Tag Archives: spacetime

Time and Two Doors

In the last week or so I read an interesting pair of books: Through Two Doors at Once, by author and journalist Anil Ananthaswamy, and The Order of Time, by theoretical physicist Carlo Rovelli. While I did find them interesting, and I’m not sorry I bought them (as Apple ebooks), I can’t say they added anything to my knowledge or understanding.

I was already familiar with the material Ananthaswamy covers and knew of the experiments he discusses — I’ve been following the topic (the two-slit experiment) since at least the 1970s. It was nice seeing it all in one place. I enjoyed the read and recommend it to anyone with an interest.

I had a little trouble with the Rovelli book, perhaps in part because my intuitions of time are different than his, but also because I found it a bit poetic and hand-wavy.

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SR #X4: Matrix Spacetime

I was gonna give us all the day off today, honestly, I was! My Minnesota Twins start their second game in about an hour, and I really planned to just kick back, watch the game, have a couple of beers, and enjoy the day. And since tomorrow’s March wrap-up post is done and queued, more of the same tomorrow.

But this is too relevant to the posts just posted, and it’s about Special Relativity, which is a March thing to me (because Einstein), so it kinda has to go here. Now or never, so to speak. And it’ll be brief, I think. Just one more reason I’m so taken with matrix math recently; it’s providing all kinds of answers for me.

Last night I realized how to use matrix transforms on spacetime diagrams!

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SR #X3: Spacetime Interval

Speaking of Special Relativity, back when I wrote the SR series, one topic I left along the wayside was the concept of the spacetime interval. It wasn’t necessary for the goals of the series, and there’s only so much one can fit in. (And back then, the diagrams I wanted to make would have been a challenge with the tool I was using.)

But now that we’re basking in the warm, friendly glow of March Mathness and reflecting on Special Relativity anyway, it seems like a good time to loop back and catch up on the spacetime interval, because it’s an important concept in SR.

It concerns what is invariant to all observers when both time and space measurements depend on relative motion.

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SR #X2: Sorry, No FTL Radio

Earlier, in the March Mathness post, I mentioned Albert Einstein was born on March 14th. That’s also Pi Day, which deserved its own pi post (about pizza pi), so old Al had to wait for me to address a topic I’ve needed to address for several months.

To wit: Some guy was wrong on the internet.

That guy was me.

Back in 2015 (also celebrating Einstein’s birthday), I wrote a series of posts exploring Special Relativity. Near the end of the series, writing about FTL radio, I said (assuming an “ansible” existed) I wasn’t convinced it violated causality if the frames of reference were matched.

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Got Time?

For the last week or so, on a physics blog I follow, I’ve been part of a debate about the nature of time. It’s been interesting and fun, but the conversation has reached that point where folks are mainly maintaining their positions, and it seems that the matter has stalled.

Some of the on-going assertions bemused me so much, that I was about to tender one more rebuttal comment… When I remembered what a wiser person, “back in the day” (before the web), said about online debates: State your view. Support it further if you need to address points raised. But once you’ve covered it well enough, just stop. After that, you’re just wasting your time; it’s rare that anyone changes their mind on the internet. Including yours.

Fair enough. I can natter on about it to myself on my own blog, though…

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Thinking About Time

dog in the nowWe sometimes say that dogs are living in the now. Sometimes we say that of people who live in the moment and don’t think much about the future (or about the consequences). Whether we mean that as a compliment — as we generally do with dogs — or as an oblique implication of shallowness depends on the point we’re making.

There is the tale of the ant and grasshopper; it divides people into workers who plan for the future and players who live in the now. The former, of course, are the social role models the tale holds heroic. The grasshopper is a shifty lay-about, a ne’er do well, a loafer and a moocher, but that’s not the point.[1]

The point is our sense of «now» and of time.

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Existence and Consciousness

My recent post about how the Big Bang and “Let there be Light” seem equally fantastic to me triggered an interesting comment from a reader. A detailed response requires more elbow room than a comment allows, so here’s a follow-up article instead.

One of the points involved that our scientific ideas, no matter how inaccurate they may turn out to be, are at least based on evidence. And to the credit of science, when we recognize errors in our interpretation of the evidence, science changes to accommodate the new interpretation.

This has been, as I mentioned in that post, hugely successful. One of the failures of our spiritual metaphysics is that it clings to frameworks defined thousands of years ago and often stubbornly refuses to accommodate new information.

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Big Bang? Let there be Light?

In an earlier post, I wrote that:

The problem for any honest theist is,
“What if it isn’t true?”
The problem for any honest atheist is,
“What if it is true?”

Ultimately both represent ways of looking at the universe. There is no factual conclusion, no proof, about either one; both are matters of faith and belief.

Science can argue all it wants that the Logic and Scientific Method is superior to believing in an ineffable reality, but given all we do know and all we don’t know, in the end it is still just a worldview.

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