Sun Definition and 1000 Threads

  1. B

    Could a Moon Be Transformed into a Mini Sun?

    Hi everybody, I apologize if this has been asked already - I searched for a similar topic to no avail. My question regards something touched upon briefly in Olaf Stapledon's book Star Maker. Stapledon writes of interstellar travel being acheived by detaching a planet from a solar system and...
  2. O

    Is the Sun Anchored? | Experiments & Feedback

    By "Is the sun anchored" I am referring to its place relative to the planets. I am pretty sure the answer is yes, as the planets also exert a gravitational force upon the sun (Newton's third law). This would cause the sun to "move" somewhat, no matter how small the force exerted. Then again...
  3. qntty

    How can I track Earth's distance to the sun on a specific date?

    A few weeks ago I saw a web page (I believe it was at NASA) that allowed you to enter a date and see Earth's distance to the sun on that date. I searched but can't find the site again, does anyone know where I can find this page?
  4. F

    Angular momentum of the sun and a white dwarf

    Homework Statement The Sun rotates about its own axis once every 26.0 days. Its mass is m_sun = 2.0E30 kg and radius is r_sun = 7.0E8 m. Assume that the Sun is a solid sphere with uniform density. Astrophysicists predict that the Sun will collapse into a white dwarf in some billions of...
  5. J

    Astronomy - ratio of the magnitude of the force of sun and moon gravity

    I've been reading and reading and trying to figure this out, but I just can't. Any help anyone can give will be appreciated. It is probably simple as hell, but for some reason my stupid brain can't get it.. The formula/equation is: What I have to do is: Now, I'm not looking for...
  6. M

    Harnessing Gravitational Energy: A Power Source Abundant Throughout the Universe

    In the world we live in, we can convert and use energy in the form of radiation and turn it into a significant power source. Gravitatoinal energy, which exists throughout the whole universe could be used someday as a power source. Think of it. A power source abundant throughtout the universe...
  7. D

    Create XML Reader in C for Sun Machine

    I have to write a routine that reads in csv data and appends it in an xml template and saves it. I am not allowed to use C# or C++. It must be in C. I am running it on a Sun machine. Our team has come up with the reader for the nodes of the xml. I've checked several websites looking for example...
  8. Z

    Is it Possible to Contaminate our Sun?

    Lets assume if we were able to gather ALL the Radioactive waste on Earth, eg. depleted Uranium, and also other un-recyclable materials - drink bottles, plastic bags etc... and fire them into the Sun. Would then, the sun be contaminated for the next billion years since most radioactive materials...
  9. P

    If the sun were to approach the earth

    ... as the sun was traveleing at a closer distance towards the Earth , would Earth bound objects start to fly away from the Earth surface and head towards the sun's surface , or would everything on Earth surface fly towards the sun's surface as the same time the Earth itself flew towards the...
  10. P

    Why is black better than white for sun protection?

    OK, so people say that wearing white is better than wearing black in the sun because white reflects light whereas black absorbs light. But at the same time it is said that black is better for sun protection (for example, darker skinned people are much less likely to get skin cancer than...
  11. D

    Would the removal of the sun result in a shockwave?

    Hello everyone, good day, So I understand that gravity travels at the speed of light and such. So naturally, if the Sun were suddenly gone, it'd take ~8 minutes for us to fly off and die. But I was reading Michio Kaku's "Parallel Worlds" and he used the trampoline/bowling ball analogy for...
  12. B

    Where does the sun rise, w/ axial tilt?

    Obviously we all know the sun generally rises in the east and sets in the west. But due to axial tilt, it is only really due east and due west at the equinoxes. At other times of the year, the sunrise will be somewhat north of east or south of east (and likewise for the sunset, but let's focus...
  13. C

    Integrating dP/dr over the Sun

    Homework Statement Consider the Sun to be a sphere of hydrogen gas of uniform density equal to its average density (1440 kg/m3). a) Integrate the equation of hydrostatic equilibrium for dP/dr from the Sun’s radius to the core to estimate the central pressure in Pa and in atmospheres...
  14. T

    Any relationship between light from the sun and electricity?

    I have a Van der Graaff machine here. When I touch it with my finger I get zapped by a big blue spark. Does this spark of light have any relationship or commonality with the light I see all around me from the sun? If not, can someone please try to convince me that it does...
  15. I

    Correcting for sun diameter and refraction in sunrise/sunset equations

    I am using the following C library for a variety of solar position calculations: http://rredc.nrel.gov/solar/codesandalgorithms/solpos/ In the library, they use the function srss() to compute sunrise and sunset times. Unfortunately, it seems that their equation is for the time that the...
  16. J

    Schools Would Sun Java Certification significantly help my grad school prospects?

    I'm a physics student in the penultimate year of my degree. I'm quite good at programming and was thinking this summer I'd put in 3 months of effort and get Sun Java Certification. Would this be worth the effort? Would it be something which would be very attractive to a prospective grad...
  17. D

    What is the Electric Field Strength of the Sun?

