MIT physicist Daniel Kleppner explains how matter changes as it is reduced in temperature and nears -459.67 degrees F, or absolute zero. br br Watch NOVA's "The Race for Absolute Zero," streaming online at a class="link" rel="nofollow" href=" br br Catch NOVA every Tuesday night on PBS. Or join us online at a class="link" rel="nofollow" href=" br br Absolute Zero is a production of Windfall Films Ltd. and Meridian Productions for TPTTwin Cities Public Television and WGBHNOVA in association with the BBC. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers.