标题： 在行星、小行星以及地球上寻找小型原初黑洞 显示英文标题

标题： Searching for small primordial black holes in planets, asteroids and here on Earth

摘要： 小的原初黑洞可能被岩石行星或小行星捕获，从内部消耗它们的液态核心并留下空心结构。 我们计算了围绕黑洞的空心结构的表面密度和表面张力，并将其与自然中出现的各种材料的密度和抗压强度进行比较，以确定允许的参数空间。 例如，花岗岩或铁可以支撑大小达到$0.1 R_\oplus$的空心小行星/行星状天体/卫星。 同样，未来的文明可能在黑洞周围建造球形结构以获取其能量。 使用我们目前知道如何制造的最强材料（多壁碳纳米管），为了承受一倍太阳质量黑洞的引力，外壳必须在距离大于$10^4 R_\odot$的地方构建。 或者，快速移动的黑洞在穿过固体物体时可能会留下一条狭窄的隧道。 例如，一个$10^{22}$克的黑洞应该会留下半径为$0.1$微米的隧道，这足以被光学显微镜看到。 我们可以在地球上非常古老的岩石中，甚至在非常古老的建筑中的玻璃或其他固体结构中寻找这样的微小隧道。 虽然我们的估算表明找到这些隧道的概率非常小，但寻找它们不需要昂贵的设备和长时间的准备，而回报可能是巨大的。 显示英文摘要

摘要： Small primordial black holes could be captured by rocky planets or asteroids, consume their liquid cores from inside and leave hollow structures. We calculate the surface density and surface tension of a hollow structure around a black hole and compare them with the density and compressive strength of various materials that appear in nature to find the allowed parameter space. For example, granite or iron can support a hollow asteroid/planetoid/moon of the size of up to $0.1 R_\oplus$. Along the same lines, future civilizations might build spherical structures around black holes to harvest their energy. Using the strongest material that we currently know how to make (multiwall carbon nanotube), to withstand gravity of one solar mass black hole, the shell must be constructed at distances larger than $10^4 R_\odot$. Alternatively, a fast black hole can leave a narrow tunnel in a solid object while passing through it. For example, a $10^{22}$g black hole should leave a tunnel with a radius of $0.1$ micron, which is large enough to be seen by an optical microscope. We could look for such micro-tunnels here on Earth in very old rocks, or even glass or other solid structures in very old buildings. While our estimate gives a very small probability of finding such tunnels, looking for them does not require expensive equipment and long preparation, and the payoff might be significant.