Planets Definition and 510 Threads

I've seen that Mars' apparent magnitude varies between -2.9 and 1.8 and Mercury's from -2.0 and 5.5 (wikipedia said so at least). I'm trying to figure out which planet would have the greatest variation in brightness, as seen from Earth. The numbers at wikipedia points in the direction of...

[SOLVED] Gravitational field between two planets. Homework Statement Planet B and Planet A are separated by a distance of R. Homework Equations At what distance will the net gravitational field be 0, express R in terms of Planet A. HINT: Use Gravitational Force. The Attempt at a Solution...

Hello all, Ok I`m new to this forum so please don`t shout at me if this is a silly question :) I have been wondering why it is that planets like Jupiter which have the gravitational pull to have moons orbiting them - why they then don`t collapse into solid spheres under their own gravity?

(my first post) so i was watching a video on einstein's general theory of relativity when i realized that every solar system diagram shows the planets revolving around the sun on a two dimensional plane. do they really revolve at all the same level of say..a flat zero degrees, or do they...

I am trying to write a simple java program to model the motion of planets according to kepler's second law. I have everything working...except I can't find how to find an equation relating position and time. I have x = a cos(t) y = b sin(t) where a and b are the semimajor and semiminor...

Once again I have no idea what my physics professor is asking- I am not asking for direct answers necessarily but any help is much appreciated! http://www.physics.utah.edu/~cassiday/p1050/homework06.html

Hi again, one and all. Been a while. As part of my 'scientific communications skills' malarky at uni we have to produce myriad things (review article, powerpoint, governmental brief, etc, etc) on the subject of the search for extrasolar planets. We're focusing (probably) largely on the search...

we know that planets revolve in elliptical orbits but Why should planets revolve in elliptical orbits?

Okay, I am doing grade 12 physics in australia and I was wondering about systems of planets interacting with each others gravity and whether this could cause chaos with orbits. If all the other planets in out solar system effect one another, does there ever end up a point where the clockwork...

Since each planet and star has it's own gravity which causes smaller bodies to orbit around them. Will our sun have an orbit around bodies with greater gravity than it?

I was doing some thinking as to whether aliens are really out there. Then I figured, they probably don't want us to find them if they are out there, so they are probably hiding (and maybe a little even embarrassed by us as a species). Then I thought, "How exactly would one go about hiding a...

how does the movement of stars compare to the movement of planets

why does planets hav eliptical orbits (pls explain -not mathematically if posssible)

I am not an astronomer or astrophysicist but lately, I have been reading a lot of books to upgrade my knowledge in cosmology. I have encountered two issues that I am baffled about and wonder if anyone can help me throw some light on them (1) If the planets are parts of the sun or came from...

http://news.yahoo.com/s/nm/20070816/sc_nm/space_dwarf_dc;_ylt=AlGS1eXRs8GTnZf2V8LFS04hANEA Interesting possibilities! :cool: http://arxiv.org/abs/astro-ph/0509193 A Dusty Disk Around GD 362, a White Dwarf With a Uniquely High Photospheric Metal Abundance...

computer modeling of motion of planets! hi everybody what would happen on the position and orbit of the Earth and the moon, if the mass of the moon will gradually increase within a day and becomes greater than the mass of the earth. will it brings a big disaster in the earth? will moon...

It may be that this question makes assumptions that are themselves invalid -- I am less than an amateur. But here goes. Is there any easy way to determine how often Point 1 on Planet A and Point 2 on Planet B will align? That is, if at Time X you could draw a straight, unobstructed vector...

How many planets can orbit one Sun?

Homework Statement Suppose you went to another planet having a larger radius than Earth but having the same total mass as Earth. Would this affect your weight? How? Homework Equations Not applicable...? I think. The Attempt at a Solution I don't really understand what radius and...

I have a question relating to astroid collisions with terrestrial planets. I was reading the Venus wiki, and linked to the wiki about colonizing Venus. One method for reducing the massive amounts of CO2 was a big impact on the planet, making the CO2 eject into space (if I remember...

No big rocky planets? Why are there no big rocky planets - all the big planets are gaseous. Did big rocky planets get smashed up and end up in the Kuiper belt?

I was showering and I realized I have no clue... all you read about is HOW they form, but I've never read whether they are still forming or not...

Homework Statement Finally, develop models for only the four innermost planets and the four Galilean moons by reducing all the orbital radii by a factor that makes the orbital radius of the first planet or moon equal to one. Give possible reasons for the similarities and/or differences in two...

Are the other planets in the solar system getting hotter like the Earth and if they are would this mean that the so-called Greenhouse effect is being caused by increased output of energy by the Sun and not by carbon dioxide?

Here's an article on a speech by Stephen Hawking: http://www.brooksbulletin.com/news/world_news.asp?itemid=59084 So even a physicist like Hawking -- who's not going to niavely believe in arbitrary comicbook fantasies about warp drive, hyperspace, etc -- is advocating that we go to the...

