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(Slate)   Astronomers find a galaxy at a record 13.3 billion light years distant, seen as it was 380 million years after the Big Bang   (slate.com) divider line 187
    More: Cool, light-years, Big Bang theory, galaxies, Hubble Space Telescope, astronomers, Hubble Ultra Deep Field, James Webb Space Telescope, redshifts  
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3638 clicks; posted to Geek » on 12 Dec 2012 at 4:36 PM (1 year ago)   |  Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



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2012-12-13 01:53:12 PM  

buck1138: 1 - v^2/c^2 is what?


Zero. Always.
 
2012-12-13 01:54:12 PM  
I'm awesome at middle-school algebra!!!
 
2012-12-13 01:56:08 PM  

ambassador_ahab: buck1138: 1 - v^2/c^2 is what?

Zero. Always.


So 1 / sqrt( 1 - v^2/c^2) is what then?
 
2012-12-13 01:58:18 PM  

buck1138: So 1 / sqrt( 1 - v^2/c^2) is what then?


A black hole.
 
2012-12-13 02:01:43 PM  

ReverendJasen: buck1138: So 1 / sqrt( 1 - v^2/c^2) is what then?

A black hole.


But, "Romans, go home" is an order. So you must use...?
 
2012-12-13 02:03:19 PM  

buck1138: Shazam999: buck1138: ambassador_ahab: buck1138: What does gamma equal when v=c?

*Raises hand*

1/SQRT 1 = 1

So if v=c what does v^2/c^2 equal?

42?

[encrypted-tbn0.gstatic.com image 228x221]


Okay, how about Gangnam Style?
 
2012-12-13 02:11:57 PM  

buck1138: Broom: Rent Party: Broom: Rent Party: No, we could do it if we could develop a working Broussard drive. What it would mean is that you could jet about the universe exploring stars, but you could never come home, as everyone you know would be centuries dead.

You don't need FTL. You need relativistic velocity and a willingness to abandon every single thing on Earth forever.

Sorry, but you'd still have to obey the laws of physics, and c is a hard, cold biatch.

It's going to take you years to get to the closest stars, and centuries to leave our galaxy. You're not going to get anywhere outside of our neighborhood during your lifetime (even according to your clock).

Thank you for letting me know you don't know how time dilation or relativity works.

At 1 G constant acceleration, 1000 light years would only be 13 years of ship time to cover. 100,000 light years (enough to go from edge to edge of the Milky Way) can be done in 22 years ship time. Increase acceleration to 1.5G, and that time drops to 15 years. At 2G, it's only 11 years ship time to span the entire galaxy.

There's math involved in this. You should check it out. Then you can participate in the conversation.

Cute, kid. Unfortunately, I set the curve in A-Bomb, and corrected the professor's key for the final - I got more right than he did, and he was allowed more than 2 hours.

Time dilation between any two observers is given by the Lorentz Factor, which is always >= 1.
t' = gamma*t
As velocity increases, the dilation of time increases, until at V=c the Lorentz Factor "gamma" is infinite.

If you were right, and gamma could decrease with velocity, one could cross the universe in a true "instant" by traveling at the speed of light. But this is not what photons do. Go check the article for an example: photons that left the galaxy 13.3 billion light years away have spent... wait for it... 13.3 billion years in transit.

Photons do not experience time, Nor does any object traveling at C.



What does gamma equal when v=c?


Hey, there's that math I was talking about.

For our wiki physicist, thar there is tau, and it governs the relative part of relativity. Like, the relative clocks between two reference frames.

Plug in some high values for v and then come back and explain how you are wrong.

Kid.
 
2012-12-13 02:28:16 PM  

Rent Party: gamma


I called it gamma cause you called it gamma. You never answered the original question. What is the Lorentz factor when c = v?
 
2012-12-13 03:00:47 PM  

Rent Party: derp


Wikipedia put it into simple words for small brained individuals like yourself...

