Where's Our Past?

[TruthSeeker]

If all that we see in the sky is in the past, shouldn't we be able to see our own galaxy, in the past, somewhere in the sky? If not, why not?

[Rappaccini]

... because we'd be recieving light waves from ourselves.

That's not really very probable.

[tablariddim]

The parts of our galaxy that we can see, are in the past. Even our sun is in the past, because its light takes about 8 minutes to reach Earth.

[TruthSeeker]

... because we'd be recieving light waves from ourselves.

That's not really very probable.
Couldn't those light waves be coming from our past, somewhere in the sky?

[TruthSeeker]

The parts of our galaxy that we can see, are in the past. Even our sun is in the past, because its light takes about 8 minutes to reach Earth.
Yeah, yeah, yeah... I know that. What I'm asking is why can't we see our own past...

[tablariddim]

What d'you mean, see your own past? It's not something that was caught on video for you to peruse at whim. We haven't left our galaxy behind, somewhere in the past, we are still part of it and it, of us, it's just that what we do see of it, is actually what it was like in the past and not the present, but yeah, yeah, yeah, you know that already.

[John Connellan]

Because the light rays from our past are long gone Im afraid! Some other intelligent beings on another planet are probably observing them now and thinking what an unsophisticated lifeforms (algae) are on our planet :D

[2inquisitive]

The closed universe, curved space model of the universe is something like what
TruthSeeker is descibing. It is no longer in favor as current observations indicate
no such curvature. In that model, you are more or less looking in circles as you look
back into time, so if you could see far enough back and light had time to circle the
universe, you could possibly see our galaxie's distant past. As I said, current observations indicate a "flat" and open universe and not a curved and closed one.

[John Connellan]

No even with that model I doubt u would see light rays from the past. The photons would have lost so much energy by the time they were curved back towards us that they would be invisible.

[2inquisitive]

We can see photons that are 13 billion years old now. Why do you think photons
will lose enough energy to become invisable?

[John Connellan]

Because those photons have incredibly high energy! I've never calculated it but i would imagine that after 3 billion years, light from the earth would be at least infra red.

[2inquisitive]

We were speaking of seeing our galaxie, not light from the earth. There are energetic
sources within the Milky Way also, true? How energetic do you believe the Milky Way
may have been soon after its formation, much the same as the distant galaxies we
now see photons from? As we look at distant light sources, we are looking into the past.

[paulsamuel]

If all that we see in the sky is in the past, shouldn't we be able to see our own galaxy, in the past, somewhere in the sky? If not, why not?
we do. every time we look up and observe the milky way, or any other part of our galaxy, we're seeing our own galaxy in the past.

[TruthSeeker]

we do. every time we look up and observe the milky way, or any other part of our galaxy, we're seeing our own galaxy in the past.
What about the entire galaxy?

[TruthSeeker]

The closed universe, curved space model of the universe is something like what
TruthSeeker is descibing. It is no longer in favor as current observations indicate
no such curvature. In that model, you are more or less looking in circles as you look
back into time, so if you could see far enough back and light had time to circle the
universe, you could possibly see our galaxie's distant past. As I said, current observations indicate a "flat" and open universe and not a curved and closed one.
Maybe I do think of the universe as that...
Oh yeah... I remind redaing that too parallel lines never cross on a flat surface, but do cross on a curved one... Does that has anything to do with what we have been talking about?

[John Connellan]

We were speaking of seeing our galaxie, not light from the earth. There are energetic
sources within the Milky Way also, true? How energetic do you believe the Milky Way
may have been soon after its formation, much the same as the distant galaxies we
now see photons from? As we look at distant light sources, we are looking into the past.

I don't know what u were talking about but Truthseeker (who I was talking to) WASN'T talking about that. He was talking about our own past. We cannot see our own past but like Im sure u have heard that the light we see from any star in the sky will be many many years old and so u are observing its past. Does that answer your question?

[2inquisitive]

quote:
If all that we see in the sky is in the past, shouldn't we be able to see our own galaxy, in the past, somewhere in the sky? If not, why not?
================================================== ==

JC, I don't know how what you thought TruthSeeker was asking, but I assumed he was
asking why we shouldn't be able to see our own galaxy as it was in the past somewhere in the sky. That was why I brought up the closed universe, curved space
model. Do you understand now?

[TruthSeeker]

You are both talking about the same thing... :rolleyes: :D
... ;)

[John Connellan]

That was already answered:


The parts of our galaxy that we can see, are in the past. Even our sun is in the past, because its light takes about 8 minutes to reach Earth.

Truthseekere still asked:


Yeah, yeah, yeah... I know that. What I'm asking is why can't we see our own past...

Surely he meant our planet? Do u understand now???

[TruthSeeker]

In the beginning, yeah, but in the last posts you seemed to be talking about the same thing...

[Starthane Xyzth]

If the Universe is curved, and closed, on some vastly unobservable scale, then in theory light can circumnavigate it and come back to its source. However, the current age of the Universe (13 billion years or so) wouldn't allow enough time for any image to have travelled all the way around. Especially since our Galaxy is younger thena the Universe, and Earth itself younger than the Galaxy.