Elad

If you have a wise account you can order the virtual or physical card which moonpay accepts. I have used it many times on trust wallet.

Then you will know that the Big Bang theory is not about how the universe started, its about how the universe evolved from a time when all the matter and energy was already present about 13.8 billion years ago. There is no scientific theory on how the universe was created and any physicist will say "we don't know".

I like this scientific side to ya Sunmaster, keep it up ???? A rotating solid disc like that is quite complicated, there's a lot of forces going on including accelerations and its not easy to explain. However, it seems a little backwards to me because time slows down with increasing radius so I would put CC at infinity where time comes to a stop on your diagram. At the center time should be flowing faster ????

To determine how the universe evolves in terms of the expansion/contraction, we need to know the energy density values for radiation, matter and dark energy. All current models show that the universe is dominated by dark energy and that the universe will continue in its accelerated expansion forever. See below Radiation (blue) was dominant in the very early universe, to then cross over to a matter (red) dominated universe, this actually slowed the expansion until around 4 billion years ago when dark energy (green) takes over. Notice how the dark energy density remains constant throughout, while matter and radiation dilute as the universe gets bigger. Also note that the matter density (red) includes dark matter + normal matter.

I was being generous using light cause it gets even worse for sound ???? Since we're on the subject of seeing events I just want you to know that in physics there's a difference between 'seeing' and 'observing'. Seeing an event (like we just discussed) is when the light from that event reaches your eyes or scientific instrument, whereas observing an event is the exact time and place the event happened. So for example if I see the explosion of a distant star tonight that was 10 lightyears away, then I would report the time of the explosion as ten years ago. In special relativity we are only interested in observing events NOT seeing events, so when we assign coordinates to events its when and where those events actually occurred in a particular reference frame. Just wanted to make that clear since its very important in understanding how time works in relativity. There's a common misconception in SR which is 'moving clocks tick slowly' and although its true that you will observe a moving clock to run more slowly than your own, there's actually more to it than that and the relativity of simultaneity shows us that its time itself that changes from one frame to another where observers take different paths through spacetime. I'll try to explain using two reference frames. Imagine yourself (Tippaporn) on Earth and me (Elad) travelling at some speed V relative to you. Since speed is relative then I could say that I'm at rest, and you, on Earth, is travelling at speed V, it makes no difference in relativity. Due to this symmetry not only will you observe my clock running slow, but I will also observe your clock to be running slow, sounds like a paradox but its not when you take the relativity of simultaneity into account. If you observe and assign coordinates to two events that occur simultaneous but at different locations in your frame, and remember this is observing so those events really do happen at the same time in your reference frame. Then in my frame, I will observe the same two events at different times lets say two seconds between each event. How can this be because if time was just slowing down then the two Events would still be simultaneous in any frame. Time changes on different paths through spacetime. In SR when we do the transformations of coordinates from one reference frame to another, the math shows us that the time coordinate depends on the space coordinates, and space depends on time, there's a mixing of space and time into one spacetime and this is how the universe seems to work. The condition of two events being simultaneous is a relative one not an absolute one. I'm finding it very hard getting this across, and I'm not the best science communicator ????but I hope it helps you to understand that time is not absolute, it make no sense to say "I wonder what aliens are doing right now in the Andromeda galaxy" because our now is not the same as theirs, if they exist. I would've liked to add some 2D spacetime diagrams to illustrate better how it works but I'm not sure you'd appreciate them. Instead of searching the thread would it be possible to send me a link on Seth's definition of time, I'd like to have a look at it.

I might respond to one or two of them but don't expect much from it because you already know I'm a bit of a materialist ???? I need to clear a few things up with @Tippaporn first with regard to time. Bear with me please because I'm not always at my laptop and I hate using the mobile.

Its just a common joke among scientists. Of course physics works, you only have to look at all the technology around you to know that.

Some cosmologists think that we live on the surface of a 3-sphere. A 2-sphere is like the Earth which is spherical, has a 2D surface, and has no beginning and no end. A 3-sphere, is a sphere with a 3 dimensional surface that has no beginning and no end, so if you traveled in a straight line for many billions of light years then you'd end up in the same place you started. Sounds plausible but I have problems visualizing it. And it solves the problem of where does the universe end, like the surface of the Earth it never ends.

