Science nerds. Richard Dawkins and Neil deGrasse Tyson have a discussion.

[1hot281]

That still was too much for me to grasp. His explanation was great but it still didn't seem to describe what is at the "end" of space at 15 billion light years away.

As Tyson suggested in the video, "nothing". He implies that you cannot look beyond the birth of our Universe because there simply is nothing there. That is why scientists are attempting to look at what took places prior to the Big Bang Theory

14 billion light years away is the "end" of our horizon in space. It's the farthest we can see, because with the Universe being 14 billion years old, the farthest we can see is how far light can travel in that time. 14 billion light years. We can't see beyond that horizon because the light beyond that horizon would need longer than 14 billion years to reach us... which is older than the universe.

Space doesn't end at 14 billion lightyears away. We just simply can't see beyond that distance due to the time it takes the light from distant stars, galaxies, and other phenomena to reach us.

"Just to clarify, so it takes light time to reach us, and the Universe hasn't been here forever. If you combine those two facts, you get an "Edge of the Universe". So, the universe has been here for 14 billion years, the farthest thing that could send us any information is 14 billion light years away."

So when he says "nothing" is beyond our universal horizon, he means that a telescope could never see beyond 14 billion light years. There's nothing to see because there's no way any information (light) could have been sent from farther away and reach us in the time available. He doesn't mean that there's no universe beyond 14 billion lightyears away.

"We don't know wether or not the ENTIRE universe is infinite, the universe could be twice our horizon or infinitely larger than our horizon... ...so if we go there (the edge of earth's universal horizon) that would be the center of their own horizon... and whatever the age of the universe is, for them at that time, that would be the radius to their horizon..."

So, for an alien species 13 or 14 billion lightyears away, they could see 13 or 14 billion lightyears farther than us, relative to us here on Earth.

 

[crew_dawg16]

14 billion light years away is the "end" of our horizon in space. It's the farthest we can see, because with the Universe being 14 billion years old, the farthest we can see is how far light can travel in that time. 14 billion light years. We can't see beyond that horizon because the light beyond that horizon would need longer than 14 billion years to reach us... which is older than the universe.

Space doesn't end at 14 billion lightyears away. We just simply can't see beyond that distance due to the time it takes the light from distant stars, galaxies, and other phenomena to reach us.



So when he says "nothing" is beyond our universal horizon, he means that a telescope could never see beyond 14 billion light years. There's nothing to see because there's no way any information (light) could have been sent from farther away and reach us in the time available. He doesn't mean that there's no universe beyond 14 billion lightyears away.



So, for an alien species 13 or 14 billion lightyears away, they could see 13 or 14 billion lightyears farther than us, relative to us here on Earth.

Edit: for some reason I couldn't see the second half of your post until I quoted it.

Sent from my phone (no "i" needed).

 

[SCBQQSTN]

So, for an alien species 13 or 14 billion lightyears away, they could see 13 or 14 billion lightyears farther than us, relative to us here on Earth.

So by your theory our universe would be a lot older than 14 billion years? Or is there no possible way to know how old the universe is because the light from beyond 14 billion years has not reached us yet?

 

[05slvrgt]

I started watching this thinking eh, a biologist, sounds boring. Now I'm 20 mins in and can't stop watching. Ive always thought if school was free I'd love to major in something with astrology.

Sure you don't mean Astronomy? Astrology is a pseudoscience.

But, I'm subd to come back and watch the video later. Richard Dawkins came and gave a lecture on campus last semester, but I couldn't make it. I was pissed, I feel like I really could have learned a lot.

 

[1hot281]

So by your theory our universe would be a lot older than 14 billion years? Or is there no possible way to know how old the universe is because the light from beyond 14 billion years has not reached us yet?

No, the universe is, according to all leading theories, 14 billion years old. But that doesn't limit the SIZE of the universe to 14 billion light years. The early Universe after the big bang expanded faster than the speed of light. (Parts of the universe today are still expanding faster than the speed of light. Which is observable, but I'm getting off topic) So it's more than likely quite a bit larger than 14 billion light years. We just don't know how much larger it is... The observable universe is probably one patch of a much larger unobservable universe. There are parts of the universe which cannot be seen because the light/energy/information cannot reach us yet. These parts of the universe are outside our current cosmological horizon. But 1 billion years from now, our horizon will move out another billion lightyears.

I think Dr Tyson explained it better:

"We don't know wether or not the ENTIRE universe is infinite, the universe could be twice our horizon or infinitely larger than our horizon... ...so if we go there (the edge of earth's universal horizon) that would be the center of their own horizon... and whatever the age of the universe is, for them at that time, that would be the radius to their horizon..."

 

[SCBQQSTN]

No, the universe is, according to all leading theories, 14 billion years old. But that doesn't limit the SIZE of the universe to 14 billion light years. The early Universe after the big bang expanded faster than the speed of light. (Parts of the universe today are still expanding faster than the speed of light. Which is observable, but I'm getting off topic) So it's more than likely quite a bit larger than 14 billion light years. We just don't know how much larger it is... The observable universe is probably one patch of a much larger unobservable universe. There are parts of the universe which cannot be seen because the light/energy/information cannot reach us yet. These parts of the universe are outside our current cosmological horizon. But 1 billion years from now, our horizon will move out another billion lightyears.

