does seem to be a repulsive force, it is a very weak force, but it seems to be a property of the fabric of space. Therefore as space expands, there is more space to provide dark energy, so the effective repulsive force becomes stronger. It's still dominated by gravity and electrostatic forces on short distances, but on very large distances there is enough of it to make things expand out at increasing speed.

[phat tony]

thank you vince i enjoyed reading the topic. treeden they know little about dark matter and they are not even sure of any of its effect on anything. i do think you are right but without knowing more about dark matter no one can really say. a total vacumm will want to be filled and i do know space is a vacuum but it does have matter and matter would want to fill that vacuum, if the space outside what we see as the universe was that total vacuum then the expansion would speed up and if that vacuum was infinite then the expansion would and could speed up until and beyond any limited we as humans have set, like light speed. some believe we are already traveling faster than light and they might be right. as a side topic, why are we orbiting that central point???? i understand why we orbit the sun and why we do most of the orbiting we do but why are we orbiting that central point, is there a mass there that is causing it or what?????.

[JulianO]

thank you vince i enjoyed reading the topic. treeden they know little about dark matter and they are not even sure of any of its effect on anything. i do think you are right but without knowing more about dark matter no one can really say. a total vacumm will want to be filled and i do know space is a vacuum

I think you're confusing dark energy and dark matter. They don't have much in common except the word dark.

[phat tony]

julianO please explain, i know little about both. do they know enough about the energy i don't know. i was thinking they no little about both. please explain i would be grateful.

i like to learn as much as i can. i could Google but sure i am here to chat and learn at the same time.

[Vince1963]

Hi Phat Tony.. yeah good question what is at the centre? is this the point of the "big bang" was this our entry point into this universe...part of a massive multiverse are we expanding or moving into or towards a new dimension/entity have we passed through a black hole to be where we are now what energy is out there that science hasn't discovered?. its great to talk and try and understand these things and i think science will have the answers one day but maybe not lol. Kind regards Vince

[JulianO]

Dark Matter - something a bit like normal matter you can touch which fills in an make things balance out quite well. There are several suggestions for what it could be, what sort of properties it has, and a lot of astronomy falls apart without it. It solves a whole host of different problems. Its still possible it could be wrong, but right now most people in the field assume it is true.

Dark energy we know hardly anything about - we see it's effects - accelerating the expansion of the universe on big distances, there are one of two suggestions for what it could be, but so far its pretty much a mystery.

So Dark Mass, maybe 80-90% understood, Dark Energy maybe 5-10%.

[Treeden]

Dark energy does seem to be a repulsive force, it is a very weak force, but it seems to be a property of the fabric of space. Therefore as space expands, there is more space to provide dark energy, so the effective repulsive force becomes stronger. It's still dominated by gravity and electrostatic forces on short distances, but on very large distances there is enough of it to make things expand out at increasing speed.

Not an easy one to get your head round is it! I tend to think of it like one of those rather impressive Maglev trains but in space. (bear with me ) There's no resistance to worry about, so all matter is passed from one electro-magnet to the next, but given a boost in energy each time. In my crude analogy, dark energy plays the role of the Maglev track. Well, it works for me!

... a total vacumm will want to be filled and i do know space is a vacuum but it does have matter and matter would want to fill that vacuum, if the space outside what we see as the universe was that total vacuum then the expansion would speed up...

If you are referring to the notion that "nature abhors a vacuum" and that a vacuum must be filled, then this relates to a difference in air pressure. Like explosive decompression in an aircraft when the cabin is punctured, or in science fiction films (a good example is "Sunshine") when members of the crew had to use this effect to get from one ship to another. They used the sudden explosive force of pressure travelling from high to low by unlocking the air-lock outer door while the air-lock was still pressurised!

