# Do superluminal shadows drop the local temperature on distant objects?

There are lots of examples online of the scenario of someone with sufficient machinery casting a shadow of their thumb on the moon. It's argued the shadow travels faster than light, instantaneously even, 'from one's thumb to the surface of the moon' but that this is not the transmission of information. I understand that I can't transmit morse code with a shadow to the moon, because the alternating light would need to travel at light speed, and I also understand that I can't locally cause information to move around between different locations on the moon. But surely the faster than light shadow is some sort of causal influence since the shadow would cause, even if ever so slightly, the temperature to drop wherever it's cast? If I told a lunar being beforehand that if it gets cast in shadow, that means bombs are coming his way, certainly that is some sort of superluminal one-way information is occurring?

• Stand up and spin around in a circle such that you return to your original position in one second. In a frame of reference fixed to your head the moon just traveled in a circular path of distance about 1.5M miles. So... the moon seemingly traveled at 1.5 million miles per second in the frame fixed to your head, which is almost ten times the speed of light! Does this violate the postulates of relativity or causality? No. It does not.
– hft
Commented Apr 12 at 20:58
• It's argued the shadow travels faster than light, instantaneously even No it isn't. Commented Apr 12 at 21:55
• This is a great example of an XY problem. The X question that’s emerged is about heat transfer in shadows. The original Y problem is a misunderstanding of what is and isn’t superluminal information transfer. Two things occurring in rapid succession with large spacing doesn’t constitute superluminal information transfer when the first doesn’t directly influence the second. Commented Apr 13 at 16:12