Planet Definition and 820 Threads

1. So for homework my teacher gave us this question (and this is quoted from his worksheet): You graduate college with a degree in astrophysics and are assigned as an astronaut to explore a distant planet for NASA. You land on this planet and are told to determine the mass of the planet...

Hi all. This may be a stupid question to some.. But please do answer it. Why do planets move in an elliptical path? Why only ellipse? Or even a circular path for approximation? Why not a path which has corners? Like an octagon or a square?

Referring to all the people who have watched the movie, i got a question. It is about one of the planets where time passes drastically slower (1 hour on the surface is 7 Earth years ) due to gravitational time dilatation. Earth moves together with the sun with speed of circa 500 km/s trough...

Given an object spinning on its own axis, in orbit around a planet with mass and that the object is traveling in the direction of its axis, does the axis continue to point at the same point in infinity as it rotates around the planet or does the axis follow the curvature of space around the...

Would there be any way to get the energy from the rotation of a planet, which is an Earth like planet in material, sized like Jupiter, and seems to have a 24 hr day. I am just starting to get into real Physics, So I am not even sure where to start getting the numbers to work with, and I would...

If an object falls through a planet's entire grav. field, before impact it's velocity will be the escape velocity. I assume the time dilation for an observer on the object will be the same as for an observer on the planet. They're not added together. Another point - since time dilation on a...

Hello everybody. Although this is just a kinematics problem, I am having a hard time figuring out what to do. The question is: An archer on the planet zorg spots an octomorph that is resting in a tree above water. The octomorph's position in the tree is 100m away horizontally and 100m...

Homework Statement A space-probe discovers a planet with a gas atmosphere, detects a non-zero value for speed of sound 60km relative to the surface of the planet. It measures a surface temperature of -5 degrees C and an average atmospheric molecular mass of 38 x 10 ^ -27kg. Find G_p the...

I apologize in advance for my low understanding, but please play along if you can. I'm working on a story and in the story I want to toy with the idea of the solar system containing two suns and one planet. The story will be fantasy so it doesn't need to follow our laws of physics totally, but...

Homework Statement hi guys this is my first post, and it relates to classical mechanics. the problems asks that if there is a planet, planet x, with the same mass as that of the Earth and orbiting the same orbit as that of the Earth but 180 degres off from earth, so that the if the Earth is at...

Let's say their is a Earth sized planet orbiting a sun like star in its habitable zone. This planet has a tilt and rotation rate similar to Earth. The planet however has an atmosphere of 0.1 bar. The planet orbits its star close enough to have an average temperature of 12 C. From what I...

Let's assume an planet with Earths mass and radius orbits a G2V type star at 1 au. This planet would have an the same tilt, rotation rate and atmosphere of 1 bar as Earth. However the planets eccentricity would be 0.3. How would this greater eccentricity effect this planet?

Homework Statement After performing a quadratic curve fit tool in Pro Logger, I was given the values: A = -1.426E-05 +/- 2.386E-06 , B = 0.02193 +/- 0.001581, C = 0.4785 +/- 0.1905. With this information, how is “g” for Planet X determined from the parameters of the curve fit equation...

when you approach it from different directions?

I know, it sounds a little more epic than it really is. It is true, however. I am in the process of writing a story and would very much like to have the specifics of the other planet described at one point to the reader so they can get a grasp on the world part of the story is taking place in...

Alright, so there's a RP website I'm on that has a fairly detailed description of their solar system. However, they have no details on their planet's moons. This is something I've been trying to work out, as I want to introduce a lunar calendar of sorts to a nation I RP there. I've managed to...

I am using the C library that comes with the book Astronomical Algorithms by Jean Meeus http://www.willbell.com/math/mc1.htm This book and C library has a calculation for two planets Conjunction and Opposition but no other planet aspects. Does anyone know a method to find when two planets...

Homework Statement A person on Earth weighs 750N. What would the person weigh on a planet with 1.2 times the radius and 1.9 times the mass? Homework Equations mg=Gmme/re2 The two ms cancel, leaving: g=Gme/re2 The Attempt at a Solution Since the two ms cancel out, I thought that the...

I've been trying to develop a equation for a ball that is shot out of a cannon and see if it would return to the surface of a circular planet. This is not a homework. It's something that I have been thinking about for a long time. Can somewhat help out to derive such a formula?

Homework Statement An astronaut has landed on Planet N-40 and conducts an experiment to determine the acceleration due to gravity on that planet. She uses a simple pendulum that is 0.640 m long and measures that 10 complete oscillations 26.0 s. What is the acceleration of gravity on Planet...

How far could you see, on average, from a planet that was surrounded with infinite number of identical stars like the Sun, randomly (uniformly) distributed with their average distance of 10 light years apart? In other words, at what point of distance will such distribution tend to "close in" and...

This is not a homework question. Whilst looking over at previous exam papers on classical physics, I came across this question in the attachment. I always assumed gravitational potential energy increased as you moved further away from a mass. But the expected answer to this question shows the...

How far from the sun would a planet of roughly Earth's mass have to be from its sun to have a year the length of two Earth years and what type of star would be needed for it to be in its system's habitable zone? Or is this widely variable? Would the star of such a planet have a lifespan long...

If you have an object that undergoes a free fall from on a planet Mars which experiences a gravitational acceleration of magnitude 3,8m/s(squared) the mass of mass is given to be 6,4*10^i23kg. Please how do I find the radius of mars

I think this is the right forum to start this thread, if not i am sorry please somebody change it . suppose a planet is in the right distance from its star and it is rocky , has water and atmosphere but the only thing is it's not rotating itself , i mean it's always facing it's star , then...

