ÿþ<html> <head><title>Einstein's Relativity and the Expanding Universe</title> <meta http-equiv:"Content-Type" content="text/html; charset=utf-8"> </head> <body background="universe.jpg" bgcolor="black" text="#eeeeee" link="deepskyblue" alink="white" vlink="orchid"> <table> <tr> <td><a href="http://www.einsteinyear.org/"><img src="einstein.jpg" height=150 border="0"></a></td> <td width=100%><center><font face="helvetica, arial"> <font size=-1> english &nbsp;&nbsp; | &nbsp;&nbsp; <a href="index_ko.html">\Õm­´Å</a> </font> <h3>World Year of Physics 2005</h3> <h2>Public Lecture in Korean</h2> </font> <hr width="400" color="#330033"> </center> </td> <td><a href="http://www.wyp2005.org/"><img src="wyp05.jpg" height=150 border="0"></a></td> </tr> <tr> <td colspan="3" width="80%"> <center> <font color="yellow" face="helvetica, arial"> <i> <h1>Einstein's Relativity<br> and the Expanding Universe</h1> </i> </center> <!-- <br> <ul> <li>Bullet one <li>Bullet two <li>Bullet three </ul> --> </font> <br> <font face="helvetica, arial" size="+1"> <center> <table cellpadding="4" cellspacing="4" width=600> <tr> <td> <font size="+1"> Lecturer: </font> </td> <td> <font size="+1"> Professor <a href="http://www.physics.umd.edu/people/faculty/paik.html">Ho Jung Paik</a>, University of Maryland </font> </td> </tr> <tr> <td valign="top"> <font size="+1"> When:</td> </font> <td> <font size="+1"> Saturday, October 15, 2005, 3:00-4:30pm<br> (4:30-6:00pm: Tour of Gravitation and Cosmic Ray Labs) </font> </td> </tr> <tr> <td> <font size="+1"> Where: </font> </td> <td> <font size="+1"> <a href="#map">Univ. of Maryland, Physics Lecture Hall, Room 1410</a> </font> </td> </tr> <tr><td colspan="2"> <hr width="400" color="#330033"> </td></tr> <tr><td valign="top"> <font face="helvetica, arial"> <b>Synopsis:</b> </td> <td> Galileo argued that the laws of motion should look the same to a person in a vessel moving at a constant speed, as to a person standing on the ground. Such "principle of relativity" is also inherent in the laws of electromagnetism. This led to Einstein's special theory of relativity: For the speed of light, and all the laws of physics, to remain identical to all observers moving at different speeds, the time and spatial coordinates of a moving object, measured by an observer moving at a different speed, must depend on their relative speed. <br> <br> To modify Newton's law of gravity to be consistent with special relativity, Einstein extended Galileo's "universality of free fall": a hammer and a feather would fall exactly the same in the absence of air. Suppose you are in an elevator and suddenly the cable that supports the elevator is broken. Then you and the elevator will fall exactly the same and you will be in a "weightless" state (until you hit the ground). Einstein realized that the gravitational force can always be removed by going to a "freely falling frame." This led to his general theory of relativity: Gravity is just a curvature of spacetime produced by the mass of an object. <br> <br> One of the most striking predictions of general relativity is that our universe is expanding. The redshift of light from distant galaxies and the observed microwave background show that the universe was born some 140 billion years ago with a "Big Bang." According to the recent observations, the expansion of the universe appears to be accelerating, contrary to our previous expectations. As Einstein put it, "the Lord is subtle" but hopefully "he is not malicious." </td> </tr> <tr><td colspan="2"> <hr width="400" color="#330033"> </td></tr> <tr><td colspan="2"> <font face="helvetica, arial"> <table cellpadding="3" cellspacing="2"> <tr> <td colspan="2"> <b>Biosketch of the Lecturer</b> </td> </tr> <tr><td>1974</td> <td>Received Ph.D. at Stanford University</td> </tr> <tr><td>1978-</td> <td>Professor of Physics at the University of Maryland</td> </tr> <tr><td>2005-2007</td> <td>President of the <a href="http://www.akpa.org/">Association of Korean Physicists in America</a></td> </tr> </table> </td> </tr> </table> <br> <hr width="400" color="#330033"> <br> <a name="map"> <table><tr><td> <font face="helvetica, arial"> <b>Map and Parking</b> <br> <img src="campusmap_en.jpg"> </td></tr> <tr><td> <font face="helvetica, arial"> For detailed directions to the campus, see <a href="http://www.physics.umd.edu/visitors/directions.html"> http://www.physics.umd.edu/visitors/directions.html</a> or <a href="http://www.mapquest.com/directions/main.adp?go=1&do=nw&rmm=1&un=m&cl=EN&ct=NA&rsres=1&1a=&1c=&1s=&1z=&2a=campus+drive+and+regents+drive&2c=college+park&2s=md&2z=">get directions from MapQuest</a> </td></tr></table> <br> <hr width="400" color="#330033"> <br> <font face="helvetica, arial"> Hosted by <a href="http://www.akpa.org/">Association of Korean Physicists in America</a> and <a href="http://www.physics.umd.edu/">UMD Physics</a><br> Sponsored by <a href="http://www.kusco.org/">Korea-US Science Cooperation Center</a> and <a href="http://dc.koreatimes.com/">The Korea Times</a><br> <br> <!-- <font size=-1> Questions? Contact Ho Jung Paik at <a href="mailto:hpaik@physics.umd.edu?subject=RE%20October%2015%20Lecture">hpaik@physics.umd.edu</a> </font> --> </center> </font> </td> </tr> </table> </body> </html>