Professor Lewin talks about some of the highlights from his early days at MIT. It began with balloon flights at very high altitude to make observations of the stars in X-rays. This led to discoveries of X-ray flaring events and a periodic X-ray source (GX 1+4). In the seventies and eighties he made important contributions to our understanding of X-ray bursts (thermonuclear fusion episodes on neutron stars). Note: Due to a serious sexual harassment complaint that occurred on the online learning platform edX, MIT has revoked Dr. Lewin's title of professor emeritus as of December 2014. See http://tech.mit.edu/V134/N60/walterle.... This lecture is part of 8.01 Physics I: Classical Mechanics, as taught in Fall 1999 by Dr. Walter Lewin at MIT. This video was formerly hosted on the YouTube channel MIT OpenCourseWare. This version was downloaded from the Internet Archive, at https://archive.org/details/MIT8.01F99/. Attribution: MIT OpenCourseWare License: Creative Commons BY-NC-SA 3.0 US To view a copy of this license, visit http://creativecommons.org/licenses/b.... More information at http://ocw.mit.edu/terms/. This YouTube channel is independently operated. It is neither affiliated with nor endorsed by MIT, MIT OpenCourseWare, the Internet Archive, or Dr. Lewin.