# QuestionTravel Light Years

#### J@i

1 Light Year = Distance travelled by light in a year's time, and one can travel to the nearest star Proxima Centauri at light speed and reach there in 4.24 Light Years. Now as we approach the star we may not exactly see what we saw from earth 4.24 light years ago however I guess theoretically there is such a place and we can reach there.

A star 1000 light years away similarly we saw the lights, we buzz at light speed and we reach there and find conditions are different than how we actually saw the stars but still that place exists and we reach a destination.

Now we saw galaxies from early universe say 4.6 billion light years. Do we say 4.6 billion light years away or 4.6 billion light years old. Is this a physical measurable distance away from earth? If so we should be able to travel to this physical distance @super warp speeds to reach distance that is 4.6 billion light years away?

#### SIDexplorer

The light itself is 4.6 billion years old since it took that long to reach us but some of those galaxies perhaps not even exist now, the ones still existing must be way older.

The distance can never be calculated on that basis alone, galaxies continuously move either away or towards us, so you can't say that we've the actual distance.

A journey towards those galaxies even at light speed would take us some place else, since the journey would take almost forever, the Universe too is expanding and very rapidly actually.

J@i

#### Catastrophe

##### "Science begets knowledge, opinion ignorance.
J@i wrote:

Now we saw galaxies from early universe say 4.6 billion light years. Do we say 4.6 billion light years away or 4.6 billion light years old. Is this a physical measurable distance away from earth? If so we should be able to travel to this physical distance @super warp speeds to reach distance that is 4.6 billion light years away?

Do we say 4.6 billion light years away or 4.6 billion light years old.

It comes to the same thing. They 4.etc. away, and we see them as they were 4.6etc ago, which means, to us, they are 4.6etc years old.

Is this a physical measurable distance away from earth?

Yes, in the sense that 1 light year = 63241.1 AU (astronomical units)
but there is no way that you could physically measure it, e.g., with a tape measure.

If so we should be able to travel to this physical distance
My emphasis.

If you could travel at these imaginary FTL (faster than light) speeds, then, yes, you could travel that distance. But, when you got there, it might not be 'there' any more. It might have disintegrated. And what would there mean anyway?

Cat

J@i and Helio

#### Helio

1 Light Year = Distance travelled by light in a year's time, and one can travel to the nearest star Proxima Centauri at light speed and reach there in 4.24 Light Years. Now as we approach the star we may not exactly see what we saw from earth 4.24 light years ago however I guess theoretically there is such a place and we can reach there.
Yes. The closer one gets to a star, the sooner the star's light will reach them. Once you're at Proxima Centauri, you won't have to wait 4.24 years to see what's up. But, you also won't be able to phone home and tell them since your phone call will also take 4.24 years to reach them.

A star 1000 light years away similarly we saw the lights, we buzz at light speed and we reach there and find conditions are different than how we actually saw the stars but still that place exists and we reach a destination.
Yes, as above, once your reach this star, you will have a 1000 year advantage over those on Earth. But 1000 years for a star is nothing. The Sun will remain about the same for more than a billion years. It will begin to swell several billion years from now and it will look different.

1000 years for a typical star, ignoring the smaller stars that live longer, is about equal to our life for 40 minutes.

Now we saw galaxies from early universe say 4.6 billion light years. Do we say 4.6 billion light years away or 4.6 billion light years old. Is this a physical measurable distance away from earth? If so we should be able to travel to this physical distance @super warp speeds to reach distance that is 4.6 billion light years away?

I like to use that magic wand for things like this. Freeze the universe and go measure it. That 4.6 billion lyr. distant galaxy had 4.6 billion years more experience in the expansion, so it will be farther away than 4.6 billion lyrs. The rate of expansion of the Universe gives cosmologists what they need to calculate such things.

J@i

Replies
3
Views
708
Replies
18
Views
1K
Replies
2
Views
1K
Replies
1
Views
708
Replies
18
Views
3K