Planet Definition and 812 Threads

Hi! I saw the definition of a planet -- basically anything differentiated that has cleared everything in the area and orbits the central star. Pluto doesn't count because it's in the middle of a belt. Ceres doesn't count because it's in the middle of a belt. Sedna -- well...

http://www.cnn.com/2006/TECH/space/08/24/pluto.ap/index.html "PRAGUE, Czech Republic (AP) -- Leading astronomers declared Thursday that Pluto is no longer a planet under historic new guidelines that downsize the solar system from nine planets to eight." ... :smile:

http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_resolution.html" I'm ok with Pluto and Charon being a planet and 2003 UB313but crers? what were they thinking!

In a recent theological discussion, I came to realize that there is a point in question regarding planet formation in the current model of the origins of the Solar System. The question itself is not theological, but has some theological ramifications. It goes like this: Planets are believed...

Why doesn't this force give the gravitational acceleration on the surface of the earth? a = G \cdot \frac{m}{r^2} I would think that it could be derived from the law of universal gravitation: F = G \cdot \frac{m_1 \cdot m_2}{r^2} Since F = m_2 a

I'd be grateful if someone can help me with this problem - Zero, a hypothetical planet, has a mass of 4.4 × 10^23 kg, a radius of 3.2 × 10^6 m, and no atmosphere. A 2.4 kg space probe is to be launched vertically from its surface. (a) If the probe is launched with an initial energy of 7.4 ×...

my question is for example if we have a commet,asteroid in an impact collision with a planet, can the planet gravitational force can stop it from colliding, and bound it so the commet,asteroid will orbit the planet? i think the answer is yes, but what minimal velocity should the the commet...

http://www.comagz.com/webmagazine/story/proportions_how_small_we_are

Can anybody help me find informations about the mathematical discovery of planet neptune ? I would like to know how Leverrier and Adams calculated the position of neptune and all this stuff... Thanks in advance.. Jack

can u help me to explain the role of gravity in the equilibrium of stars in their production of enegry , and an explanation of the role of gravity in the formation of planets. thankssssssss

Ive been wondering about this for a while. i read in the newspaper about jupiters new red spot, but anyways they mentioned that it was a gas planet. does this mean that if you were to fly to Jupiter and keep going, eventually you'd go right through it and out the other side? or is it so dense...

2 part question The density of a certain planet varies with radial distance as: D(r) = Do*[1-(a*r/Ro)], where Ro= 3.1623×106 m is the radius of the planet, Do = 3160 kg/m3 is its central density, and a = 0.160. Calculate the total mass of this planet. Calculate the weight of a one kilogram...

Drake equation and planet finding I've just finished reading a Discover mag article on the Drake equation. It suggests that - despite the 45 year difference wherein many terms have been changed or anchored with more precision - the final number is about the same as it always was; there should...

This is the on planet that Ancients haven't seen(and I have never seen).

If there was a planet and there was no real energy source near it (say like our sun) would a few stars around 100million light years away on all sides of the planet(like our stars) be enought to keep atoms on the planet moving enough to stop BEC, or would BEC occur. Also if there was only one...

So I heard a theory once that a planet, gaining mass through collisions, could over time become a feelble star (if it gained about 10x the mass of jupiter), through adding kinetic energy and pressure, etc., and that this would create nuclear ignition. My question is this: If somehow we could...

http://television.esa.int/default.cfm Anyone with some inside information?

http://arxiv.org/abs/astro-ph/0601469 Comparative Planetology and the Search for Life Beyond the Solar System Charles A. Beichman, Malcolm Fridlund, Wesley A. Traub, Karl R. Stapelfeldt, Andreas Quirrenbach, Sara Seager To Appear in Protosars and Planets V "The study of planets beyond...

It is said that high massive planets can eject small planets in planetary forming systems. I don't understand that since gravitation is supposed to attrack things. Do you know of any article that expains that kind of phenomenum?

Life on a brown dwarf or a fissioning rogue planet? Is life on a brown dwarf or a rogue planet with a fissioning core any less feasible than life in a solar system?

I was thinking about this while reading the thread about destroying a star, I thought well what would you have to do to simply annihilate a planet? Note I am not simply talking about making it devoid of life but actually destroying it utterly.:devil:

The former is a hypothesis that originated with observations of (apparent) periodicity in the extinction record, and has had its share of fame and controversy; the latter began as an innocent follow-on to the discovery of Pluto ('that puny little thing, a planet??') but in the late 20th century...

Hi, I need to find the density \rho(r) of an ideal gas at constant temperature T surrouding a planet of mass M and radius R. The gas is attrated by the planet and is also self-attracting. First, I used the hydrostatic equilibirum equation...

Does anyone know anything about this? http://tv.yahoo.com/news/wwn/20050912/112653720001.html I'd love to hear what people who know what they're talking about, physics-wise, have to say about this. \phi The Rev

I have heard of terrestrial, gas giant, liquid and (speculatively) crystal planets. It seems to me that the conditions for forming a glass planet would be relatively common (more than those for their crystal cousins) - enough so that such bodies might eventually be detectable in our galactic...

