Moon Definition and 1000 Threads

Hello, I think I quite understand what is happening with Earth and Moon. Losses of angular momentum due to tidal effects. But I would like to find some article or text where this is described mathematically. I guess using some lagrangian function or something like that and for example the...

I know that Earth orbits the sun because it has initial momentum and that prevents it from falling into the sun. But does moon that orbits the Earth also have initial momentum?

Homework Statement If I know only the circumference of the orbit of the moon, and the time it takes to make an orbit (29 days), how far does the moon fall in one second? The Attempt at a Solution I'm failing to understand how certain assumptions can be made in the geometry here. From Figure...

Note the explanation text below the videocheers Dave

We are placing everyday more telescopes in satellites in orbit. Would't it be convenient to have some permanent telescopes placed on the moon's surface? I guess if we don't do that it's because that would be much more expensive than launching satellites? Are there no plans to place telescopes on...

Edit: since creating this post i found a video showing all of the rotations and phases of the moon for a year So for my purposes that should be sufficient. Thanks. ------------------------------original message----------------------------------------------- Hi, Can somebody explain why...

I have reasons that have convinced me that Mars would be better, but I want to know what everybody else thinks.

Homework Statement The Moon’s nearly circular orbit about the Earth has a radius of about 385 000 km and a period T of 27.3 days. Determine the speed of the Moon. Determine the magnitude and direction of the Moon’s acceleration. Mark Criteria: A)determining the correct period of motion in...

How can I prove to my 9 year old daughter that the moon is closer to Earth than the sun? At the moment, she has read it in books and this information has the same status as unicorns and fairy princesses!

I went for a walk in a big park for 3 days. On first day I saw moon above Mars relatively in sky . Mars was looking like a pointy star being red in colour. The next day I saw Mars relatively above moon. The third day moon above Mars again and they rising high and high. Are they both having a...

I was trying to get a couple of quick handheld shots of the waxing crescent moon with Venus with my Nex-5N last night, when just for fun I thought I'd snap Jupiter and see if the moons showed up with the Sony 200mm zoom. Much to my surprise I was able to see a couple of the moons with just a...

Let's say we built a tunnel through the (arbitrary) center of the moon, and lined the surfaces of the walls with millions of loops of copper wire. If we dropped a massive magnet in through the moon, would it produce a substantial amount of current due to the magnetic field passing through the...

Hi all, This isn't a homework question, its just something I'm personally wondering about. I understand why an astronaut in orbit around the Earth feels weightless, because he is in a constant state of freefall, traveling towards the Earth just as fast as the Earth is dropping away underneath...

In Principle, gravitational constant is measured very precise, but the problem is that it is measured together with mass of sun, Earth or moon, G M_s or G M_e; or G M_m. But, is it possible to measure mass of the moon without use of G? Maybe the principle, where the rocket was accelerated when...

I'm working on a potential sci-fi story that takes place on a post-apocalyptic Earth. The idea is Something Horrible 1A happens, then, 15-20 years later, Something Horrible 1B comes to finish us off. In a perfect world, the Moon is gone after 1A. Initial possibilities included a long orbit...

Homework Statement Determine the mass of Jupiter using the data for the moon Io. Mass of Io: ##8.9*10^{22}## Period: ##1.77## Earth days Mean distance from Jupiter in km: ##422*10^3## Homework Equations Centripetal acceleration ##a = \frac{v^2}{R} ## Universal law: ##\frac{GMm}{R^2} ## The...

Homework Statement There exists a spaceship orbiting between the Moon and the Earth. Find the perfect spot where the gravity due to Earth is equal to the one caused by the Moon. I have already solved for the ratio ## \frac {R_E}{\sqrt{M_E}} = \frac {R_M}{\sqrt{M_M}} ##. ## R_E ## is the...

I'm wondering if it's possible to send a man to the moon using only classical mechanics. If not, where would the classical equations fail?

If gravity is the effect of spacetime curvature, then why is it stronger on Earth than the moon? In other words, it is the curvature of space and time that gives the effect of pulling an object towards a larger object, so once that direction of pull is established why would the size of the...

Can a person suspended in space with nothing to push off of, turn themselves around?

Is there an admin or other established member with the Dark Side of the Moon artwork as their avatar? For some reason I remember seeing it, but can't find the user. I don't want to be using someone else's avatar, but DSotM is more or less my life, so if nobody else is using it, I will. If it's...

I was just reading about the barycenter of bodies in space. My question might not make sense but, if we sent hundreds of thousands (or millions) of spacecraft to the moon filled with dirt and rocks could we change the barycenter enough for the Earth to orbit the moon? I know this is a huge...

This could be an astronomically stupid question but I cannot think of a sensible answer. What is the sum of all the quantum spins of all the particles that make up the moon ? If it was a whole number I suppose the answer would be 'yes'.

Suppose a rocket take off from the moon surface and is hovering above the moon at a constant height, does it stay in the same place relative to the surface like an helicopter on Earth or because there is no atmosphere there it will shifted eventually because of the moon spin?

We all know the confusion between Mass and Weight, from the language barrier. Would I be correct to say that: On Earth Bathroom weigh scales = 100kg. Mass therefore is 100kg. Weight = 981N On the Moon Bathroom weigh scales = 16.7kg. Mass is still 100kg. Weight = 167N In Space, (away from any...

http://www.nasa.gov/jpl/asteroid-that-flew-past-earth-today-has-moon/ Radar observations of small object apparently orbiting an asteroid near Earth. Edit: a sharpened video. http://www.space.com/28438-asteroid-2004-bl86-moon-sharp-video.html...

It is said that the tides on Earth are due to the moon's gravity. But the moon consists half of silicon oxide, the stuff that also comes with the new camera/shoes in that little bag, and acts like a moist absorber. So maybe there are two reasons for the tides?

