I think I've mentioned this before, but I'm just going to post it and close the tab.

https://www.researchgate.net/publication/297527784_Challenge_to_the_Special_Theory_of_Relativity [www researchgate net]

Someone has a challenge to the Special Theory of Relativity. If the challenge stands, it could overturn both Einstein's Special Relativity theory and the General Relativity theory built upon it.