Is the Speed of Light Truly Constant in Deep Space?

[Twich]

Evidence has surfaced that the speed of light is not c in deep space. Is it true?

<<unacceptable link removed>>

 

[Dale]

No, it isn't. The source you cited does not meet PF's standards for legitimate references.

In particular, the Pioneer anomaly has a much more mundane explanation:
http://arxiv.org/abs/0901.4597

Note that this reference is peer-reviewed and meets the PF standards.