Hi I have some questions for you people. My friend believes the first moon landing was faked, among a lot of other conspiracy's apparently proven all over the internet. The purpose of this post is to question his thoughts with some logical answers to some of the questions he has asked me. One...

Homework Statement Homework EquationsThe Attempt at a Solution For a), I initially tried to consider the component of the gravitational force of the moon acting normally to the Earth's surface. This would be F=F_0 cos(theta) where theta is the angle between a horizontal line going through A...

Homework Statement Hello the text is in swedish but ill try my best to translate, What it says is: Determine the resultant force on the moon with regard to thr gravitation force from the sun and the Earth when it's in this position shown in the figure [ picture http://m.imgur.com/AfJOVZo ] J...

I am interested in theoretical (what if) possibility of our Earth having more than one moon, I wonder if they can be arranged at the same orbital resonance as the Galilean moons 1:2:4 If yes, would such system be stable? If yes, should our Moon be the first, second or third satellite out of the...

I'm doing a project that has been done many times before, bouncing a signal off the moon, but I'm trying to do it with low power. I'm told the expected S/N ratio is -30dB. The problem I'm trying to figure out is whether or not it is theoretically possible to pull out the signal out from the...

The average distance to the moon is about 1.28 light seconds. Today the Dawn probe is about 1.5 light seconds from Ceres. http://dawn.jpl.nasa.gov/mission/live_shots.asp Ceres diameter is about 1000 km, which means roughly 1/3 the size of the moon (diam = 3500 km) The Dawn spacecraft is...

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown > An unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 50.0km . To the dismay of scientists on earth, an electrical fault causes an...

Hey guys, Lately I have been getting really really into the moon landings, and I want to take a look at some of the image archives to get a better look at what all they did and saw on the moon. Unfortunately, no mater how much I search, all I can seem to find is the same hundred or so photos...

Homework Statement I already searched for solution and i found similar one but I'm still confused. -In which point between Earth and Moon gravity field equals 0 if distance between moon and Earth is 60.3 * radius Earth and mass of the Earth is 81 * mass of the moon. Homework Equations...

Hi all, This is a bit of a bizarre question, but: If some way, some how, the moon crashed into Earth... then (oh so many) years later humanoid life appeared, what might its bone structure be like in contrast to ours? That is all

I'm developing a plot in which the Moon gets blown up. But I am not sure about the possible results of such a cataclysmic event. I'm thinking about particles of the moon forming into a ring around the Earth, tidal waves stopping altogether and more asteroids entering the Earth's atmosphere...

Homework Statement The orbit of the moon is approximately a circle of radius 60 times the equatorial radius of the earth. Calculate the time taken for the Moon to complete one orbit, neglecting the rotation of the earth. Equatorial radius of the Earth = 6.4 *10^6m 1 day = 8.6*10^4s...

A moving magnetic field will produce current in a wire. The Earth's magnet field goes beyond the moon. Does that mean bases on the moon could somehow get free energy from a coil setup as it's effectively perpetually moving through Earth's magnetic field?

I know that the the satellite will lose speed(due to perhaps small air resistance), and therefore lose centripetal force? I am not sure how losing centripetal force and speed causes the satellite in orbit to lose radius. If force is the same, and velocity is lowered, than radius would increase...

Homework Statement On Earth, an average person's vertical jump is 0.40m. What is it on the Moon? Homework Equations Fg 1 on 2 = G(m1m2/r^2) G= 6.67 x 10^-11 The Attempt at a Solution r= 0.40m F Earth on person on Earth's surface = 6.67x10^-11(m Earth x m person)/(0.40)^2 r=? G moon = ? F moon...

Homework Statement If an exchange particle held the moon together, what would the mass of the exchange particle be? Moon radius = 1737 km Homework Equations Well, I know that the range of an exchange particle is as follows: R=\frac{\hbar}{2mc} where m is the mass of the exchange particle and c...

Hi All, Again, thanks to all the Physics Forums gurus. I posted a question about a year ago concerning the finite propagation speed of information and electrostatic forces between charges, which seemed confusing. I still was hoping to resolve it, so I simplified it a bit :). Imagine a...

Hi everyone, For one of my project in school, i need to calculate the travel time to the moon. To do that, I thought to use Kepler's third law which is : (2(pi) / P )2 * a3 = GM where : P : period of travel a : major semiaxes (not sure in english, but it is the half the longest radius of the...

Homework Statement The acceleration of gravity on the Moon is 1/6 what it is on Earth. The radius of the Moon is 1/4 that of the Earth. What is the Moon's mass compared to the Earth's? Homework Equations F_g = \frac{GMm} {r^2} => mg = \frac{GMm} {r^2} => g = \frac{GM} {r^2} => M = \frac{gr^2}...

Hello! Why does the moon has different rise and set timing for different phases? And also, why does it rise from different directions during different phases? Help me out please!

http://www.huffingtonpost.com/2014/10/16/ufo-flies-across-moon I don't know what method is being used to keep the moon in frame, but if it's a fixed telephoto lens the black dot "UFO" could be a dead-pixel. If the 1 pixel-sized black-dot was a real object orbiting Earth , (rather than an...

It's generally said that a moon walker should be able to jump six times higher on the moon, than he can on Earth, which sounds sensible since gravity is one sixth , but consider this... Two men , one on the Earth, one on the moon, both bend their knees the same amount ready to do a 'standing'...

Newton showed that if gravity at a distance R was proportional to 1/R2, then indeed the acceleration g measured at the Earth's surface would correctly predict the orbital period T of the Moon. (Remember Earths gravity causes the moon to orbit the Earth.) We can find the answer using MKS system...