No one is claiming to be a scientist here but even if they were, so what, scientists aren't special people they get things wrong all the time, especially the physicists. Have you ever heard that saying: If it smells, its chemistry If it wriggles, its biology If it doesn't work, its physics ????

I don't really like to speculate but it wouldn't surprise me if there were extra dimensions. Have you ever heard of a 3-sphere?

I'm no Einstein trust me ???? but I have been studying physics part time for the last 9 years or so, I'm no expert but I dare say I know more than the average person when it comes to physics. In Minkowski spacetime, the time axis becomes a length so its has the same units as the x,y,z, and when you measure the spacetime separation between events from any inertial reference frame its an invariant quantity. Events with a positive >0 separation are time-like Events with a zero (or null) separation are light-like Events with a negative <0 separation are space-like. I can't really go into it anymore without using some math ????

It's how we visualize it in Minkowski spacetime, if you look at the lightcone above, all events within the lightcone are time-like and can be causally connected, events that occur on the edge of the lightcone are light-like which could be connected by light signal. Events that occur outside the lightcone are space-like and these events cannot be causally connected. This is all part of special relativity.

It's hard to visualize any higher dimensions, but some people think the universe is expanding into another dimension. Whats your definition?

Yes, that is a 3D lightcone 1 time and two space. For a 4D lightcone those cones would become spheres. When I look at my friend, Im looking slightly into the past lightcone. What other options does it have?

We are actually always looking into our past lightcone. If you are talking to a friend who is stood 1 m away from you, then it takes light about 2 nano seconds to reach your eyes and then your brain has to process that information, so in that sense, everything you do in your life what you think is the now, is actually slightly in the past.

In relativity we use a 4D spacetime manifold, which seems to be the universe we live in. Observers won't agree on the times and lengths between events but they will all agree that two events have an invariant spacetime separation. You can actually apply extra spatial dimensions in relativity and it doesn't make any difference it just makes the math harder, Leonard Susskind does just that in some of his lectures on relativity. If you or Tippaporn have a personal theory of time then the relativity of simultaneity shouldn't be used as an example for it. It's nice to think about higher dimensions but how do you know they exist?

I'm afraid you and Seth are just wrong about time. Time is real, its relative and there is no absolute time in the universe, the notion of NOW universally doesn't exist. Time being relative has been verified experimentally with atomic clocks on satellites orbiting the Earth. For satellites in orbit there's two factors of time dilation going on, gravitational time dilation where clocks in a weaker gravitational field tick more rapidly, and there's time dilation due to special relativity where moving clocks tick more slowly. For satellites in a low Earth orbit where the orbital speed is higher then the effects of special relativity dominates and the clocks on board tick more slowly relative to Earth based clocks. For satellites in a high Earth orbit (like our GPS at 20,000 km above the Earth's surface) where orbital speeds are much slower, then the gravitational time dilation dominates and those clocks tick faster than the Earth based clocks. In fact there exist an orbit where both effects of time dilation cancel each other out which is about 1.5 Earth radii or 3,200 km above the surface, and clocks there keep in sync with Earth clocks. If time was just an illusion as you say, then why do we have to correct for these effects on our GPS because if we didn't make these corrections, then the errors in positions of GPS receivers would accumulate at the rate of tens of km per day. The fact that we have to make these corrections verifies that time is real. And BTW its not just the clocks that are ticking more slowly/rapidly, if a human was in the same reference frame as the clock then their heartbeat, metabolism and any biological processes slow down or speed up relative to someone on Earth. These effects are very small for Earth orbits but when speeds are close to the speed of light or gravity is very strong then the effects are significant. I noticed you were using relativity of simultaneity in relation to events within our past and future light-cones. Did you know that relativity of simultaneity is specific to space-like separated events (i.e. events that are not causally connected and not within our past and future light-cone) where two space-like events are simultaneous in one frame of reference, are not in other frames. In fact the ordering of events can be reversed for space-like events, if event 1 precedes event 2 in one frame, then there will exist a frame where event 2 precedes event 1. No paradoxes involved here because the events are not causally connected. For time-like separated events (i.e. events that are causally connected and therefore within your past and future light-cone) then the ordering of events cannot be reversed nor can they be simultaneous no matter what the reference frame. For time-like separated events the causal event always precedes effect. @Tippaporn you should take some time to study special relativity, to where you can read Minkowski spacetime diagrams, use the Lorentz transformations and understand the relativity of simultaneity, then come back here and tell us if you think time is real. ????

