美国华盛顿大学Prof. Lawrence A. Crum学术讲座通知
讲座名称：
美国华盛顿大学Prof. Lawrence A. Crum学术讲座通知
讲座时间：
2014-09-17
讲座人：
Lawrence A. Crum
形式：
校区：
兴庆校区
实践学分：
讲座内容：
美国华盛顿大学Prof. Lawrence A. Crum学术讲座通知
讲座时间：2014.09.17 9:30-12:00
讲座地点：教二北楼308室
讲座人：Lawrence A. Crum
讲座内容：
1. Sonofusion: Star in a Jar?
Abstract: When a sound wave of moderate intensity is propagated through water, light emissions can be observed. This conversion of sound energy into light energy is called Sonoluminescence (SL) and represents an energy amplification per molecule of over eleven orders of magnitude. The discovery in our laboratory (J. Acoust. Soc. Am. 91, 3166-3183 (1992) that a single, stable gas bubble, acoustically levitated in a liquid, can emit optical emissions each cycle for an unlimited period of time stimulated considerable interest in this topic. Presumably, the oscillations of the bubble cause the gas in the interior to be heated to incandescent temperatures during the compression portion of the cycle. Because the lifetime of the optical pulse can be on the order of 50 picoseconds, it is likely that some rather unusual physics is occurring. One explanation for the short pulse length is that a shock wave is created in the gas which is then elevated to high temperatures by inertial confinement. If shock waves are the mechanism for SL emission, then optimization of the process has been speculated to lead to extraordinary physics, including thermonuclear fusion. Recent reports from Taleyarkhan, et al. (Science, vol. 295, 1868-1873, 2002; Phys Rev Lett. 2006 Jan 27;96(3):034301.) have even provided evidence for the nuclear emissions that should be associated with this phenomenon. Since this mechanism (thermonuclear fusion) is the energy source that drives our sun, one can even speculate that a miniature “star in a jar” has been created. A broad overview of this intriguing phenomenon will be presented as well a critical review of the potential for acoustic inertial confinement fusion.
2. Space travel, Special Relativity, Transhumanism, and the Singularity
Abstract: There was a recent TV Program in which Stephen Hawking described how one day humans would travel to planets on other stars and what they might find. I dug out my old Special Relativity Lecture Notes and did some calculations. First of all, I think Hawking is wrong; Humans will never travel to other star systems—physics, and physiology, doesn’t allow it. Then, I did some research on what serious futurists believe will be the technologies of the next one hundred, even one thousand years. My thesis in this lecture is that unless humans evolve beyond their present mental capabilities and physical limitations, humans as we now know them, will never travel beyond our own solar system, and, according, never find (by ourselves) other intelligent life forms. On the other hand, we could evolve into transhumans that might solve some of the challenges of intra-galactic space travel. Finally, there are those who have estimated when computers will have vastly superior “intellectual” powers to humans—the so-called “Singularity”—and what this might imply. This lecture is for general audiences, but may offend personal sensitivities.
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