Planetary Definition and 306 Threads

Homework Statement A space station is in orbit between the Earth and the moon. The force due to gravity on the space station from the moon is the same as the force due to gravity from the Earth. (FGmoon = FGearth). How far away from the Earth is the space station? How far from the moon is the...

Hello, I am very new to gears I am fairly confused about planetary gears. I want to know the load on the gears contact point between the sun and the planets and the planets and the ring, assuming the ring not moving. Given I have the solid works file ,the pressure angle, and the gear ratios, I...

Is there any evidence of the enlargement of planetary orbits over time? Are the planets moving further from the sun?

Hi! first time poster here. I'm making an orbital simulation and I am having a problem with one minor detail. The gravity is working great, and I've programmed it using this formula: A force vector is applied = DirectionOfCentralBodyNormalized * ((GravConstant * centralbodymass *...

I was curious if anyone knew of any schools that offered graduate degrees in planetary sciences, specifically studying other planets atmospheres. May be it the study of the atmosphere itself or remote sensing techniques for planetary atmospheres. I know how to find schools that offer the...

Hi, I'm new to the forum and have an idea for a novel. I can't find anything on this question so I thought I'd sign up for a forum to ask. I'm not a scientist and lack much of the higher technical knowledge. Here's my question: Most planets in close orbits (they'd have to be to support liquid...

Hello. I was thinking about gravity and how matter bends the ST (space time) creating gravity.which lead on to singularities. I wondered how much mass it would take to either make a hole in spacetime, or how much it would take to make a black hole. So I googled it. This is where my confusion...

According to Cornell university's ask an astronomer site, we figure out the layers and their density of planets by checking the trajectory of a satellite /space probe or something like that, near the planets. But planets are quite spherical. then their density profile shouldn't be effecting the...

In light of the strong desire to begin colonizing Mars in the near future, how easy will it be to remove Mars from the list of planets covered by the planetary protection treaty?

I'm writing a story involving multiple sentient species, interstellar travel, and a long history of colonisation. My main character is a Human living on the planet "Tender", whose ancestors colonised it from the planet "Ardel" a few centuries ago. Is it possible to arbitrarily write up the...

Homework Statement A planet orbiting a star experiences a force of magnitude 3x1022N due to gravitational attraction to the star. If the planet has a speed of 2x107 m/s to complete on orbit, calculate the mass of the planet and radius of the orbit? Assume the orbit to be a perfect circle...

Does anyone have a membership to The Planetary Society? How do you like it? I'm thinking about joining the student membership. I am thinking there are interesting things to learn from their magazines and I am hoping to get to invitations to their events--although I am not sure what they can...

Hello. I'm wondering if my numbers on my diagram are correct. I've drawn the sun to the left of a plain piece of blank printer paper. To the right I have calculated using millimeters mm representing a million miles. 1mm=1million miles. Mercury is two dots to the right that are 36mm-57.9mm to...

All of the planets should have individual orbits, and should be between the mass of Mercury and Mars. What can their orbits be in AU's? Is there a way to find out how close they can be without destabilizing each other? If we assume the star is about the same size as Sol.

Just watched a Youtube of a TV show about "weird planets". They show early on a collision between two planets, proportioned about the same as the Earth and the Moon. The interesting thing is that they show part of the "Earth" being pulled up to meet the "Moon." Could this happen? Could it...

A while back I did research in planetary system dynamics that involved the code package Mercury. Unfortunately, I found that Mercury would occasionally crash for no reason or give nonsensical results. This happened for a small subset of initial conditions and while I spent some time debugging...

Whose observations did Kepler use to prove that planets do in fact orbit in ellipses ?? Was it Tycho's observations? Thanks.

Homework Statement The period of a comet is 75.8 years. The perihelion distance is 0.596 AU (1 AU = 1.5 ⋅ 1011 m). The velocity at perihelion is vp = 5.45 ⋅104 m/s. a) Find the length of the major semi-axis of the elliptical orbit. b) Find the aphelion distance and the velocity at aphelion...

I am stuck at this part page 1, $$\frac{\partial{L}}{\partial{\dot{φ}}}=\mu{r^2}\dot{φ}=const=l------->\dot{φ}=\frac{l}{\mu{r^2}}......(8)$$ Why is this a constant? Isn't r and dφ/dt variables of time? Source: http://www.pha.jhu.edu/~kknizhni/Mechanics/Derivation_of_Planetary_Orbit_Equation.pdf

The graph I have made of Average Orbital Distance from the Sun vs. Average Orbital Velocity illustrates a decreasing exponential function. How, if it does, would this suggest that there is dark matter present in our solar system?

I had a dream about groups of nomads constantly traveling around a planet in one direction to stay in the 'dusk/dawn' zone of their planet as if they strayed too far behind they would freeze and if they ventured too far ahead they would cook and vice versa. What might a planetary system look...

First off, let me start by saying this isn't a thread asking about career prospects or salary prospects or anything like that. I've finally reached a point in my life where I know I want to pursue physics, and I'm extremely thrilled by the idea of Planetary Science. Nor do I have a romanticized...

Homework Statement Hi, I've been tasked with showing that the length of vector F_gravity is inversely proportional with radius squared (i.e. |F_vector|=c/r^2) and is central, i.e. consistently directed toward the same point. Apparently, this is the same as (<=>) the acceleration of a particle...

Hi! So I've begun the process of looking at colleges now and I really would like to go to a school in the US or Canada with an astronomy major, an observatory of its own, and some sort of planetary science program. I've made a list of the schools that I've been able to find with those things...

