PDA

View Full Version : Does the Sun Light Up the Universe?



Forealfc
2004-Jan-12, 06:00 PM
I have a probably dumb question, but when it is daylight here on our side of the earth, does everything light up in space as well or does it remain black. Can this be explained. :D

Tiny
2004-Jan-12, 06:53 PM
If the sun light cant reach the dark side of Earth, the temperature will be like Mercury... people freeze to death ^^
Bright side get more sunlight, dark side get less sunlight

Forealfc
2004-Jan-12, 07:07 PM
Thanks for replying, but that is not what Im asking...

If we look at the sun here from earth, does everything between the earth and the sun light up as well? Not including the Earth, but in space itself. Okay here is a good one, if you were on the ISS station, and you come upon the SUN shining on you, Does space light up?

Littlemews
2004-Jan-12, 07:15 PM
I have a probably dumb question, but when it is daylight here on our side of the earth, does everything light up in space as well or does it remain black. Can this be explained.
Yes, because light travel everywhere in the universe, but it takes some times to reach, usually its dark 95%...

Forealfc
2004-Jan-12, 07:18 PM
So what would space look like lighted up? I mean, we have clouds to see in the sky down here on earth.. What would space look like?

Littlemews
2004-Jan-12, 07:34 PM
Dark and alot of dots (red color most likely)

Guest_Adrian
2004-Jan-12, 08:08 PM
Forealfc; Think of yourself being in the deepest and darkest part of the universe. In your hand you hold the most powerful torch ever made. You shine this torch ahead of you and see nothing. The reason, is that the light leaving the torch is travelling away from you at light speed, so unless it reflects off something and bounces back you will never see it.

Nightime on earth is exactly the same, because the sun is blasting its energies past the planet at such speed you cannot see them. Except of course when its light is reflected back to us from the moon or those planets in our solar system which are visible to us.

Could stars light up the universe, no, because well over 99% of the universe is dark empty space, and in dark empty space light just carries on popping along at 186.000 miles a second forever apparently?

Tinaa
2004-Jan-13, 12:09 AM
It may also help to remember that when you look up at the night sky, all those bright stars are similar our sun. Does their light, light up the space between here and there? Space does get lit up only when there is dust clouds or gaseous clouds for the light to bounce off of. Check out this site. (http://bioch.szote.u-szeged.hu/astrojan/nebula1.htm)

Matthew
2004-Jan-13, 01:31 AM
Light is made up of little particles travelling a c, these will not change direction unless they hit something, so in space with no dust, stars, planets, light will never com back to you. So the only way for 'space' to light up is if you're in a dust cloud or a gas cloaud.

Forealfc
2004-Jan-13, 03:04 PM
Originally posted by Guest_Adrian@Jan 12 2004, 08:08 PM
Forealfc; Think of yourself being in the deepest and darkest part of the universe. In your hand you hold the most powerful torch ever made. You shine this torch ahead of you and see nothing. The reason, is that the light leaving the torch is travelling away from you at light speed, so unless it reflects off something and bounces back you will never see it.

Nightime on earth is exactly the same, because the sun is blasting its energies past the planet at such speed you cannot see them. Except of course when its light is reflected back to us from the moon or those planets in our solar system which are visible to us.

Could stars light up the universe, no, because well over 99% of the universe is dark empty space, and in dark empty space light just carries on popping along at 186.000 miles a second forever apparently?
You all are too awesome. This totally makes sense to me now. I really do appreciate this. I should have had the answer all along but really didn't think too much about it. Thank you so so much. I really do appreciate it!!!!

MissV
2004-Feb-23, 01:28 AM
I had seen a really great picture that would illustrate this. It showed that from distances out in space, looking back, that you could see stars, depending on how bright they were. Ours is fairly hot so it shows yellow, Sirius is really hot and shows white, and a star that isn't very warm, like Epsilon Indi shows kind of orange. Let me look and see if I can find that link, hang on.....................Ok here you go, at 12 light years away, looking back;
http://www.anzwers.org/free/universe/12lys.html

devilmech
2004-Feb-23, 01:35 AM
It would be impossible for the sun to light up the universe, simply because for most of the universe, there's nothing to light up.

There are two types of light that we can see, direct light and reflected light. Direct light is light entering our eyes from a source, and we see all of the light in that case. Reflected light enters our eyes by bouncing off an object. In this case, we only see those colors of the light that the object did not absorb.

The above paragraph has nothing to do with the question, I just find it fascinating :P

GOURDHEAD
2004-Feb-23, 01:30 PM
The sun is believed to be much younger than the universe and can have illuminated, in a very feeble way, only that portion contained within a sphere with radius equal in light years to the age of the sun since it began radiating. The watts per square meter at the outer edge of the sun illuminated area is very, very tiny (something like 1.3 times 10 to the -26 watts per square meter) and is very likely below the detection threshold using current human technology.

We can not detect a single star the age and size of the sun in galaxies ~5 billion light years away. The sun is not illuminating the entire universe but it is working on it (as caveated). ;)

stevo_jimmy
2004-Feb-23, 02:57 PM
Also due to the inverse square rule (or is it inverse cube rule for a sphere, i think it is) the intensity of sunlight becomes less and less the further away you get and so light being reflected off faraway objects on the halfway to the edge of the Sun illuminated area (as this is the limit of where we can see light originating from the Sun) would be so dim that we would be unable to see it.