摘要：Newton力学认为在宇宙中速度没有上限，而Einstein的狭义相对论（SR）却规定了上限。按照SR，高于光速的速度没有存在的可能。对带电粒子的加速表明，接近光速时质量增加很大，为了小的增速需输入很多能量。故在美国Stanford直线加速器中电子速度只能达到0.9999999c。但这仅为用电磁方法对带电粒子加速的情形。理论和实验均已证明，可以设法驱动不带电的光子，使它以超光速运动。

自然界有4种基本的物理作用，在电磁作用（光作用）之外还有3种。故不能说光速c是宇宙中的速度上限。例如，“引力以光速传播”的假定就是错误的，美国天文学家已指出引力传播速度可大于2×10¹⁰c，即达6×10¹⁵km/s以上。如果不用化学燃料推进火箭，亦摆脱电磁原理，而是以引力原理设计推进系统，人类有可能以极高速度航行，有望乘飞船到达宇宙中的任何地方。

在对1962~2008年间的超光速研究作审视后，我们认为超光速是一种可实现的科学陈述。例如，物理学家建议改变邻近飞船处的空间特性以实现超光速航行。目前的地外文明探索的突出成果之一是发现了太阳系外行星Gliese-581c，它与地球相似而成为宜居星球，但距地球20.5光年（1.89×10¹⁴km）之远。用束芯反物质火箭到该处需40年，用超空间引擎只需几秒。我们可以想象前往别的太阳系，但必须有概念新颖的火箭才能到达该处。

关键词：宇宙航行学；超光速宇宙航行；超光速宇宙飞船；地外文明探索

收稿日期：2009-07-06  修订日期：2009-08-11

作者简介：黄志洵（1936- ），男，北京市人，中国传媒大学教授、博士生导师，中国科学院电子学研究所客座研究员。

推荐语：

    黄志洵教授的文章“超光速宇宙航行的可能性”是长期思考和研究的成果。2004年他参与了宋健等发起的以“宇航科学前沿与光障问题”为主题的第242次香山科学会议。在会上宋健作了题为“航天、宇航和光障”的主题评述报告，并提出超光速宇宙航行的观念。黄教授的文章就是从科学观点来分析其可能性及对科学技术发展可能起到的推动作用。很有启发性，本人强烈推荐发表。

推荐人：曹盛林

曹盛林，北京师范大学天文系教授,从事相对论天体物理的教学科研，发表有关论文百余篇。

Possibility of Faster-than-Light Travelling in Universe

Huang  Zhixun

(Communication University of China, Beijing 100024)

Abstract: Newtonian mechanics imposes no maximum upper limit to attainable velocities in the universe, but Einstein’s special relativity（SR）theory does.  According to the SR, velocities greater than that of light have no possibility of existence. As charged particles are pushed up near the speed of light(c), they grow heavier and more energy input is required to gain a smaller increment of increased velocity. For example, the Stanford Linear Accelerator electrons reached only 0.9999999c. But it’s the electro-magnetic method of charged particles acceleration. Theoretical and experimental facts have proved that it’s possible to drive a photon traveling faster than light.

We know that there are four basic physical interactions in nature, three actions unlike the electro-magnetic action, i.e. light action. And so, we can’t say that the light speed(c) is the velocity upper-limit of universe. For example, the assumption “gravity propagates at the speed of light” is wrong. The U.S. astronomer showed that the speed of gravity greater than 2×10¹⁰c, i.e. greater than 6×10¹⁵km/s. If we can produce a propulsion system based on gravitational principles rather than electro-magnetic or chemical ones, we could travel at absolutely enormous speeds——we could hope to push a space-craft anywhere in the universe.

After rethinking superluminal research in year 1962~2008, we obtain the conclusion that “fater than the speed of light” is a realizable scientific statement. Physicist has suggested that the ability of a spacecraft to modify the properties of space in its immediate vicinity could allow it to travel faster than light. Now, the Gliese-581c is the first terrestrial extrasolar planet discovered in the habitable zone surrounding its star, where surface temperature might be similar to those on earth, and therefore be suitable for life. The distance to earth is 20.5 light years, i.e.1.89×10¹⁴km  away. Using the beamed core antimatter rocket, the approximate time to Gliese-581c is 40 years. If we use the super-space engine, the time is a few seconds. So we can fancy a trip to another solar system, but we need a pretty revolutionary kind of rocket to get there.

Key words: astronautics; faster-than-light travel; faster-than-light spacecraft; search for extra-terrestrial intelligence