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Always Free · 5th June 2004, 10:48 PM

If you were in deep space in your space craft and there were no nearby planets or suns etc, only stars many light years away, and you had to take a space walk, could you see your own hand in front of your face? Could you see your space ship if there were no lights anywhere on it? Is it completely dark? Or would the combined light from the distant stars give off enough light to see nearby objects?

toddjh · 5th June 2004, 11:03 PM

Quote:

Originally posted by Always Free
If you were in deep space in your space craft and there were no nearby planets or suns etc, only stars many light years away, and you had to take a space walk, could you see your own hand in front of your face? Could you see your space ship if there were no lights anywhere on it? Is it completely dark? Or would the combined light from the distant stars give off enough light to see nearby objects?

Outside the atmosphere, and away from blinding light sources, the stars appear a lot brighter than they are on the ground. Things would be dim, but you'd be able to see nearby objects better than you can on a dark night. Maybe bright enough to read by, for someone with very good eyes.

I hear that the galaxy, when viewed from slightly outside it (far enough to get out of the obscuring dust cloud we're in), would be very bright indeed.

Jeremy

Walter Wayne · 5th June 2004, 11:05 PM

As a first guest I would go to the country (as far on from the city as possibly, and check things on a cloudless and moonless night). During the big east coast power outage it was easy to come close to walking into a street sign once the moon went down.

Walt

Eos of the Eons · 5th June 2004, 11:39 PM

If there were no light sources, then space would be dark. Suns are a light source. Are there any others?

Without the universe in space, then there would be nothing but complete darkness.

If we didn't have the sun for our light source, then there would not be enough energy, light, etc. to sustain life on this planet from those other stars far away. You wouldn't be worrying about seeing anything-you wouldn't be here and nothing else would be either. Just our little planet with no warmth.

toddjh · 5th June 2004, 11:46 PM

Quote:

Originally posted by Eos of the Eons
If there were no light sources, then space would be dark. Suns are a light source. Are there any others?

Without the universe in space, then there would be nothing but complete darkness.

If we didn't have the sun for our light source, then there would not be enough energy, light, etc. to sustain life on this planet from those other stars far away. You wouldn't be worrying about seeing anything-you wouldn't be here and nothing else would be either. Just our little planet with no warmth.

There's the cosmic microwave background, which is "light" of a sort. And I don't know if primordial black holes have been ruled out yet. If they haven't, you might periodically (very periodically) get very bright bursts from one of those decaying. And of course there will be random events (collisions and so on) that release a bit of radiation from time to time.

It's not total darkness in the literal sense, but in the practical sense it sure is.

Jeremy

Always Free · 7th June 2004, 03:14 AM

Would I be right to think that where ever I may be, I should be able to see objects nearby, due to the combined light given off by the celestial bodies within the known universe?

MRC_Hans · 7th June 2004, 03:59 AM

Yes, normal, healthy human eyes, given suffecient time to develope full night vision (about 30 minutes) would be able to discern objects with medium to good reflectivity in the ambient light of interstellar space (interstellar space being far from any one star, but within a galaxy). Dark, non reflective objects will probably be invisible. In intergalactic space (where the nearest galaxies are distant), the light level will be much lower. We know this because all galaxies visible from Earth are several orders of magnitude fainter than the brightest stars; indeed most galaxies are not visible to the naked eye. So in intergalactic space we could probably see very little with the unaided eye.

The cut-off level of our vision in dark is a distinct treshold which is age-related. This is due to noise. If you stare into pich darkness (close your eyes in a dark room), you will "see" a background of noise. It looks much like "snow" on a TV screen, but very faint. This is the noise floor of your vision; anything much weaker than that will be invisible to you.

Your noise floor rises as you age.

Hans

Always Free · 7th June 2004, 06:06 AM

I see!

Thanks for your answers guys

Mark · 7th June 2004, 07:30 AM

Quote:

Originally posted by Walter Wayne
As a first guest I would go to the country (as far on from the city as possibly, and check things on a cloudless and moonless night). During the big east coast power outage it was easy to come close to walking into a street sign once the moon went down.

Walt

I have done this many times in Arizona and the California desert, and you can see well enough to walk...if you are very careful.

garys_2k · 7th June 2004, 07:43 AM

Quote:

Originally posted by MRC_Hans

The cut-off level of our vision in dark is a distinct treshold which is age-related. This is due to noise. If you stare into pich darkness (close your eyes in a dark room), you will "see" a background of noise. It looks much like "snow" on a TV screen, but very faint. This is the noise floor of your vision; anything much weaker than that will be invisible to you.

