Orbit Definition and 1000 Threads

Scientists want to place a 2500 kg satellite in orbit around Mars. They plan to have the satellite orbit a distance equal to 1.8 times the radius of Mars above the surface of the planet. Here is some information that will help solve this problem: mmars = 6.4191 x 1023 kg rmars = 3.397 x 106...

"Flyaround" video of Vesta as seen from low orbit by Dawn http://science.nasa.gov/science-news/science-at-nasa/2011/16sep_vestaflyaround/

Why does the moon's orbit move from low in the sky to higher in the sky, then back? I have tried accessing information on precession, etc. with no understandable answer. Wikipedia was no help. It's a minor issue, but one that has left me scratching for a long time.

Homework Statement Prove that the following system has at least one periodic orbit. x' = x - y - 2x3 - 2xy2 + x2sqrt(x2 + y2) y' = x + y - 2x2y - 2y3 + xysqrt(x2 + y2) Homework Equations The Attempt at a Solution I converted to polar coordinates to get r' = (xx'+yy')/r and...

I get different result than stated in the book. What am I doing wrong? Homework Statement A spacecraft returning from a lunar mission approaches Earth on a hyperbolic trajectory. At its closest approach A it is at an altitude of 5000 km, traveling at 10 km/s. At A retrorockets are fired to...

Homework Statement Communications satellites are placed in a circular orbit where they stay directly over a fixed point on the equator as the Earth rotates. These are called geosynchronous orbits. The altitude of a geosynchronous orbit is 3.58*10^7 m. What is the apparent weight of a 2000...

Can an antiproton(negatron) "orbit" around a regular nucleus? Since it's negatively charged like an electron, can it orbit around a "normal" nucleus? Or a more general question: can something be part matter and part anti-matter? Edit: I guess this answers my question...

Hi guys, i can't seem to find the answer . A satellite in Earth orbit has a perigee velocity of 8 km=s and period of 2 hours. From this information, determine all the orbit parameters that you can. From those parameters, determine its altitude at perigee...

This was an idea I had when when learning about ramjets. I was wondering if you could use a specially designed rail gun to launch a probe or satelitte ,at a very high velocity vertically upwards and then when the object is decelarating at 9.8 m/s due to gravity use a small rocket propulsion...

Homework Statement If a satellite in orbit changes it's orbiting radius to 4 times its initial one, how does it's velocity change? I get different answers by using Newton's Law of gravitation and conservation of angular momentum. Homework Equations F = \frac{G M m}{R^2} a_c =...

the answer for a is .571 rad/s for b, I am not sure do i use like kinematics?? and I am lost on c? If feel a is velocity = distance/time so is it 2pi*3040/60? and not sure on b either.Sorry these are a lot of questions, but i am trying to learn and get an A, so i want to make sure I get all of...

Greetings I have been trying to find the orbit of Mercury using the geodesic equations with the Schwarzschild Metric, more precisely I have been using the equations derived in "General Relativity, An Introduction for Physicists" by M.P. Hobson, etc, that is: <math>\left(1-\frac{2\mu}{r}\right)...

Homework Statement A rocket is in an elliptical orbit around the earth; the radius varies between 1.12 Rearth and 1.24 Rearth. To put the rocket into an escape orbit, its engine is fired briefly in the direction tangent to the orbit when the rocket is at perigee, changing the rocket's velocity...

Backward "orbit" of the planets How do you tell when a planet is going backwards in its "orbit" of the earth? Do you have to plot a graph and pick out the points? There must be an easier way!

To explain weightlessness to my students, I use the analogy of a falling elevator (lift) as folows - if we stand on weighing scales in an elevator and the elevator cable snaps, the scales will show zero since they are falling to the ground at the same acceleration as us, therefore registering no...

I'd like to share with you people this great discovery! http://arxiv.org/abs/1107.2389 A 12 minute Orbital Period Detached White Dwarf Eclipsing Binary Warren R. Brown (1), Mukremin Kilic (1), J. J. Hermes (2), Carlos Allende Prieto (3), Scott J. Kenyon (1), D. E. Winget (2) ((1) SAO...

