【龙腾网】有关黑暗森林理论的讨论，可怕的科学理论(6)
所以又如何呢？我在这里唯一看到的是基本的物理学：在三维空间中均匀传播的能量密度会按照距离的平方速度消减，所以如果你想要将它传递出去，所需要的能量将随着距离的平方而增加。在任何给定的频谱中，宇宙背景噪声的水平既不受发射机控制，也不受接收机的控制，因此，如果我们在广播一个非常微弱的信号，是宇宙限制了它能被“听到”的距离，而不是潜在接收者的技术。注意，“听到”的意思是“能够从背景噪音中被辨别出来”。
Ronald W. Garrison
Not really true. With a sufficiently large antenna or telescope mirror, you can get as directional as you want, and therefore can discriminate against noise as much as you want, and collect an arbitrarily large signal. However, there could be some limiting of how far this could be carried, because of the interstellar medium dispersing signals in frequency and time. At some wavelengths, interstellar debris could block some signals over long enough distances.
并非如此。如果有了足够大的天线或望远镜的反射镜，你就可以探测到任意方向的东西，因此可以尽可能地辨别噪音，并收集任意多的信号。然而，由于星际介质在频率和时间上分散了信号，这可能会限制它的传播距离。在某些波长上，星际碎片可以在足够长的距离内阻挡住某些信号。
John McCormick
That is not really true either. Propagation in free space is subject to the laws of quantum physics. We can’t even collimate a laser from Earth’s surface to a spot on the Moon smaller than a football field. Across the solar system it would be huge. Between stars it would be so attenuated that it would be invisible against the background radiation of the cosmos.
Ronald W. Garrison
Not really true. With a sufficiently large antenna or telescope mirror, you can get as directional as you want, and therefore can discriminate against noise as much as you want, and collect an arbitrarily large signal. However, there could be some limiting of how far this could be carried, because of the interstellar medium dispersing signals in frequency and time. At some wavelengths, interstellar debris could block some signals over long enough distances.
并非如此。如果有了足够大的天线或望远镜的反射镜，你就可以探测到任意方向的东西，因此可以尽可能地辨别噪音，并收集任意多的信号。然而，由于星际介质在频率和时间上分散了信号，这可能会限制它的传播距离。在某些波长上，星际碎片可以在足够长的距离内阻挡住某些信号。
John McCormick
That is not really true either. Propagation in free space is subject to the laws of quantum physics. We can’t even collimate a laser from Earth’s surface to a spot on the Moon smaller than a football field. Across the solar system it would be huge. Between stars it would be so attenuated that it would be invisible against the background radiation of the cosmos.
论肌肉猛0的自我修养