Your noise floor rises as you age.

Hans

When I close my eyes, or sit in a dark room, I wouldn't describe what I "see" as "snow," it's more like swirls of darkish colors, loosely patterned and shifting. I can glance around and the shifting doesn't follow my gaze, but just seems to carry on. Pressing my eyeballs against my head (increasing ocular pressure a bit) brightens the light show up quite a lot.

sorgoth · 7th June 2004, 12:48 PM

Quote:

Originally posted by garys_2k

When I close my eyes, or sit in a dark room, I wouldn't describe what I "see" as "snow," it's more like swirls of darkish colors, loosely patterned and shifting. I can glance around and the shifting doesn't follow my gaze, but just seems to carry on. Pressing my eyeballs against my head (increasing ocular pressure a bit) brightens the light show up quite a lot.

Do that and rub your eyes for a while...it's quite the show...I often get a 'tunnel' effect, and no, I do not take drugs

.

MRC_Hans · 7th June 2004, 12:55 PM

Quote:

Originally posted by garys_2k

When I close my eyes, or sit in a dark room, I wouldn't describe what I "see" as "snow," it's more like swirls of darkish colors, loosely patterned and shifting. I can glance around and the shifting doesn't follow my gaze, but just seems to carry on. Pressing my eyeballs against my head (increasing ocular pressure a bit) brightens the light show up quite a lot.

Yes, the perception varies somewhat from person to person, as always with sensory phenomenons just at the limit of perception. I know the light-show effect by pressing the eye-balls, but don't do it too much, I have heard it is not healthy for your eyes.

Hans

garys_2k · 7th June 2004, 02:58 PM

Quote:

Originally posted by MRC_Hans
Yes, the perception varies somewhat from person to person, as always with sensory phenomenons just at the limit of perception. I know the light-show effect by pressing the eye-balls, but don't do it too much, I have heard it is not healthy for your eyes.

Hans

Yeah, it probably deprives the nerves of blood (oxygen) or something. As usual, the fun things are the ones we shouldn't do.

Always Free · 16th June 2004, 12:41 AM

Quote:

Originally posted by Walter Wayne
As a first guest I would go to the country (as far on from the city as possibly, and check things on a cloudless and moonless night). During the big east coast power outage it was easy to come close to walking into a street sign once the moon went down.

Walt

I went on a three day trip this past weekend and on my journey home I had to travel through forested areas and it was fairly late at night, 11:00pmish and I remembered you telling me about going away from city lights to view a dark moonless night. I realised that there was no moon or clouds so I decided to stop my car and get out and have a look. Well---I have viewed the night sky many times from the small city I used to live in and it was so much clearer than the night sky I now look at in my city of Melbourne. As I stood next to my car and looked up I couldn't believe what I was looking at. I have never seen a more fabulous, breathtaking sight since I saw my first super nova cloud several years ago. I grabbed the binochulars from my bag and---well you have all probably done the same thing, but the difference in what you can see up there with no outside light interference compared to a small amount of local street lights, is incredible.
I also did take my eyes off the stars to look around to see just how much I could see in this dark moonless night and yes, I can make out objects, the car, my hand, the road. The trees across the road were totally black, only a sillouette against the sky.
Well it was bloody marvelous. I have to get out to the country more often and will get more value out of my telescope from there.

5th June 2004, 10:48 PM	#1
Always Free Critical Thinker Join Date: Oct 2002 Posts: 406	Is there light in space without suns? If you were in deep space in your space craft and there were no nearby planets or suns etc, only stars many light years away, and you had to take a space walk, could you see your own hand in front of your face? Could you see your space ship if there were no lights anywhere on it? Is it completely dark? Or would the combined light from the distant stars give off enough light to see nearby objects?
	__________________ "Stand Up For Your Freedom, Stand Up For Yourself"

5th June 2004, 11:03 PM	#2
toddjh Illuminator Join Date: Mar 2002 Location: USA Posts: 3,252	Re: Is there light in space without suns? Quote: Originally posted by Always Free If you were in deep space in your space craft and there were no nearby planets or suns etc, only stars many light years away, and you had to take a space walk, could you see your own hand in front of your face? Could you see your space ship if there were no lights anywhere on it? Is it completely dark? Or would the combined light from the distant stars give off enough light to see nearby objects? Outside the atmosphere, and away from blinding light sources, the stars appear a lot brighter than they are on the ground. Things would be dim, but you'd be able to see nearby objects better than you can on a dark night. Maybe bright enough to read by, for someone with very good eyes. I hear that the galaxy, when viewed from slightly outside it (far enough to get out of the obscuring dust cloud we're in), would be very bright indeed. Jeremy