From last week's Science Daily headlines: Underlying Cause Of Massive Pinyon Pine Die-off Revealed http://www.sciencedaily.com/releases/2005/10/051011073510.htm The article says nothing about man's contribution to warming; it is merely another datapoint of the changing face of the planet.

my evil teacher is making me and my friend to do a 12 page report. and the question is "how does the distance of a planet from the sun affect the temperature?" i would really apperciate it. thanks.

I think I have done this problem correctly, The mass of a robot is 6680 kg. This robot weighs 3070 N more on planet A than it does on planet B. Both planets have the same radius of 4.00 x 10^8. What is the difference Ma - Mb in the masses of these plantes? I used this equation F = G *...

What is the name of the new planet found in the universe,and what is the name of its moon. Thanks. http://www.handshakeit.com

Alright I am obviously retarded since I am unable to figure this question out. The question is: You have just landed on Planet X. You take out a ball of mass m, release it from rest from a height of h and measure that it takes a time of t to reach the ground. You can ignore any force on...

Hello everyone, I'm a physics/astronomy noob, actually I don’t even begin my curricula till later this 2006.Yes, the credibility of this source is well umm… it’s a tabloid! But my friend who studies astronomy sent me this and this is the debunking thread afterall. :biggrin...

"10th Planet" resonance with Neptune The "10th Planet" is locked in resonance with Neptune. 2003 UB313 is in a 17:5 resonance with Neptune. I've never seen a number as high as 17 be part of a resonance before . 2005 FY9 is in an 11:6 resonance with Neptune. Here's a page I made...

Interesting article; makes you wonder what we would really define as a "planet." http://news.scotsman.com/international.cfm?id=1707552005

A new solar system object past Pluto and Neptune's object with a moon, which is smaller than Pluto has been discovered. (This is also very delicate wording. The sensational way to word it would be: "New Planet Discovered Past Pluto!", but given that Pluto just barely qualifies to be a planet...

http://news.yahoo.com/s/space/20050713/sc_space/triplesunsetplanetdiscoveredin3starsystem :cool: Awesome! A newly discovered planet has bountiful sunshine, with not one, not two, but three suns glowing in its sky. It is the first extrasolar planet found in a system with three stars...

The idea popped into my head today of building an extreme telescope (larger than hubble) to orbit an outer planet such as Jupiter etc.. I'm thinking that with it being past the asteroid belt, we would be able to see farther and clearer than with the hubble. Is this an accurate assumption? The...

Could it happen or is it very unlikely?

Q: Your starship, the Aimless Wanderer, lands on the mysterious planet Mongo. As chief scientist-engineer, you make the following measurements: a 2.50-kg stone thrown upward from the ground at 15.0 m/s returns to the ground in 7.00 s; the circumference of Mongo at the equator is 1×10^5 km; and...

any body can explain why the circulation of the molten core inside a planet can produce magnetic field?

Intelligent beings on the plantet Xeno have developed a unit of distance called the xen. The number of square xens in the surface area of Xeno is exactly the number of cubic zens in its volume. If Xeno is a spherical planet with a diameter of 2160 Kms, how many km are there in one Xen...

An atlas of environmental change compiled by the United Nations reveals some of the dramatic transformations that are occurring to our planet. It compares and contrasts satellite images taken over the past few decades with contemporary ones. These highlight in vivid detail the striking...

A planet with mass m, and radius r... what is the acceleration due to gravity on the surface of the planet? a = Gm/r^2 correct? I'm pretty sure I'm right, but I will sleep better if someone can confirm this :smile: thanks

A planet has mass Mplanet = 4.46e24 Kg and a radius Rplanet = 5900 Km Some space explorer lands on the equator of this planet and he weighs 161lbs, whereas he weight 185lbs on Earth. He journeys over to the North pole and he finds himself weight only 95% of what he did at the equator. Now the...

There's a planet with a moon that orbits the plant in 30 days and moves at a distance of 370million meters from the center of the planet. i need to find the mass of the planet and I've used the following equation that was derived from the keplers laws: P = 2pi(a^(3/2))/(GM)^(1/2). P is the time...

Q: 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 packets through...

I believe man evolved to invent the microchip. Communication is a natural self organizing principle of nature. This is inevitable as water running down hill, or the formation of snow flakes. The Components of the universe organize around the a flow of information. These currents can be gravity...

A speck of crystal is the oldest bit of Earth found according to this article: http://www.foxnews.com/story/0,2933,152930,00.html How in the world (pun intended) does one set out looking for the oldest bits? …

In a planet, if the spin numbers were +1/2, 0 , and -1/2 and their magnetic quantum numbers take the values 0, 1, 2,...L ( Everything else including the ordering and naming of the orbits are same except the spin numbers and the magnetic quantum numbers as provided above.) how would the...

Check it out! Cool!

Why is it difficult to measure the perihelion advance of the planet Venus? Please help me answer this question in details...Thank you~ :smile: