Planet Definition and 820 Threads

What is the chance of planets forming from gas clouds without a star? has anyone calculated this? are they more likely to form than stars? could there be billions of rogue planets floating arround our galaxy?

Homework Statement Consider a spherical, nonrotating planet of mass M, and radius R, with no atmosphere. A satellite is fired from the surface of the planet with speed v0 at 45o from the local vertical. In its subsequent orbit the satellite reaches a maximum distance of 5R/3 from the centre...

In preparation for my upcoming first exam I was doing all of the suggested problems throughout the chapters. Everything was fine until this problem: Homework Statement An astronaut on the planet Zircon tosses a rock horizontally with a speed of 6.95m/s. The rock falls through a vertical...

Homework Statement Two moons orbit a planet in nearly circular orbits. Moon D has orbital radius r, and moon E has orbital radius 4r. Moon D takes 20 days to complete one orbit. How long does it take for moon E to complete one orbit Homework Equations None - I think The Attempt...

Homework Statement A satellite circles planet X once every 99 min at a mean altitude of 530km. Calculate the mass of the Planet, if its radius is 5.78 * 10^6 So this is the Question i am having trouble with, these gravity questions are really killing me. Homework Equations...

Homework Statement A satellite is in a circular orbit very close to the surface of a spherical planet. The period of the orbit is T = 1.78 hours. What is density (mass/volume) of the planet? Assume that the planet has a uniform density.Homework Equations T^{2}=4*PI^2*r^3/G*M Density =...

Hi I'm writing a story and I need to figure out what color the sky is on a planet orbiting Zeta Tucanae that has close to the same atmosphere as earth. just so you know Zeta Tucanae's Spectrum is F9V and Color Index is 0.576 It would be great if you can tell me how to find the color...

If a planet had red and pink plants and vegitation what kind of athmosphere would it have.If it had a purple sky and it was 112 million miles from a blue sun what kind of athmosphere would create yellow transparent water instead of green or blue.

Might one have a warming planet, without CO2 increase? The last 15,000 years is evidence for such case, since pre-industrial CO2 is considered as ~280. If one had a slow down in vertical mixing (i.e. lower surface water turnover; say 1% over 100 yrs for 15,000 yrs- giving 150%), resulting...

Problem: Suppose a spacecraft is in a circular orbit about a distant planet. The spacecraft emits a continuous radio signal with a wavelength of 6 m. You observe the signal's wavelength to vary between 5:99969 m and 6:00031 m; the period of variation (i.e., the full period of the signal) is...

Homework Statement the problem asks to find the distance from the sun to a planet. the only information the question gives the the orbital period of 27 years and asks for the answer in km. Homework Equations c= (2)(pi)(r) The Attempt at a Solution assuming the planet revolves...

Homework Statement a planet is 5x10^8 km from its sun, from the planet, the sun has an angular size of 1 degree. what is the diameter of the sun? Homework Equations The Attempt at a Solution ive drawn a diagram with the sun and the planet, with the distance between written in and...

hi guys, i have been hearing a lot of speculation about planet x / Niburu's orbit taking it through the centre of our solar system in 2012 obviously with catastrophic effects to bio life. the documentaries i have seen on this event have not come sources which i would consider concrete...

Homework Statement The data is taken from a graph. The initial velocity is 31m/s. I found the horizontal velocity to be 21m/s. The time the ball travels is 5 seconds. The total distance the ball traveled is 105m. The ball lands at the same vertical level at which it starts. Air...

Ah, please, someone help me. I've been working on this problem for half an hour, it's the last question on my review before my test, which i want to write right now (correspondence). Homework Statement If a satellite requires 2.5 h to orbit a planet with an orbital radius of 2.6 x 10^5 m...

Homework Statement i need to find the mass of a new found planet at a given radius from the sun (R) and with a given cycle length (T) Homework Equations Kepler and Newton The Attempt at a Solution of course if R and T would fit with keplers third law then there would be no way to...

