地平线系列：神秘的暗能量

<p>Horizon looks at dark energy - the mysterious force that is unexpectedly causing the universe&#39;s expansion to speed up. The effects of dark energy were discovered in 1998 but physicists still don&#39;t know what it is. Worse, its very existence calls into question Albert Einstein&#39;s general theory of relativity - the cornerstone of modern physics. The hunt for the identity of dark en...</p>