There is no such reality in the standard BB model.
No, south only makes sense on a sphere. There is no general direction in space called south. Yes, south stops at the South Pole.
Feel free to ask.
Physicists tend to use the word “light” for any electromagnetic wave, whether it is from visible light or not. So, radio is considered to be “light” since it is simply an electromagnetic wave of low frequency.
This differs, of course, with common language. It is also the...
When you hear an echo, you are hearing the sound made in the past. When you see lightning and hear thunder a few seconds later, you are hearing the sound made in the past. This happens because it takes time for sound to travel.
It also takes time for light to travel. So, when we see light from...
Yes. The cosmic background radiation was formed when the universe cooled enough to become transparent. We can observe this radiation in all directions today. That is literally the earliest light we can possible detect.
Now, it might be possible in the future to detect the neutrino background...
And the Big Bang might be the conceptual limit of time. According to general relativity, the time coordinate cannot be extended past that point in a way very similar to the inability to extend latitude past the South Pole. The geometry is similar, although the curvature is more in the BB.
The analogy is that for every point on earth it is possible to go south. But there is an exception at the South Pole. There is no south of the South Pole. There is no “southlessness”. Or isn’t “southless nonexistent”. It is simply that south cannot be defined there.
The analogy is that for every point on earth it is possible to go south. But there is an exception at the South Pole. There is no south of the South Pole. There is no “southlessness”. It is simply that south cannot be defined there.
Actually, we do not know this. If the simplest versions of the BB hold, then we cannot count backwards forever. There was a point when time started— no before, no counting further backwards.
This comes from the math of general reality.
No telescope travels in time. Telescopes can detect light that has been traveling for long periods of time. That light carries information from when it started on ours journey.
But, no, no telescope can pick up information from before the point when the universe became transparent. That...
No, I am NOT saying that. As I see it, the universe is a four dimensional construct that includes ALL space and ALL time. Since 'creation' implies causality and that implies that time exists, all 'creation' happens *within* the universe.
In the four dimensional spacetime universe, the 'changes'...
Well, it extends back about 13.7 billion years in our current reference frame. We know a fair amount about the geometry of spacetime and how it interacts with matter and energy.
And the fact that science is possible (it is possible to test hypotheses) shows that physical things exist (all with appropriate definitions).
The *definition* of physical used in your link was 'testable'. So, anything testable is, by definition, physical.
But that means that anything...
That links went pretty well for a while. It essentially *defines* physical to be testable. It went off the rails, though, when it *assumed* that ghosts are not testable. Why would that be the case? Under this use of the word, why would ghosts necessarily be non-physical?
But we can go a bit...
No. You make the mistake of assuming that time is infinite into the past. While that may be the case, it is far from proven.
The word 'eternal' has a couple of meanings:
1) for all time.
2) for an infinite amount of time.
For the first definition, the universe is eternal because *time is part...