5th June 2004, 11:39 PM	#4
Eos of the Eons Mad Scientist Join Date: Jul 2003 Location: Alberta Posts: 13,894	If there were no light sources, then space would be dark. Suns are a light source. Are there any others? Without the universe in space, then there would be nothing but complete darkness. If we didn't have the sun for our light source, then there would not be enough energy, light, etc. to sustain life on this planet from those other stars far away. You wouldn't be worrying about seeing anything-you wouldn't be here and nothing else would be either. Just our little planet with no warmth.
	__________________ Motion affecting a measuring device does not affect what is actually being measured, except to inaccurately measure it. the immaterial world doesn't matter, cause it ain't matter-Jeff Corey my karma ran over my dogma-vbloke The Lateral Truth: An Apostate's Bible Stories by Rebecca Bradley, read it!

7th June 2004, 03:14 AM	#6
Always Free Critical Thinker Join Date: Oct 2002 Posts: 406	Would I be right to think that where ever I may be, I should be able to see objects nearby, due to the combined light given off by the celestial bodies within the known universe?
	__________________ "Stand Up For Your Freedom, Stand Up For Yourself"

7th June 2004, 03:59 AM	#7
MRC_Hans Penultimate Amazing Join Date: Aug 2002 Location: Whithin earshot of the North Sea Posts: 16,604	Yes, normal, healthy human eyes, given suffecient time to develope full night vision (about 30 minutes) would be able to discern objects with medium to good reflectivity in the ambient light of interstellar space (interstellar space being far from any one star, but within a galaxy). Dark, non reflective objects will probably be invisible. In intergalactic space (where the nearest galaxies are distant), the light level will be much lower. We know this because all galaxies visible from Earth are several orders of magnitude fainter than the brightest stars; indeed most galaxies are not visible to the naked eye. So in intergalactic space we could probably see very little with the unaided eye. The cut-off level of our vision in dark is a distinct treshold which is age-related. This is due to noise. If you stare into pich darkness (close your eyes in a dark room), you will "see" a background of noise. It looks much like "snow" on a TV screen, but very faint. This is the noise floor of your vision; anything much weaker than that will be invisible to you. Your noise floor rises as you age. Hans
	__________________ Don't. Just don't.

5th June 2004, 11:05 PM	#3
Walter Wayne Wayne's Words Join Date: Jul 2002 Location: Ottawa, ON Posts: 2,451	As a first guest I would go to the country (as far on from the city as possibly, and check things on a cloudless and moonless night). During the big east coast power outage it was easy to come close to walking into a street sign once the moon went down. Walt

5th June 2004, 11:46 PM	#5
toddjh Illuminator Join Date: Mar 2002 Location: USA Posts: 3,252	Quote: Originally posted by Eos of the Eons If there were no light sources, then space would be dark. Suns are a light source. Are there any others? Without the universe in space, then there would be nothing but complete darkness. If we didn't have the sun for our light source, then there would not be enough energy, light, etc. to sustain life on this planet from those other stars far away. You wouldn't be worrying about seeing anything-you wouldn't be here and nothing else would be either. Just our little planet with no warmth. There's the cosmic microwave background, which is "light" of a sort. And I don't know if primordial black holes have been ruled out yet. If they haven't, you might periodically (very periodically) get very bright bursts from one of those decaying. And of course there will be random events (collisions and so on) that release a bit of radiation from time to time. It's not total darkness in the literal sense, but in the practical sense it sure is. Jeremy

7th June 2004, 06:06 AM	#8
Always Free Critical Thinker Join Date: Oct 2002 Posts: 406	I see! Thanks for your answers guys
	__________________ "Stand Up For Your Freedom, Stand Up For Yourself"

7th June 2004, 07:30 AM	#9
Mark Former Spinal Tap Drummer Join Date: Sep 2001 Posts: 5,529	Quote: Originally posted by Walter Wayne As a first guest I would go to the country (as far on from the city as possibly, and check things on a cloudless and moonless night). During the big east coast power outage it was easy to come close to walking into a street sign once the moon went down. Walt I have done this many times in Arizona and the California desert, and you can see well enough to walk...if you are very careful.

