Skip to main content
29 votes

What it the outer part of the sun, that we see with our eyes, called?

I think you're talking about the effect of a "fluffy glowing ball" around the solar disk, shown on the right in this photo: This is called solar aureole, and it's caused by the aerosols in ...
Ruslan's user avatar
  • 967
17 votes

Why are the solar prominences visible during a total solar eclipse - orange? Is the sun orange?

There are several things going on here. Structures that are seen in emission off the photospheric limb of the Sun - know as prominences - are emitting a lot of light at the specific wavelength of the ...
ProfRob's user avatar
  • 155k
15 votes

What it the outer part of the sun, that we see with our eyes, called?

What it the outer part of the sun, that we see with our eyes, called? I am not sure there is a single word for this, since the effect is a little complicated. We might call it "the glare of the ...
uhoh's user avatar
  • 30.7k
11 votes

Why are the solar prominences visible during a total solar eclipse - orange? Is the sun orange?

The surface of the sun is (roughly) a black body emitter. It emits light over a wide band from the ultraviolet to the infrared. When we see this light it appears "white". Its actually hard ...
James K's user avatar
  • 125k
11 votes

Why are the solar prominences visible during a total solar eclipse - orange? Is the sun orange?

And according to the pictures from NASA it looks like a solar prominence has the same color as the sun. Note the photo you've linked here is taken in UV, not visible light. The prominence and the ...
BowlOfRed's user avatar
  • 2,150
9 votes
Accepted

Can an average person see stars from the bottom of a well or through cardboard tubes? Definitive answer required!

This article (Hughes 1983, "On Seeing Stars (especially up chimneys") from the Quarterly Journal of the Royal Astronomical Society seems like a pretty good account of the "phenomenon&...
Peter Erwin's user avatar
  • 17.2k
9 votes

Divergence of light rays - parallel approximation

Is he using a small angle approximation? Yes! Consider this triangle: The bottom side which I labeled "384403000 m" as the Earth-Moon distance, and "1 m" is the diameter of the ...
Polaris5744's user avatar
8 votes

Why do I see rainbows around the moon?

There are a couple of atmospheric phenomena that can create rings around the moon. Corona are caused by water droplets diffracting the moon's light, they are fairly small, and close to the moon. They ...
James K's user avatar
  • 125k
8 votes
Accepted

Could a Martian observer witness the Moon's formation with naked eye?

How bright would a 6000 km radius blob of magma be? A quick luminosity calculation assuming the surface to be 1000 C gives an absolute magnitude of 21.63 and an apparent magnitude of -9.056 at 225 ...
Anders Sandberg's user avatar
8 votes
Accepted

What objects in the night sky have the narrowest range of visible light

...the narrowest spectrum of visible light... is tough because most process that make electromagnetic radiation either result in broad continua or multiple emission lines. I originally wanted to ...
uhoh's user avatar
  • 30.7k
7 votes

What it the outer part of the sun, that we see with our eyes, called?

None of the other responses seem to answer the question "What is the name of the thing the solar filter is eliminating?" In fact, the solar filter doesn't eliminate anything. It just makes ...
Matt Timmermans's user avatar
6 votes
Accepted

Can Jupiter's rings be seen with the naked eye by an astronaut nearby? How difficult would it be?

Here is an answer based on photometric arguments: The astronaut probably would not be able to see the rings, but it would be worth a try. I would recommend the astronaut float somewhere at a distance ...
giardia's user avatar
  • 2,098
4 votes

Starlight: are the rays that we see here on Earth parallel?

Light will travel in a straight line through the 4D Space-time continuum. It does not wiggle around and is only deflected by gravity. Light from distant stars reaches us more or less parallel due to ...
Slarty's user avatar
  • 359
4 votes
Accepted

Is it dangerous to look at an L-type brown dwarf from too close?

A typical L-type brown dwarf is about 1200-2200 K in surface temperature and is about the size of Jupiter. Using the Stefan-Boltzmann law, we can deduce that the hottest brown dwarfs have a luminosity ...
WarpPrime's user avatar
  • 6,683
4 votes

Is Olbers' Paradox Nonsense?

