Albert Einstein's time machine
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"Albert Einstein's time machine" is a title based upon conjecture.
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Albert Einstein was working on a time machine when an accident brought him on board the Doctor's TARDIS. He believed that, when constructed, it would be superior to the TARDIS. Einstein believed that he had developed bionic fusion liquid, which he thought was the key to completing his machine. However, the Eleventh Doctor informed him that the liquid wasn't in fact bionic fusion liquid. (TV: Death is the Only Answer)