Planet Definition and 820 Threads

Homework Statement An extra solar planet is discovered that is 500 light-years away. It is found through spectroscopic analysis that the abundance of potassium - 40 to potassium - 39 on the planet is 99.9%. Assuming that the planet was created with equal amounts of the two potassium isotopes...

Homework Statement A planet similar to the Earth has a radius 4.4*10^6m and has an acceleration of gravity of 10 m/s^2 on the planet's surface.The planet rotates about its axis with a period of 25h. Imagine that the rotational speed can be increased. a/If an object at the equator is to have...

When I was in college years ago, I came across this test question: How will the periodic table of elements look like in another planet? Perhaps, it is asking for a general answer. Do you know if it will change the order of the elements?

Homework Statement >>the time separating high tides is 12 hours and 25 minutes. if high tide occurs at 2:10 P.M. one afternoon: Homework Equations >>when would you expect low tides to occur the next day? The Attempt at a Solution Tide is caused by gravity of moon. High tide means is...

[SOLVED] radius of synchronous satellite from a planet Homework Statement A "synchronous" satellite, which always remains above the same point on a planet's equator, is put in orbit about a planet similar to Jupiter. This planet rotates once every 7.8h, has a mass of 1.8e27kg and a radius of...

What keeps the atmosphere of a planet in place? THZ

The problem: Consider a spherical planet of uniform density \rho. The distance from the planet's center to its surface (i.e., the planet's radius) is R_{p}. An object is located a distance R from the center of the planet, where R\precR_{p} . (The object is located inside of the planet.)...

On your first trip to Planet X you happen to take along a 150 g mass, a 40-cm-long spring, a meter stick, and a stopwatch. You're curious about the acceleration due to gravity on Planet X, where ordinary tasks seem easier than on earth, but you can't find this information in your Visitor's...

Hi, I recently read a sci-fi story where they implied that the planet was much larger than Earth, but because that planet was rotating much faster than Earth, a person's weight on this planet was similar to what it was on Earth. I always thought it was strictly the masses that controlled...

Hi, I have a question here: http://tinyurl.com/2v9vp7 I expect the answer to be c, but it ends up to be b, what is the reason?

Homework Statement I am trying to find the velocity vectors for a planet in orbit. dx/dt = -a sin \theta \dot{\theta} dy/dt = b cos \theta \dot{\theta} Where a and b are the lengths of the sem-major and semi-minor axes, resp? What is the time derivative of theta expressed in terms of a...

First post. I am doing research for a script I am writing. Figured this was a good place to pose the question. Could a solar flare burn off our atmosphere and/or cause enough radiation, heat, and damage that life could not survive? Basically, I need a natural way for the Earth to be...

Imagine if there were another planet similar in mass and volume to Earth on a parallel orbit, on the other side of the sun. Would such a planet disturb the equilibrium of the solar system? And if there were indeed such a planet, how would its existence be known to humans? I believe...

Homework Statement A space traveler weighs 500 N on earth. What will the traveler weigh on another planet whose radius is three times that of Earth and whose mass is twice that of earth? answer in Newtons Homework Equations The Attempt at a Solution i think the formula...

Here's a problem which I encountered a while ago: "There is an alien on the surface of a spherical planet. The alien can run at a top speed of u. An alien hunter is hunting the alien in his spaceship which can fly at a top speed of v. Once the hunter sees the alien, he fires, and the alien...

I'm having a hard time picturing this in my mind: Calculate the largest possible angle as viewed from Earth between the Sun and a hypothetical planet orbiting the Sun in a circular orbit with a=0.65 AU. Assume Earth's orbit is circular and that Earth and the hypothetical planet orbit the...

Homework Statement I have two planets of equal mass at points (0,-1) and (0,1) on my axes and I want to find the y-velocity of the planet at (0,1) that will make this a closed orbit. We can uniquely determine the y-velocity of the with this because linear momentum must be zero. Any ideas? What...

[SOLVED] Acceleration of free falling object on another planet Homework Statement A ball is shot vertically upward from the surface of another planet. A plot of y versus t for the ball is shown in the figure below, where y is the height of the ball above its starting point and t = 0 at...

Is there anything special that can be attribituted to standing on a planet vs. some other mechanism of generating an upward force? The only unique attribute that I can assign to this case is that it keeps you in a constant part of the planet's curvature of spacetime. Maybe I can get my...

The only way the human race can really have a good chance of surviving in the long run is if we habit other planets then the earth. I figure that some planets may be habitable but without water, heat, and energy, it is a waste of money. Most planets are just not in the right spot to where...

A light year is the unit of distance that light, with a speed of 2.99792e8 m/s, travels in one year. What is the surface area of a planet whose radius is 1300 km? Answer in units of lightyears^2. I am wondering if my method is correct. SA of a sphere is 4[pi]R^2. With R = 1300, the...

Is it physically possible to have planets consisting entirely of liquids? I don't mean an ocean world, but a planet with nothing but liquid?

Within the uncertainty of solar system models and their computation, what and when was the closest occurrence (in terms of solid angle) of the inner eight planets forming a radial alignment outward from the Sun?

As usual, I don't know if this is the right place, but, I have been thinking, and if samarians ( if that's spelt right ) were right about planet x, then it should be near us soon in a few years or a few decades, now, if this is true, wouldn't that explain that if the ufo sightings are true...

What are the main things that are needed for life to exsist on another planet, or can micro bacteria or whatever just adapt to heat, cold, water, ect, what was on our planet when we first came about?