Let me see if I can show why your "inverse-square-law means you can't get light from distant sources" intuition is wrong. For the sake of argument let's assume stars really are point sources, and ...
Peter Erwin's user avatar
  • 17.2k
4 votes
Accepted

Can a star emit a larger fraction of its total light in the visual range than the Sun does

Surely this is exactly what the V-band bolometric correction assesses. The numerically larger the bolometric correction, the more of a star's flux (as a fraction) is in the V-band. The Sun's ...
ProfRob's user avatar
  • 155k
4 votes
Accepted

What is the intensity distribution of visible light over the solar disk?

What is the intensity distribution of visible light over the solar disk? What is the distribution of the visible spectrum over the solar disk Hopefully I've answered all the different questions. ...
Rob's user avatar
  • 2,666
4 votes

What it the outer part of the sun, that we see with our eyes, called?

The part of the sun you see (but you shouldn't look at the sun except through a filter) is the photosphere: https://en.wikipedia.org/wiki/Photosphere The scattering effect in your second photo is due ...
jamesqf's user avatar
  • 139
4 votes

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?

This is not due to where the light is emitted, but where it is measured. When light enters a medium, such as air, it slows down. This is called refraction (and is the reason that prisms etc can bend ...
James K's user avatar
  • 125k
4 votes

Shadow Bands: How can atmospheric turbulence obscure the sun-crescent immediately before a total solar eclipse? and why are they 'bands'?

Think about the patterns that you have seen on the bottom of a swimming pool when the sun shines through ripples on the surface. These are a related phenomenon. When the sun shines through a medium ...
James K's user avatar
  • 125k
4 votes

Why are the solar prominences visible during a total solar eclipse - orange? Is the sun orange?

The camera might be looking in the reddish-orange 656nm H-alpha emission line, but probably the telescope's solar filter is just orange instead of neutral-density. I had a solar filter that made ...
Miss_Understands's user avatar
3 votes
Accepted

What colors do other stars have when seen from space close to them?

This site shows the colours that stars would have if their intrinsic spectra were viewed. The simulations do not have any intervening atmosphere and assume that the star is bright enough that the ...
ProfRob's user avatar
  • 155k
3 votes

Back when the CMB was predominantly in the visible spectrum, would it have been visible to the naked eye?

It wouldn't be like staring into the Sun so much as being inside the Sun (its photosphere, anyway). What we really see is not distant objects, but light that enters our eyeballs. The CMB radiation ...
benrg's user avatar
  • 3,860
3 votes

Back when the CMB was predominantly in the visible spectrum, would it have been visible to the naked eye?

The cosmic microwave background (CMB) was emitted as a blackbody at a temperature of about 3000 K. The CMB temperature then falls as the universe expands and is currently at a temperature of 2.73 K. ...
ProfRob's user avatar
  • 155k
3 votes

Are any bow shocks seen in the visible spectrum?

I'm far from an expert in this topic, but I was curious about this question and looked into it myself. Sadly, I was only able to come up with a pretty weak answer. The very Wikipedia page you got the ...
Cody's user avatar
  • 1,180
3 votes

Is Jupiter as opaque as it looks?

What you see are clouds, big clouds, and these are as opaque as the cumulus clouds on Earth. The pale bands are ammonia clouds and the darker bands are ammonium hydrosulphide clouds. The ammonia ...
James K's user avatar
  • 125k
3 votes

How can the author of this article conclude that earth-shine on the moon is 100 times brighter than moon-shine on earth?

The author says that the difference between the factor of 100 and the geometric increase due to area and albedo is because of "atmospheric absorption and directional effects". The former is ...
ProfRob's user avatar
  • 155k
3 votes

Is there any scientific correlation between cold nights and star-lit skies?

Yes. Clear skies allow the Earth to cool more effectively at night. If there are clouds, these re-radiate some portion of the infrared flux from the Earth back towards the ground, keeping it warmer.
ProfRob's user avatar
  • 155k
3 votes

What is the biggest magnitude (faintest light possible) seen by JWST?

I went kind of far afield with this answer, so the super-short and straightforward response is: "The faintest object it can view is limited only by the amount of time that we're willing to devote ...
Jason Patterson's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible