Hi folks There was a thread titled "Twin Paradox and Time Dilation" in the Astronomy sub-forum which was accidentally deleted by me while I was trying to handle a particularly nasty spammer. I have apologised to Rajesh for what happened and have informed the owners to see if there is anything they can do to salvage it. Normally I will remove a thread a spam thread from view and then delete it as a double check measure when it is on the same page as other normal non spam threads. Sadly this particular spammer had posted something which flagged every security software I have on my computer and everything lagged as I was trying to delete them as spam and next thing I know, the Twin Paradox thread disappeared from my screen. At a guess, someone posted as I was trying to click to delete the spam and because it froze my computer, Rajesh's thread was a casualty of my manic clicking to try to get my page unfrozen. I do apologise to everyone who posted in it and I have contacted the owners to see if it can be salvaged.