Speed of light

[Chris Peterson]

From a 3D perspective, that's completely true. Of course, from a 3D perspective every point is the center of the Universe.

Only if the universe is infinite .. which it's not IMOPO.

No, the Universe does not need to be infinite for every point to be considered a 3D center, any more than the surface area (or volume) of a balloon needs to be infinite for any point on the surface to be considered a 2D center of the entire surface.

[Chris Peterson]

Oh yeah? Well, how about the optics involved here? How about when we actually SEE that the stellar universe comes to an end, and something else begins? THAT observation is not far off.

That observation will never happen optically. The limits of optics end when we see back to when the Universe was opaque. It's possible that gravity wave measurements will let us see beyond that, to nearly the BB. There is no "beyond" that, of course, unless our Universe is embedded in some sort of hyperuniverse. But there's no reason to think we can ever see that, with any kind of instrumentation. At best, we might hypothesize properties based on indirect effects on our universe, at the very beginning.

[Superdoc]

you gotta be joking, on the last post.

[bystander]

... The limits of optics end when we see back to when the Universe was opaque. It's possible that gravity wave measurements will let us see beyond that, to nearly the BB. ...

Cosmologists aim to observe first moments of Universe
Science Centric - 17 February 2009

During the next decade, a delicate measurement of primordial light could reveal convincing evidence for the popular cosmic inflation theory, which proposes that a random, microscopic density fluctuation in the fabric of space and time gave birth to the Universe in a hot big bang approximately 13.7 billion years ago.

... South Pole Telescope (SPT) with a team of scientists from nine institutions in their search for evidence about the origins and evolution of the Universe.

Now on their agenda is putting cosmic inflation theory to its most stringent observational test so far. The test: detecting extremely weak gravity waves, which Einstein's theory of general relativity predicts that cosmic inflation should produce.

[apodman]

you gotta be joking, on the last post.

Truly I heard it in class from a public school teacher. I believe the teacher was serious, but (for good reason) I don't believe everything I was taught. I dunno about this one. I just passed it on. If it's not true, I still don't know whether it's a joke, ignorance, or propaganda. I was treated to all three. That's what passed for a balanced education in my town. Don't get me started.

[aristarchusinexile]

I suppose if aliens wanted to interbreed with human to create a new race, India would be a great place to begin.

[Chris Peterson]

I heard in the 1960s that diaphragms sent without instructions to India for population control were mostly placed on the altars among the fertility gods.

Yeah, that's right up there with the third world aid workers who demonstrated condoms using bananas. Birth rates didn't decline, and an investigation revealed... you guessed it, the locals were putting condoms on bananas and then having sex.

Good stories, but I don't really buy them.

[apodman]

I actually saw the banana demonstration in the 1990s on tv right here in the US, so at least that much of it is true. Some of these stories may start with a grain of truth before they get embellished.

[Superdoc]

so you are saying the aliens are stupid and will treat the human made equipment as a god till they realize the scientific facts after their ancestors? who knows maybe our ancestors also thought objects falling from sky were blessings from god...

[aristarchusinexile]

That observation will never happen optically. The limits of optics end when we see back to when the Universe was opaque. It's possible that gravity wave measurements will let us see beyond that, to nearly the BB. There is no "beyond" that, of course, unless our Universe is embedded in some sort of hyperuniverse. But there's no reason to think we can ever see that, with any kind of instrumentation. At best, we might hypothesize properties based on indirect effects on our universe, at the very beginning.

IMOPO your opinion on the size of the universe is greatly exagerated.

[apodman]

so you are saying the aliens are stupid and will treat the human made equipment as a god till they realize the scientific facts after their ancestors? who knows maybe our ancestors also thought objects falling from sky were blessings from god...

Have you seen this movie?

A Sho in the Kalahari desert encounters technology for the first time--in the shape of a Coke bottle. He takes it back to his people, and they use it for many tasks. The people start to fight over it, so he decides to return it to the God--where he thinks it came from.

It's categorized as comedy.

[makc]

Chris, with indians you just never know...

Apodman, that N!xau guy was real thing. Also, his movies were just awesome.