How do we know for sure that that it's not possible to walk on Jupiter and that it is a gas planet? Did something ever land on it?

Hi Guys! Is there any chance for Pluto to clean up it's orbit and become a big boy someday? Thanks a lot.

can dual star and triple star have planet around it ( possible ? ) . alpha centauri is a triple star right ? is it having any planet around it ? thanks for any response in advance .

I wonder if I might pick the brains of the forum's experts? I am embarking on creating a new gaming campaign world, something I've wanted to do for years but never quite manged: an entirely alien world (i.e. not populated by humans or the like), yet with the same sort of technology as you'd...

by Jacob Aron Do you feel there is never enough time in a day? Then don't move to Beta Pictoris b. A day on this fast-paced exoplanet lasts just 8 hours, making it a poor choice for the temporally challenged. Link: New Scientist

Hi! Could we (at least) in theory change a planet's weight with denser core material so that it could be as large as it is, but have increased the gravity to the level like earth?

The two mass is similar. I read a line about this and i thought L should be conserved before. What is the background knowledge behind? Thank you.

Homework Statement On the surface of Planet X, the gravitational acceleration is 2g. If the diameter of Planet X is 1/3 that of Earth's, what is the mass of Planet X, expressed as a multiple of Earth's mass? Homework Equations F=G\frac{m1m2}{r^2} The Attempt at a Solution let...

Homework Statement A asteroid of mass m=5*10^20 kg , speed u=10km/s is on a direct course to hit earth. If nuclear weapons are used to split it into two equal pieces at a distance away of the moon's orbit, d, what is the minimum energy required for each half to miss Earth by s=600km...

Homework Statement A satellite is moving in a circular orbit around a massive planet of radius R. The altitude of the satellite above the surface of the planet is 3R and its speed is v. In order to place the satellite in an elliptical orbit which will bring it closer to the planet ,its...

Homework Statement A satellite is describing a circular orbit around a massive planet of radius R. The altitude of the satellite above the surface of planet is 3R and its speed is v_0. To place the satellite in an elliptical orbit which will bring it closer to the planet, its velocity is...

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...

Although I have taken Discrete Mathematics I am really bad with probability and would appreciate your insight in this. I had a discussion with a friend about aliens. So the question that arose is what is the probability that aliens on a different planet somewhere look similar to an animal...

Please forgive me. My education is lacking go easy on me. The radius of 6378.1 km has enough gravity to hold this atmosphere in place and has a magnetic field strong enough to protect it. 1. My question is would Mars have the same atmosphere and magnetic field if it were the same radius ((+/-...

This idea stems from the Pascal B nuclear test, which placed a 900kg steel plate over a shaft in where a nuclear explosive was detonated: http://en.wikipedia.org/wiki/Operation_Plumbbob#Propulsion_of_steel_plate_cap The plate shot up at an estimated 66km/s, or 6x escape velocity. Say you...

A body is orbiting the sun and rotates about its axis (z). My coordinate system is co-rotating with the body. I need to determine how does a vector that points to the sun change after a certain period of time. Initially the sun vector lies in the xz plane. Basically I need to find the rotation...

Hello! I'd like to thank everyone in advance for any help I receive! Homework Statement In January 2006, astronomers reported the discovery of a planet comparable in size to the Earth orbiting another star and having a mass of about 5.5 times the Earth's mass. It is believed to consist...

Hey there friends, I'm currently world building for a story and potentially a graphic novel. I'd describe the universe as a fair blend of high-fantasy/spirituality/science. While there's a lot of "magic" within the world, I'd like the "material plane" to be pretty solidly grounded in correct...

I have the following data in an epicyclic gear train: Angular speed on ring = 1500 rpm, teeth on ring = 30 Angular speed on sun = 3200 rpm, teeth on sun = 10 Angular speed on carrier = 1925 rpm, teeth on planets = 10 (The ratios of teeth are for simple calculation assumed 3: 1: 1 among...

Hi. I was wondering about this. In the "Star Trek" movie of 2009, the destruction of the planet Vulcan is shown, by a black hole being formed in its core. I'm curious: supposing you had some means to create, or collapse part of the planet to form, a black hole in its core, what would, according...

I'm curious which kind of fossil energy sources could one find on a young Earth-like planet which is in its equivalent of Cambrian era. Yes, I understand it's clearly too early for mining carbon. So presumably peat instead, right? What about oil or natural gas? (EDIT: including more exotic...

For a point mass acting as a source of a g field we draw lines that point inwards from infinity. Where we have an extended body like a planet, I've always drawn the field lines terminating on the surface. However, I've seen a question in an exam paper that implies that it's okay to continue...

While studying a seemingly inconsequential young star and its large planetary debris field, around 300 light years from Earth, they made an interesting observation. They discovered an exoplanet that is 654 ± 3 AU from its star. As a comparison, Pluto, at its furthest point in its orbit...

Question: Just as in the title. How large can a planet be and still have the Earth's mass? Obviously, this depends on its composition, just as long as it's solid and life can exist on it.

Maybe not the correct sub-forum for the question, but is the total amount of water on the planet constant ? I know the basics of meteorology and the whole sky, sea and land cycle but we put so much water into the land, how does that water get recycled ? If it is constant then why is it...