an imaginary hole from one side to other...

[SLOW6]

<p>Hi, my first post on here.</p><p>&nbsp;Ive always wondered if anyone has figured out what would happen if you could drill an imaginary hole straight through the earth or any other planet I suppose. Perfectly from one side to the other going straight through the core to the other side. If you were to jump into this whole or even drop say a basketball, would the speed it picked up on the way to the centre over come the gravity pulling it back once it passed the centre? or would it be a perfect sort of pendulum motion and contantly fall from one side to the next forever??? or would it slow down and possibly compress???? This is of course assuming it or the person does not burn up under the intense heat etc ! </p><p>&nbsp;Just a random Q!</p><p>Thanks.. Gregg</p> <div class="Discussion_UserSignature"> <strong><em>In an infinite Universe, any point can be said to be the centre as there are an infinite number of stars either side of that point... </em></strong> </div>

 

[starsinmyeyes44]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Hi, my first post on here.&nbsp;Ive always wondered if anyone has figured out what would happen if you could drill an imaginary hole straight through the earth or any other planet I suppose. Perfectly from one side to the other going straight through the core to the other side. If you were to jump into this whole or even drop say a basketball, would the speed it picked up on the way to the centre over come the gravity pulling it back once it passed the centre? or would it be a perfect sort of pendulum motion and contantly fall from one side to the next forever??? or would it slow down and possibly compress???? This is of course assuming it or the person does not burn up under the intense heat etc ! &nbsp;Just a random Q!Thanks.. Gregg <br />Posted by SLOW6</DIV></p><p><font size="2" color="#0000ff">I actually watched a show on the Science Channel about this theoretical journey this last weekend.&nbsp; The trip would take 42 minutes.&nbsp; Here is some information I found just now.</font></p><h1 align="center">Journey through the center of the Earth</h1><table border="0"><tbody><tr><td><img src="http://sitelife.space.com/ver1.0/Forums/imgmech/eartholeb.gif" alt="" />

 

[starsinmyeyes44]

<p><font size="2" color="#0000ff">Oh...and welcome to SDC!<img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-smile.gif" border="0" alt="Smile" title="Smile" /></font></p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p><font color="#ff00ff">In the book of life, the answers aren't in the back.<br /></font><strong>Charlie Brown</strong></p> </div>

 

[neuvik]

The asthenosphere being the weakest of the earths mantle structure would fill the gap; convection currents of the earths mantle would fill in the hole in the ascending levels.&nbsp;&nbsp; From the hole would emerge the "neglected" extremly hot gases, steam, and molten rock.&nbsp;&nbsp; Hahah!&nbsp;&nbsp; Although the Science Channel makes it more fun with just having a hole and nothing to fill it up <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">I don't think I'm alone when I say, "I hope more planets fall under the ruthless domination of Earth!"</font></strong></p><p><font color="#0000ff">SDC Boards: Power by PLuck - Ph**king Luck</font></p> </div>

 

[SLOW6]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The asthenosphere being the weakest of the earths mantle structure would fill the gap; convection currents of the earths mantle would fill in the hole in the ascending levels.&nbsp;&nbsp; From the hole would emerge the "neglected" extremly hot gases, steam, and molten rock.&nbsp;&nbsp; Hahah!&nbsp;&nbsp; Although the Science Channel makes it more fun with just having a hole and nothing to fill it up <br />Posted by neuvik</DIV><br /><br />Yeah.. I was talking more theoretically, but thanks! </p><p>&nbsp;and thank you for the SDC welcome!!! </p> <div class="Discussion_UserSignature"> <strong><em>In an infinite Universe, any point can be said to be the centre as there are an infinite number of stars either side of that point... </em></strong> </div>

 

[origin]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I actually watched a show on the Science Channel about this theoretical journey this last weekend.&nbsp; The trip would take 42 minutes.&nbsp; Here is some information I found just now.Journey through the center of the EarthSuppose you could drill a hole through the Earth and then drop into it. How long would it take you to pop up on the other side of the Earth? Your initial acceleration would be the surface acceleration of gravitybut the acceleration would be progressively smaller as you approached the center. Your weight would be zero as you flew through the center of the Earth. For our hypothetical journey we will assume the Earth to be of uniform density and neglect air friction and the high temperature of this trip. For a spherically symmetric mass, the net gravity force on an object from that mass would be only that due to the mass inside its radius, and that would act as if it were a point mass located at the center. When this is analyzed in detail, you find that the gravity at any radius r less than REarth will be linearly proportional to the distance from the center. Gravity force of spherical shellOn mass outside the shellOn mass inside the shellTaking positive r as outward from the center of the Earth:This is the same form as Hooke's Law for a mass on a spring. It would cause the trans-Earth traveler to oscillate back and forth through the center of the Earth like a mass bobbing up and down on a spring. The angular frequency and period for this oscillation areFor this case the period of oscillation is The traveler accelerates toward the center of the Earth and is momentarily weightless when passing through the geometric center at about 7900 m/s or almost 17,700 miles/hr. The traveler would pop up on the opposite side of the Earth after a little more than 42 minutes. But unless he or she grabs something to hold on, they will fall back for a return journey and continue to oscillate with a round-trip time of 84.5 minutes. As a further feature of this fanciful journey, suppose a satellite could be put in a circular orbit about the Earth right above the surface. Ignoring air drag and the terrific sonic boom that would accompany such an orbit, suppose it passed overhead just above the falling person as they popped up out of the hole. The period of such an orbit would be such that it would be passing overhead every time the oscillating person popped up on either side of the Earth.The period of the orbit is calculated fromwhich is the same as the period of the oscillating body.http://hyperphysics.phy-astr.gsu.edu/Hbase/mechanics/earthole.htmlWell, the pictures didn't show up....so the link is above. <br />Posted by starsinmyeyes44</DIV><br /><br />That is of course neglecting any friction from the atmosphere or scrapping the side of the hole (ouch!). <div class="Discussion_UserSignature"> </div>

 

[neilsox]

<p>Rock pressure would squeeze your hole shut without an increadibly strong liner. Super thermal insulation is also desirable. We would need to blow a huge amout of cold air though the hole to&nbsp;cool the temperature. The air would be much denser near the center, due to weight of 6000 kilometers of air. To fall at high speed you would need to pump nearly all&nbsp;of the air out of the hole. With high vacuum in the hole you would need propulsion to avoid scraping the walls of the hole, as corriellus effect would cause you not to fall straight down. If you solve all these problems you would pass the center at several thousand miles per hour and coast to the surface of earth on the far side. Unless you got out of the hole you would fall repeatedly, forever, assuming no energy losses.</p><p>While present technology make this impossible, we could dig a straight tunnel about 1000 miles long. Vehicles would coast down hill to the center and be climbing the last half even though the tunnel is straight. The tunnel would be a cord of the Earth.&nbsp;&nbsp;&nbsp; Neil</p>