The sun Definition and 634 Threads

Homework Statement A planet P orbiting the Sun S is acted upon by a force F= -(mu*r)/r3 (itex won't work here for some reason :S ) per unit mass where \mu is a positive constant and r is the vector \stackrel{\rightarrow}{SP} If the orbit of the planet is a circle of radius a, show that the...

Hi. I need help please with a textbook illustration that has confused me. Is the caption a typo? Should be "neutrons into protons" instead? Thanks.

Hey guys, I am trying to create a 2d simulation of the Earth going around the sun. However I am facing an issue. I am not sure what are the forces that apply on the Earth in a 2d aspect. I know there is the gravitational pull GM1M2/R^2. I know there is momentum, which is P = V * R...

Homework Statement The sun has a mass of 2*10^30kg and gives off energy at a rate of 3.9*10^26 watts. If the source of the sun's energy energy were ordinary combustion of methane how long will it last. Homework Equations delta Enthalpy of the combustion of methane is -802 kj...

Homework Statement A comet revolves around the sun in a closed elliptical trajectory. Ignore any force acting upon it besides gravity. Prove that the angle between the position vector (sun in the origin) and the velocity vector of the comet at its perihelion and aphelion is 90º. The...

I'm trying to figure out which layers of the sun emit different types of radiation For instance; I know that most of the visible light is emitted from the photosphere but what about IR, UV, x-ray, etc...? Anyone know?

If i rip the sun and make it into tiny packets, a size of about a normal house and then align it in a straight line, each box having 10 cm separation, then how strong will be the gravity at the end of the line? Will it have gravity stronger than a normal sun?

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...

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?

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...

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?

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...

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

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...

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...

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/

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...

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).

Are we just really lucky that the time it takes for Earth to orbit the sun is 365.25 days? I mean if it was something like 365.71 days, then we couldn't have our simple leap year every four years. We would have to have a 71 leap years every century, or even if we were to simplify it a bit, 7...

On Earth, fire needs oxygen. If space has no oxygen, how does the sun continue to burn? Thanks! :) Ω

Homework Statement Homework Equations The Attempt at a Solution I'm only stuck on part b). I make a) to be 3.87E26 W, but it gives that anyway in part b). OK, so here's my attempt: \int_{r=0}^{r=R}dT(r)T(r)^3 = -\frac{3L(r)}{16\pi acl_{mfp}}\int_{r=0}^{r=R}dr\frac{1}{r^{2}}...

This excerpt is from "The Universe and the Atom" by Don Lichtenburg: I was under the impression that photons made in the nuclear fusion bounced off of particles for a long time, before they inexplicably were able to escape from the sun. Why does the sun absorb the most energetic photons...

Homework Statement My physics teacher today said that the Earth exerts the same amount of gravitational pull on sun;as the sun exerts on the earth. Is this really true? Homework Equations There is no equation. The Attempt at a Solution I am very confused with this. How can the...

- possible sun timeline - 3,130,000 years for molecular gas to condense into protostar - 40,000,000 for core to condense and heat up to 15 million K - 43,130,000 total - sun has only enough matter to 'burn' by gravitational pressure for 100/300 million yrs - first stage of...

I used this equation to find the time in seconds for the Earth to complete 1 orbit around the Sun. p=2\pi\sqrt\frac{\alpha^3}{\mu} I put in 149598261000 metres for the semi-major axis, and 1.33E+20 for the gravitational parameter. I got 3155391.8 seconds for the period. This I believe...

Homework Statement The Earth has a mass of 6 x 10 24kg and orbits the sun in 3.15 x 10 7 seconds at a constant circular distance of 1.5 x 10 11 m. What is the Earth's centripetal acceleration around the Sun? Homework Equations The Attempt at a Solution

I was wondering if a spacecraft (or any other object) could 'co-orbit' the Earth by orbiting the Sun beyond our Hill sphere. For example, could this object 'hover over' the North (or South) Pole at >1,500,000 km? Thanks in advance!

Alright, Not the best at math and need help with find a equation for the amount of energy needed for destroying the sun. This isn't based on real life, based on a TV series and I'm nerdy enough to want to know how much energy it would take lol. I have a number for how much energy it would take...

I'm recently studying heat transfer processes. I saw that the heat current emited by a radiating body is given by: \frac{dQ}{dt}=H=A e \sigma T^4 I was wondering how to calculate the H from the sun to a unit area here on earth. How should I do it? I've seen exercises where they use this...

1/ when serching for mesurement Earth-Sun distance, I got this in the sechon answer, to use this method, we need mass of the Sun but when I searched for Sun' mass http://en.wikipedia.org/wiki/Solar_mass 2/ r=GMT^2/(4(πr)^2)The Attempt at a Solution there are the other ways to caculate Sun...

Hi guys, can I say that since the sun orbits around the centre of mass of the solar system, it has angular momentum L=mvr. And since L=Iw, the sun itself will rotate about its own axis. Am I right to say that? However, conceptually speaking, is there a reason why the sun rotates? Also, what...

"Determine the relative distances of each of the planets from the Sun given [...]." Homework Statement Devise methods to determine the relative distances of each of the planets from the Sun given the information available to Copernicus (observable angles between the planets and the Sun...