I think Dr Tyson explained it better:

So without altering our current time, we were able to somehow instantly teleport to the edge of earths Horizon of the universe 14 billion lightyears away, there's the possibility of discovering billions of more lightyear in the edge of that horizon (Or perhaps an infinite amount billions of lightyears)? Freaking mind boggling.....

 

[dsg04MACHone]

Sure you don't mean Astronomy? Astrology is a pseudoscience.

But, I'm subd to come back and watch the video later. Richard Dawkins came and gave a lecture on campus last semester, but I couldn't make it. I was pissed, I feel like I really could have learned a lot.

Yeah good catch.:beer:

 

[dsg04MACHone]

No, the universe is, according to all leading theories, 14 billion years old. But that doesn't limit the SIZE of the universe to 14 billion light years. The early Universe after the big bang expanded faster than the speed of light. (Parts of the universe today are still expanding faster than the speed of light. Which is observable, but I'm getting off topic) So it's more than likely quite a bit larger than 14 billion light years. We just don't know how much larger it is... The observable universe is probably one patch of a much larger unobservable universe. There are parts of the universe which cannot be seen because the light/energy/information cannot reach us yet. These parts of the universe are outside our current cosmological horizon. But 1 billion years from now, our horizon will move out another billion lightyears.

I think Dr Tyson explained it better:

Okay this makes sense. If he explained it better i missed it because he lost me at "nothing". Thanks.:beer:

 

[2V99GT]

worms have eyes?

 

[1hot281]

I'd also like to take the time to explain a few things;

When we're talking about the universal horizon being roughly 14 billion light years away, one, that's a 14 billion lightyears radius, in any direction from earth, giving the "bubble" of the universal horizon a diameter of 28 billion lightyears... and two, for the universal horizon at topic here and in the OP video, we're referring to light travel distance (the distance the light/heat or whatever form of information has traveled by the time we observe it today)... not the comoving or proper distance, the position the objects we are observing are, in relation to earth's position at our current time.

Remember that anything we can currently observe in the universe, we are seeing it as it was when that light we are now receiving was first emitted. So objects we are observing, approximately 14 billion light years away at the time the light was emitted, we are seeing it in the past, at the crossroad where the maximum amount of time the light could use to travel to us, and the maximum amount of distance the light could travel in that time, intersect...

For the proper size of the observable universe, it really depends on which theory of cosmology you subscribe to, as variables in theory can greatly affect the outcome of the equations used. But for some of the most common theories, the distances that objects we can observe, are, at current time, because of the expansion of the universe, much farther away than we see them... The estimated present time proper distance to the edge of the observable universe, if the universe turns out to be flat (which some data suggests is true) is somewhere in the neighborhood of 46 billion lightyears... giving the present era visible/observable universe a diameter around 92 billion lightyears.

 

[neatofrito1618]

I was just getting ready for bed, damn you to hell.

 

[silver2001cobra]

man, thats was great, thanks for sharing

 

[50 Deep]

Damn man. I took a lot of science classes my last semester of college and it blew my mind a little. This is even crazier.

 

[James Snover]

OP, great find. Neil De Grasse Tyson is the man.

 

[05slvrgt]

Good video. When I started it, I thought I would just watch a little of it seeing as it is 75 minutes long. Nope, watched it in its entirety. I'm a semester away from my bachelor's in biology, yet I'm always blown away hearing guys like these speak. Dr. Tyson knows his stuff. I really wish I would have taken some upper level physics and astronomy classes out of sheer interest, but I simply didn't need them. Not to mention how tough they likely are and the need more than just calc 1, which again I don't need.

 

[Common]

ROFL

http://www.youtube.com/watch?v=afGkv0IT4dU&feature=related

 

[neatofrito1618]

ROFL

http://www.youtube.com/watch?v=afGkv0IT4dU&feature=related

Little homie got got.

For those that don't already know, this is the orgin on the "watch out, we got a badass over here." meme.



http://www.youtube.com/watch?NR=1&v=ezR97NIKWFU&feature=endscreen

 

[carrrnuttt]

ROFL

http://www.youtube.com/watch?v=afGkv0IT4dU&feature=related

Yup. That's the exact moment at the end of the video I was referring to in my earlier post:

Going back to the topic, what a ****ing waste that last question from the audience was. Am I the only one thinking that was someone with an agenda? I won't name names, but most of the ones that watched that video all the way through would know what I am implying.

 

[Satyr]

So by your theory our universe would be a lot older than 14 billion years? Or is there no possible way to know how old the universe is because the light from beyond 14 billion years has not reached us yet?

Imagine it like this (I am using somewhat of an omniscient perspective): there exists a room that is very, very large. There is a light hanging in the center of the room that illuminates only a portion of the room. Now, with an omniscient view, we know that, although only some of the room is lit, that there exists space far beyond the reach of that light. However, as a typical bystander within the light, we don't know what is beyond the reach of the light: more space or walls? Dr. Tyson was applying a similar description with our universe. It seems reasonable that there is space beyond 14 BLY, but we don't have the capacity to see beyond it (much like the light bulb in my analogy lacks the capacity to illuminate the room beyond its terminal means).