Trek at 50: The quest for a unifying theory of time travel in Star Trek by Xaq Rzetelny [Ars Technica] [more inside]
"At some time in the future humanity will embark upon the most distant and most important journey it is ever likely to take. It will be necessary to travel 4.6 billion years into the past to complete a massive engineering project to create Earth's Moon." Who Built the Moon?
The concept of time as a way to measure the duration of events is not only deeply intuitive, it also plays an important role in our mathematical descriptions of physical systems. For instance, we define an object’s speed as its displacement per a given time. But some researchers theorize that this Newtonian idea of time as an absolute quantity that flows on its own, along with the idea that time is the fourth dimension of spacetime, are incorrect. They propose to replace these concepts of time with a view that corresponds more accurately to the physical world: time as a measure of the numerical order of change.
DRUNK SCIENCE! Or, a short story about time travel, evolution, and ska. (SLYT, NSFW language, brief pedobear imagery) [more inside]
Rules for Time Travelers [Spoiler? alert.]
A Guide to Science Fiction Chronophysics, a serious look at some of the hard questions ignored in soft-science fiction and fantasy. While we wish some time lines had never come to pass, or would go back in time and shake hands with themselves, there are circumstances that can lend themselves to great deal of fun.
Just how plausable is time travel? Could you go back in time and kill your own grandfather?. Would you want to? Time travel is a popular subject for films, but do the writers work out exactly what is happening? Current opinion seems to be that time travel is only possible to the future, and is only one way, by travelling at near light speed. However despite this, time machines seem to already be on sale.