how   do   planets   help  us?
488676
The planets do not help us directly.  They have no influence on our lives.  Despite what they tell you in astrology columns, your body experiences more affect from the gravitational field of the obstetrician or midwife than from any planet besides Earth.\n\nHowever, the planets have inspired our study of astronomy.  If there were no other planets in our solar system, we might never have thought up astronomy other than the study of the Moon.  Except for the Moon and the Sun and planets, the rest of the sky looks pretty static.  We might still think it was a screen or painting, instead of a myriad of distant suns.
141087
mainly :\nstars generate light, planets only reflect\nplanets move through an orbit (around stars), stars don't
625130
Gravity is only one of the reasons that the planets move in an eliptical path instead of a perfect circle.  As the planets move closer to the Sun they build up speed, which causes what is known as the Sling Shot Effect.  NASA uses the same effect to build enough speed on their space craft to produce the proper lunar tragectory.  As the craft moves around the Earth it builds up speed; when combined with boosters it allows the craft to break the gravitational pull of Earth and shoot out towards the Moon, Mars, etc.  The thing about the planets is that they don't have boosters, and the gravitational pull of the Sun is so strong that it's impossible for them to break their path, but the planets weigh enough that their momentum directs them in an eliptical path, instead of a circular one.
581530
There are a few tree huggers, like us, who would be worth saving. Now if you could build a starship and find another habitable planet, we'd be in business.
299350
No we still have a lot to learn about our solar system, especially the outer planets.  This is in part because they are fairly far away and it takes a while, and a good deal of funding to get out there.  In the case of the gasious Jovian planets this is also because we cant see beneath the very tops of their clouds.  There are strange things that appear to be going on in their interiors but it's hard to get data on this when the pressures would easily crush any spacecraft soon into its decent.
803114
Well, it's the general belief that this is how the planets formed in the first place.  When our Sun formed from a big cloud of dust and gas some 4.5 billion years ago, there was left-over material in a disc around it.  Particles of dust in the disc clumped together to make "planetesimals", which in turn clumped together to make planets.  If the new planet was large enough and in the right region of the solar system, it could pull in gas, too.  That's why the larger planetesimals which were further out became the gas giants.\n\nOur solar system is fairly stable now, with each planet in its own "orbital zone" so this doesn't happen too much any more.  Still, this is a really interesting question, so let's imagine that we have some future technology where we could bring some large supply of asteroids to the Earth and add them to its mass.  (Note, however, that even the combined mass of the main asteroid belt between Mars and Jupiter still has much less mass than even our moon, so we'd have to find some magical source of material.)\n\nSince our mass would be increasing, the first thing we'd notice would be increased gravity on the surface.  We'd have to be careful, though, because by adding the extra mass we're decreasing the gravitational potential energy of the asteroids we brought in...all that energy has to go somewhere, most likely into heating up the Earth.  If we added enough asteroids, it might be enough to boil the oceans and melt the Earth's crust, in which case we'd all be in big trouble.\n\nSomething else to consider is any "angular momentum" (such as rotation or the "spinniness" of the orbit) the asteroid might have...If the asteroid was orbiting or rotating in the same direction as Earth, we'd speed up the Earth's rotation and thus shorten the length of our day.  Similarly, if the asteroid had angular momentum in the opposite direction of Earth, the Earth would slow down and the days would be longer.\n\nNow if we keep adding mass, we're going to get a very large planet indeed.  Eventually we'd get to the mass of Jupiter (which is 317 times as massive as the Earth)...but if we're adding asteroids (which are mostly rock with some metal and carbon), we probably wouldn't be a gas giant like Jupiter since there's not a lot of gas in the asteroids.  Some of the rock might vaporize and we might get increasing volcanic activity which would thicken our atmosphere, but we'd have nowhere near the gas content of Jupiter.  Deep in the interior of our Mega-Earth, metals would sink to the core while molten rock would float above...all this increased metal in the core would probably strengthen our magnetic field.  As the heat increased even more, molecules would start to break apart.\n\nAs we start adding more mass, something weird happens.  All that pressure in the core would cause the material to become "degenerate matter", a rare and exotic form of matter in which you can think of the electrons in the atoms as running out of room to get denser, so instead they just start moving faster.  One of the strange properties of degenerate matter is that as you add more matter, it actually shrinks!  So as we add more mass, the planet's size would actually start getting smaller.\n\nOnce we got to 8 times the mass of Jupiter, something special happens.  There would be so much heat and pressure at the planet's core that deuterium (a certain kind of isotope of hydrogen) can start undergoing nuclear fusion...this would produce lots of heat at the center which would casue us to start expanding again.  This is what astronomers call a "brown dwarf", somewhere between a planet and a star.  However, deuterium is not super-common, so brown dwarfs usually just fizzle out once they burn up all their deuterium.\n\nOnce we reached 80 times the mass of Jupiter then suddenly there's enough heat and pressure to star
246065
MAYBE YOU SHOULD GO TO A WEB SITE ON ANSTRONAMY OR GO TO THE LIBRARY THERE IS ALL KINDS OF BOOKS ON PLANETS. GOOD LUCK AND GOD BLESS.
