尽管暗物质本身不会被照亮，也没有温度，不会发热，但它们会发光！当然，它们并不发射可见光，而是发射伽玛射线。暗物质粒子间相互碰撞会有一定几率发生湮灭反应，转化成伽玛光子。对一些大型行星，这种伽玛光子可能足够多从而使行星上保持液态水，进而孕育生命。

Dark Matter And The Habitability of Planets

Abstract: In many models, dark matter particles can elastically scatter with nuclei in
planets, causing those particles to become gravitationally bound. While the
energy expected to be released through the subsequent annihilations of dark
matter particles in the interior of the Earth is negligibly small (a few
megawatts in the most optimistic models), larger planets that reside in regions
with higher densities of slow moving dark matter could plausibly capture and
annihilate dark matter at a rate high enough to maintain liquid water on their
surfaces, even in the absence of additional energy from starlight or other
sources. On these rare planets, it may be dark matter rather than light from a
host star that makes it possible for life to emerge, evolve, and survive.