7th June 2004, 07:43 AM	#10
garys_2k Muse Join Date: Jan 2003 Posts: 756	Quote: Originally posted by MRC_Hans The cut-off level of our vision in dark is a distinct treshold which is age-related. This is due to noise. If you stare into pich darkness (close your eyes in a dark room), you will "see" a background of noise. It looks much like "snow" on a TV screen, but very faint. This is the noise floor of your vision; anything much weaker than that will be invisible to you. Your noise floor rises as you age. Hans When I close my eyes, or sit in a dark room, I wouldn't describe what I "see" as "snow," it's more like swirls of darkish colors, loosely patterned and shifting. I can glance around and the shifting doesn't follow my gaze, but just seems to carry on. Pressing my eyeballs against my head (increasing ocular pressure a bit) brightens the light show up quite a lot.
garys_2k Muse Join Date: Jan 2003 Posts: 756	__________________ - Gary

7th June 2004, 12:48 PM	#11
sorgoth Muse Join Date: Aug 2002 Posts: 977	Quote: Originally posted by garys_2k When I close my eyes, or sit in a dark room, I wouldn't describe what I "see" as "snow," it's more like swirls of darkish colors, loosely patterned and shifting. I can glance around and the shifting doesn't follow my gaze, but just seems to carry on. Pressing my eyeballs against my head (increasing ocular pressure a bit) brightens the light show up quite a lot. Do that and rub your eyes for a while...it's quite the show...I often get a 'tunnel' effect, and no, I do not take drugs .
sorgoth Muse Join Date: Aug 2002 Posts: 977	__________________ L'univers et moi, nous sommes seuls ensemble.

7th June 2004, 12:55 PM	#12
MRC_Hans Penultimate Amazing Join Date: Aug 2002 Location: Whithin earshot of the North Sea Posts: 16,604	Quote: Originally posted by garys_2k When I close my eyes, or sit in a dark room, I wouldn't describe what I "see" as "snow," it's more like swirls of darkish colors, loosely patterned and shifting. I can glance around and the shifting doesn't follow my gaze, but just seems to carry on. Pressing my eyeballs against my head (increasing ocular pressure a bit) brightens the light show up quite a lot. Yes, the perception varies somewhat from person to person, as always with sensory phenomenons just at the limit of perception. I know the light-show effect by pressing the eye-balls, but don't do it too much, I have heard it is not healthy for your eyes. Hans
	__________________ Don't. Just don't.

7th June 2004, 02:58 PM	#13
garys_2k Muse Join Date: Jan 2003 Posts: 756	Quote: Originally posted by MRC_Hans Yes, the perception varies somewhat from person to person, as always with sensory phenomenons just at the limit of perception. I know the light-show effect by pressing the eye-balls, but don't do it too much, I have heard it is not healthy for your eyes. Hans Yeah, it probably deprives the nerves of blood (oxygen) or something. As usual, the fun things are the ones we shouldn't do.
garys_2k Muse Join Date: Jan 2003 Posts: 756	__________________ - Gary

16th June 2004, 12:41 AM	#14
Always Free Critical Thinker Join Date: Oct 2002 Posts: 406	Quote: Originally posted by Walter Wayne As a first guest I would go to the country (as far on from the city as possibly, and check things on a cloudless and moonless night). During the big east coast power outage it was easy to come close to walking into a street sign once the moon went down. Walt I went on a three day trip this past weekend and on my journey home I had to travel through forested areas and it was fairly late at night, 11:00pmish and I remembered you telling me about going away from city lights to view a dark moonless night. I realised that there was no moon or clouds so I decided to stop my car and get out and have a look. Well---I have viewed the night sky many times from the small city I used to live in and it was so much clearer than the night sky I now look at in my city of Melbourne. As I stood next to my car and looked up I couldn't believe what I was looking at. I have never seen a more fabulous, breathtaking sight since I saw my first super nova cloud several years ago. I grabbed the binochulars from my bag and---well you have all probably done the same thing, but the difference in what you can see up there with no outside light interference compared to a small amount of local street lights, is incredible. I also did take my eyes off the stars to look around to see just how much I could see in this dark moonless night and yes, I can make out objects, the car, my hand, the road. The trees across the road were totally black, only a sillouette against the sky. Well it was bloody marvelous. I have to get out to the country more often and will get more value out of my telescope from there.
	__________________ "Stand Up For Your Freedom, Stand Up For Yourself"