relativity

Tag archives for relativity

Ask Ethan #17: The Burden of Proof

“Never waste your time trying to explain who you are to people who are committed to misunderstanding you.” -Dream Hampton Perhaps no word in the English language generates as much misunderstanding as the word theory. In scientific circles, this word has a very specific meaning that’s different from everyday use, and — as a theoretical…

“Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it.” -Terry Pratchett It’s the end of the week once again, and so let’s have a go at another Ask Ethan! Perhaps inspired by a great…

“I wouldn’t know a spacetime continuum or a warp core breach if they got into bed with me.” -Patrick Stewart It’s the end of the week once again, and so it’s time for another Ask Ethan segment! There have been scores of good questions to choose from that were submitted this month alone (and you…

“It followed from the special theory of relativity that mass and energy are both but different manifestations of the same thing — a somewhat unfamiliar conception for the average mind.” -Albert Einstein You’ve heard and seen it plenty of times: Einstein’s most famous equation, E = mc2. I’ve taken you inside this equation before, which…

Putting Einstein to the Test

“The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will…

“You wait for a gem in an endless sea of blah.” -Lawrence Grossman On the one hand, we have General Relativity, our theory of space, time, and gravity. It describes the Universe on both large and small scales perfectly, from the hot Big Bang to our cold accelerating expansion, from vast superclusters of galaxies down…

“There is no such thing as magic, supernatural, miracle; only something that’s still beyond logic of the observer.” -Toba Beta It might be hard to believe, but science tells us truths about the Universe that we might never have intuited or philosophized about if the Universe itself didn’t reveal them to us through investigation. Bap Kennedy…

Say Something Smart

“You must learn to talk clearly. The jargon of scientific terminology which rolls off your tongues is mental garbage.” -Martin H. Fischer I’ve always thought that the Universe is absolutely amazing; that everything from the tiniest indivisible particles all the way up to the largest structures and superstructures making up the Universe has an amazing…

Is Dark Energy the same as Acceleration?

In a comment on my last post, What is Dark Energy, Kendall asks the following, which is such a good one I think it deserves its own post: I thought the expansion was accelerating? Aren’t you saying that it is on its way down to 85% of its current rate? Sounds like expansion is slowing,…

Why doesn’t Light Age?

There’s a graduate student that I’m sort-of mentoring/working with at Arizona, named Xiaoying Xu (hi Xiao!). She’s bright and curious, and she asks some very good questions. She asked me one yesterday that’s pretty tough to wrap your head around: How do I explain to someone why light doesn’t age? Well, here on Earth, time…