Can you shoot a cannon ball fast enough to make it circle around the earth?

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Kewell

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<p>Can you shoot a cannon ball fast enough to make it circle around the earth?</p><p>Can it physically be done? What would keep it from flying out of our atmosphere? Our professor just brought up this topic, thought it was interesting.</p> <div class="Discussion_UserSignature"> </div>
 
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schmack

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Can you shoot a cannon ball fast enough to make it circle around the earth?Can it physically be done? What would keep it from flying out of our atmosphere? Our professor just brought up this topic, thought it was interesting. <br />Posted by Kewell</DIV><br /><br />All&nbsp; you would really need to do is figure out the correct amount of energy needed to lift it into orbit. Then it is, in effect, circling the earth except it is doing via the energy of free fall rather than the energy used to launch it. So Yes, imo, it can be done that way. </p><p>As far sas shooting a "cannon ball" ,which is a far from aero dynamic object, around the&nbsp;equator (i'll&nbsp;"assume you mean't the equator)&nbsp;would be nearly impossible. The circumference of the Earth at the equator is 40,075.16 kilometers (24,901.55Mi). So, as i don't have the time to do the maths today, maybe someone will be able to calculate the energy required to send say a 10-15 kg ball on a 40,000Km, in atmosphere, trajectory. </p> <div class="Discussion_UserSignature"> <p><font size="4" color="#ff0000"><font size="2">Assumption is the mother of all stuff ups</font> </font></p><p><font size="4" color="#ff0000">Gimme some Schmack Schmack!</font></p> </div>
 
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Saiph

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<p>Over the years I've run accross information on a canadian engineer that's designed, or trying to build, a giant artillery piece capable of launching micro-satallites into low earth orbit.&nbsp;&nbsp;&nbsp; The main problem isn't if it's physically possible, but no country has even considered letting him try to build the thing.</p><p>&nbsp;</p><p>So, if this guy isn't completely nutters, it is physically possible to use a cannon to launch objects into space.</p><p>&nbsp;</p><p>&nbsp;</p><p>Also, if you want an object to circle the earth, you basically have to get it beyond the atmosphere (or 99.99% of it anyway).&nbsp; Otherwise drag will either bring the object down, or burn it to cinders. </p> <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>
 
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MeteorWayne

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Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Over the years I've run accross information on a canadian engineer that's designed, or trying to build, a giant artillery piece capable of launching micro-satallites into low earth orbit.&nbsp;&nbsp;&nbsp; The main problem isn't if it's physically possible, but no country has even considered letting him try to build the thing.&nbsp;So, if this guy isn't completely nutters, it is physically possible to use a cannon to launch objects into space.&nbsp;&nbsp;Also, if you want an object to circle the earth, you basically have to get it beyond the atmosphere (or 99.99% of it anyway).&nbsp; Otherwise drag will either bring the object down, or burn it to cinders. <br />Posted by Saiph</DIV><br /><br />Also a single impulse that a cannonball reveives will result in an elliptical orbit with perigee at tha launch point, so be sure an duck later on! <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>
 
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CalliArcale

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Over the years I've run accross information on a canadian engineer that's designed, or trying to build, a giant artillery piece capable of launching micro-satallites into low earth orbit.&nbsp;&nbsp;&nbsp; The main problem isn't if it's physically possible, but no country has even considered letting him try to build the thing.&nbsp;So, if this guy isn't completely nutters, it is physically possible to use a cannon to launch objects into space.&nbsp;&nbsp;Also, if you want an object to circle the earth, you basically have to get it beyond the atmosphere (or 99.99% of it anyway).&nbsp; Otherwise drag will either bring the object down, or burn it to cinders. <br /> Posted by Saiph</DIV></p><p>That would be the late Gerald Bull.&nbsp; He was working on the HARP program (not to be confused with HAARP), a Canadian project to convert artillery pieces into rocket launchers.&nbsp; The idea was that the gun-launching system would serve as a first stage, theoretically converting an inexpensive sounding rocket into something capable of hitting very distant targets or even acting as an ICBM or satellite launcher.&nbsp; After some successful small-scale tests with existing artillery pieces and sounding rockets, the project was cancelled.&nbsp; Bull searched far and wide for more funding.&nbsp; Unfortunately for his future prospects, the person who ultimately sponsored his continued research was Saddam Hussein.&nbsp; Bull moved to Iraq and began work on the Iraqi Scud missile program, working to develop an indigenous variant based on clustered Scud-C rockets which could act as an ICBM or satellite launcher.&nbsp; He also worked on the Babylon Gun, a project shrouded in secrecy and whose ultimate aims remain unclear.&nbsp; Satellite launcher?&nbsp; Military weapon?&nbsp; It's not clear, in large part because it was never completed.&nbsp; Gerald Bull was shot to death as he left his apartment in Belgium in 1990.&nbsp; To this day, no one knows who ordered the hit.&nbsp; Some think the Mossad did it, because his contributions to Iraqi artillery made them much more threatening to Israel (and the Babylon Gun would likely have been able to shell Israel from deep within Iraqi territory).&nbsp; Some think Iran did it (since Bull's contributions also threatened Iran).&nbsp; Some even think Iraq did it, ordering his death to prevent him giving information to the Americans as the first Gulf War ignited.</p><p>Gerald Bull was not completely nutters.&nbsp;&nbsp; But he was not particularily wise, politically. </p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>
 