I think you're wrong there Sunmaster. Einstein was an atheist, he did use the word god very loosely for things we don't understand, Stephen Hawking did the same and he was an atheist. I don't know why religious people quote Einstein, why not quote Isaac Newton he was religious and so believed in a personal god, he was also smarter than Einstein IMO.

In evolution there are no sudden jumps from one species to another, its a gradual process of small incremental steps over thousands and millions of years. There never was a first of any species, just like there never was a first human. There was never a moment where a Homo erectus mother gave birth to a Homo sapien child, it doesn't work like that. It's analogous to how a human grows old from a baby to child, adult to middle aged or middle aged to an old man, There's never a moment, you don't go to bed a middle aged man then wake up in the morning an old man, but if you wait a sufficient number of years you become old. That's how evolution works but now we are talking about thousands and millions of years and it's very hard to grasp those time scales.

Blimey whats happened to this thread. It used to be quite interesting, but now, just reading some of these posts is like pulling teeth. It seems we have religious fundamentalists in here, and you cannot debate a fundamentalist. Why? because evidence means absolutely nothing to them, no matter how much you put on the table. An example would be the American young Earth creationist Kurt Wise who has a PhD in Geology from Harvard university. Kurt Wise said: " I am a young age creationist because that is my understanding of the Scripture. As I shared with my professors years ago when I was in college, if all the evidence in the universe turns against creationism, I would be the first to admit it, but I would still be a creationist because that is what the Word of God seems to indicate." https://en.wikipedia.org/wiki/Kurt_Wise You can't do anything with a mind like that, and a mind like that is a disgrace to the human race.

You've probably been watching too many popular science programs on discovery. The big bang wasn't an explosion within space, it was the beginning of space and time itself. A regular explosion within space has a center, whereas the universe has no definite central location, in fact the center of the universe is everywhere, the big bang happened everywhere. If you measure the expansion of the universe from Earth or from a Galaxy a billion light years away, the expansion is always centered on you. Also, the big bang theory is not a theory of how the universe started, its a theory of how the it evolved from a time after t = 0 and all the matter/energy within the universe is already there, it doesn't say anything about how the matter/energy got there. The reason we see order in universe is due to the constants of nature being fixed, and as far as we know they do not change with time. When the laws are fixed systems become in equilibrium. Take the stars for example they are in equilibrium, the outward pressure from fusion is exactly balanced by gravity trying to crush the star inwards. If the gravitational constant was not fixed and changed just slightly, then the stars would either implode or blow themselves apart, the universe would be chaotic and life as we know it would not exist.

I'm pretty sure that you can not extend a visit visa or turn it into a settlement visa, so your girlfriend will have to go back to Thailand before the visa expires. When she returns to Thailand she can apply for settlement, however, for a spouse settlement you will need to get married. I do believe there is a fiance settlement visa which gives you six months to marry in the UK, then you get an extension for a further 2 years (she wont need to leave the UK). Another option would be to marry now and when she returns you can go straight for the spouse visa. Not sure if they still allow marriage on visit visas though.

So we don't know how gravity works and yet we can send a telescope to a region of space (L2) millions of miles away, a place where we know the gravitational effects of the Sun and Earth cancel each other out. And this was done using Newton's Law's that are accurate to one part in 10 million. Einstein's theory is accurate to one part in 10^14, thats a 1 with 14 zeros. God must be hiding at the 14th decimal place. ????

If the aliens laid out undeniable evidence for the existence of a supernatural being, then I would throw my atheistic view of the universe out the window and become a believer, because its all about the evidence. On the other hand, if the aliens showed us that everything can be explained by nature, like how life and the universe started, how it will end, and how consciousness is all part of the physical. Would you be willing to give it all up?

Well I don't know what that is but its not calculus, if its supposed to be algebra then its very, very poorly written, its unreadable.