Submitted by Suitable-Victory-105 t3_1252a9g in space
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Suitable-Victory-105 OP t1_je2420f wrote
Does this mean that we can see stars when the earth is blocking the sunlight?
CitizenLaim t1_je25gd9 wrote
Yes. It’s called nighttime.
OnlyAstronomyFans t1_je26jto wrote
You mean night?
LaunchTransient t1_je25v89 wrote
If you are in any kind of shadow, yes.
It's basically the limit set by the dynamic range of the optical instrument viewing. Given that sunlight is 60 million times brighter than starlight, it's no wonder that it washes out.
Micke_xyz t1_je2hg82 wrote
Now, let's take a moment to appreciate the wide dynamic range of the humen eye. Sure, if you look at the sun you will damage your eyes but it's still possible to see the contours of the sun, it's not a big white blur in that part of the sky.
And with that same "tool", we are able to clearly detect stars at night.
LaunchTransient t1_je2jqny wrote
Yes, human eyes are amazing - but note that they cannot observe both phenomena at the same time. In sunlight, your irises constrict a lot and it's still dazzling - under a night sky they quadruple in diameter, so that's an 16:1 ratio when they fully dilate to when they fully constrict.
I doubt you could be able to gather enough light to see stars at full constriction, and your retina would be utterly overwhelmed if you tried viewing the sun with a fully dilated iris.
PistolNinja t1_je2neiz wrote
You can mimic the same effect with a DSLR camera. Take a shot of anything with the aperture wide open, let's say say f1.2. Then without changing anything else, tighten the aperture to f5.6 or higher and the image will be WAY darker.
[deleted] t1_je246pc wrote
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SnakeOfAustralia t1_je3pnbl wrote
Shadow are just dark light
svarogteuse t1_je22qxr wrote
Pictures of other objects in space, say astronauts, are taken in the daylight so said foreground objects are lit. You don't see stars in the daylight on Earth (or large cities with lots of light pollution) either because they are to faint. Same thing applies to space.
The sky is black because the bright sun light is not scattered producing blue not because its dark.
Suitable-Victory-105 OP t1_je23nbs wrote
Does this mean that at night, we would be able to see stars when the earth is blocking the sunlight from us?
Edit: reworded the question better.
Fantastic_Jason t1_je24hhw wrote
All of them except the sun. 😂
BProbe t1_je4j58v wrote
Akshuallyyyyyyy... You gotta think about the portion of the "sky" that the Earth itself blocks, so basically 1/2 of them at any given time.
PyramidBusiness t1_je2okh8 wrote
Have you ever been outside past sunset before?
Rich_Firefighter_269 t1_je35gsp wrote
Go and drive out to the least populated place you can feasibly go. The less lights from houses, cities, cars the better.
There is literally a river of stars in the night sky aka the Milky Way. It will change your life when you see it.
svarogteuse t1_je26e01 wrote
Yes. However you also likely need a camera taking a longer exposure or with a more sensitive sensor that those use for daylight photos, just like you need on Earth.
Nerull t1_je2h14d wrote
You don't actually need Earth blocking the sun for you, you just need to look away from the sun and anything lit by the sun.
DrSartorius t1_je30enk wrote
OMG!! is it always Daylight in space?? wow
svarogteuse t1_je4upzo wrote
No one suggested its always daylight in space. However its almost always daylight when/where we take photos because all black doesnt make good copy.
Klondike2022 t1_je23mt3 wrote
I mean, James Webb and Hubble see a lot of stars from space
imagicnation-station t1_je2onb2 wrote
The reason for that is because the JWST is orbiting the Lagrange point 2, which sits behind the Earth, making it "nighttime" all of the time.
PhoenixReborn t1_je2uet8 wrote
JWST isn't in the Earth's shadow. It orbits L2 to keep getting power to its solar panels. The imager is pointed away from the sun at all times and protected by its sun shield.
imagicnation-station t1_je2we7f wrote
You are right. It orbits in and out of Earth's shadow. But at L2, that's the most stable compared to the other Lagrange points.
CremePuffBandit t1_je22mn6 wrote
Because most space pictures are taken during the day on their respective planet/moon. The sun washes everything else out, just like what happens during the day on Earth.
Suitable-Victory-105 OP t1_je23c7i wrote
Thank you it does make sense that the sun washes out the light from other stars now.
dusty545 t1_je27zo8 wrote
Go through Thomas Pesquet's flicker account and look for the nighttime photos where the ISS is in the dark.