Time dilation would make it possible for passengers in a fast-moving vehicle to travel further into the future while aging very little, in that their great speed slows down the rate of passage of on-board time. That is, the ship's clock (and according to relativity, any human traveling with it) shows less elapsed time than the clocks of observers on earth. For sufficiently high speeds the effect is dramatic. [16]For example, one year of travel might correspond to ten years at home. Indeed, a constant 1 g acceleration would permit humans to travel through the entire known Universe in one human lifetime.[17] The space travelers could return to Earth billions of years in the future. A scenario based on this idea was presented in the novel Planet of the Apes by Pierre Boulle.

Apparently I got more from my "wikication" than you got from wherever you learned whatever you call the shiat you spewed in your post.

/My minor in physics probably didn't hurt either.
 
2012-12-13 03:05:19 PM  
Here it is again 'constant G acceleration'. Is there any idea out there what that would actually take? How much power?
 
2012-12-13 03:25:21 PM  

ambassador_ahab: RedVentrue: The Eath, and the Universe both have edges, called the surface, or outer edge.

So my "traveling around the surface of the Earth" analogy was more or less correct? Because that would explain why from any point of reference, you are always in the "center," but could move relative to other places...


You are trying to apply a two dimensional analogy to a three dimensional problem.
 
2012-12-13 03:28:39 PM  

RedVentrue: You are trying to apply a two dimensional analogy to a three dimensional problem.


I thought the surface of the earth was a 3-D sphere.
 
2012-12-13 03:33:27 PM  

Clash City Farker: Here it is again 'constant G acceleration'. Is there any idea out there what that would actually take? How much power?


Your question doesn't define enough parameters to give you any sort of answer.
 
2012-12-13 03:50:47 PM  

Fish in a Barrel: Clash City Farker: Here it is again 'constant G acceleration'. Is there any idea out there what that would actually take? How much power?

Your question doesn't define enough parameters to give you any sort of answer.


Cant you think of one example? An orange? A golfball? The Starship Enterprise to cross the universe at 1G constant acceleration?
 
2012-12-13 03:51:55 PM  

Fish in a Barrel: Clash City Farker: Here it is again 'constant G acceleration'. Is there any idea out there what that would actually take? How much power?

Your question doesn't define enough parameters to give you any sort of answer.


So I guess I could just explain this to you. Some of Fark's physicists can correct me if I get any of this wrong; it's been a long time since high-school physics.

Power = T * mass * acceleration

The formula for tau (T) has been posted already. An acceleration of 1 G is 9.81 m/s2, so if you pick a mass and a velocity you can work out the power required for yourself. Note that power increases exponentially as you approach C.
 
2012-12-13 04:03:10 PM  
Well what do you know? Wikipedia says NASA is pretty certain the universe is flat. On my phone so no linking but "shape of the universe" should get you there if you're interested.
 
2012-12-13 04:04:56 PM  

Fish in a Barrel: Fish in a Barrel: Clash City Farker: Here it is again 'constant G acceleration'. Is there any idea out there what that would actually take? How much power?

Your question doesn't define enough parameters to give you any sort of answer.

So I guess I could just explain this to you. Some of Fark's physicists can correct me if I get any of this wrong; it's been a long time since high-school physics.

Power = T * mass * acceleration

The formula for tau (T) has been posted already. An acceleration of 1 G is 9.81 m/s2, so if you pick a mass and a velocity you can work out the power required for yourself. Note that power increases exponentially as you approach C.


Oh, and that's from an external frame of reference. From the frame of reference on board the ship it's just P=M*A, but the distance to your destination contracts as you speed up so you'll never hit C before you get to where you're going.

If you want to know the energy required to cross the galaxy under constant acceleration... someone else is going to have to tackle that one. I think that's going to involve some calculus. Too much relationship between mass and velocity for me to ponder that this close to vacation.
 
2012-12-13 04:17:16 PM  

ambassador_ahab: RedVentrue: You are trying to apply a two dimensional analogy to a three dimensional problem.

I thought the surface of the earth was a 3-D sphere.


You were speaking of traveling across the surface, not inside the sphere. I was only pointing out that a sphere has one edge; inside/ outside.
 