[aristarchusinexile]

so you are saying the aliens are stupid and will treat the human made equipment as a god till they realize the scientific facts after their ancestors? who knows maybe our ancestors also thought objects falling from sky were blessings from god...

Humans treat human made equipment as gods (nuclear bombs for instance).

[aristarchusinexile]

From a 3D perspective, that's completely true. Of course, from a 3D perspective every point is the center of the Universe.

Only if the universe is infinite .. which it's not IMOPO.

No, the Universe does not need to be infinite for every point to be considered a 3D center, any more than the surface area (or volume) of a balloon needs to be infinite for any point on the surface to be considered a 2D center of the entire surface.

I can accept fully your 2D balloon surface .. but cannot understand why you say the same thing about a 3D body with volume .. which I assume is what we are discussing (?).

[Chris Peterson]

No, the Universe does not need to be infinite for every point to be considered a 3D center, any more than the surface area (or volume) of a balloon needs to be infinite for any point on the surface to be considered a 2D center of the entire surface.

I can accept fully your 2D balloon surface .. but cannot understand why you say the same thing about a 3D body with volume .. which I assume is what we are discussing (?).

The balloon analogy is intended as a visualization tool, since most people are not well equipped to picture four dimensions. So the idea is, reduce the number of dimensions by one. Thus, the entire Universe becomes 3D (the balloon), and the spatial dimensions of the Universe become 2D (the surface of the balloon). This model helps to clarify how space expands (the surface area increases as the balloon is blown up), how there is no center to the 2D surface, and how the center of expansion is outside the 2D surface (it is a 3D point).

Hopefully, this helps one to imagine what's going on in the actual Universe, which is 4D, with a 3D spatial surface (what I think you are calling volume). The 3D surface (volume) is expanding, but there is no center to that expansion, except about a 4D point which is outside any spatial direction we can look in.

[Superdoc]

I only started this topic to get a scientific reason for my question but no wonder why it has transformed into a meaningles subject, makc what does your video link indicate here? i dont see it contributing anything to this topic.

[bystander]

makc what does your video link indicate here?

See apodman's post above.
http://asterisk.apod.com/vie ... 03#p101003

[apodman]

I only started this topic to get a scientific reason for my question but no wonder why it has transformed into a meaningles subject ...

Wrong. You started a topic with a meaningless subject. It was initially locked by a moderator for obvious reasons. Time-traveling aliens are stuff for Saturday morning cartoons at best. After the topic was unlocked, the rest of us made it interesting. And now you act superior and expect us to stand at attention, salute you, and apologize? What a joke. Even serious contributors know they have no control over a thread once it is started. Note that the first reply (mine) was 100% serious, and a lot better answer than your question deserved.

[makc]

wow, this was locked? hmm... I missed it.

[makc]

...since most people are not well equipped to picture four dimensions.

just a side note, there are 4D and 5D rubik's cube games out there, and people who can actually solve them.

[apodman]

wow, this was locked? hmm... I missed it.

Unless I'm mistaken, and what are the odds on that? Truly there was a brief passing lockage, and I believe it was this topic. I thought maybe you did it. Either way, think of all the valuable information we would have missed.

[makc]

and what are the odds on that?

I dont know, but bystander lately CCs all his moderation-related PMs to me, so I thought I would remember this...here is last thread I locked, and it remains locked atm.

[bystander]

'Twasn't me, either! Scanned mod logs for past month, can't see it was ever locked.

[Chris Peterson]

'Twasn't me, either! Scanned mod logs for past month, can't see it was ever locked.

Interesting, because I'm pretty sure I saw it locked for a day or so, and then unlocked again. I remember wondering what happened.

[apodman]

Nereid locked "Red Shift Alternative" at about the time this thread originated (January 20 or 21, depending on time zone). She could have spilled coffee in her lap and hit the wrong button before recovering and fixing it. (Logs too? I'm sure we were on red alert when I ejected the pod.) Not to point an unsupported "theory" in anyone's direction, you understand. Or are occasional phpBB anomalies caused by cosmic rays? Anyway, I originally thought the time-traveling aliens were the trigger and that later the judgment was reconsidered, which IMO wasn't so far-fetched. In any case, I humbly withdraw the phrase "for obvious reasons" that I used earlier, as the reasons are no longer obvious. Even mysterious.