Tag Archives: light year
We’re finally sliding into home plate in this series (it’s baseball season, so I get to use baseball metaphors now). After spending a lot of time looking into how Special Relativity works, we’re able to at last explore how it applies to the idea of faster-the-light travel.
Last time we saw that FTL radio seems hopeless — at least at communicating between frames of reference in motion with regard to each other. It’s possible there might be a loophole for FTL communication between matched frames. (If nothing else, it may be fertile background for some science fiction.)
Today we examine the idea of FTL motion — of “warp drive!”
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2 Comments | tags: ansible, Cougar Town, faster than light, FTL, light, light speed, light year, science fiction, Special Relativity, speed of light, warp drive | posted in Physics
Over the last five weeks I’ve tried to explain and explore Einstein’s Theory of Special Relativity. We’ve seen that motion, velocity, simultaneity, length, and even time, are all relative to your frame of reference and that motion changes the perceptions of those things for observers outside your frame.
All along I’ve teased the idea that the things I’m showing you demonstrate how the dream of faster-than-light (FTL) travel is (almost certainly) impossible. Despite a lot of science fiction, there probably isn’t any warp drive in our futures.
Now it’s (finally) time to find out just exactly why that is.
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7 Comments | tags: ansible, causality, causality violation, Ender's Game, faster than light, frame of reference, FTL, light, light speed, light year, Orson Scott Card, science fiction, simultaneity, Special Relativity, speed of light, Ursula Le Guin | posted in Physics
Last time we saw that Em non-paradoxically time-travels over three years into Al’s future by flying 12 light years at half the speed of light for just over two decades. Her journey completed, Em has aged only 20.8 years while Al has aged 24.
That may not seem like much of a gain, but Em was only moving really fast — not really, really fast. If she travels at 99% of light-speed, her round trip shortens to 1.7 years while Al doesn’t wait much longer than it takes light to make the six light-year round trip: 12.12 years! And at 99.9% c, Em’s whole trip takes her only half a year!
Today we break down dime tilation. I mean, time dilation!
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6 Comments | tags: Albert Einstein, Emmy Noether, gamma factor, length contraction, light speed, light year, space-time, Special Relativity, speed of light, time, time dilation, Twins Paradox | posted in Physics
So far this week we have Em taking a round-trip to planet Noether at half the speed of light. Upon her return she discovers that, while she’s aged 23.8 years, Al (who stayed home on Earth babysitting Theories) has aged 27. It took her well over twenty years to do it, but Em effectively traveled 3.2 years into the future.
Last time we saw that — so long as Em is in constant motion — there is symmetry between Al and Em with regard to who is moving and who isn’t. Both can claim the other is (or they are). Both views are valid. Until Em stops. Or starts, for that matter.
Today we look at Em’s “time shadow” — it’s a key to the puzzle!
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Leave a comment | tags: Albert Einstein, Emmy Noether, length contraction, light, light speed, light year, space-time, Special Relativity, time, time dilation, time-space diagram, Twins Paradox | posted in Physics
Last time we watched friend Em make a six light-year trip to planet Noether while friend Al stays home on Earth working on Theories. It turns out that Al ages 27 years while Em ages only 23 (point 8). This is not due to special diet, but to Special Relativity slowing Em’s clock on account of her fast motion through space.
We also saw that once Em stops at Noether, this breaks the symmetry of the two valid points of view regarding their motion (Em and ship are moving vs Al, Earth, and space, are moving).
Today we examine the trip before that point, while it is symmetrical.
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5 Comments | tags: Albert Einstein, Emmy Noether, length contraction, light, light speed, light year, space-time, Special Relativity, time, time dilation, time-space diagram, Twins Paradox | posted in Physics
We’ve covered a great deal of ground in the last four weeks. (Writing a series of posts this long is a new experience for me! I hope you’re getting something out of it, too.) We’ve learned that motion, velocity, simultaneity, and length, are all relative to your frame of reference — motion changes your perception of these things. This week we’ll see that time is also relative — motion changes that, too!
So far, we only needed a (very imaginary) train to demonstrate the effects of Special Relativity. An Earthly frame of reference was enough to illustrate how motion affects velocity, simultaneity, and length.
But when it comes to time, we’re gonna need spaceships!
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51 Comments | tags: Albert Einstein, cosmic rays, Emmy Noether, length contraction, light speed, light year, muon, space-time, Special Relativity, time, time dilation, time-space diagram, Twins Paradox | posted in Physics
It’s Friday, and I’m sure you’re thinking about the weekend, so today will be just a review and some more details about the speed of light.
And speaking of light, today is the Vernal Equinox. For the next six months (for those of us in the northern hemisphere), our days will be longer than our nights. No doubt the combination of spring, the Equinox, and the weekend, have you wondering what you’re doing at your computer reading about Special Relativity.
I’ll try to be very brief…
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8 Comments | tags: Albert Einstein, equinox, Galilean invariance, Galileo Galilei, light, light speed, light year, moon, Special Relativity, spring equinox, Sun, vernal equinox | posted in Physics
It’s party time! Friday night, and everything’s right.
For your consideration, there’s celebration in the air (that’s no exaggeration). We’re talking ’bout elation; lookin’ for participation. Ya gotta feel the situation. Join with the recreation; enjoy the circulation (and the conversation).
Listen to that good vibration, trackin’ jubilation destination. Forget your reputation; forget your moderation; ain’t no humiliation (that’s a stipulation). There’s no registration, no identification authentication.
I’m sure it’s no revelation; fermentation fascination will bring inebriation (and hallucination). Hesitation just won’t do; you have an invitation! There is no limitation at this here presentation.
That was my narration; how ’bout a small ovation?
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26 Comments | tags: beer, celebrate, Champagne, galaxy, Kessel Run, light year, Milky Way, parsec, Pluto, Sol, solar system, sun sign | posted in Brain Bubble, Life
Logos con carne 