I don't think this applies to normal space because (generally speaking) the pressures are balanced. This dark energy, that scientists came up with to explain the gaps in their equations, is exerting a force on all the matter in the universe (both visible and dark matter) and it is this that is causing the increase in acceleration. Unfortunately, it can't be detected by normal astronomical observations so there is plenty of room for the theory to be modified as our knowledge improves

[hobbesy]

Dark matter and dark energy are essentially place holder names for some things that we think need to be there for our observations to be explained but are as yet undetectable. Just like neutrinos were theorised before they were found (and most likely the Higgs Boson.)

Just a small point not aimed at anyone but worth keeping in mind. When people implore others to be open minded or think outside the box, its often because the reality is weirder and much cooler than they can grasp and they're tied down by an awfully prosaic idea of "common sense." (For example the question "what is the Universe expanding in to?" which is not only pointless to ask but spectacularly point missing.) those who rail against closed minds are often the ones who are dismissive of the real mind-blowing things in the universe.

We are relatively simple organisms programmed through millennia for pattern recognition, causal linkage and egocentric self belief. Now this will help stop you being eaten by a sabretooth but it won't help you grasp the size of the universe or the expansion of space time.

All the while you try to make things fit with our astonishingly brilliant and effective but necessarily simplistic and parochial conception of "what makes sense" (given our tiny existences) then you won't be able to scratch the surface of how awesome the universe actually is.

[Vince1963]

hobbesy....Sound's like Dr hobbesy as got me on his couch to me. What do you mean? "egocentric"?. It is you that is egocentric with your statement aimed at me. I am open minded... I have a lot of respect for scientists, I have listened to what they have to say and i can see there point of view,without learning from these scientist, I would not have an opinion/theory. But like i say they don't get it right every time, they don't have all the answers...YET. And in your statement "what is the Universe expanding in to?" which is not only pointless to ask but spectacularly point missing", Do you have the scientific back ground to tell me that some of my questions are pointless?...I doubt it!!.I Have always been fascinated with the universe since i was very small and yes somethings are hard to grasp and understand. but i'm not the one who is so inflated by my own ego and "education", That i am not open minded... We are having a debate and kicking around idea's that is all,looking for answers, and this is what science does all the time.. No one man is so arrogant that he thinks he as come up with all the answers to science by himself, It takes idea's and viewpoints of other scientists (ok there are some "egocentric" scientists out there that like to think they know it all) . I'm sorry to say we are not programmed through millennia to recognise patterns....the reason being is that these patterns have always been there in us, it is the building block of everything in not just our world but the universe and beyond what ever is out there.And yes the universe is "awesome".

[hobbesy]

Egocentric as a species. I think that was pretty clear.

[Doughzer]

I don't think hobbesy is having a dig vince.

I think discussions like these are great as long as they are taken in a good heart.

I also think people who haven't taken a "phd" in the sciences can have valid questions to ask on things we can only surmise on, and also be educated and advised by those who have.

Thanks for those who have made input to this thread, really interesting.

I think this is what I like about astronomy and objects in the universe in general, so many figures, wonders, objects, new discoveries, the sheer scale of things, and knowing there are things waiting to be discovered.

Shame I will only live for about 80-90 odd years lol.

[Macavity]

hobbesy....Sound's like Dr hobbesy as got me on his couch to me. What do you mean? "egocentric"?

I'd say, "honours were equally divided", at very worst? LOL. But I saw no REAL wrong. You seem now (as not uncommonly) to use the word "Dr" in that... "vaguely pejorative" way? <sigh>. I experienced THAT one quite a lot, once I left academia. Open minded? But you do "load the language" of your posts quite a bit too?

What if scientists are WRONG? They don't know EVERYTHING! That is how "we" all learn... EVEN a scientist? <G> You throw "us" a few tidbits... Scientists are PROBABLY right... But then immediately, remind us: "There is NO 100% proof"? etc. etc. But a more generous view of scientists on your part? Hey, I'm only saying...

Scientists are not *that* different from the general population. We ALL have our "pathologies" and our virtues? Ignore "Brain Corks" and his (BBC-funded) "societal change" types? <yawn> We mostly try to help, rather than deliberately deceive the public? If we insult you, it's mostly "in the cause of science", and rarely personal!