615320
No way, there must be many, many planets throughout the universe that are similar to our own and support life. There are probably many others that support life that is much different than we are accustomed to also.
651352
A rather large benefit is that of Satellites - without them the world wide web, global communication, weather prediction and at least recognizing pollution as a problem would, if they existed at all, be far less advanced.\n\nIt can also be said that the advance of computer technology has been  partially due to the requirements of space travel.\n\nApart from all these obvious scientific advances the social realization achieved when seeing how small earth is maybe helped in world politics: the realization that it is one tiny little planet helped knock the wind out of national pride and build towards international co-operation. (a bit... not that much though, some people just have thick skulls).
1152640
While I agree with other people here that we should take better care of our planet, eventually the Earth will be destroyed.  Even if all comets and planet-killing asteroids miss us, the sun will eventually expand into a red giant and engulf the Earth.   Though that isn't likely to happen for possibly another billion years, it will eventually happen.\n\nThat being said, the more planets that we as a species inhabit, the greater our chance of survival.  Especially when we consider the possibility of colonizing other worlds in distant solar systems.  The endeavor will not be an easy one, and is indeed not possible at our current level of technology.  However technology may eventually advance that allows us to traverse great distances of space in but a few moments, perhaps through the creation of artificial wormholes.  Maybe we'll be lucky enough to see it in our lifetime.
1178704
Ask a scientist and they will say it effects every aspect of your daily activities. You and your surroundings are made of atoms that are mostly empty space. It is swarms of electrons with super tiny yet massive nuclei interspersed. All these forces acting on mass. Strong nuclear force holding the nucleus of an atom together. Electromagnetic forces holding the atoms together, and making molecules. Gravity attracting all massive objects to one another. Nature uses these forces to build planets, stars, even life itself. Engineers use these forces to manipulate matter in ever more amazing ways. Everything you see, hear, smell, or feel is physics in action.
657305
It is basically the reverse is true.  All the planets revolving round the sun are trying to move away from the sun.  The sun exerts some magnetic forces that keep the planets revolve in their own orbits.  The forces acting on a planet at a given time are both repulsive and attractive.  They are almost equivalent in magnitude and the difference is very meagre.  They nullify each other and that is why the planets are in place.  More over the planets are they themselves in motion whereby an equilibrium is attained between the motion of planets and that of the sun.\n\nMore over the universe is itself a giant magnetic field which is in space and the planets are kept in motion inside it.  There are many such universes available in space (as per scientists & astronomers).
232112
planets, stars, and quasars
463132
Yes,it exerts gravitational pull and it is due to this gravitational pull all the planets are revolving around the sun in fixed orbits.
1022705
The sun keeps the planets in an unwavering orbit, which keeps the hunks of rock from spilling out into the universe. As time goes on, the sun expands, but not even noticeably for millions of years, which will in time envelop the planets around it, and implode into a white dwarf (dead star).
1029405
You've almost answered your own question:  Stars are "stationary" sources of energy (nuclear) and give off light.  Planets do not and they orbit stars.
1130994
Yes, the planets go through phases. Celestial phases are basically light hitting different hemispheres at different times.