I am trying to back-calculate the greenhouse effect on planetary equilibrium temperature for Earth (in the hope I can then attempt applying it to other calculations.) I know that the actual equilibrium temperature of Earth is 287.89K, +33K above the calculated equilibrium temperature: Teq = (Q...

Is there any star systems (planetary) that are influenced by the EM Force, hence as usual,sum of the charges of elements in the universe are electrically neutral.

I am disappointed by my graduate-level classical mechanics course, and especially the treatment of Lagrangian/Hamiltonian mechanics. Now, I scanned my notes and some crazy idea popped into my head, further fueling my discontent towards this course, because all the problems covered in class were...

Hello every one. It's obvious that all of the major planetary objects in our solar system orbit the sun in roughly the same plane. My question is, is our solar system in a similar plane as it orbits the center of the Milky Way? If so, do most star systems share the same plane? This came to mind...

Homework Statement A 500-kg satellite is in a circular orbit at an altitude of 500 km above the Earth’s surface. Because of air friction, the satellite eventually falls to the Earth’s surface, where it hits the ground with a speed of 2.00 km/s. How much energy was transformed into internal...

Just bringing to everybody's attention that there's a very nice alignment of planets in the morning sky. Venus, Jupiter and Mars are within a few degrees of each other, next to the constellation of Leo. In two weeks' time, while they'll spread out a bit by then, the Moon will also swing by. If...

Hi there, The University of Arizona has these two institutes (among many others, of course): - Lunar and Planetary Laboratory, LPL for short - Steward Observatory As far as I understand, both are into space research and astronomy. If I wanted to join either one or the other, I would have no...

Homework Statement Using the equation T = kr^p I drew a loglog graph of orbital time period against orbit radius for the planets Mars to saturn. lnT = plnr + lnk My value for gradient was 5.25/0.48 = 10.94 Meaning p = 10.94 How do I compare this to the actual value? What is it?Homework...

The question is: If quantum mechanics were detectable in planetary orbits, how much larger than the currently accepted value would Plancks constant need to be? Relevant equations ΔxΔpx ≥ħ/2 p=mv Earth-Sun dist 1.496E11 Earth orbit speed 28,900ms^-1 Earth mass 5.972E24 kg The attempt at a...

I don't know how long this solar sail idea has been here , the Planetary society's second solar sail failed to achieve its objective right ? I am interested in the applications of this technique. 1) Is it possible to use them to deflect large asteroids and comets away from the Earth ? 2) Is...

All About Epicyclic gearing This Video illustrates : - How does Epicyclic gear Work - some Application of Epicyclic gear - How to make Epicyclic gear calculation

the Moon is currently very close to Venus and Jupiter in the sky this pic I did last nite 20-6-2015 Tonite the Moon will have moved eastwards ( to the right) and will be directly above Jupiter cheers Dave

Hello, This problem has probably been done before in different guises but I am struggling, and hoping for help. I am struggling to understand a phenomena which I am assuming is one and the same: Equatorial Bulge of the Earth Flat Plane in which the Planets rotate Protoplanetary disks are flat...

How can we relate mathematically the time interval in which a planet is in retrograde motion and the devided distances from the sun of the planets ? My first drawing was this: Where S is thee sun , P is the planet, T si the Earth. The v's are the corespondent speeds If we take a look at...

Homework Statement Hi there, I wish to use Newton's Laws in conjunction with Euler's Method to model the motion of a planet around a star.Homework Equations 2nd Law F = m*a Law of Universal Gravitation F = -G*M1*M2/r^2 The Attempt at a Solution [/B] First I combined the two laws above...

Essentially just a consequence of inertia and gravity?

Hi everybody, last week I was messing arround with Stelarium; I saw something which bothered me.http://postimg.org/image/l9fsnnqkv/ http://postimg.org/image/l9fsnnqkv/ (link because the image might not be seen) . As far as I know all planets rotate around the solar equator, but here, Mercury...

First of all I'm not sure where in the world this topic would fit at, so I put it in Electrical Engineering because my assumption is that electrical engineers may have the answers for this question more so than anyone else, but mods, if you feel this thread would be better off in a different...

Homework Statement calculate approximately how much more massive the Earth would have to be before it could retain a significant hydrogen atmosphere, assuming the Earth’s density to be the same as its current value. Homework Equations Temperature limit to retain hydrogen in the Earth's...

there is a relation between the no of teeth in ring gear,sun gear and plant gears are there(2R=S+P) Like that any relation between no teeth in plant and sun gears?

Homework Statement Two stars of masses M and m, separated by a distance d, revolve in circular orbits around their center of mass.Show that each star has a period given by T^2= (4π^2)(d^3)/ G(M+m) Homework Equations [/B]The Attempt at a Solution I[/B] know the Kepler's Laws can be...

I think we have a problem with this rule. This is my understanding of the existing rule. Am I close? The rule for calculating the power distribution on a power split planetary gear system is based on the equal force rule. To calculate the power on the sun and ring of a planet set with input...

Could a planet orbiting around a sun be considered an example of perpetual motion? I know that the planet wouldn't be doing any work, since it goes back to the same spot every year, but does an object have to be performing for it to be considered perpetual motion? The two might have nothing to...

I read this interesting paper showing that in less than a million years, one star will fly past our Sun at a distance of about 0.13 light years [1]. How might I calculate the maximum disruption this could cause on the orbit of an object in orbit around our Sun, such as planets and comets...

Does someone else remember a program made to simulate the potential outcome of the collisions of celestial objects?

Suppose an observer flies through our solar system at ##v \approx c## relative to the Sun, such that he sees each planet's (and the sun's) mass as greatly increased. What happens to the orbits of the planets? Since he sees the center of mass of the solar system as flying past him at ##v \approx...