Can anybody else see how the solar system works?
541625
Not sure how you want this question answered, but here goes:\n\nThe solar system consists of the Sun, the 10 planets, the asteroid belt, The Kuiper belt, and the Oort cloud. The Sun is a main sequence G2 star that contains 99.86% of the system's known mass. Its two largest orbiting bodies, Jupiter and Saturn, account for more than 90% of the remainder; the Oort Cloud might hold a substantial percentage, but as yet its existence is unconfirmed.\n\nIn broad terms, the charted regions of the solar system consist of the Sun and its planetary system: the eight bodies in relatively unique orbits commonly called planets or major planets and two belts of smaller objects, which can be called minor planets, planetoids, meteoroids, or planetesimals. Pluto, the ninth planet, is also considered a member of the outer belt, and its status is currently uncertain, particularly since the discovery of 2003 UB313 (see below). Most objects in orbit round the Sun all lie within the same shallow plane, called the ecliptic plane, and orbit in the same direction. Many are in turn orbited by moons, and the largest are encircled by planetary rings of dust and other particles.\n\nThe major planets are, in order, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Eight of the nine planets are named after or derived from gods and goddesses from Greco-Roman mythology.\n\nDistances within the solar system are measured most often in astronomical units, or AU. One AU is the mean distance between the Earth and the Sun, or 149 598 000 kilometres. Other units in common use include the gigametre (Gm, one million kilometres) and the terametre (Tm, one billion/milliard kilometres). Pluto is roughly 38 AU (5.9 Tm) from the Sun, while Jupiter lies at roughly 5.2 AU (778 Gm).\n\nUsing radiometric dating, scientists can estimate that the solar system is 4.6 billion years old. The oldest rocks on Earth are approximately 3.9 billion years old. Rocks this old are rare, as the Earth's surface is constantly being reshaped by erosion, vulcanism and plate tectonics. To estimate the age of the solar system scientists must use meteorites, which were formed during the early condensation of the solar nebula. The oldest meteorites (such as the Canyon Diablo meteorite) are found to have an age of 4.6 billion years, hence the solar system must be at least 4.6 billion years old.\n\nThe current theory of solar system formation is the nebular hypothesis, first proposed in 1755 by Immanuel Kant and independently formulated by Pierre-Simon Laplace. The nebular theory has been refined over many years and now has a great deal of evidence supporting it.\n\nTo briefly summarize, the nebular theory holds that the solar system was formed from the gravitational collapse of a gaseous cloud called the solar nebula. It had a diameter of 100 AU and was 2-3 times the mass of the Sun. Over time a disturbance (possibly a nearby supernova) squeezed the nebula, pushing matter inward until gravitational forces overcame the internal gas pressure and it began to collapse. As the nebula collapsed it began to spin faster to conserve angular momentum, and became warmer. As the competing forces associated with gravity, gas pressure, magnetic fields, and rotation acted on it the contracting nebula began to flatten into a spinning protoplanetary disk with a gradually contracting protostar at the center.\n\nGrains of dust (silicates and metals) and ice (hydrogen compounds) condensed from the gas, and began to accrete into larger and larger clumps, forming planetesimals. Inside the frost line, planetesimals were composed of rock and metal, because those are the only grains that can condense at those temperatures, and remained relatively small because they were only 0.6% the mass of the disk. The larger icy planetesimals beyond the frost line became massive enough to capture and hold onto helium and then hydrogen gases, which caused them to rapidly grow into jovian protoplanets.\n\nAft
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.
1727
Yes -- in fact you are living on one.  The earth and moon is quite unusual in being relatively the same size to earth other compared to other moons around other planets in the solar system.\n\nIn that respect you can consider the earth and moon as being twin planets.\n\nAs to how often this happens outside the solar system, you would probably have to wait a few years as we have only just started to be able to detect planets around nearby stars but currently have no real means of actually observing them.
1023489
No.  But we see only the side that faces earth.\n\nHere's a good diagram that explains it better than I can...\n\n\nhttp://www.windows.ucar.edu/tour/link=/the_universe/uts/moon2.html
1149344
do you really think they dont have telescopes? if they have the tech to transverse solar systems then dont you think they can devise a device to look at us from afar? after seeing what a warring species we are it seems theyd rather study us from afar. we're dangerous.
302598
An interesting question. The question that may comes to \neveryone's mind is "IS the earth round?"  \nAnd the answer is no, at least \nnot perfectly round.  But it is round compared to your average cube, that is \nfor sure!  Now, my understanding of how solar systems form is pretty \ninadequate; all I can tell you is what I see on "Nova."  But basically, I \nguess it has to do with gravity, which is a CENTRAL FORCE.  What that means is \nthat gravity pulls things together along a straight line, and the more massive \none of the things is, the stronger it pulls.  When the earth was forming, it \nwas basically a big ball of dust left over from an exploded sun (a supernova).  \nGravity caused a lot of the matter to condense into a big fiery ball (our \nsun), but some of the dust was far enough away from the Sun so that the \nstronger forces were between planetary dust particles and not the sun.  SO, \nthey swirled together into a ball.  You can see something similar when you \nmake a painting with one of those "spin-art" machines; you put a card on the \nspinner, which whirls around real fast, and then you squirt paint on the card.  \nThe whirling causes the paint to go out away from the center (this is like the \nexplosion of the supernova) and droplets go out along an interesting path \nuntil they stop, which happens when the spinning force is equal and opposite \nto the force which attaches paint to the card (this is like gravity).  Now, if \nthe force attaching paint to the card were not so strong,eventually the drops \nwould get bigger - "planets."
