I've just finished reading a book concerning star gazing.....

askyourgran | 20:53 Tue 20th Sep 2011 | Science

28 Answers

There was a passage in which someone is looking at the stars and promises on the star to do something. The answer to that was that the starlight she sees takes so many thousands of years to reach us that by the time we see it it may not exist any more. I couldn't quite take that in. I'd never thought about that before and it surprised me. Did everyone else know that? Or do I need to catch up. Any more profound things I should know?

Solitaire

Life on Earth Originated from the Sun?

Answers

21 to 28 of 28

First Previous 1 2

Best Answer

No best answer has yet been selected by askyourgran. Once a best answer has been selected, it will be shown here.

For more on marking an answer as the "Best Answer", please visit our FAQ.

askyourgran

Question Author

I'm loving this, but I must go to bed now. Thanks so much everyone.

Ann

Isn't God's creation wonderful?

askyourgran

Question Author

Absolutely awesome Ann.

Andyvon

Sound has a similar but more familiar effect Gran. You can often see an event - such as a firework or a flash of lightning - but only hear the sound some time afterwards. That's because sound travels at about 760mph at sea level and it takes a certain time to reach your ears depending how far you are away. By the time you hear the event it's over and happened in the past.

Light travels at 186,000 miles - not per hour - but every second. If the sun is 93 million miles away the light leaving the sun only reaches Earth 8 minutes after leaving the star. When we see the sun set below the horizon - the sun actually set several minutes earlier! (there is a time effect caused by the refraction of the atmosphere too). We see the Moon 2 seconds late as it takes that long for light to travel 250,000 miles from there to us. The nearest galaxy to our Milky Way is the Andromeda Galaxy which is just visbile in the constellation Andromeda. That's 2.2 million light years away which means the light we see now set out from the Andromeda Galaxy 2.2 million years ago. It's taken that long to travel across space at the speed of 186,000 miles every second to enter our eyes. That light set out before modern humans even existed! The light arriving now from many distant galaxies set out even before our solar system formed 4.6 billion years ago.

As I said, it's the same effect that causes sound to enter our ears some time after we see the event.

douglas9401

"Isn't God's creation wonderful?"

Possibly, but back to the stars.

askyourgran

Question Author

That's interesting andyvon. I was aware that it takes about thirty minutes for daylight to start from one end of the country to another but that was the breadth of my knowledge. Doh! Douglas, after looking at the vid links it made me wonder about the religious side of all this. It was strange to see what very small planet Earth is compared to the huge, what looks to be unoccupied giants looming about up there. We are really nothing when compared to them.

mibn2cweus

But without people like us with the ability to discover and appreciate it for what it really is, there wouldn't be much point in any of it . . . would there?

The wonder of the universe as we have come to learn about and understand it is perhaps exceeded only by our ability to make up stories about where it came from and 'who' created it.