LIGHT SPEED

Source: here

Just for funnies!

originally posted by: eriktheawful
It's simple really:

Light travels at 299 792 km/s.

The Andromeda Galaxy is approaching our galaxy at 110 km/s.

So the light from Andromeda is going 2725 times faster than the galaxy itself is actually moving.

We measure it's distance based upon what we see (the light). The Andromeda Galaxy is at about 2.5 million light years away, so indeed, the light we are seeing is from where it was 2.5 million years ago.

So yes, it's actually closer than what we are seeing, because it is approaching us.

But how much closer?

We can calculate that. 1 lightyear is 9,460,730,472,580 km. Multiply that by 2.5 million:

23,651,826,181,450,000,000 km.

That is how far away it was, 2.5 million years ago. But, because we know it's coming towards our galaxy at 110 km/s, we can figure that out too.

It's velocity is 3,468,960,000 km per year. Multiply that by 2.5 million:

8,672,400,000,000,000 km is how far it has traveled towards us in that 2.5 million years.

Now, subtract that number, from how many kilometers there are in 2.5 million light years:

23,651,826,181,450,000,000 - 8,672,400,000,000,000 = 23,643,153,781,450,000,000 km.

Now, divide the answer by the amount of kilometers in a light year:

23,643,153,781,450,000,000 / 9,460,730,472,580 = 2,499,083.32 lightyears.

So, even though it's had 2.5 million years to approach us, at only 110 km/s, it's still well over 2.4 million lightyears away.

It certainly would not look too much bigger to our eyes or telescopes!

Thank you Sir have a :cheersn me

Make it stop..please make it stop...my head hurts.....

a reply to: eriktheawful

LOL, I am sitting here like "I could write a program to calculate this for us" then you go off and solve it with out needing to write a program to do it.... damn humans and their brains.

originally posted by: KROandSOTV
What i am asking is,At this point in time NOW how many light years is it from our galaxy it cant be 2.5million light years away or is it.

That depends on whether it's moving toward us or away.

originally posted by: Bedlam

originally posted by: KROandSOTV
What i am asking is,At this point in time NOW how many light years is it from our galaxy it cant be 2.5million light years away or is it.

That depends on whether it's moving toward us or away.

I read that it will engulf us so i would say its moving towards us OR is it going in a straight line and our Galaxy is heading towards it.(if that makes any sence).

originally posted by: MrAoxx
a reply to: eriktheawful

LOL, I am sitting here like "I could write a program to calculate this for us" then you go off and solve it with out needing to write a program to do it.... damn humans and their brains.

Well, I did use a calculator.

According to NASA our galaxy The Milky Way will crash into the galaxy Andromeda in about 4 billion years.

predicted to happen four billion years from now. It is likely the sun will be flung into a new region of our galaxy, but our Earth and solar system are in no danger of being destroyed.

Our findings are statistically consistent with a head-on collision between the Andromeda galaxy and our Milky Way galaxy

science.nasa.gov...

Adromeda is about 2.5 million light years from Earth so it takes light 2.5 million years to reach us which means we see Andromeda as it looked 2.5 million years ago. Apparently.

Astroguys think there are billions of other galaxies in the universe. Mind blown.

Makes you realize how slow the speed of light is. Even if we could travel at the speed of light it would take 2.5 million years to get to the next galaxy. We really need that warp drive.