    Sorry if this is the wrong forum (its difficult to tell) What is the electric field strength of the Sun, how is it measured and what is its origin? Thanks
  18. B

    How does the 'atmosphere' of the sun affect ligth from stars passing behind it.

    When the sun goes down over the horizon, we can still see the sun because the light of the sun is bent by our atmosphere. I would imagine that if one were outside of our atmosphere on the far side of Earth away from the sun, yet in a path in line with that light they would also see the sun...
  19. L

    Distance from sun to earth= 1.5 x10^11m

    Please help! 1. Homework Statement Find the point between Earth and the Sun at which an object an be placed so that the net gravitatinal force exerted by Earth an the sun on this object is zero. Me=5.98 x 10^24kg Ms=2 x 10^30kg Distance from sun to earth= 1.5 x10^11m 2. Homework...
  20. L

    Finding Balancing Point Between Earth and Sun

    Homework Statement Find the point between Earth and the Sun at which an object an be placed so that the net gravitatinal force exerted by Earth an the sun on this object is zero. Me=5.98 x 10^24kg Ms=2 x 10^30kg Distance from sun to earth= 1.5 x10^11m Homework Equations F=Gm1m2/r^2...
  21. A

    Calculating Final Speed & Energy of 0.1 Solar Mass Falling into the Sun

    Homework Statement (b) If an object of 0.1 Solar masses fell into the Sun (starting at rest at infinity) calculate what its final speed and energy would be. Mass of the Sun = 1.99 x 10^{30} kg Radius of the Sun = 6.96 x 10^8 m The Attempt at a Solution Having done the rest of...
  22. I

    How long does it take the Sun to melt a block of ice

    Homework Statement How long does it take the Sun to melt a block of ice at 0 celcius with a flat horizontal area 1.0 m^2 and thickness 1.0 cm ? Assume that the Sun's rays make an angle of 30 with the vertical and that the emissivity of ice is 0.050. Homework Equations delta [Q] /...
  23. Philosophaie

    Why Do Planets Travel in Elliptical Orbits Around the Sun?

    Why do the planets travel in elliptical orbit around the Sun?
  24. S

    How do you see the sun after it has set?

    How do you see the sun after it has set?? Homework Statement The density of the atmosphere decreases with height, as does the index of refraction. Explain how one can see the sun after it has set. Homework Equations Snell's Law: sin x1 * x1 = sin x2 * x2 The Attempt at a...
  25. D

    Meteor Entering Orbit of a Sun (cons. energy & momentum) [very hard algebra]

    Homework Statement Alright, so I've given this guy a few cracks, and I think I'm close to it, but apparently I'm not right, so here's how it goes. Simple in concept. A meteor moves toward the solar system with speed v0 in a direction such that it would miss the sun by a distance d if it...
  26. G

    Why at the south hemisphere the sun rises from the west?

    Hello I wanted to ask why at the south hemisphere the sun rises from the west? We know that Earth rotates reversely than the watch pointers(this happeness to both hemispheres),so all the "sky" (the stars etc..) goes to the opposite direction. If someone could explain me.. Thank you!
  27. Helios

    Ecliptic Longitude and Right Ascension of the Sun

    Here's a question. Where do the ecliptic longitude and the right ascension ( of the Sun )reach their maximum difference? What is the declination for these events? What calendar dates do you suppose this happens? I know the answer. I've never heard anyone make this observation except me. These...
  28. Philosophaie

    Dipole Moments of the Planets and the sun

    I am wondering if there is a source of the magniude of the Dipole moments of all the planets and the sun, m. m(earth) is 8*10^22 A*m^2. The Magnetic Field and the Electric Field such that: Br = Mu0/4/pi*2*m*cos(Theta)/r^3 Btheta = Mu0/4/pi*m*sin(Theta)/r^3 Mphi = 0 Er =...
  29. GarageTinker

    Use Sun to dispose of radioactive waste?

    Hello All, Just from the stand-point of the Sun itself and it's environment, is it possible or not to utilize the Sun to safely dispose of spent radioactive waste fuel from reactors and what would be the possible ramafications (positive or negative) for the Earth and it's environment as a...
  30. Philosophaie

    Find Longitude of Sun - Learn How Now

    How do you know where the Longitude of the Sun begins?
  31. R

    Where does gravitation of earth and sun cancel

    Homework Statement For a spacecraft going from the Earth toward the Sun, at what distance from the Earth will the gravitational forces due to the Sun and the Earth cancel? Earth's mass: Me the Sun's mass: Ms Earth-Sun distance: r Homework Equations F=Gm1m2/r^2 The Attempt...
  32. J

    Neutrino Flux: Sun vs Reactors

    Regardless of the measured flux, is the expected neutrino flux from the sun greater or less than the expected flux from nuclear reactors? I don't know if I'm using the word flux correctly. I mean number of neutrinos per square meter per second on the surface of the earth.
  33. Philosophaie

    Calculating the Earth's Elliptical Orbit around the Sun

    To help me you will need tho know Excel VBA very well. Earth has an elliptical orbit around the sun. JPL's website has the data to calculate this orbit: http://ssd.jpl.nasa.gov/txt/p_elem_t1.txt In the spreadsheet the parameters are calculated from widely used equations and some of my...
  34. H

    Hurricane size whirlpool on the Sun

    I wonder if the whirlpool that was recently discovered on the sun effects our weather on earth. http://space.newscientist.com/article/dn14878-hurricanesized-whirlpools-spotted-on-the-sun.html
  35. S

    Is the Sun Dying? | Facts & Speculation

    Is the sun actually dying because I have heard a lot of good scientists near where I live say that it is and is not, and, of course, argue. I'm really wondering will t happen, I know if it does it'll be in like 4.4 Billion years but I want to know is IF it will happen.
  36. C

    Specific Energy Generation of the sun.