2012-12-13 04:19:31 PM  

Fish in a Barrel: Fish in a Barrel: Clash City Farker: Here it is again 'constant G acceleration'. Is there any idea out there what that would actually take? How much power?

Your question doesn't define enough parameters to give you any sort of answer.

So I guess I could just explain this to you. Some of Fark's physicists can correct me if I get any of this wrong; it's been a long time since high-school physics.

Power = T * mass * acceleration

The formula for tau (T) has been posted already. An acceleration of 1 G is 9.81 m/s2, so if you pick a mass and a velocity you can work out the power required for yourself. Note that power increases exponentially as you approach C.


This is why no massive object can achieve C by acceleration.

We'll have to cheat.
 
2012-12-13 04:29:53 PM  

RedVentrue: traveling across the surface


Which is still 3-D, because the Earf is a farking sphere.
 
2012-12-13 04:35:42 PM  

ambassador_ahab: RedVentrue: traveling across the surface

Which is still 3-D, because the Earf is a farking sphere.


I liked your analogy. RedVenture might not have a good understanding of projecting n-dimensional objects onto (n-1)-dimensional spaces to represent (n+1)-dimensional concepts.
 
2012-12-13 04:42:36 PM  

buck1138: I liked your analogy. RedVenture might not have a good understanding of projecting n-dimensional objects onto (n-1)-dimensional spaces to represent (n+1)-dimensional concepts.


You understand better what I was trying to say, but your vocabulary is more precise than mine.
 
2012-12-13 04:53:20 PM  
It pleases me that everybody is calling Earth Earf.
 
2012-12-13 05:04:05 PM  

ambassador_ahab: RedVentrue: traveling across the surface

Which is still 3-D, because the Earf is a farking sphere.


You would have to be inside the Earth for that to apply.
 
2012-12-13 05:19:56 PM  

RedVentrue: You would have to be inside the Earth for that to apply.


If an alien was in Africa, right now, and he wanted to teleport to visit me in Michigan, and that alien knew nothing of the size or shape of the Earth, I would have to provide 3 coordinates to properly instruct him on where Michigan is relative to Africa.

Because the Earf isn't flat. Not even the surface. Since humans only travel around the surface, we can use 2-dimensions to navigate because we know that the 3rd point is "somewhere on the surface." It's kind of like how GPS works. 3 spheres will intersect at exactly two points in space, but the GPS knows that whichever of those two points is on the surface of the earth is the point you are actually at, because your car is probably not floating around in orbit or buried in the center of Earf.

(I know modern GPS needs a 4th or more for error correction, but trying to keep it simple.)
 
2012-12-13 05:56:34 PM  

ambassador_ahab: RedVentrue: You would have to be inside the Earth for that to apply.

If an alien was in Africa, right now, and he wanted to teleport to visit me in Michigan, and that alien knew nothing of the size or shape of the Earth, I would have to provide 3 coordinates to properly instruct him on where Michigan is relative to Africa.

Because the Earf isn't flat. Not even the surface. Since humans only travel around the surface, we can use 2-dimensions to navigate because we know that the 3rd point is "somewhere on the surface." It's kind of like how GPS works. 3 spheres will intersect at exactly two points in space, but the GPS knows that whichever of those two points is on the surface of the earth is the point you are actually at, because your car is probably not floating around in orbit or buried in the center of Earf.

(I know modern GPS needs a 4th or more for error correction, but trying to keep it simple.)


Alright, but how would that apply to the expansion of the universe?

We are not on the surface of the universe, either. We are inside it. Point A to point B requires moving through something, and changing relative position in the universe as a whole. Not everything can be at the center of the universe all the time, unless the universe is infinite, right?
 
2012-12-13 06:02:42 PM  

buck1138: ambassador_ahab: RedVentrue: traveling across the surface

Which is still 3-D, because the Earf is a farking sphere.

I liked your analogy. RedVenture might not have a good understanding of projecting n-dimensional objects onto (n-1)-dimensional spaces to represent (n+1)-dimensional concepts.