Quite difficult to be TRULY "Open Minded", innit Eh?

[Treeden]

In our fairly recent past the greatest scientists of the time were convinced that the world was flat. They were also convinced that the Earth was the centre of the universe and that the sun revolved around it. At that time these ideas were considered to be facts not opinions or theories.

We are making huge advances in our knowlege and understanding of the universe, but there are still gaps that remain unfilled. We still have a long way to go.

We all want to learn the answers to the big questions. We're all on the same journey.... let's be nice to each other on the way.

[Vince1963]

Hi Macavity... Very good and very true, I'm only trying to stimulate the passion for knowledge and the truth, and discussion forums are great for that. I Have a lot of respect for scientists and i know they are not trying to deceive. I would have no argument or discussion if i didn't know what i know today all of which is science based. But i am "still" sorry to say, they don't have al the answers, but they do have science based "best Guess" LOL. I just hope one day they will be able to answer the unanswerable and i hope its before i'm gone... In the mean time i will keep reading and listening to science as i always have.

[Vince1963]

Treeden... Bravo

[JulianO]

Scientists don't have all the answers, but I think one of the key differences is that they are aware of the constraints.

It's good to think outside the box, and many scientists are open minded. When the recent neutrino going faster than the speed of light thingy came up, one of the local professors of theoretical physics was quite excited, he had already thought of several PhD projects to investigate possible answers. That means ignoring the status quo that Einstein was right, and the speed of light can't be exceeded. Its a willingness to explore new ground.

However, you can't just say "neutrinos go faster than light, case closed" you have to explain why most other observations (including those from very distant supernovae) do show them travelling at the speed of light. These are the constraints into which a new theory has to fit. That was one reason lots of scientists were sceptical about the results - there is/was a lot of evidence showing they don't go faster than the speed of light, both actual and theoretical. Therefore it would have to be a pretty special case to affect those neutrinos and not others (I did wonder about the lab being close to the Vatican might have somethign to do with it )

It's not like removing a speed sign saying 70mph, and now cars can travel faster than 70. A new theory has to explain why cars can now go faster then 70. So a non specialist in the field might think its just a change in the top speed, but the specialists have to worry abut lots of other things - do they have big enough engines, why don't they go at 100 over ploughed fields, there is an anomalous value for cars that travel between Dover and Calais at what appear to be two fixed speeds, they are rarely seen to cross the Atlantic or go into orbit despite managing to travel vast distances. How do we get a theory of cars that explains all these things?

[phat tony]

no scientists don't know everything, but they know a lot more than me. if i keep asking questions and keep offering up theory's then i will one day know them answers i am in search of. juilano, thank you for your help and thank you for your wise words they mean a lot. the best way to learn is to share our knowledge, pool it all together and see what can swim. peeps please don't argue, we are all allowed to say what we think, some might not like it but we are still living in a kind of free world. now for something compleetly different well slightly off topic, i have a friend who is one of them scientists and he has so much brain i keep having to tell him its showing, i then poke it back in for him. hahahaha to put that in English he sometimes leaves people with their heads tilted to the side two words into a convo. the funny thing is about 5 months ago i dropped in to see him and he was trying to put together some flat pack furniture, when i arrived he was almost 2 hour in and still hadn't started, i put it together for him in about 10 minutes. all people shine in different ways.

[Macavity]

Hi Macavity... Very good and very true, I'm only trying to stimulate the passion for knowledge and the truth, and discussion forums are great for that. I Have a lot of respect for scientists...

Hi, Vince. Oh, lest there be doubt, I was just messing. A bit of "pro-rationalist", Devil's Advocacy? <G> And, since I am often circumspect re. modern science (media, presentation) myself, firmly tongue in cheek. Questions are ever good, in my opinion...

Aside: I notice that (according to "polls") a LOT of people have faith in science - And still, habitually, MORE faith, than in politicians and bureaucrats etc? Probably because scientists (forumites etc.) will allow - Usually TRY to answer the question. <group hug> - In a "scientific" way, of course.