    Homework Statement (a) Compute the specific energy generation rate of the Sun as a whole. (b) Assume a human of weight 100 kg has a “luminosity” of 100 W. Compute the specific energy generation rate of a this human. Homework Equations Need help with the equations part. The...
  37. K

    Estimate the Time for the Sun to Disappear Again

    HELP! (again) Homework Statement The sun sets, fully disappearing over the horizon as you lie on the beach, your eyes 20cm above the sand. you immediately jump up, your eyes now 150cm above the sand, and you can again see the top of the sun. if you count the number of seconds until the sun...
  38. B

    How Long Until Earth Collides with the Sun if its Orbit Stops?

    Homework Statement If the Earth were suddenly stopped in its orbit, how long would it take for it to collide with the sun?(Regard the sun as a fixed point mass. You may make use of the formula for the period of the Earth's orbit. Homework Equations tau=(4*pi^2*R^3/M*G)^.5 The...
  39. F

    Find Length of Sun Mass in km: Solving G, c, M Units

    Homework Statement Find some combination of G, the speed of light c, and some arbitrary mass M, that has units of length. Then evaluate your expression for the mass of the Sun (that is, find the characteristic length associated with that mass). Give your answer in units of km. The...
  40. S

    Comparing Light Intensity: 100W Bulb to Sunlight

    Homework Statement I'm carrying out a lab to investigate the power of the sun. I'm supposed to compare the light intensity of a 100W light bulb with the light intensity from the sun, by comparing the radiating heat on my cheeks (one cheek pointing to the sun, the other to the bulb). I found...
  41. B

    Is the Pioneer Anomaly really directed towards the Sun ?

    Is the Pioneer Anomaly really directed towards the Sun ? How sure are we ? Why not directed around the Sun ?
  42. Mk

    Nuclear decay rates possibly correlate with distance from Sun

    http://arxiv.org/abs/0808.3283 This is weird as hell. As far as I knew, nuclear decay rates were not affected by anything, except beta decay under electromagnetic fields. This could possibly have huge consequences in other sciences. Personally, I immediately went to post this in Earth...
  43. S

    Asteroid in a circular orbit about the Sun

    If the Earth's period is 365.25 days and its distance to the (center of the) Sun is one astronomical unit (AU), what is the period, to the nearest day, of an asteroid in a circular orbit about the Sun with a radius of 3.04 AU? please show steps so that I can learn. thanks a lot.
  44. C

    Gravitational equilibrium between earth and sun

    Can someone tell me at what mileage point a rocket launched from Earth toward the sun would have its primary gravitational draw shift from the Earth to the sun?
  45. P

    Stargazing Is It Safe to Watch a Sunset Eclipse?

    There's coming sun eclipse on Aug 1. I know that looking directly at the sun even though it is mostly obscured is unsafe to the eyes. But is it safe if I look at the sun eclipse when it is about to set?
  46. Z

    Determining Sun-Earth Distance: Parallax vs. Kepler's Law

    How is the sun Earth distance currently determined? I read about a method where the distance between the Earth and Mars is determined when they are in opposition using parallax. Knowing the orbit period of both Mars and the earth, Kepler’s third law is then used to determine the Earth sun...
  47. D

    General Relativity- the Sun revolves around the Earth?

    Someone I know recently stated according to General Relativity, the following statements are both correct: 1. The Sun rotates around the Earth. 2. The Earth rotates around the Sun. Is this true?
  48. L

    Calculating Mars's Orbital Period Using Kepler's Third Law

    Homework Statement Mars's orbit has a diameter 1.52 times that of Earth's orbit. How long does it take Mars to orbit the Sun? in years. Homework Equations I tried using T^2=4(pi)^2r^3/GM I got 1.88years...but its wrong... The Attempt at a Solution
  49. ZapperZ

    VOTE Photo Contest - Fun In The Sun

    A surprisingly small number of photos submitted for a theme that is right smack in the middle of the summer months here in the northern hemisphere. Still, we have a good group of photos. Please choose a photo that best depicts the spirit of having fun in the sun. 1. matthyaouw 2...
  50. ZapperZ

    PF PHOTO CONTEST - Fun in the Sun (7/5-7/11)

    [FONT="Comic Sans MS"][SIZE="5"]Fun in the Sun This week's theme involves all the fun activities we do during the warm days of summer. Zz. [SIZE="4"]Contest Rules: 1. Any digital photo or digitally-scanned photo relevant to the theme will be accepted within the contest period. In...
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