Immovable Object vs. Unstoppable Force … Who Wins?
Well … the first one doesn’t really exist in the scope of relativity, and the second one would result in the end of the universe. Another fun physics thought experiment from MinutePhysics!
On the Technical Explanation for Santa Claus's Ability to Deliver Presents Worldwide in a Single Night
Or, put more simply, how the heck does Santa hit hundreds of millions of homes and cover 122 million miles in a single night?
Their explanation involves a subterranean community of Norwegian exiles that have been independently evolving at the North Pole for centuries, development of “relativity clouds” in which they can control time and space relative to the outside world, molecular morphing in order to sneak into children’s homes via the tiniest cracks, an immense antenna network to listen to children’s thoughts, and nano-toy-makers to manufacture gifts on the spot.
What takes the jolly old guy six months in “Santa time” appears to happen in a blink of an eye to us! Basically, he’s like Einstein in a red suit.
It could happen.
Remember in Super Mario Brothers, how the music and time would speed up when you started running low on the clock? Well, here’s a new level of video game time-freakiness, all about relativity.
Strange things happen to our perception of the universe when we travel close to the speed of light (you know, if we could travel close to the speed of light). Special relativity, as worked out by Einstein and others, gives us plenty of weirdness when it comes to our perception of time and distance at those extreme speeds. MIT’s Game Lab has developed a game that simulates that experience. It’s called A Slower Speed of Light.
The closer we get to the speed of light, time slows down for us relative to someone watching us (“time dilation”), light shifts to red and blue, and the lengths of things contract in the direction we are moving. Weirded out yet? Ethan Siegel has a pretty good explanation of all those strange effects.
In the game, the object is to collect these orbs. As you grab each one, the speed of light slows down a bit. That means that you get closer and closer to traveling at the speed of light, and the game shifts the visuals and your movement to give you an idea of what that might feel like. It is not unlike a relativistic drug trip.
The game is available for Mac and PC. Pause the Halo and give relativity a whirl. It’s a video game that Einstein would have approved of!
(via Discovery News)
As is noted in the letter above, this is a universe in which the laws of special relativity declare that an object moving near the speed of light will experience time dilation, the relative slowing of time, compared to an observer.
This is also a universe that can not fully explain its expansion or what happened at the very moment at which it was formed, and therefore must invoke the idea that there are many universes, each existing like a bubble in a sudsy bathtub.
But even if the second is true, that there are many universes, perhaps an infinite number, I’m glad I live in the one where Carl Sagan wrote Timothy Leary a letter about the first.
“Just imagine if we had the same kind of freedom to move through time as we do to move through space.”
A favorite of sci-fi authors and movie directors, is time travel really possible? What are the scientific and philosophical implications? Dan Falk takes a look at what it would take to move forward through time (you know, faster than we already do), with input from H.G. Wells to Einstein.
He looks at whether moving backward in time could be possible in Part 2.
Bonus: This reminds me of my favorite Harry Potter link on the internet, ever: Temporal Anomalies in Harry Potter and the Prisoner of Azkaban.
(via Dan Falk)
Theoretical physicist Ronald Mallett has put himself on record that time travel will be figured out, despite the fact that most physicists don’t agree. It’s a nice idea, and while I’m skeptical that we will ever be able to accomplish the feat (wouldn’t we have received notification to that end by now?), the physics of how time is malleable is well accepted. It’s all about relativity.
So while you wait for you grandchildren to appear from thin air and tell you that we’ve figured it out, let Dr. Mallett explain Einstein’s time theories as part of the new EPIPHANY video series.
(via Boing Boing)
Source: Boing Boing
120 years ago this month, Hendrik Lorentz published his landmark paper that laid out the basis for “electron theory”. This was not proof of the electron as a particle, as that didn’t happen until 1897, thanks to J.J. Thomson.
Lorentz took the collected equations of James Clerk Maxwell and distilled their mess into simple rules of charge and motion. It laid the groundwork for Einstein’s special relativity, and allowed fields like materials and electronics to exist.
It was elegant work, a melding of a half century’s worth of varied influences and observations, distilled into simple equations that spawned entirely new fields of physics. A true collaboration of curiosity.
Einstein himself said of Lorentz: “For me personally he meant more than all the others I have met on my life’s journey.”
(via Scientific American. Of course, Lorentz would know that electrons look nothing like what I drew above.)
Continuing “Joe’s Answer Bag Week”:
This is kind of a science and english literature question. In Science Fiction novels, traveling at the speed of light causes time dilation. So time slows down for the person traveling, while time passes at the same rate for someone on Earth. Why is this? And is there any specific measurement? Like, would traveling 1 one light year mean that the amount of years passed on Earth be 10?
Even though I’m trained in biology, I don’t mind trying my hand at physics from time to time. I often do an okay job! This may be one of those times, or it may not.
Let me start by saying you could probably teach an entire physics class on this subject, so this will be hugely simplified. I’ve included as many links as I can for you to go learn more.
Time dilation actually exists outside of science fiction novels! Astronauts and atomic clocks have proven this. So this is much more than a literature question. It’s a well-proven tenet of Einstein’s theories of special and general relativity. Time dilation in general relativity actually has to do with gravity’s effects at various distances, and while it is also very real (GPS satellites must take it into account), I’ll leave it out and focus on special relativity.
Before we start, I’d like you to watch the following video. Pay close attention to the spaceships shooting lasers near 3:30 …
This example of special relativity is entirely based on the idea that the speed of light is the speed of light, no matter what. Odd things start happening when you travel close to c, as you saw in the video. Time slows down on the ship traveling close to the speed of light, relative to time being “constant” on the other one (which could actually be stationary in this example).
So, we can’t change the speed of light. But what can we change? Let’s say I’m sitting on an asteroid, asteroid-Tumblring away, and you pass me in a ship going near the speed of light. Looking through your window, I see your ship has a clock in it where light bounces between two mirrors.
To anyone in your near-light-speed spaceship, the pulses are traveling straight between the mirrors in a line. Easy physics, easy to measure time. But from my asteroid, I also have to take into account the motion of you whooshing by me, which makes it look like the light pulse traveled a longer distance. Since I can’t change the speed of light, I just have to assume that it took longer according to where I’m sitting. So time on the ship “slows” from my point of view. Look at this GIF and try to fill in the blanks:
Confused? Watch this clip from Carl Sagan’s Cosmos involving two Italian brothers and a mo-ped. Still confused? This minutephysics episode on special relativity might help too. Still confused?? Well, it’s really hard stuff. Don’t feel bad, just take it slow and start from the top.
The best part? We can calculate the dilation of time, thanks to some nifty math. Imagine if you hopped in your spaceship and rocketed away from Earth, instantly reaching a speed of 0.9999999999 times the speed of light (we’ll call this ”Ludicrous Speed”, or LS for short). For every day you travel at LS, nearly 194 years will pass on Earth. This is based on some simple but elegant math done by a guy named Hendrik Lorentz. Look here for more time dilation calculations.
That’s about as complicated a question as I can imagine explaining without a big budget, some animators and a green screen (which is why it took me a whole day to write out this answer). I’ll leave you with this: As we approach speeds infinitely close to the speed of light, we could travel across the whole known universe in one human lifetime!
If any physicists want to correct me, do so gently. :)