Water found on distant planet from PhysicsWeb News at 17:01 PM GMT An international team of astronomers has obtained the first convincing evidence of water in the atmosphere of a planet outside our solar system. They came to this conclusion using NASA's Spitzer Space Telescope to measure the...

How would the solar system capture an extra solar planet ?? Hello! - my first post here...and an informative site to be sure! I have checked the archives here and checked additional online resources, the point of my question being... How would the solar system capture an extra solar...

Are there any planets visible this time of day, today?

I have a few questions that I'm not sure on how to do: 1) A 20kg mass is connected to a 8kg mass by a thin frictionless string on a pulley. It accelerates to 1.5m/s2 and the heavier mass slides along a rough surface. What is the coefficient of friction? 3) 1.00g of U-238 fuel is consumed...

Okay obviously a hypothetical situation, this planet has a radius R, uniform density, and it doesn't rotate. Pressure in a liquid is given by p=\rho g d where d is the depth. So the liquid pressure a distance r from the centre of the planet is. p=\rho g (R-r) (where r<R) But g is also...

Discovery's "Planet Earth" Is anyone else watching this series? I am extremely impressed and engrossed in this program. The HD is amazing and some of the shots are darn right heavenly. So far my favorite episode is either "Shallow Seas" or "Caves".

This is a past paper exam question: Homework Statement One of the moons of Saturn is in an orbit which has approximately the same radius as that of the Earth's moon. Given that the speed of the saturn moon is ten times the speed of the Earth's moon, calculate a value for the mass of Saturn...

We debated on it, scientest were divided oner Pluto is a planet. I say I could be a special type. People are thinking it's an escaped moon or a Keiper belt object. I just don't see since Ceres an asteroid is being considered as a planet and it's far smaller. Then there's Jupiter. Aside from...

Homework Statement The residents of a small planet have bored a hole straight through its center as part of a communications system. The hole has been filled with a tube and the air has been pumped out of the tube to virtually eliminate friction. Messages are passed back and forth by dropping...

Hi, is there a way to find the radius of a planet by only knowing that the maximum depth in brightness of a transiting planet over a star is 0.7% ?

Suppose you are going to meet an alien from another planet. How can you make sure that the alien is not build of antimatter without touching it? My teacher told me that I have to compare the rate of the C-P violated processes. I didn't understand this point.

I was thinking, the amount of "gravity" a person feels on the surface of a planet is not only dependent on gravity, but also the centripetal force... For example, if Earth spun 17.04 times as fast as it does now (i.e. 1 day = 1.4 hours) then anything on the surface of the Earth would...

Homework Statement Find the orbit of a planet in a grav. field corresponding to the metric d\tau^2=(1+\alpha^2(x^2+y^2))dt^2-(dx^2+dy^2+dz^2) in the Newtonian limit with the initial conditions at t=0, x=R, dx/dt=\beta,0=y=z=dy/dt=dz/dt where alpha and beta are cositive constants. Homework...

While I know iron isn't the most common element in the universe, is it possible that there is a Jupiter + size planet made primarly of iron? Also, when it comes to black holes - would a massive iron planet form a black hole due to it's immense mass? What would be the minimum mass to form a black...

Why does the Earth have a core and can a planet exist without one?

Suppose someone from Planet X, In another part of our galaxy, is trying to communicate with the earth. He sends out a message. This is, of course an electromagnetic wave that travels through space with the sepeed of light. Assume that it takes ten years for the message to travel to earth. Twelve...

I'm looking for an radial equation to find the pressure or density of the interior of a moon or rock planet. It would involve Young's modulus or Poisson's ratio or something like. Any help?

1. If you know the distance to a planet and the centripetal force on it, could you calculate the mass of the planet? Explain. Fc = (MV^2) / (R) I don't even know where to start; in the equation above, you can only substitute the known centripetal force in, but you can't substitute the...

Homework Statement The premise of the Planet of the Apes movies and book is that hibernating astronauts travel far into Earth's future, to a time when human civilization has been replaced by an ape civilization. Considering only special relativity, determine how far into Earth's future the...

Consider a spherical planet of uniform density p. The distance from the planet's center to its surface (i.e., the planet's radius) is R_p. An object is located a distance R from the center of the planet, where R < R_p. (The object is located inside of the planet.) Find an expression for the...

ok guys, we've been fiddiling and fuming about all this nuclear reactors for the past few generations right? when all they essentially do is produce heat. this heat drives a turbine which in turn produces electricity ta da! as we all know, nuclear reactors can pose a very dangerous...

A satellite, mass of satellite=5850 kg, is in circular orbit of 4.1x10^5m above the surface of a planet, which has a radius of 4.15x10^6m. The period for the orbit is 2 hours. A) calculate the tangential velocity of the satellite. B) find the mass of the planet. C) how much would the...

"On the moon of a distant planet, an astrnaut measures the period of a simple pendulum, 0.85m long, and finds it is 4.7 seconds. Back on Earth, she could throw a rock 13m straight up (while wearing her spacesuit). With the same efoort, how far up can she throw the same rock at her present...

It is Earth like, and reachable in a reasonable time, with new spaceship design, only (basic) tools and equiptment can be transported with you, would you go?

Planet X is observed to have a small moon. This moon is observed to orbit the planet once per month at a distance of 15 Planet X diameters. What is the mass of Planet X in solar masses? [Hint: Use Newton's form of Kepler's Third Law: P2 is proportional to a3/M, where M is the mass of Planet X...