Yeah, I took SolidWorks too.
 
2012-12-13 06:22:44 PM  

RedVentrue: ambassador_ahab: RedVentrue: You would have to be inside the Earth for that to apply.

If an alien was in Africa, right now, and he wanted to teleport to visit me in Michigan, and that alien knew nothing of the size or shape of the Earth, I would have to provide 3 coordinates to properly instruct him on where Michigan is relative to Africa.

Because the Earf isn't flat. Not even the surface. Since humans only travel around the surface, we can use 2-dimensions to navigate because we know that the 3rd point is "somewhere on the surface." It's kind of like how GPS works. 3 spheres will intersect at exactly two points in space, but the GPS knows that whichever of those two points is on the surface of the earth is the point you are actually at, because your car is probably not floating around in orbit or buried in the center of Earf.

(I know modern GPS needs a 4th or more for error correction, but trying to keep it simple.)

Alright, but how would that apply to the expansion of the universe?

We are not on the surface of the universe, either. We are inside it. Point A to point B requires moving through something, and changing relative position in the universe as a whole. Not everything can be at the center of the universe all the time, unless the universe is infinite, right?


Either 1. Infinite. Or 2. Finite but unbounded. But it looks like it's probably infinite.
 
2012-12-13 07:30:39 PM  

sxacho: RedVentrue: ambassador_ahab: RedVentrue: You would have to be inside the Earth for that to apply.

If an alien was in Africa, right now, and he wanted to teleport to visit me in Michigan, and that alien knew nothing of the size or shape of the Earth, I would have to provide 3 coordinates to properly instruct him on where Michigan is relative to Africa.

Because the Earf isn't flat. Not even the surface. Since humans only travel around the surface, we can use 2-dimensions to navigate because we know that the 3rd point is "somewhere on the surface." It's kind of like how GPS works. 3 spheres will intersect at exactly two points in space, but the GPS knows that whichever of those two points is on the surface of the earth is the point you are actually at, because your car is probably not floating around in orbit or buried in the center of Earf.

(I know modern GPS needs a 4th or more for error correction, but trying to keep it simple.)

Alright, but how would that apply to the expansion of the universe?

We are not on the surface of the universe, either. We are inside it. Point A to point B requires moving through something, and changing relative position in the universe as a whole. Not everything can be at the center of the universe all the time, unless the universe is infinite, right?

Either 1. Infinite. Or 2. Finite but unbounded. But it looks like it's probably infinite.


How can the universe be infinite and expanding?
 
2012-12-13 10:18:47 PM  
How many b's are in an infinite string of a's?
 
2012-12-13 10:44:19 PM  

dragonchild: Abe Vigoda's Ghost: A whole bunch of educated guesses take place on these things.

Not as much as you might think. There's no doubt there was a Big Bang. None. If you drew a graph that mapped the diffusion of the afterglow on a piece of letter-sized paper, the curve would be so smooth that the margin of error would be less than the width of the pencil's line. We know this because we have the data on the Big Bang's afterglow. There are few, if any, pieces of information in existence that are so precise. It's the scientific equivalent of nailing a three-point shot in Madison Square Garden. . . if you fired the basketball from Los Angeles. With, for good measure, a cannon shot from Dallas you'd need to aim perfectly to blow open a hole in the roof for the ball to pass through.

I'm talking about the Cosmic Microwave Background Radiation, of course, which XKCD turned into his "SCIENCE. It works, biatches" comic. You really don't want to question the CMBR findings as "a whole bunch of educated guesses" if you don't want to look like an epic idiot.


Whoa,

Hold on cowboy. I have a PhD in astrophysics and I'm not sure things are as ironclad as you make them out to be, or, more likely, I misunderstand your point. My apologies, if thats the case.

Yes, the CMBR is very smooth, not perfectly (which gives rise to a real can of worms) but enough so that a Big Bang of some sort is the only plausible explanation. No one who knows anything about astrophysics doubts this, as far as I know.

Exactly what the Big Bang was is "educated guesses" if you ask me. Something that happened in an infinitely small space? Beyond a certain point, things like time and space no longer make any sense. It might be impossible to ever even ask an intelligent question about what the Big Bang actually was. In all seriousness, I doubt the sanity of a few of the people who have advanced many of the theories that abound. Or, perhaps, theories that make no sense and that no one can understand and that really don't answer any fundamental questions are good for enough publications to et them tenure. Perhaps they're not crazy after all.

Having said this, I also must admit that I wish I was intelligent enough to really understand cosmology....
 
2012-12-14 09:44:29 AM  

enemy of the state: dragonchild: Abe Vigoda's Ghost: A whole bunch of educated guesses take place on these things.

Not as much as you might think. There's no doubt there was a Big Bang. None. If you drew a graph that mapped the diffusion of the afterglow on a piece of letter-sized paper, the curve would be so smooth that the margin of error would be less than the width of the pencil's line. We know this because we have the data on the Big Bang's afterglow. There are few, if any, pieces of information in existence that are so precise. It's the scientific equivalent of nailing a three-point shot in Madison Square Garden. . . if you fired the basketball from Los Angeles. With, for good measure, a cannon shot from Dallas you'd need to aim perfectly to blow open a hole in the roof for the ball to pass through.

I'm talking about the Cosmic Microwave Background Radiation, of course, which XKCD turned into his "SCIENCE. It works, biatches" comic. You really don't want to question the CMBR findings as "a whole bunch of educated guesses" if you don't want to look like an epic idiot.

Whoa,

Hold on cowboy. I have a PhD in astrophysics and I'm not sure things are as ironclad as you make them out to be, or, more likely, I misunderstand your point. My apologies, if thats the case.

Yes, the CMBR is very smooth, not perfectly (which gives rise to a real can of worms) but enough so that a Big Bang of some sort is the only plausible explanation. No one who knows anything about astrophysics doubts this, as far as I know.

Exactly what the Big Bang was is "educated guesses" if you ask me. Something that happened in an infinitely small space? Beyond a certain point, things like time and space no longer make any sense. It might be impossible to ever even ask an intelligent question about what the Big Bang actually was. In all seriousness, I doubt the sanity of a few of the people who have advanced many of the theories that abound. Or, perhaps, theories that make no sense and that no one can un ...


Thank you for the honest answer. A real scientists should answer "We don't really know for sure, but here's what we think" about origin theories.

I don't hear much of that anymore.
 
2012-12-14 04:36:16 PM  

RedVentrue: Thank you for the honest answer. A real scientists should answer "We don't really know for sure, but here's what we think" about origin theories.


Science doesn't prove certainties, only high probabilities. Everything every scientist says about anything is prefaced with "we don't know for sure, but here's what we think".

You must understand, however, that most of the time "here's what we think" means its probably true with 99.999% accuracy.
 
2012-12-15 04:34:47 PM  

Ishkur: RedVentrue: Thank you for the honest answer. A real scientists should answer "We don't really know for sure, but here's what we think" about origin theories.

Science doesn't prove certainties, only high probabilities. Everything every scientist says about anything is prefaced with "we don't know for sure, but here's what we think".

You must understand, however, that most of the time "here's what we think" means its probably true with 99.999% accuracy.


Understood. My issue is with the people who take the position that if a scientist says it, it must by 100% true. They treat science as a religion.
 
2012-12-15 06:35:43 PM  

RedVentrue: My issue is with the people who take the position that if a scientist says it, it must by 100% true. They treat science as a religion.


Yes, but that's neither the fault of science nor scientists.
 
2012-12-15 07:11:37 PM  

Ishkur: RedVentrue: My issue is with the people who take the position that if a scientist says it, it must by 100% true. They treat science as a religion.

Yes, but that's neither the fault of science nor scientists.


Definitely. :)
 
2012-12-15 10:20:22 PM  

RedVentrue: Definitely. :)


But it's not like it's anyone's fault. This explains why.
 
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