Which planet orbits the sun fastest?

[symbolite]

I don't mean which planet orbits in the quickest amount of time, i just mean which planet actually moves physically the fastest? <br /><br />Or maybe its the same order anyway from fastest to slowest because for some reason I imagine an object closer to the sun to move faster because of the gravity from the sun. Correct me if im wrong. This question has been bothering me all day. <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

Yes, the planets closest to the sun move the fastest.<br />In fact, since planet's orbits are not circular, each planet also moves the fastest when it is closest to the sun.<br /><br />It has even more of an effect with comets, whose orbits are very elliptical.<br />For example Halley's comet moves at<br />54.5 km/sec at perihelion (33.8 mi/sec, or 121,913 mph) (closest to the sun)<br />41.53 km/sec at 1AU (25.8 mi/sec, 92,900 mph)<br />0.9 km/sec at aphelion (0.52 mi/sec, 2013 mph)<br /><br />Meteor Wayne<br /><br />Edit to correct brain lockup re earth<br /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[hal9891]

Mean orbital speed of the planets (km/s): <br />Mercury - 47.8725<br />Venus - 35.0214<br />Earth - 29.7859<br />Mars - 24.1309<br />Jupiter - 13.0697<br />Saturn - 9.6724<br />Uranus - 6.8352<br />Neptune - 5.4778<br />Basicly, as you see closer the planet - faster it goes. <div class="Discussion_UserSignature"> <div style="text-align:center"><font style="color:#808080" color="#999999"><font size="1">"I predict that within 100 years computers will be twice as powerful, 10000 times larger, and so expensive that only the five richest kings of Europe will own them"</font></font><br /></div> </div>

 

[symbolite]

Thanks for the quick reply's. Im quite surprised that what i was thinking was actually right for once.<br /><br />If outer planets orbited at a quicker speed would that just cause their orbits to get larger? get flung out of the system? and if it slowed would orbits become smaller or even plummet toward the sun? <div class="Discussion_UserSignature"> </div>

 

[lukman]

<blockquote><font class="small">In reply to:</font><hr /><p> Basicly, as you see closer the planet - faster it goes.<p><hr /></p></p></blockquote><br /><br />Interestingly, for a galaxies. the further you are from the center, the fastest it goes -) <div class="Discussion_UserSignature"> </div>

 

[h2ouniverse]

In reply to:<br />"If outer planets orbited at a quicker speed would that just cause their orbits to get larger? get flung out of the system? and if it slowed would orbits become smaller or even plummet toward the sun? "<br />---------------------<br /><br />Yes.<br />Btw this is how we increase satellites orbit altitude, by accelerating them with a boost parallel to the speed direction. <br />Ec + Ep = orbit energy with Ec the cinetic energy (1/2.mv^2) and Ep the potential energy (mgh). By increasing Ec at time t you increase orbit energy, so some time later you enable exchanges between Ec and Ep (at perihelion Ep is low, Ec is high, at aphelion, Ep is high, Ec is low).<br /><br />Another example: a part of the spin energy lost by the Earth due to Moon's tidal effect is transferred to the Moon as an acceleration, resulting into a gradual increase of Earth-Moon distance.<br /> <br />Best regards.<br />

 

[arkady]

It is also good to keep in mind, that since the orbits aren't circular, but elliptical in nature, the velocity of the planets are not constant, but rather they speed up as they approach the focal points (the Sun) and slow down as they recede. Mars is a prime example in that this effect is so apparent. Some of the other planets describe almost circular orbits where as the eliptical nature is quite clear when it comes to Mars.<br /><br />Before Kepler it was thought that the planets described perfect circles, and it's a sobering thought that hadn't Tycho Brahe been so forsightful as to recommend the young Keppler to start his investigations with Mars and instead Mercury or Venus for instance, chances are that his famous laws could have escaped him altogether, as these elipses is so close to circular that he wouldn't have had much chance to identify what I described because the instruments of the time wasn't accurate enough. <br /><br />(Kepler's Laws and the story behind them would be a good place to start if you wan't to delve into this subject yourself) <div class="Discussion_UserSignature"> "<font color="#0000ff"><em>The choice is the Universe, or nothing</em> ... </font>" - H.G Wells </div>

 

[ashish27]

HAL, if i may ask, from where did you find these exact data?

 

[hal9891]

<blockquote><font class="small">In reply to:</font><hr /><p> HAL, if i may ask, from where did you find these exact data? <p><hr /></p></p></blockquote><br /><a target="_blank" href="http://en.wikipedia.org/wiki/Table_of_planets_and_dwarf_planets_in_the_Solar_System">http://en.wikipedia.org/wiki/Table_of_planets_and_dwarf_planets_in_the_Solar_System > http://en.wikipedia.org/wiki/Table_of_planets_and_dwarf_planets_in_the_Solar_System </a> <div class="Discussion_UserSignature"> <div style="text-align:center"><font style="color:#808080" color="#999999"><font size="1">"I predict that within 100 years computers will be twice as powerful, 10000 times larger, and so expensive that only the five richest kings of Europe will own them"</font></font><br /></div> </div>

 

[lukman]

<blockquote><font class="small">In reply to:</font><hr /><p> Not quite.<br />It slows down as you move away from the center untill you so far out.<br />Then the velocity is roughly constant to the edge.<br />Hence the need for dark matter to balance the mass-velocity-gravity equasion. <p><hr /></p></p></blockquote><br /><br />I have the information from this link <div class="Discussion_UserSignature"> </div>

 

[ashish27]

thanks <img src="/images/icons/smile.gif" /><br /><br />

 

[nyrath]

NASA Planetary Fact Sheets. All hail Planetary Fact Sheets.<br /><br />http://nssdc.gsfc.nasa.gov/planetary/planetfact.html<br />the orbital periods are here:<br />http://nssdc.gsfc.nasa.gov/planetary/factsheet/index.html