The Sun is an almost perfectly symmetric yellow dwarf star [spectral class G2V] which is at the center of our Solar System.
12
votes
2answers
234 views
Hydrogen as a fuel in Sun
The source of Sun's incessant energy is hydrogen; which is continuously converting to helium through nuclear fusion reaction releasing energy. Why does not all hydrogen convert into helium in one big ...
6
votes
1answer
30 views
Refraction and scattered light for NLCs
For helping with judging NLC candidates (are they NLC or not) I have a set of formulas to calculate the minimum altitude (in km) of the candidate given an observed altitude (in degrees) of the ...
22
votes
4answers
2k views
Why is a new moon not the same as a solar eclipse?
Forgive the elementary nature of this question:
Because a new moon occurs when the moon is positioned between the earth and sun, doesn't this also mean that somewhere on the Earth, a solar eclipse ...
9
votes
2answers
263 views
Effect of gravitation on light
Einstein predicted that the gravitational force can act on light. This was verified in one solar eclipse that light from a star near to the sun's disc bent due to Sun's gravity as predicted. Since ...
2
votes
1answer
135 views
Will the sun cool and produce a disrupting EMP?
Scientists say rare drop in sunspot activity could cause global cooling
http://www.globalpost.com/dispatch/news/business-tech/science/110615/science-news-solar-flares-sunspots-global-warming
...
1
vote
3answers
645 views
Are dangerous rays emitted during Solar Eclipse?
It is said one should avoid staring at Sun as it can damage the eyes, but it is also said that one should not come out in sun during eclipse as it emits dangerous rays. Is that true? If yes, why?
1
vote
2answers
317 views
Nuclear decay rate affected by sun and quantum randomness
If nuclear decay rate were affected by sun,
then emission probabilities would be subject to sun state and its influence,
so quantum randomness would depend on it,
Would it still be truly random?
One ...
7
votes
2answers
96 views
How to create unusual sundial?
I am considering small "artsy" project. I would like to create sundial by placing gnomon on the window and painting hour lines on the window facing wall.
Since this is to be placed in bedroom I am ...
6
votes
3answers
84 views
What frame(s) of reference are used to measure the rotation of the Sun around the galaxy ?
I can find various speeds and estimated durations listed at numerous places but none specifically describe the frame of reference.
Possible options as example of kind of answer I expect.
Local ...
4
votes
1answer
25 views
Are solar physics images of use to the night-time community?
I'm actually interested in cases of cross-discipline data re-use.
I know that the SOHO/LASCO coronographs are used for comet finding, that solar telescopes were used to get information about Venus's ...
3
votes
1answer
186 views
If 100% of the energy from the sun is reflected back into space
100% of the energy from the sun is reflected back into space, it's just shifted from a low-entropy state to a high-entropy state, and from a high frequency (ultraviolet) to a low frequency (infrared). ...
13
votes
2answers
242 views
Is the length of the day increasing?
In Frontiers of Astronomy, Fred Hoyle advanced an idea from E.E.R.Holmberg that although the Earth's day was originally much shorter than it is now, and has lengthened owing to tidal friction, that ...
16
votes
6answers
681 views
Can the apparent equal size of sun and moon be explained or is this a coincidence?
Is there a possible explanation for the apparent equal size of sun and moon or is this a coincidence?
(An explanation can involve something like tide-lock effects or the anthropic principle.)
2
votes
1answer
98 views
Solar Cycle UV Variation
The average energy we receive from the Sun is 1,366 w/m^2, and this only varies by 0.1% from the activity peak to trough of its 11 year cycle. About 9% of the energy comes from wavelengths less than ...
3
votes
0answers
384 views
live Kp index data
I need to create an online service displaying latest Kp index.
Where I can take the data?
The data should be in machine-readable format, i.e. text files, XML, or CGI gateways, for instance. No ...
5
votes
3answers
472 views
Why does the light side of the moon appear not to line up correctly with the evening sun?
I live at roughly 52.4,-2.1. On a sunny evenings I've often looked at the moon and the sun and noticed that the light part of the moon does not appear to line up with the sun. For example, at about ...
0
votes
3answers
311 views
How does solar activity affect the ISS?
Currently the sun is launching some intense solar flares.
http://www.guardian.co.uk/science/2011/feb/17/solar-flares-northern-lights-uk
Th article I've linked also mentions how a "coronal mass ...
6
votes
2answers
368 views
3
votes
1answer
264 views
Producing energy from magnetic flux loops
I've simplified this down by quite a lot but as far as I understand it, magnetic fields on the Sun's surface twist together and when it gets all a bit too much they release energy.
My question is why ...
3
votes
3answers
467 views
Energy of the electron-muon reaction
Lets see the reaction:
$e^- \mu^- \to e^- \pi^- \nu_\mu \;\;\;\;\;\;\;\;\;\;\; {(1)}$
I suppose, that this reaction occurs as follows
$e^- \mu^- \to e^- \mu^- \pi^+ \pi^- \to e^- \pi^- \nu_\mu$
Is ...
10
votes
2answers
282 views
How are the northern lights produced?
Although I've never seen it myself, I hear the northern lights are a sight to be seen! I know they're related to the Earth's magnetic field but I don't know much more about them. What is the physical ...
3
votes
1answer
497 views
Formula for getting time of sunrise at a particular location?
Is there a formula that can get sunrise at a particular latitude and longitude (and elevation from sea level)? If so, what it is? (Why does it work?)