879967
if you have a good enough telescope - you can see some stuff.\nyou can also see the robotic tractor that was left on Mars. (though you need more than a standard telescope for that)\nIt has been done by many people
779719
Try NASA's site:\nhttp://www.nasa.gov/vision/universe/solarsystem/index.html\n\nor Wikipedia links from:\nhttp://en.wikipedia.org/wiki/Planets
1047185
The following link is a list of solar system objects by mass from most massive to least massive. If it was really by radius, not mass, you were after there is a blue link to it at the link below so it should be easy to view.
53346
The solar system always works.
1054859
if ur asking if we, as humans, can be sure the no one else exists on the other planets? then no..no one can be so sure, but the facts gathered about the other planets, such as chemicals in the air, etc... can tell something about the planets..
1182373
a solar system includes the sun, planets & their moons,meteors ,debris, comets  etc. the sun(star) due to gravitational force attracts the planets & other things & it might lead to development of centripital force b/w the sun & the planets.\nthis forms the solar system
871968
Here is the math for finding our solar system's barycenter. (It's under the heading "Barycenter").\nhttp://en.wikipedia.org/wiki/Center_of_mass
415144
Depends what time of the year it is etc. but you can nearly always see Jupiter and Saturn and if a planet is at opposition then it is at its brightest when viewed from earth. Venus and Mars are also easy to spot. Mercury is elusive as it is generally close to the sun. I don't think you can see Pluto without a telescope, or Neptune and Uranus without some form of magnification e.g. binoculars
606341
It depends on whether you are talking about a planet in our solar system or an extra solar planet. I'll describe both.\n\nFor a planet in our solar system, the apparent size can be directly measured optically. One way is to take a picture of the planet through the telescope and measure the size of the picture with a ruler. Calculations based on the focal length of the telescope will tell you how many degrees (or fractions of a degree, since it will be less than 1) wide the planet appears to be in the sky for a given measured size on the photograph. Then the distance to the planet must be measured, which is not so easy. Basically it comes from triangulation to nearby asteroids combined with kepler's laws. Knowing the distance and apparent size allows you to calculate the real size and volume. To get the density, you need to know the mass. If the planet has Moons, the orbital period of the moons gives you the planet's mass from orbital mechanics calculations. If the planet has no moon, like Mercury and Venus, then theoretically their mass can be gotten from the effect their gravity has on the orbits of other planets, asteroids and comets, but this is not so accurate since those other objects don't usually pass close enough to the planet we want to measure to show much of an effect on their orbits. Fortunately we have sent space craft to Mercury and Venus and measured their mass directly by the effect their gravity had on the space craft's path.\n\nFor a planet orbiting another star, it is not so easy, because such planets cannot even be seen. Their presence is deduced from tiny Doppler shifts of the star they orbit. A planet does not just orbit a star, the star and planet orbit each other around their common center of gravity. Since the star is much heavier than the planet, it doesn't move much, but it does move, and modern instruments can measure the tiny Doppler shift in the star's light to get the motion of the star. Stellar evolution models tell us how heavy the star is and orbital mechanics tell us how heavy the planet is. (We can calculate the mass of double stars using orbital mechanics and the Doppler shift of each star's light, but we have no direct knowledge of the mass of single stars.) If the planet also happens to orbit in a plane parallel to our line of site, it will cross directly in front of the star once each orbit, like Venus sometimes crosses the face of our sun as seen from Earth. When it does, it blocks a small percentage of the star's light and the star looks slightly dimmer. If the star dims by 1%, then the disk of the planet has 1% the area of the disk of the star. Again, from stellar evolution models, we can deduce the diameter of the star and so get the diameter of the planet. (We can measure the diameter of some large, nearby stars, directly with the largest telescopes and adaptive optics, but for most stars we have no direct knowledge of their diameter.)\n\nThere is much more detail, but enough is enough, don't you think?
334761
Actually, there aren't as many solar systems as there are stars. Unlike our star, most stars are gravitationally bound to other stars, forming binary stars. So, most solar systems have multiple stars.
1005733
Since most people have either accurately or sarcastically answered your question, here is some fun things you can look for while planet gazing.  \n\nThe inner planets (Mercury & Venus) will show you phases the same as the moon has except when they get close to a full "planet" (like a full moon) they will be very close to the other side of their orbit and will be difficult to see due to being close to the sun.  The closer in the orbit crescents are more interesting anyway.  On the outer planets, Mars will be reddish with some darker parts and sometimes you can see the polar "ice" caps (said to be frozen carbon dioxide).  Jupiter (the largest) has the ongoing "red spot" (thought to be a giant storm) that passes around it.  Another interesting Jupiter tidbit is you can clearly and easily see four of its moons (which will change position from night to night) with just a moderately powerful telescope.   Saturn has, of course, it's rings which will be at different angles of view depending on what part of its orbit it's in.  The rest (Uranus, Neptune and Pluto) are very, very distant and extremely difficult to see with anything except very expensive equipment. \n\nAnd don't just focus on the planets.  There is a multitude of clusters , galaxys, multiple star systems and nebulae to check out (not to mention the occasional comet and meteor shower that comes now and then)\n\nHope you have fun with it...