How Many People Have Ever Lived on Earth?

[3db]

Just think about how much we can't (and never will be able) to see.

I'd sure hate to drop my car keys in one of them thar black holes. I'd never find them. I already lost a set somewhere at home.

 

[haraldo]

"Man, I'd like to see her dark matter."

Remark made at every scientific conference where this theory is discussed.

Even more crazy that we don't even really know how this stuff behaves, and the physical laws that govern these things.....

I'd sure hate to drop my car keys in one of them thar black holes. I'd never find them. I already lost a set somewhere at home.

your car keys will suddenly appear somewhere magically in 3000 years from now

Sometimes it seems like me and my wife fall into a black hole, at least time disappear from us, almost daily

 

[haraldo]

That depends on just what the word "observable" means. If a person with excellent night vision observed the night ski,summer & winter in both the North & South hemispheres, he would see less than 10,000 different stars. But just using binoculars the count goes way up.

The way I understand it observable means distinctly observable by the best possible telescope by any means, optical or... well... any other way of identifying a star.... not sure if we an identify single stars in the Andromeda galaxy.....

 

[shadyJ]

I absolutely disagree. I mentioned a theory.


Apparently they could read the documents, but not legitimately discuss them. Btw, in your scenario, their observable universe would be larger than those documented but less populated.

You can discuss unobservable universe, of course, but since you can not test it, even in theory, that discussion doesn't lay in the domain of science proper. Boundaries of the universe may appear to shrink but evidence would remain of stuff gone from visibility, so that does make those vanished parts of the universe observable, technically speaking. These things could arguably be said to be apart of the observable universe as they would be stuff from within the particle horizon but outside a cosmic horizon. That is my understanding, but I am not a cosmologist. Also, the universe wouldn't appear to be larger from spatial expansion, after all, space can not expand into itself. What happens is farthest objects simply redshift out of existence.

From the Wikipedia article on the big rip, the odds-favored outcome of the universe at this time:

A universe dominated by phantom energy expands at an ever-increasing rate. However, this implies that the size of the observable universe is continually shrinking; the distance to the edge of the observable universe which is moving away at the speed of light from any point moves ever closer.

 

[haraldo]

You can discuss unobservable universe, of course, but since you can not test it, even in theory, ......

You can test for it, the gravitational effects are observable indeed...

The gravitational effects of a dark atom disk on stars in galaxies could eventually be detectable via the European Space Agency's Gaia space observatory scheduled to launch in October, which aims to map the movement of approximately 1 billion stars in the Milky Way.

 

[3db]

You can test for it, the gravitational effects are observable indeed...

The gravitational effects of a dark atom disk on stars in galaxies could eventually be detectable via the European Space Agency's Gaia space observatory scheduled to launch in October, which aims to map the movement of approximately 1 billion stars in the Milky Way.

+1. The gravitational effects are very real and are observable indirectly

 

[Adam]

You can test for it, the gravitational effects are observable indeed...

Harald, I'm not talking about dark matter.

 

[Adam]

You can discuss unobservable universe, of course, but since you can not test it, even in theory, that discussion doesn't lay in the domain of science proper.

I get what you're saying, and it might just be semantics, but I do disagree. According to your thinking, String Theory is not science proper. IMO, it is. It's not String Law, nor will any true scientist claim that it is - but it is a legitimate theory that has merit. Right now, we as a species are unable to test it, but someday we might be able to. What makes it a compelling theory is how strongly the math supports it. Just like math supported the existence of black holes back when we couldn't test it. And math supports the existence of objects farther away than light has traveled in the perceived duration of the current universe. The fact that we can't currently observe those objects doesn't mean that we won't be able to someday. The speed of light in a vacuum is, again in theory, the maximum speed that information can travel through space...but space itself is not constrained by that limit. If we find a way to harness that, then the distance at which we can perceive things will expand.

Also, the universe wouldn't appear to be larger from spatial expansion...

Agreed. I was referring to the extra distance that light would have traveled in the time between us and the hypothetical people of the future.

 

[Adam]

Even more crazy that we don't even really know how this stuff behaves, and the physical laws that govern these things.....

I'm assuming that you're still talking about women.

 

[haraldo]

Adam, it's two things I just can't comprehend
1. Women
2. The string theory

I consider myself quite up-n-going in physics... but string theory is something I just don't get......

 

[Adam]

Adam, it's two things I just can't comprehend
1. Women
2. The string theory

I consider myself quite up-n-going in physics... but string theory is something I just don't get......

I don't know the math behind string theory and am not that interested to ever know it, but I think that I get the general concept thanks to Brian Greene. Stings vibrate, and depending on how they vibrate, their "notes" represent different types of matter. Or something like that.

Women, though? Well, I don't know what they want, but I know at least one thing that they don't.

 

[shadyJ]

I get what you're saying, and it might just be semantics, but I do disagree. According to your thinking, String Theory is not science proper.

String theory is scientific because it makes predictions and is testable. Maybe not testable with present technology, but it does make claims that are theoretically verifiable. However talk about stuff beyond the edge of the observable universe is another thing altogether. From our perspective it does not exist, there is no possible way to gather information about anything outside of our light cone ie the observable universe. Science can only deal with claims that are falsifiable, and no such claims can be made there. That being said, I think, given the uniformity of space from our vintage, that you could reasonably speculate space should roughly resemble what we see even if you were standing on a planet a hundred billion light years away. But that speculation comes from inferential reasoning, not scientific deduction.

 

[Adam]

String theory is scientific because it makes predictions and is testable. Maybe not testable with present technology, but it does make claims that are theoretically verifiable.

And that was my point about detecting "stuff" outside of our light cone. Light speed isn't the limit...just the theoretical limit through space.

 

[haraldo]

I only also know that women don't know what they want, they only know what they don't want

 

[haraldo]

And that was my point about detecting "stuff" outside of our light cone. Light speed isn't the limit...just the theoretical limit through space.

Well there's been detected particles that go faster than light, again.... that doesn't contradict general relativity theory....

 

[Irvrobinson]

Well there's been detected particles that go faster than light, again.... that doesn't contradict general relativity theory....

That finding was refuted. The only thing faster than the speed of light that I've heard of is whatever force is behind entanglement, and even that's not describing anything with mass traveling faster than light in a vacuum.

Now if you want to make your brain hurt entanglement is how to do it. Think about it, take two subatomic particles, like photons, entangle them, separate them by a hundred kilometers or so, and when you observe the quantum state of one, the entangled "other" is affected immediately. Ponder that for a second. There are uncountable billions of similar particles around, and you take just two and entangle them. Then you move one to another place, far away, where there are billions more of these particles, yet when the state information is transmitted from something a small number of picometers across over that distance the information only affects the one particular entangled particle; the others are unaffected. Any one of these factors looks too ridiculous to be true: the infinite speed regardless of distance, communication of information by something so tiny over so large a distance, or the perfect selectivity. If not for the generally accepted nature of Bell's Theorem by people who actually have expertise in this field I wouldn't believe any of it. I'm still not sure I really do believe it...

 

[haraldo]

that you could reasonably speculate space should roughly resemble what we see even if you were standing on a planet a hundred billion light years away.....

You seem to know more than we do..... as far as I understand the far edge of the universe is 13.8 billion light years away

 

[Adam]

You seem to know more than we do..... as far as I understand the far edge of the universe is 13.8 billion light years away

Harald, I'm still not sure if you get what Shady and I are discussing. We're not talking about dark matter. We're talking about the existence of things that are so far away that we can't now, nor perhaps ever will be able to, perceive them. Light has traveled a certain distance over the duration of our current universe, allowing us to perceive information (e.g. the existence of matter) from as far away as that distance. However, it has been postulated (and correctly, in my I-know-it-isn't-proven opinion) that there is more to the universe past that distance. One easy way to think about it is this - do you really think that we are at the center of the universe? What are the odds of that? I say, "no," but rather that it appears that way because we perceive the same distance away in all directions. The same is almost surely true no matter where you are located, meaning that if you were 10 billion light years away is some direction, then you should be able to perceive things 10 billion light years further in that direction that we can. Throw in the whole curvature of space thing, though, and it gets a bit dicier, I know.

 

[shadyJ]

Adam, it's two things I just can't comprehend
1. Women
2. The string theory

I consider myself quite up-n-going in physics... but string theory is something I just don't get......

You need a unifying field theory to bring them together which will give you a new perspective and a greater understanding of both. I have formed such a hypothesis, I call it the 'G-string theory'.

 

[panteragstk]

Just so you guys know, women don't understand women either.