I mean the smallest, lowest mass, and/or lowest g terrestrial planet that can hold onto and support a favorable atmosphere for potential life, and is in the zone where water can exist as a liquid. I'm really asking: what's the smallest "Earth" possible? I heard that the upper limit for...

I was speaking with a friend about this today, I don't see a thread on it. http://www.msnbc.msn.com/id/32391095/ns/technology_and_science-space/

Let's speculate! For background, I am a neurobiology student. Ergo, I've got the requisite chem n' o-chem under my belt. (Would like to fit in some biochem, but I don't know if that's possible right now.) From my own perousing of the material on the internet, it seems that carbon is...

Homework Statement Now you take off to an unknown planet with the same pendulum as in part (a). You measure the period of the pendulum on that planet and you find it to be twice as much compared to the one of the pendulum while on Earth. What is the ratio of ge on Earth to the gx of the...

Is there an upper limit to the density of a planet's core?

Imagine you were safely enchambered right at the center of the earth. Here you would "experience" strong gravitational "forces" but since they all point in opposite directions you would float around as if you were in zero-gravity. My question is, whether you would experience time dilation or...

And if we increased the size of our imaginary planet, how massive and large could it get before it undergoes fusion? Also, I'm pretty sure you could never actually get a Uranium planet, but is there enough to have Uranium asteroids in a star system, or at least asteroids that are radioactive...

Homework Statement An Astronaugt is doing an experiment on an alien planet. She fires a ball straight up towards a target ball that is dropped at the same time as the lower ball is launched. If air resistence is ignored, how long does it take for the two balls to collide? Homework...

An astronaut on the planet Zircon tosses a rock horizontally with a speed of 6.55 m/s . The rock falls through a vertical distance of 1.20 m and lands a horizontal distance of 8.60 m from the astronaut. What is the acceleration of gravity on zicron? I have no idea how to even start.

Is there a PDE describing temperature as a function of time for a sphere in a vacuum (a moon in space)? Since it can only radiate, the boundary would be a function of temperature to the fourth power (nonlinear), right? Is there a book or thread out there I can reference? Maybe this can...

Homework Statement On an alien planet you throw a stone upward and measure the times Ta and Tb. The difference in heights of point a and point b is h. Calculate the acceleration due to gravity. Ta = 7.1s; Tb= 4.4s; h = 15.1m Homework Equations a = dv/st v(t) = vo - gt The...

Homework Statement A 92 kg man weighs 189 Newtons on the surface of an unknown planet. What ist he acceleration of gravity on this planet? Basically, I thought the formula to finding the gravitational force was G(gm)/r^2, but I'm missing the distance that the man from the planets center...

Everone is curious if there is any extra terrestrial life beyond our blue planet. do aliens really exist? Some organizations claim that they've got the strong evidences about existence of alien or the landing of alienship on earth, is it true? any comments'd be appreciated. cheers...

I was thinking about a situation like this: You have a planet that has a nonuniform density (mass) like this \rho = a - r where a is just some number and r is the radius away from the center of the planet. Then you have an object falling through the planet. I had no idea how to solve this...

Homework Statement The mass of a hypothetical planet is 1/100 that of Earth and its radius is 1/4 that of Earth. If a person weight 600 N on Earth, what would he weigh on this planetHomework Equations F = (G x M x m)/(R2)The Attempt at a Solution Well I know the mass of the person is the same...

The gravitational force is zero at the center of a planet, but the GPE is at a peak minimum (most negative). What happens to the time dilation factor inside the surface of a planet of uniform density versus at the surface of that planet.?

Homework Statement assume that the rotation period of saturn at the equator, very deep in the atmosphere is 10 hrs. higher in the atmosphere, the equatorial winds blow west to east at 250 m/s. What would be the rotation period of this higher level in the atmosphere? also know - maximum...