Ritari_Assa-arpa t1_je28wr9 wrote
When looking sky during daytime our atmosfare makes sky blue, which means there is some matter what effects way we see sky and space. When taking pics shooting parameters are adjusted to get best possible, or wanted, outcome to taken pic; ISO, shutter speed, aperture. If you take on the moon sky will appear black.
However, if you take pic about sky from moon it shouldnt matter if its moons day or night. Sun might lit whole moon, but without atmosfare there cant be same light pollution we have on earth. Same goes if you are on space walk, facing away from earth, moon and sun, there is nothing to reflect sun light since its empty vacuum. There cant be light pollution which will effect taken pic. Then it should be possible to take picture of all stars when you adjust settings right for stars and you are back against sun, earth and moon.
There is another way to think this over; when we are on earth during night we see sky as black, full of stars (depending on light pollution here on earth), but night for us, on dark side of earth, is illusion created by body of earth. Night sky we see is only partially shadowed by earth body, and space around that shadow is full of sun light, we just dont see it because there is nothing to reflect it to us.
Since earth is "round" we can play with idea we are precisely middle of the night on middle of calm pacific ocean. This means you are looking sky from surface of ball limited only horizon and you are from your point of view, middle of the night, at the "highest point' of that ball, earth precisely between you and sun. We all know how light goes straight line from sun, and night is just shadow created by body of earth, and this means sky around horizon cant be in earths shadow. Still we can see those stars. Sun doesnt wash away stars, but during night time without lit atmosfare we see clearly what space looks like.
Suitable-Victory-105 OP t1_je29o2l wrote
Thank you for writing this. Makes a lot more sense now.
Obvious_Cranberry607 t1_je25wqd wrote
The ones you are talking about are adjusted to properly expose an object that is brighter than the stars, which means the stars will usually be too dim to notice. If you look at some pictures of dim objects, like the Earth at night from the ISS (https://eol.jsc.nasa.gov/Videos/CrewEarthObservationsVideos/) you can definitely see the stars.
mmixLinus t1_je282wq wrote
Take a shoe outside during a sunny day and take a picture of it.
At night, take a picture of the Moon.
What do these images have in common? They are both of sunlight reflected once, which means they were taken using the same settings!
So anything sunlit in space is going to be so bright you will have to lower the exposure settings to not get an over-exposed image, which will also result in no stars, as they are so much weaker.
Nerull t1_je2gtig wrote
If you have access to a camera with manual exposure settings, here's an experiment: Setup the exposure for a properly exposed, sun lit daytime photo.
Without touching the settings, take the camera outside at night, point it at the sky, and snap a photo. What do you think you'll capture?
The answer is: nothing. The stars are far too dim, compared to sunlight, to show up in the exposure at all. Most space photography is done in sunlight, of things that are sun lit. The cameras are set to properly exposed these sun lit things, and the lack of an atmosphere doesn't change the fact that the stars are just too dim to show up in the same exposure.
[deleted] t1_je22zhw wrote
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Suitable-Victory-105 OP t1_je2e8nc wrote
If you are an astronaut, can you see stars other than the sun?
Nerull t1_je2has8 wrote
If they aren't looking at the sun, or anything lit by the sun, they can see stars just fine. Your surroundings just need to be dark enough to let your eyes become dark adjusted.
[deleted] t1_je2fm5g wrote
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[deleted] t1_je2gu0d wrote
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montagdude87 t1_je2y8xq wrote
I see stars in lots of images taken from space. See: Hubble, JWST.
Deyln t1_je411k9 wrote
The space satellites aren't really dslesigned to take pictures in the range that humans see either.
TreeHawkFeather t1_je6miap wrote
So much light pollution on the moon. We really need to scale back development 😆😜
blue4204 t1_je22hva wrote
Because on Earth the light from the stars illuminates the air in front of us. While in space there's nothing for the light to illuminate.
Suitable-Victory-105 OP t1_je22m4x wrote
Thank you. That now makes a lot of sense.
One_Astronaut_483 t1_je23haw wrote
This doesn't make any sense for me. Light doesn't need something to see it. It's the other way around actually, the light bounces in the atmosphere and it's losing energy.
Suitable-Victory-105 OP t1_je23tiy wrote
I realise this now. I think it is now because the light from our sun washes out all other starlight.
MovingFjordward t1_je23hpm wrote
Light exposure. Big bright sun is much brighter so the dim stars disappear. Same reason you don't see stars during the day on Earth. Turn your phone brightness all the way down during the day putside and you will barely be able to see the screen if at all. Do it again at night in a dark room and that same setting is completely visible.