Hi. I can't seem to understand why a planet has to rotate about its own axis as it revolves about the sun. Why can't it just revolve around the sun without any rotation? What is the cause of rotation of a planet? Also, on what factors does the angle between the axis of rotation and...

Im not sure if this is done right... Im guessing use Net force = ma The net force is the Gravitational force, Gm1m2 / r^2 is = m2 4 (pie)^2 r/ T^2 for the 4 (pie)^2 r/ T^2 r is the distance form the planet's center, to the moon, for T, find how many second 40 days is. and the other r...

Two objects attract each other gravitationally with a force of 3.5 10-10 N when they are 0.33 m apart. Their total mass is 4.0 kg. Find their individual masses. larger mass kg ? smaller mass kg ?

A colonist on a distant planet with a radius 0.92 times the Earth's is pulling on a box of mass 12 kg across the floor. The coefficient of static friction between the box and the floor is 0.70. He has to pull with a force of greater than 73N to start the box moving. a) Determine the mass of the...

A friend and myself were having a conversation today just about the nature of planets in motion and orbits (Originally we were talking about getting a rocket to Mars but I digress) The Earth and sun, assuming no other bodies were in the solar system and the system was as it is now - Earth...

Ok well, I have used up 2 out of 3 of my submissions for this question. I have tried to do a system of equations and failed twice. I really don't even know where to start so I was hoping that you guys could help me. The problem is. The mass of a robot is 5720 kg. This robot weighs 3720 N more...

current issue of SCIENCE http://www.sciencemag.org/cgi/content/short/313/5792/1413 Exotic Earths: Forming Habitable Worlds with Giant Planet Migration Sean N. Raymond, Avi M. Mandell, Steinn Sigurdsson "Close-in giant planets (e.g., "hot Jupiters") are thought to form far from their...

When is a Planet a planet...? and when is it just a ball of gas..? My personal belief is that Jupiter, Saturn, Neptune and Uranus...should NOT be considered planets. How can you call a spheroid ball of rotating gases a planet ? Surely, if you can't step on it, land on it or float on it...its...

Being new to astronomy, I was wondering, do all planets have moons? What are they? how did they get there?

Theoretically, what would be the closest one planet could safely exist away from another?

What's preventing Saturn's rings from condensing into a moon? Or Jupiter's, Uranus' and Neptune's for that matter?

Please explain why there is no pluto any more

Some fascinating resolutions were made at this years' IAU (international astronomical union) General Assembly 2006 Meeting One that has caught our attention recently: definition of a "planet". Pluto is not amoung them. (instead it is placed in a new category: "dwarf planet" )

Call them DOLPHINS (not "dwarf planets") they are out beyond and around Neptune and old paintings of the god Neptune often have dolphins cavorting around. so call them Dolphins and that makes Pluto the first Dolphin to be discovered and Sedna and Xena are recently discovered Dolphins...

The International Astronomical Union is about to decide the Solar System has 12 planets. The new planets: Xena would become the most distant planet. Charon would become a planet. Since Pluto and Charon both orbit a point in space outside of both, Pluto and Charon become a double planet...

Hello, I wanted to know if the translational motion of the stars & planets are according to a polynomial sequence or not?? if not then how can the scientists predict the position of a specific star/planet after a specific period of time?? Thankyou for your answer...

If the planets are constantly orbiting the Sun won't they eventually run out of energy, succumb to the gravitational pull and fall into the Sun? They don't seem to be doing... why not?

I'm writing up a simple simulation of the solar system for my computer simulations in physics class, which you can see at myweb.dal.ca/cr376499 (java applet) Now, I have the correct position data for the planets thanks to a website giving them relative to Earth for telescope users. What I...

http://arxiv.org/abs/astro-ph/0603200 Authors: Barrie W Jones, P Nick Sleep, David R Underwood Comments: Being refereed We have used the measured properties of the stars in the known exoplanetary systems to estimate their present habitability, and compared the outcome with earlier work...

Even the Moon is moving away from the Earth each year by approximately 1 inch. What keeps the planets in their alignment? Why aren't they either being drawn into the Sun or pushed away(like our moon to Earth)?

HI friends, Has there been any sound recorded on any other planets when spaceships visited there?

Question: The variable period of a moon of Jupiter, which is the basis of measurement of the speed of light in Roemer's method (whoever he is), is regarded as the Doppler affect. The period of the orbital motion of one of Jupiter's moons is approximately 42.5 hours; the speed of light is...

Why are the planets in our solar system spread out in a plane instead of being more randomly spread around the Sun? And why is our galaxy in the shape of a plane instead of all the stars in our galaxy being more randomly spread around the middle of our galaxy? Thanks,

I'm reading Parallel Worlds by Michio Kaku and I keep wondering if space is flat, then what would happen if you kept moving directly downward under our solar system (or directly down from any other planet)? What would you see and where would space end or simply curve back around. Thanks!

According to General Relativity the stars and planets cause a warp in the fabric of space time, right? Now, if planets' orbits are governed by the warping of the fabric of space time, then how are the gas clouds in Nebulas affecting that fabric? Also how do galaxies affect that fabric? Do they...