Questions tagged [visible-light]
Questions regarding a wavelength of light ranging from 380 to 700 nm. This is the spectrum that we can see.
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Why is the H-alpha line slightly shorter in wavelength (656.28 nm) in air than in vacuum (656.46 nm)? Shouldn't it be longer?
Perhaps this is a question better suited for Physics SE, but since the H-alpha line is so important in astronomy, I'm posting this here....
I would, naively, assume that wavelengths would be longer, ...
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Could a Martian observer witness the Moon's formation with naked eye?
Suppose a human observer was standing on Mars during the early Solar System, looking up into the night sky, in the approximate direction of the young Earth, as the Theia planet hypothesized in the ...
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What objects in the night sky have the narrowest range of visible light
What objects visible to the naked eye at night have the narrowest spectrum of visible light reaching the earth. Put another way, Which objects are most visible as a specific color or colors rather ...
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Back when the CMB was predominantly in the visible spectrum, would it have been visible to the naked eye?
The CMB is a near-perfect black-body spectrum, and assuming this has been true since the de-coupling, we should have been able to see the glow. In fact, at a certain point, it should have been almost ...
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How luminous does a brown dwarf have to be to illuminate an Earth-sized planet with 0.5 lux at 2,000,000 kilometers away?
A brown dwarf is a deuterium-fusing substellar object, and, in the cases of the larger ones, a lithium-fusing one. They often emit electromagnetic radiation in frequencies that humans cannot see. ...
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Formula for calculating if an object can cast a visible shadow on the ground or not
I know that we can see the shadow cast by the light of Venus on the ground. I also talk with one person who said they were able to see the shadow even from Jupiter.
Recently I've read something like ...
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Can Jupiter's rings be seen with the naked eye by an astronaut nearby? How difficult would it be?
Maybe a basic question, apologies.
I understand that there would be different answers depending on how far is "nearby", depending on how inclined our orbit is, and what is our alignment with ...
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What color would stars have with an apparent magnitude of ~-30? [duplicate]
The light of the Sun is white because our eyes are evolved to work with it as the primary light source. Other stars look white in the night sky because they are too faint to activate the color ...
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What it the outer part of the sun, that we see with our eyes, called?
When we look at the sun with our eyes it seems much larger than it actually is. When we use a solar filter we are seeing what the sun actually is.
So, what is the name of the thing the solar filter is ...
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What would shadows look like on a planet with two suns?
On planet Tatooine which has two (main-sequence I guess) suns people still have one shadow only. Tatooine's suns seem quite close to each other, so it may actually be the case that the two shadows are ...
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What colors do other stars have when seen from space close to them?
The Sun looks yellow from Earth because we see it through the atmosphere; in space the Sun looks rather white. Do A-, B- and O-type stars look blue from both their planet's atmospheres and outer space?...
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Is it dangerous to look at an L-type brown dwarf from too close?
Are some L-type brown dwarves bright enough so that it would be dangerous to the eyes if one looked at them from habitable distance or closer? If not, are the weakest M-type stars undangerous to look ...
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Are there gas clouds in space so dense that we couldn't see out of them if one where to be inside it?
The images of telescopes capturing gas clouds are quite intriguing to me, which keeps me wondering about visibility inside them.
Are there gas clouds in space so dense that we couldn't see out of them ...
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How can the author of this article conclude that earth-shine on the moon is 100 times brighter than moon-shine on earth? [duplicate]
I don't understand the reasoning of the author of this article, on page 26. How can he conclude that full earth-shine on the moon is 100 times brighter than full moon-shine on earth?
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Which unit is most suitable in comparing needed light intensity for night reading on the Moon, vs on Earth?
Which unit is best to use, and why, when determining how many times easier it is to read a newspaper (or any other printed text) on the moons surface at night under a full earth, compared with reading ...
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Starlight: are the rays that we see here on Earth parallel?
Are the rays of light emitted from stars that are perceived by an eye here on Earth parallel?
Do they travel in a straight line from the star to the eye, never crossing, and equidistant?
Do they ...
kmiklas
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Is there any scientific correlation between cold nights and star-lit skies?
I've many times heard expressions such "cold, starry nights". It's apparently poetic to describe star-lit night skies as being "cold".
Is this based on reality in some way? Is ...
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Can an average person see stars from the bottom of a well or through cardboard tubes? Definitive answer required!
A debate about seeing stars or planet during the day below this answer to the Aviation SE question At what altitude might a pilot be able to see at least the brightest stars during the day? seems ...
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Is Jupiter as opaque as it looks?
Although it is impossible to tell what is and isn't false color (aside from the adage that it probably is false). It's inarguable that no picture of a gas giant shows any depth or significant ...
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Do Satelites travel in train like formation? [duplicate]
This morning approx 5.30am i seen roughly 12 travelling in perfect formation approx 15cm apart , im 200km south of sydney Australia travelling from a north west direction
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Is Olbers' Paradox Nonsense? [closed]
Ok, this is a bold question, I know. But, let me explain: After first hearing about Olbers' paradox, I found that something seemed 'off' about it, so I looked into the subject as much as my skills (...
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Can a star emit a larger fraction of its total light in the visual range than the Sun does
If one sets both the bolometric and visual luminosity of the Sun to 1 (and use a linear scale), can a star then have a higher visual than bolometric luminosity?
It makes sense that this will not be ...
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What is the intensity distribution of visible light over the solar disk?
What is the distribution of the visible spectrum over the solar disk?
Images of the Sun using the visible spectrum suggest that the light emmitted from the edge is almost equal to the light emmited ...
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Why do I see rainbows around the moon?
Regularly, I see rainbows around the moon. Here is approximately what I see:
Right at the edge of the moon, I see a bright blue ring of light. Further out, I see an inner rainbow. This is not as ...
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Are any bow shocks seen in the visible spectrum?
Are any of the images of bow shocks created from visible light, or are they all from infrared light? While I'm including two of the better known images, my question is about any known bow shock.
LL ...
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