4. For a wide range of orbital radii, stars in the Galaxy (including our sun) move in nearly circular orbits with a speed v0 »220 km/s which is independent of the orbit's radius. Find the force law and the form of the potential energy function for a star moving through the Galaxy (it is not an...

http://www.thrfeed.com/2009/03/discovery-universe-hawking.html I'm really excited about this. Planet Earth was such an amazing series that did what a lot of hopefuls failed to do: tap into the sit-com audience. For a lot of us, 'Universe' will just be a cool rehash of things we already know...

I was just searching the net to find something to read about 2012 (doom's day) :-) ... And i got to know about nibiru , south pole telescope and black patches in google sky etc...suddenly one thought struck my mind..i knew that NASA was going to launch a new satellite to find Earth like...

Homework Statement Hi, A spinning shiny red-appearing planet at 130 billion km from the sun, has a diameter of 1700km. Estimate temperature of planet using simple heat balance equation. Estimate also the temperature obtained by Wien displacement law. Homework Equations I've been...

Homework Statement A planet moves in an elliptical orbit around the sun. The mass of the sun is M_s. The minimum and maximum distances of the planet from the sun are R_1 and R_2 , respectively. Using Kepler's 3rd law and Newton's law of universal gravitation, find the period of...

how gravity make planet to rotate? If you asked anybody why things rotate;they will answer you if you mean in astronomy the reson is gravity and if you mean at the level of atom the resone is electracal force but that is not what i want . i want to know how gravity do this and what really it...

For a gas and dust cloud to collapse under gravity to form a star and planets, is the concept of friction important at all? In other words: let's consider a large number of billiard balls, no internal degrees of freedom, participating in completely elastic collisions, with random initial...

Homework Statement To measure the acceleration due to gravity on a distant planet, an astronut hangs a 0.055 kg ball from the end of a wire. the wire has a length of 0.95 n and a linear density of 1.2*10 ^-14 kg/m. using electronic equipment, the astronaut measures the time for a transverse...

Lets suppose we have a planet made from two half-sphere with the same radius (R) made from matter with different density. The left-half-sphere is made from rocks (5gr/cm3) and the right-half-sphere is made from iron (8gr/cm3). Then we pour water on up to about one-tenth of the sphere...

I've noticed lately that FMC has been running the old movie series, Planet of the Apes. http://en.wikipedia.org/wiki/Planet_of_the_apes I was just wondering if we have any ape fans and how these movies play to a modern audience. Back when the movies first came out they were hugely popular. I...

I'm having a bit of difficulty figuring out the theoretical efficiency of a compound epicyclic gear train. The math involved is a bit over my head. This train is meant to run at very slow speed under light load. I want to find the theoretical efficiency of the design so I can determine if it is...

hey, how to find the distance of two planets, say, Earth and moon? i know it can done by apply equations of circular motion and gravitation, but it seems to me that there's always a piece of information missing. like, mass of Earth M : mg = GMm/r^2 M = gr^2/G u still need r to find M...

Homework Statement Hint:Disregard any dissipative effects of the atmosphere of the planet. A projectile is launched from the surface of a planet (mass M, radius R) with a launch speed equal to 60 percent of the escape speed for that planet. The projectile will rise to a maximum height and...

You will find people making endless donations to their campaigns and you find endless bumper stickers of politicians attached on the bumpers of cars, people becoming emotional at political rallies at the mere presence of a politician, even though the politician will not fullfill all of there...

Homework Statement There is a gaseous spherical planet with a nonconstant density rho(r) = rho_o (1 - r / R), where rho_0 is the maximum density attained at the planet's core, R is the radius of the planet, and r is the distance from the center of the planet. Use calculus to find the total...

Homework Statement When a moon orbits a planet, it can be shown that the period of the moon's orbit depends only on the mass of the planet and the radius of the moon's orbit. a) Draw and label a diagram to illustrate the variables. b) Derive a formula for the period of a moon's orbit. The...

I am making a three dimensional planetary orbit simulator but I can't figure out a formula that can work out where a certain planet is at a certain time e.g. if a planet with speed s was at position a with the sun at position b at time 0 then how would I calculate the position of the planet at...