You will see it in 425 years time
When you see a galaxy that is 8 billion light years away, the light that's dribbling into your eye left that galaxy 8 billion years ago, and has been traveling toward you ever since then. If you just happen to see the galaxy explode or turn blue while you're watching it, you'll know that it actually exploded or turned blue 8 billion years ago. Similarly, if the galaxy explodes or turns green tonight, you won't know about that for another 8 billion years from tonight.
The duration of Light Years Away is 1.75 hours.
I would like to explain that in fact, Betelgeuse is closer to 640 light-years away than it is to 425 ly. So, if it goes supernova tonight, the light from this massive explosion would take 640 years to get to Earth. So, we would observe this supernova only 640 years after it has actually happened.
Arcturus is approximately 37 light years away from Earth.
Phrekad is approximately 48.6 light-years away from Earth.
It's light will reach us - eventually, but any "destructive" gamma rays will not. VY Canis Majoris is about 4,900 light years from us. Too far away to cause us any concern.
Sirius is about 8.6 light years away from us.
49,666,845 light years away from earth
Million Light Years Away was created in 1998.
Light Years Away was created on 1981-05-20.
A Million Light Years Away was created in 2002.
The Andromeda galaxy is approximately 2.537 million light-years away from Earth.