time and space

[Jessun]

When the Sun sits right atop the horizon, it's already gone - due refraction in the atmosphere, but that's another thing. But yeah you're right.

What's even more puzzling is that if the Sun vanished instantly, not only would it take 8 minutes until we found out about it - by looking at it - but it would also take 8 minutes until the Earth left its orbit because of the lack of gravitational pull!!

/Jesper

[sparkyjon]

i love trying to explain this to my missus it is mind boggling but always amazes me..

these exoplanets they are finding now by watching the light dip or the star wobble , does this mean that some of the ones they have found might technically not be there any more..????

[AndyWB]

so let me get this right.

the light from the sun takes 8 minutes roughly to reach us.

i"m looking at a sunset 2 minutes before its going to dip below the horizon.

actually its already gone ?

Basically, yes. I believe that sunsets are also complicated by other factors - light entering the Earth's atmosphere is effectively 'bent' by changing from travelling in a vacuum to travelling in air - but the gist of what you're driving at is true. Even the moon is 1.3 seconds away. If you fired radar pulses straight up at the moon, it takes 1.3s each way - so 2.6 seconds total before you'd receive the 'echo'.

[mullac2001]

i love trying to explain this to my missus it is mind boggling but always amazes me..

these exoplanets they are finding now by watching the light dip or the star wobble , does this mean that some of the ones they have found might technically not be there any more..????

this surely has to be true.

as does the probability that life exits beyond our solar system given the statistics?