What effect does color on the upper and lower side of umbrella have?
This question isn't referring to the general use of umbrella to provide protection from rain rather it concerns the optical effects of the color on lower and upper portion of umbrella. Umbrella are...
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How do you calculate light attenuation by wavelength at a given air mass...
I am trying to get a good view of light wavelength distribution as a function of viewing angle, with a specific interest as $z \approx 90^\circ$ near the horizon (sunrise/sunset). Air mass coefficient...
View ArticleWhat is the difference between granulatiion, mesogranulation,...
Help me understand the differences between granulation, mesogranulation, supergranulation, and giant cells and at what depth they are created.
View ArticleEstimate distance of a halogen lamp to simulate sun
I'd like to simulate sun effects on a material affected by UV and IR.Actually is winter and I'll need to wait 6 months to have maximum sun intensity and be able to expose it to direct sun.I've a...
View ArticleIs there a simple yet accurate formula for where on Earth the Sun and Moon...
I'm trying to improve a site that shows the region of the Earth currently under daylight, and I need a formula that, given the current time, tells where (latitude/longitude) the sun and moon are...
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Why do sunbeams diverge even though the sun is much more than a few...
Consider this picture of sun beams streaming onto the valley through the clouds.Given that the valley is only (at a guess) 3km wide, with simple trigonometry and the angles of the beams, this gives the...
View ArticleIs the orbit of Earth currently decaying?
As we know, interplanetary space is not completely empty. This would cause a drag to Earth, spiralling it towards the sun in a long enough timescale, which appears to be what has happened for many...
View ArticleWhere is there visible light inside the Sun?
The solar core has a temperature of 15 million K, but the visible color temperature is only between 1000 K and 10000 K. Also, the plasma is very dense at the core, so it won't be able to travel...
View ArticleThe Sun is giving us a low entropy, not energy
While I was watching a popular science lecture on YouTube, I came across this sentence"Sun is giving us a low entropy, not energy"which was said by Prof. Krzysztof Meissner.I am not a physicist, but...
View ArticleWhy can we not measure the distance to the Sun directly using Radar?
My question is specifically WHY CAN WE NOT USE Radar to measure the distance to the Sun? What is the reason for that? Sorry if this is a lame question, I'm not an expert on these things and just...
View ArticleWhat is the albedo of our Sun?
I think the Sun is the closest to a perfect natural black body we can get in the Solar System, if so then what happens to the light if I point a laser pointer at the Sun?
View ArticleWhy the Sun does not shoot relativistic jets?
I saw the features of the Sun here and it has almost everything include nanojets and CME but not relativistic jets. Isn't the Sun magnetically active so why isn't it capable of shooting out...
View ArticleHow big can solar flares get and could they boil away Earth's atmosphere?
Is there a known theoretical maximum size for a solar flare and would it mean curtains for life on Earth?
View ArticleHow do we know that the Sun is 71% Hydrogen by mass from emission/absorption...
In my Intro to Astronomy ("intro" is very important, please keep responses as simple as possible) course, we're currently learning about light and electron orbitals and such, and I came across this in...
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Brightness of the light source at twilight computation
I would like to determine the brightness of the light source at twilight based upon its apparent magnitude.In the question here:What are the average wavelengths and brightnesses of sunlight across the...
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What exactly is delta-14C and why are there periodic plateaus in the...
I downloaded the IntCal13, IntCal09, and IntCal04 datasets (parent site), and when I plotted the last 24k years was surprised to see a plateau or even reversal appear every ~5300 years. Apparently we...
View ArticleFusion in the sun for 4 hydrogen to Helium-4. How is the energy produced
So please correct me if I am wrong but:First 2 proton’s (each with an electron) fuse together,The mass stays the same so no energy is produced?Then 1 of the protons turns into a neutron with a Neutrino...
View ArticleMoon vs Sun size and distance 400 times
I have seen below statement, and it doesn't sound right:The Sun and Moon seem to have the same size because of this amazing coincidence: the moon is 400 times smaller than the Sun and 400 closer than...
View ArticleEffect of radiation pressure on Earths orbit in large timescales
I have seen some posts concerning the radiation pressure exerted by the Sun on Earths surface (Force on Earth due to Sun's radiation pressure). Though it is fairly small may it have a considerable...
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How big a coincidence is the Sun and Moon having almost equal apparent sizes?
It's consensus that the very similar apparent sizes of the Moon and the Sun as seen from Earth is a coincidence (as already answered in this site).This provides us with almost exact total solar...
View ArticleLuminosity and absolute magnitude relationship
Context : an exercise gives the temperature, mass, distance and apparent magnitude of Sirius B and asks to calculate its density.One key step of the calculation is to get the luminosity from the...
View ArticleIs Sun not the biggest source of energy to us?
Probably in my 5th or 6th grade, I learnt in my science classes that sun is the biggest source of energy to us.However, I was watching this youtube video according to whom the energy of earth is...
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What creates the Global Dipole Magnetic Field in the Sun?
I understand that the Sun undergoes convection and with rotation, the convective cells have a helical motion because of the Coriolis Force. My confusion comes from the fact that via the right-hand...
View ArticleThe speed of an impulse transmitted along a string
A supernova explosion on the far side of the Sun ejects a mass with approximately the same mass of the Sun directly at the back side of the Sun. If this ejected mass is travelling arbitrarily close to...
View ArticleDoes sunlight have a modulation frequency?
By frequency, I don't mean electromagnetic frequency, I mean modulation frequency. For example, I can put a PWM square wave on an LED at some frequency, which I can detect with a photodiode and a...
View ArticleWhat is the minimum size of an object to cast a shadow on the entire Earth?
When I fly up(don't ask me how), I see how my Sun's shadow on Earth is getting bigger but dimmer as the Sun's light is reflected from other objects.As I flew higher and higher in the direction of the...
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Why isn't sunlight polarized?
My guess:Because polarization happens only when am amplitude exists, and because the Sun is so big that the light rays arriving on Earth literally come from all directions, their amplitude is then...
View ArticleWhy is sunlight spectrum continuous?
My teacher explained today that unlike the spectrum obtained by analyzing the sunlight, the spectra of atoms are not continuous.I have a question about this - the sunlight is emitted by the atoms of...
View ArticleUsing Infrared light to absorb UV rays in a vacuum [closed]
Please explain what a shield of infrared light(thru absorption) would do as sunlight/UV rays were to pass through the infrared.it should absorb the uv. Please test it.
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Sudden drop in temperature in Sun convective zone
In the solar temperature graph, why does the temperature drop suddenly in the convective zone? Is it because some energy is needed for ionisation?
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