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So if a SpaceShip ... (Light Speed, Some Other Interesting Thoughts)

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posted on Mar, 22 2013 @ 05:30 AM
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A space ship goes from planet A in a single direction at the speed of light.
After one year travel, the space ship reached a distance of 1 light year.

Guy on the space ship takes out a telescope and points it back in the direction of planet A, where they came from.
Since planet A is seen "one year in the past" (because light from planet A needs one year to reach the space ship), the guy on the space ship can observe their own space ship launching. If he's lucky (and assuming he has a really great telescope), he can even see himself waving at himself


Correct?

Related: When we glance into space with large telescopes, such as Hubble etc, the further we look, the more distant back into time we look. Correct? Say, we point a telescope at an area where we know the area is, say, a billion light years out there, we see the light from a billion years ago.

I had an interesting thought yesterday, what if we assume that our own galaxy, at one point in the past, was at the exact same spot where we look at with a telescope today. So, we look at the spot from a billion or so years ago, and we see our OWN galaxy?

I mean, let's take the classic big bang theory which says that the universe is 13 bil years old. 13 bil years ago, all galaxies/matter was condensed at a rather small spot. (Since the universe is expanding). Correct?
So..if we look at a spot we know is "13 billion years in the past" (because it's 13 bil light years away), and we happen to see a whole bunch of cosmic matter - we need to conclude we are looking at the beginning of the universe with our own galaxy in it?



posted on Mar, 22 2013 @ 05:45 AM
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edit on 22-3-2013 by bhaal because: (no reason given)



posted on Mar, 22 2013 @ 05:46 AM
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reply to post by flexy123
 


I think if he was travelling at the speed of light away from the planet and looked back it would appear static and 'paused' as he is travelling at the same speed as the light from the planet.

He would not be able to look back and see himself launching as that light would already be in front of him being already ahead of him after he launched whilst he was still accelerating to light speed, he would always be chasing it unless of course his speed surpassed light speed in which case he would start catching it up.



posted on Mar, 22 2013 @ 05:49 AM
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Originally posted by CrimsonMoon
reply to post by flexy123
 


I think if he was travelling at the speed of light away from the planet and looked back it would appear static and 'paused' as he is travelling at the same speed as the light from the planet.



Correct, sorry forgot to mention the space ship stops and then the guy starts observing.



posted on Mar, 22 2013 @ 05:54 AM
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reply to post by flexy123
 



A space ship goes from planet A in a single direction at the speed of light.
After one year travel, the space ship reached a distance of 1 light year.

Guy on the space ship takes out a telescope and points it back in the direction of planet A, where they came from.
Since planet A is seen "one year in the past" (because light from planet A needs one year to reach the space ship), the guy on the space ship can observe their own space ship launching. If he's lucky (and assuming he has a really great telescope), he can even see himself waving at himself

Correct?


No, because he would be traveling at the same speed as the light. Once he stops, all of the light instantaneously passes him by. Technically, it immediately crosses over the horizon of his "light cone."


Related: When we glance into space with large telescopes, such as Hubble etc, the further we look, the more distant back into time we look. Correct? Say, we point a telescope at an area where we know the area is, say, a billion light years out there, we see the light from a billion years ago.

I had an interesting thought yesterday, what if we assume that our own galaxy, at one point in the past, was at the exact same spot where we look at with a telescope today. So, we look at the spot from a billion or so years ago, and we see our OWN galaxy?


No, because the light from our own galaxy is moving away from us, not towards us.


I mean, let's take the classic big bang theory which says that the universe is 13 bil years old. 13 bil years ago, all galaxies/matter was condensed at a rather small spot. (Since the universe is expanding). Correct?
So..if we look at a spot we know is "13 billion years in the past" (because it's 13 bil light years away), and we happen to see a whole bunch of cosmic matter - we need to conclude we are looking at the beginning of the universe with our own galaxy in it?


That is a more complicated question, and involves things like the curvature of space-time. I'm not sure anyone can actually answer that question in a way that is truly comprehensible, yet I'll try. Yes, radio astronomers can detect the hum of very ancient matter that eventually may have coalesced into our galaxy.



posted on Mar, 22 2013 @ 06:31 AM
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Gravity affects time, but technically yes, what we see at 10 light years away happened 10 years ago.

If you would move 13 billion light years AWAY from the milky way, you would see what happened 13 billions years ago.



posted on Mar, 22 2013 @ 06:37 AM
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Originally posted by flexy123
A space ship goes from planet A in a single direction at the speed of light.
After one year travel, the space ship reached a distance of 1 light year.

Guy on the space ship takes out a telescope and points it back in the direction of planet A, where they came from.
Since planet A is seen "one year in the past" (because light from planet A needs one year to reach the space ship), the guy on the space ship can observe their own space ship launching. If he's lucky (and assuming he has a really great telescope), he can even see himself waving at himself


Correct?


Nope. As soon as the spacehip takes off (assuming instant speed of light) his "past" travels with him. The moment he stops that light will also have traveled 1 year and instantly passes him by. So when he looks back through his telescope, he will see the planet as it was when he left, as if it was paused.



I mean, let's take the classic big bang theory which says that the universe is 13 bil years old. 13 bil years ago, all galaxies/matter was condensed at a rather small spot. (Since the universe is expanding). Correct?
So..if we look at a spot we know is "13 billion years in the past" (because it's 13 bil light years away), and we happen to see a whole bunch of cosmic matter - we need to conclude we are looking at the beginning of the universe with our own galaxy in it?


Let's say the universe started exactly 13 billion years ago by means of a big bang, at which light was eminated at the speed of light. That light would have traveled 13 billion light years indeed, but matter does not propagate at the speed of light. So if we (matter) are looking at other matter 13 billion light years away, that must mean that the big bang happened earlier in order to account for matter being that far apart.
edit on 22/3/2013 by RationalDespair because: typos



posted on Mar, 22 2013 @ 07:25 AM
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reply to post by flexy123
 


ID SAY CORRECT

Like the way you are thinking outside the box


flag and star for thinking like me
edit on 22/3/2013 by maryhinge because: (no reason given)



posted on Mar, 22 2013 @ 09:52 AM
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Originally posted by flexy123
A space ship goes from planet A in a single direction at the speed of light.
After one year travel, the space ship reached a distance of 1 light year.

Guy on the space ship takes out a telescope and points it back in the direction of planet A, where they came from.
Since planet A is seen "one year in the past" (because light from planet A needs one year to reach the space ship), the guy on the space ship can observe their own space ship launching. If he's lucky (and assuming he has a really great telescope), he can even see himself waving at himself


Correct?

Related: When we glance into space with large telescopes, such as Hubble etc, the further we look, the more distant back into time we look. Correct? Say, we point a telescope at an area where we know the area is, say, a billion light years out there, we see the light from a billion years ago.

I had an interesting thought yesterday, what if we assume that our own galaxy, at one point in the past, was at the exact same spot where we look at with a telescope today. So, we look at the spot from a billion or so years ago, and we see our OWN galaxy?

I mean, let's take the classic big bang theory which says that the universe is 13 bil years old. 13 bil years ago, all galaxies/matter was condensed at a rather small spot. (Since the universe is expanding). Correct?
So..if we look at a spot we know is "13 billion years in the past" (because it's 13 bil light years away), and we happen to see a whole bunch of cosmic matter - we need to conclude we are looking at the beginning of the universe with our own galaxy in it?




Wrong op, because if the ship is travelling the speed of light, the light from the headlights still travels at the speed of light away from the ship, which is where time dilation comes from, it is natures way of preserving the speed of light.

Light seems at present to be immune to time, perhaos it is because time only effects mass, as light doesnt have any.

I will make another post and address your other questions, if you have any further need of explanation on this I can provide a much more in depth discription.



posted on Mar, 22 2013 @ 10:06 AM
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reply to post by flexy123
 

Wow, your second question is a lot more indepth in its description, sorry bare with me.

As I stated previously, light travels at the speed of light at all times in all situations in a vacuum, relative to all matter no matter its speed.

We will say you are stopped relative to the rest of the universe, and I am travelling away from you at the speed of light. You shine a lazer beside me, it would pass me going the speed of light relative to me, and still go the speed of light relative to you.

How is this possible? Time dilation. It is the reason for the light speed limit, as any mass accelerates to the speed of light, their spe ific time relative to the rest of the universe slows down.

If you looked in my ship as I travelled close to C ( C denotes the speed of light in physics) you would see everyone and everything inside travelling in super slow motion. While to me inside the ship, the universe outside would be flying by in a rapid pace, the pyramids would be built in mere seconds, I would see the ice age come and go kike a time lapse video etc...

If I look 13 billion light yearz into the universe, I would in fsct see 13 billion years into the past, but our galaxy has been moving and evolving in that time period, so we woukd not be able to see it, as it is us, and our light has long since travelled at C away from us.

Think of shooting a bullet at 600 mps, and now thinking you could travel at the same 600 mps and get in front of it to catch it, this is not going to happen.

This is not an exactly correct reply, but it is close enough without involving complex maths to get the point across.



posted on Mar, 23 2013 @ 02:17 AM
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reply to post by flexy123
 


I had an interesting thought yesterday, what if we assume that our own galaxy, at one point in the past, was at the exact same spot where we look at with a telescope today. So, we look at the spot from a billion or so years ago, and we see our OWN galaxy?

We would not. Earth travels through space at much less than the speed of light, so the light emanating from any previous point along its path will have passed any future location along that path long before Earth arrives at it.

However fast you travel, you cannot catch up with your own light. You don't need an Einstein
to show that travel at or above the speed of light is impossible; just try to imagine what would happen to any light you emitted. See?


So..if we look at a spot we know is "13 billion years in the past" (because it's 13 bil light years away), and we happen to see a whole bunch of cosmic matter - we need to conclude we are looking at the beginning of the universe with our own galaxy in it?

Any spot in the sky could be 13 (or even 13.82) billion years in the past. It depends on how far you look.

We can even see light from the Big Bang. It's called the Cosmic Microwave Background, and as you might expect, it's spread out over the whole universe. In general, the older cosmic light is, the more spread out in space, the more red-shifted and the dimmer it appears to us. The oldest galaxy spotted by the Hubble Telescope is only about 400 million years younger than the universe itself. Astronomers believe the James Webb Telescope, Hubble's successor, will show galaxies even older than that.



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