Sun Definition and 1000 Threads

Is the rather continuous spectrum of the Sun due to redshift/blueshift of the radiation emenating from the Sun? I understand that the emission spectrum of Hydrogen in the visible range is quantized to four discrete values, but I'm trying to understand how all frequencies of visible light are...

Homework Statement Estimate the deflection of starlight by sun using an elementary analysis. gsun = 275 meters / sec2 Diameter of sun = 1.4 * 109 meters. In the following, assume that the light just grazes the surface of Sun in passing. A) Determine an "effective time of fall" from the...

Now I know the sun can't go supernova ever, but let's say the sun somehow acquires enough mass to eventually undergo a supernova with an energy output of one foe, what would happen to the solar system? Would the outer planets such as the gas giants and pluto survive?

NASA's horizon system shows the angle (S-O-T) of Sun and planet from the view of Earth. Could you please tell me how one measure the angle of Sun and Mars when opposition nearly takes place. In other words, if S-O-T approaches 175/176/178 degrees, how does one from the view of Earth measure this...

Homework Statement Using Planck's law, calculate the spectral radiance of 400nm sunlight arriving at earth. Assume 1/3600 steradians of view and 5800 K of temperature. Homework Equations Planck's law The Attempt at a Solution I am not the best at typing formulas. Lets...

When Earth is between sun and moon,we have full moon. But I can not really understand that. How light of sun reach at moon? Does not hit in earth? Or maybe light follow a curve as general theory says? Thank you!

Homework Statement See Attachment Homework Equations The Attempt at a Solution So basically I will not bother writing the derivation from my notes but ultimately it turns out an approximation of deflected light around a mass body is 2\delta\phi=4GM/R where R is distance of closest...

Why sun rays are not considerably hot when reaching earth..? is there any specific reason for the sun rays to lose its potential(temperature) as it travels a long distance in space where there is no forces to contain it nor disturb its motion. Does space have property too,because as far as i...

Homework Statement This is for my intro to General Relativity class, using Hartle's text Gravity: An intro to Einstein's GR. 12.1 "How many protons must combine to make one He nuclei every second to provide the luminosity of the Sun? Estimate how long the Sun could go on at this rate before...

Sun now has only a south magnetic pole??! This article in the popular press ["Strange Doings on the Sun", Wall Street Journal] mentions that the sun's regular oscillation in the location of its magnetic poles is now not synchronized, as it's expected to be. The sun's north magnetic pole has...

My understanding is that fluid dynamics in the convective zone generate electric fields and are what drives the magnetic fields which are then pushed up into the photosphere by differential rotation. Question is are electric fields or currents also present in the plasma filled magnetic and...

Homework Statement Calculate the number of proton-proton reactions that occur in the Sun each second. For simplicity consider only the energy generation produced by the PPI chain. Consider that the Sun produces its energy in a steady state from the pp chain. Homework Equations...

Is the radiated energy that reaches the Earth from the Sun diminishing? Some meteorologists think it is due to the reduction of Sun spots. Is this the normal 11 year cycle, or is there more to it?

Hi All, Not sure where this topic should be placed but it involves optical and electronics. I want to design a solar simulator that can concentrate the light onto a photovoltaic of area of 3600mm2. The concentration of sunlight target is 500suns to 1000suns. The goal is to be able to...

Or get so close that human life will be destroyed

Would a nearby Gamma Ray Burst (GRB) cause the Sun to cast a shadow on Earth if it were to shine from behind it?

How can SSM be utilized to predict the radius of the Sun when it becomes a red giant?

Hey! Some time ago i saw this video: [crackpot link deleted] And, although I'm a comp sci guy and did studied physics on the first two years, i could say i have almost none knowledge of physics, i mean, real knowledge, not just how to make my guy jump on a 3D game. I wonder if this guy is just...

Hi everyone, new member here. Anyway, for my astronomy class my professor wants us to calculate the zone time the center of the sun sets on the winter solstice, at 40 degrees north latitude, and I'm a bit stuck. I know on the winter solstice, the declination of the sun is -23.5 degrees and the...

Hi, I recently did a homework problem for my introductory Quantum Mechanics course and in the problem we were given the sun's temperature in Kelvin as well as the diameter of the sun and instructed to calculate the rest mass lost per second to radiation by the sun. I was able to solve the...

Homework Statement Flight to Mars. To send a satellite from Earth to Mars, a rocket must accelerate the satellite until it is in the correct elliptical orbit around the sun. The satellite does not travel to Mars under rocket power, because that would require more fuel than it could carry. It...

Hi! I was wondering if anyone of you know how to calculate the astronomical unit 1 AU, using data from a Venus transit and not using the parallax method. I already have all the data from the 2012 transit; the time it was in phase 1 when it contacts the Sun's disk and when it leaves the disk...

Is it possible to calculate the distance from the sun to a star like this? (what I mean is can the angles from the diagram actually be calculated?) From the diagram: γ = ∏ - α - ∂ = ∏ - (α + ∂) D / sin(γ) = d / sin(∂) sin(γ) = sin(∏ - (α + ∂)) = sin(α + ∂) D / sin(α + ∂) = d...

Is it likely that the Earth will survive or more likely that it will be engulfed?

Does the sun contribute to global warming?

I understand how conservation of momentum leads to planet formation and planet rotation. However, after studying this model, I have ran into a point of confusion that I cannot find the answer to: Why don't the planets collapse into the sun just as dust particles collapsed inward via...

Hi! I wonder why our sun, being a star and all, is yellow and not white? What is it in our atmosphere or jonosphere that makes it yellow? Roger

A four minute video from NASA http://www.space.com/22264-sun-s-magnetic-field-will-soon-flip-stormy-space-weather-ahead-video.html Let's hope the climate scientists start talking with the solar scientists.

a few days ago another member posted a thread about the Fox new report on a chunk of the sun flying towards Earth here's yet another news item one an Australian online news site... Sun's magnetic field about to flip Aug 07, 2013 8:34am NO, it doesn't happen every 11 years on and NO it...

Why can't the Sun (or any star) fuse elements higher than iron? Could anyone provide a technical answer? Thanks!

http://video.foxnews.com/v/2574867146001/nasa-spots-giant-dark-hole-in-the-sun/ Say goodbye everyone :(

I know that the Sun radiates vast amounts of energy partly due to nuclear fusion. I've also heard that nuclear fusion can occur in the Sun due to quantum tunneling. I'd like to know how the process of quantum tunneling in the Sun allows nuclear fusion to take place. Thanks!

Is there a Metric for the Sun and Earth other than the Schwarzschild Metric who has the Schwarzschild Radius on the interior of the body? What are the assumptions that turn that from GR to Newtonian? Rs(Earth)=8.87*10^-3m Rs(Sun)=2954m

Hello, New here, hoping to get some answers... So here's my dilemma, me and my friend are having this debate. He claims that a beam of energy, of any size, even smaller than an ant, should be enough to destroy the sun. His theory is that, if the beam carries enough energy to rival the...

Hi PF! So I was reading about the possibility of life on planets orbiting red dwarf stars, and it was said that the major problem was that the planet would become tidally locked. With half the planet in eternal darkness, the whole atmosphere would freeze on the dark side, leaving the planet...

I have a sailboat with 2 solar panels installed. They work well, except at the end of the season when the days are shorter, the nights are longer and the sun is lower, so I built a mechanism to tilt and rotate the panels so that they could be pointed directly at the sun. With low sun angles I...

Homework Statement Find the point between Mercury and the sun at which an object can be placed so that the net gravitational force exerted by Mercury and the sun on this object is 0. Homework Equations Mass of sun = 1.991 x 10^30kg Mass of Mercury = 3.18 x 10^23kg distance between...

Gravity moving toward the center of the Sun?? Ok can someone tell me if I am wrong in my understanding here (in a heated debate with a physics professor) : As you move from the surface of the sun to the center, does the force of gravity increase or decrease and why? The point I am trying to...

^^This is how the Sun would look from a distance of 4 light-years. If you add all the relativistic effects and stuff, wouldn't the Sun disappear from the visible spectrum? I was told that from a mathematical point of view, it is correct to say that some visible photons would still reach you, but...

My roku device has a channel for wunderground.com, which shows the weather. But it also shows a time-lapse video of the past 24 hours in a local neighborhood. The caption says "Facing West," and you can indeed see the sun setting in the evening as you would expect. But in the video the sun...

At which speed does the Sun disappear from the visible part of the spectrum if I were to travel towards it at high speed? Let's assume there are no other stars in the visible universe and I'm a few light-years away.

Hello. Why wouldn't the Earth gravitate towards the Sun? I have done some online research on this question and it appears that the reason is due to the Earth's rotation. I am not convinced and see no reason why that should be the reason. According to the Rutherford's model of the atom, an...

I have watched the Sun's shadow make its trek from the solstice moments for many years. I have it marked and like to observe it as Earth's tilt reaches it's maximum point, from Summer to Winter and back. I used a heliodon to built a large structure (80 feet long/12 feet tall=roofline of my...

Three years of images from NASA’s Solar Dynamics Observatory (SDO). http://svs.gsfc.nasa.gov/vis/a010000/a011200/a011255/

When the sun is collapsed will it form a black hole?

Homework Statement When a star like our Sun exhausts its fuel, thermonuclear reactions in its core cease, and it collapses to become a white dwarf. Often the star will blow off its outer layers and lose some mass before it collapses. Suppose a star with the Sun’s mass and radius (the radius of...

I have never heard about a plan of cosmic objects endangering Earth to be directed towards the Sun in order to get rid of them. It is unfeasable ? "Sun wind" blowing from the star is stronger than its gravitation ?

Question: Light experiences zero time and zero distance so for a photon it must be here and there at the same instance. As the moment a photon is created it must be at position A and B at the same moment. So for a Photon it takes zero time to reach Earth from the sun. Why do we then see...

Dear Sirs , Could someone please tell me this. See the attached picture, is Earth orbiting Sun this way or other way around, or changes dynamically? And why does only Moon orbiting Earth while Earth doesn't orbiting the Moon? Don't they both have relative gravitational force to each other?

The thought came to my mind yesturday : does not Earth in its movement looks like pendulum tied to the Polaris ? Only the very long one - comparable to an object swinging about 1 cm circle at a tie of about 15 000 km (if my quick calculations now are correct).