Hi all, If one were to consider a classical particle in a box of length L in Minkowski space then clearly the time taken to go between the walls of the box is L/v with v velocity. In the GR case with some metric coefficients A(r) and B(r) (spherically symmetric system, say) it's clear that...

Dawn spacecraft is nearing Vesta and is planned to go into orbit 16 July. http://science.nasa.gov/science-news/science-at-nasa/2011/06jul_vestamoon/ The craft will orbit Vesta for several months and then move on to another asteroid, Ceres. The NASA press release mentions that several...

Hello PF. I learned, for some time ago, that objects in space in orbit are weightless and to this day it still blows my mind. Its rumored that Issac Newton sat under the apple tree and in the same view he saw that apple drop from the tree to the ground he also noticed the moon up in space and...

Hey folks I'm looking into halo orbits and I have a question about how to find the initial conditions from the third order approximation solution... A good run through of the third order solution calculation is found in this paper...

Good morning, I've searched about this case in the internet but just found things about asteriods sharing the same orbit as Earth over the sun, but I wonder if an asteroid can get stuck in Earth's orbit like the moon. Thanks!

I was wondering... Suppose that the mass that was being orbited, in place of the earth, was stable and constant - then substitute the moon with another constant but suppose the orbit is the same as the mass and distances between them are the same - would/could this be an example of perpetual motion?

How did Kepler knew that the time of Mars' orbit was 687 days ? It doesn't seem to me a simple task to determine that timing because after 687 days, Earth is at a different place in the solar system and Mars seems to be also in a different place in the solar system. How was that 687 days...

Homework Statement At teh Earth's surface, the curvature is such that if you traveled in a straight line at a tangent to the surface of the Earth for 8kms the Earth would drop away 5 m. How fast would you need to travel to be in orbit at the Earth's surface? (radious of the Earth...

Hello! I don't know if this is in the right place or not. So if it's not, I won't misplace it in the future. Anyway, I was recently thinking about the orbits of planets around Binary Stars, and was wondering if it's possible to have a similar orbit around the Earth and the Moon. Have a...

Hi all, Im new here so please be gentle. Whilst in the pub last night a game was started with spinning a coin. We got to the point where we could all spin the coin with our hands in a circle around the salt shaker, about 3cm diameter. We then moved on to the pint glass and achieved that...

Interesting news about planets with no orbit: http://news.yahoo.com/s/ap/20110518/ap_on_sc/us_sci_wandering_planets Perhaps enough mass to explain dark matter?

According to Einstein's theory of general relativity, light bends--or rather space bends--around mass. So, in theory, is it possible for a photon to orbit around a body of sufficiently large mass?

Hello, I would like to ask why if the Earth rotate around the Sun in circle orbit, it must have an kinetic energy equal to negative half of potential energy it has at anytime rotating round the sun, which Ek = -Ep/2 ! If this situation cannot be achieved, our Earth will move in a new ellipse...

The question is... A satellite is in a circular orbit about the Earth (M = 5.98 x 1024 kg). The period of the satellite is 6.72 x 104 s. What is the speed at which the satellite travels? I know the speed is equal to (2piR)/6.72x10^4s But I can't figure out the radius. I know the Earth's...

Theoretically how much potassium nitrate would you need to get a 10 kg rocket out of the atmosphere and orbit as at the moment me and a group of highly intelligent freinds are working on a rocket to get out of orbit to prove a point to the man ect ect... and we need help

Homework Statement Two satellites are in circular orbits around Jupiter. One, with orbital radius r, makes one revolution every 16 h. The other satellite has orbital radius 4.0r. How long does the second satellite take to make one revolution around Jupiter? A. 130 hours B. 120 h C. 140 h D...

This is my first question here, so I'm a little new at this. I've really learned a lot from this forum in the past. Here goes: 1. Suppose you are responsible for a no-engine rocket project which carries a new satellite into space a. What is the the minimum initial speed of the rocket to...

Why is j=0 to j'=0 forbidden by the parity rule if spin orbit interaction is significant?

Hello, I am planning to design, and maybe build, a CubeSat, or a satellite that is 10cm x 10cm x 10cm, and weighs less than about 1.5 kg. I am looking to have 6 solar panels on the cube, one on each face, and also have a full 360º in all directions radar, along with a GPS and some radio...

How we can prove (using geomtry and not differential equation) that the orbit of planet have to be a conic section.

I am programming a game that involves objects orbiting in 3d space circularly around an axis. I have the orbits working for a fixed radius using centripetal forces, however, I want to be able to change the radius while the program is running. I have tried to just make the magnitude of the...

Homework Statement How much work must be done by a rocket engine to lift a 1000kg payload from rest on the Earth's surface to a circular orbit of radius 2Re (2 times the radius of the earth)? Homework Equations Eg = -GmM/r Ek = GmM/2r The Attempt at a Solution I know ΔE = W I...

1. The pro blem statement, all variables and given/known data the question: 9.0 × 10^3 kg satellite orbits the Earth at the distance of 2.56 × 10^7 m from Earth’s surface. What is its period? They give me a multiple choice, but let's figure this out without it. okay so my variables known...

Homework Statement A 6000 kg lunar lander is in orbit 80 km above the surface of the moon. It needs to move out to a 200 km -high orbit in order to link up with the mother ship that will take the astronauts home. How much work must the thrusters do? Homework Equations...

What would the equation be for the distance of an object orbiting another object in an elliptical orbit with time as the variable? How would I derive this equation? A comet would be an example. I am looking for the equation that would plot the distance from the sun at any given time.

For an object in an elliptical orbit around the moon, the points in the orbit that are closest to and farthest from the center of the moon are called perilune and apolune, respectively. These are the vertices of the orbit. The center of the moon is at one focus of the orbit. A spacecraft was...

If the proton in the nucleus of, say a hydrogen atom, exerts an attractive force on an electron that is in orbit, why doesn't the electron move towards the proton? And does this have anything to do with the electric force being the centripetal force?

Homework Statement A comet from the Oort cloud, with perihelion 6AU, is perturbed by Saturn into an orbit with perihelion 4AU. What is the semi-major axis and eccentricity of the new orbit? Homework Equations Perihelion = a(1-e) The Attempt at a Solution hey i could really...

Homework Statement A satellite is to be launched from Earth to venus. It is to make two complete circuits of the earth, then travel to venus, and complete one orbit of venus in 12 hours. Find the velocities of the satellite around venus, around the earth, and the radius of the orbit around...

Just looking for a place to start, not all the work. Homework Statement 3 The asteroid belt between Mars and Jupiter consists of many fragments (which some space scientists think came from a planet that once orbited the Sun but was destroyed). (a) If the radius of the asteroid belt (where...

Homework Statement What is the height of a geostationary satellite measured from the Earth's centre? Homework Equations r^3/T^2 = GM/4pi^2 T of Earth = 3.16 * 10^7 s The Attempt at a Solution GM/4p2 = r3/T2 3root[T2 * GM/4p2 ] = r 3root[(3.16*107 s)2 *...

Homework Statement A comet of mass 5x10^16 kg moves in an elliptical orbit around the sun, with the sun at one focus. At the perihelion, 10^6 m, the comet has a linear velocity of 1.5x10^7 m/s. Find the angular momentum of the comet with respect to a focus at the sun. Homework Equations...

Homework Statement We have been asked to work out the approximate time of orbit, T, of a satellite orbiting above the centre of Mars, radius 4000km.Homework Equations We have been given the equation: R^3/T^2 =1x〖10〗^13 m^3 s^(-2) The Attempt at a Solution When using the equation...

Can someone explain the cause of the Precession of Mercury’s Orbit in a "language" so simple that my grandmother can understand it? I mean only the part (43 arc second) that is due to relativity.