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derekmcd

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Can you shoot a cannon ball fast enough to make it circle around the earth?Can it physically be done? What would keep it from flying out of our atmosphere? Our professor just brought up this topic, thought it was interesting. <br /> Posted by Kewell</DIV></p><p>If we could ignore atmospheric drag, the drop rate of the cannon ball would have to be about 8 cm per kilometer which is about what the curvature of the earth is.&nbsp; Considering the cannon ball is going to drop at a rate of 9.8 meters per second.&nbsp; Again, ignoring atmospheric drag, this cannon ball would need a velocity of about 1225 kilometers per second.&nbsp; Of course, this is at sea level and assuming a circular orbit with no atmosphere.&nbsp;&nbsp; Factor in the atmosphere and the need for an elliptical orbit, the ballistics almost seem impossible in reality.&nbsp; I'm sure mathematically you could create an orbit, but I doubt we have any material to withstand the stresses of a single shot like a cannon. </p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>
 
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rubicondsrv

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<p>&nbsp;</p><p>light gas guns launch projectiles ay orbital velocity regularly.</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> </div>
 
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MeteorWayne

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Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;light gas guns launch projectiles ay orbital velocity regularly.&nbsp; <br />Posted by rubicondsrv</DIV><br /><br />Ah, but have they ever placed an object in orbit? :) <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>
 
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aphh

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<p>A rocket with multiple stages spends some 10 minutes to accelerate to orbital velocity. <br /><br />On a gun, the acceleration would need to happen inside the barrel of the gun, so the impulse would last only milliseconds.</p><p>As soon as the projectile leaves the barrel of the gun, it is no longer accelerating. So the force needed to give the required impulse in milliseconds would destroy both the barrel of the gun aswell as the projectile.</p><p>Let's assume for a moment, that the target orbit required orbital velocity of 7500 m/s (roughly equivalent to ISS orbital velocity). Not accounting for athmospheric drag (which would be a major issue) the projectile would need to survive an acceleration of some 765 G's (7500 m/s^2) / (9.8 m/s^2), assuming that the acceleration inside the barrel lasted one second.</p><p>This would make the barrel of the gun (7.500 m/s * 1 s) / 2 = 3.75 km long. Allowing 2 seconds for the acceleration would halve the G-forces, but made the barrel twice as long. </p>
 
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DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Can you shoot a cannon ball fast enough to make it circle around the earth?Can it physically be done? What would keep it from flying out of our atmosphere? Our professor just brought up this topic, thought it was interesting. <br />Posted by Kewell</DIV></p><p>Yes, if you go fast enough and neglect the effect of air resistance.&nbsp; But remember that the launch point, and initial launch direction are part of the orbit.&nbsp; So the perigee will be a tad bit low.&nbsp; As MeteorWayne said, be sure to duck.</p><p>As a practical matter orbit will not be achieved due either to launch at an angle that provides an orbit that intersects the Earth, or due to air resistance that prohibits a circular orbit at the height of the initial launch point.&nbsp; To mitigate the effect of air resistance you would need to launch at fairly high angle so as to leave the atmosphere quickly, but tht orbit would intersect the Earth.&nbsp; Launch parallel to the Earth, or nearly so would incur a lot of air resistance, and that is the reason that cannon shells do not travel further than they do.&nbsp; The velocity required for such a low orbit would be extremely high with correspondingly high air resistance.</p> <div class="Discussion_UserSignature"> </div>
 
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aphh

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<p>The projectile would need to be shot through the athmosphere at a steep angle, but after that there is no way to circularize the orbit by correcting the trajectory. Hence the cannonball would fall back to earth at orbital velocity.</p><p>I think this is approaching the idea of the Babylon Gun mentioned above. &nbsp;</p>
 
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skeptic

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Yes, if you go fast enough and neglect the effect of air resistance.&nbsp; But remember that the launch point, and initial launch direction are part of the orbit.&nbsp; So the perigee will be a tad bit low.&nbsp; As MeteorWayne said, be sure to duck.As a practical matter orbit will not be achieved due either to launch at an angle that provides an orbit that intersects the Earth, or due to air resistance that prohibits a circular orbit at the height of the initial launch point.&nbsp; To mitigate the effect of air resistance you would need to launch at fairly high angle so as to leave the atmosphere quickly, but tht orbit would intersect the Earth.&nbsp; Launch parallel to the Earth, or nearly so would incur a lot of air resistance, and that is the reason that cannon shells do not travel further than they do.&nbsp; The velocity required for such a low orbit would be extremely high with correspondingly high air resistance. <br /> Posted by DrRocket</DIV></p><p>Actually the path of the projectile will be an ellipse with the center of the earth at one focus.&nbsp; The perigee will always be inside the earth. </p>
 
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DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Actually the path of the projectile will be an ellipse with the center of the earth at one focus.[/Quote]</p><p>true</p><p>&nbsp;Replying to:<BR/><DIV CLASS='Discussion_PostQuote'> will always be inside the earth. <br />Posted by skeptic</DIV></p><p>Not true.&nbsp; That depends on the orbit and most particularly the speed at which the projectile is launched.&nbsp; If you go fast enough then the orbit will be sustainable (neglecting air resistance as originally stated.)<br /></p> <div class="Discussion_UserSignature"> </div>
 
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silylene old

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>That would be the late Gerald Bull.&nbsp; ...</p><p>Posted by CalliArcale</DIV><br /><br /><em>NOVA</em>&nbsp; had a show on him, shortly after Mossad (?)&nbsp;or maybe the Iranians assassinated him.&nbsp; Gerald Bull had a project with the US military in the 60's which succeeded in firing projectiles about 250 km high, and other projectiles from Florida clear across the Carribean to land hundreds of km downrange.&nbsp; Bull had plans which he convinced Canada, and later Iraq, to finance putting a shot into orbit.&nbsp; His supergun in Iraq was captured and disassembled and is in display in a museum somewhere.&nbsp; It would have been capable of hitting targets anywhere in Isreal and iran.</p> <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>
 
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