Showing posts with label multiverse. Show all posts
Showing posts with label multiverse. Show all posts

Wednesday, August 5, 2015

Effective Mandela Theory

There are at least hundreds of thousands (or even millions) of people around the world who were shocked to hear that Nelson Mandela died recently.  Their shock wasn't that a world-famous civil rights advocate had passed away.  They were shocked because they thought
the man had died thirty years ago!

According to an impressively large number of people, Nelson Mandela originally died back in the 80s when he was in prison.  They remember seeing it on the news and hearing about riots that broke out all across South Africa.  It's a very specific memory, and a lot of people share it.  It didn't happen (apparently, anyway), but thousands and thousands of people insist on remembering Mandela's death in prison and the resultant riots, and their accounts are fairly uniform (as uniform as memories ever are, anyway).

Now, people misremember things all the time.  And usually, people can be pretty stubborn about what they remember, especially when it's two memories against each other.  But when presented with something like every single newspaper ever printed that contradicts their claims, most people relent and admit that they're wrong.  With Nelson Mandela's death, the people who swear he died earlier believe this memory so strongly that they will not let go of it, despite being contradicted by every relevant fact in existence.  It isn't because they're just that stubborn, or that stupid.  The memory has a certain quality to it.  For whatever reason, their brain refuses to discard it.

This sort of phenomenon has become known (for better or worse) as the Mandela Effect.  It is when a large number of people share and insist on a fairly cohesive counterfactual memory.

Monday, June 23, 2014

On the Berenstein Bears Switcheroo

Two years ago, I wrote a post about one of the icons of my childhood, the Berenstein Bears.  Except, as I learned, they aren't called the Berenstein Bears.  As it turns out, they're the Berenstain Bears.

BerenstAin.  With an "A".

My mind was blown.  I had very distinct memories of the bears.  I grew up reading their books and watching them on TV in school, and remember how it used to be spelled.  I tried to figure out when the name had changed.

Thursday, January 23, 2014

Everything Cool is Impossible

Physics has known for a long time how to build a time machine.  The possibility in a real spacetime geometry was first noted by Van Stockum, but this possibility was only really first analyzed by Frank Tipler in the 70's.  All you need is a massive rotating cylinder.  And also it has to be infinitely long.

This illustrates how frame dragging
can lead to time travel 
Since then, at least a dozen other possibilities have been proposed for time travel to the past, and physicists have proven that these spacetime geometries result in what are called "Closed Timelike Curves" (CTCs), which are trajectories a massive object could follow to go back in to its own past.  We know that they would work within the theory of General Relativity.  But, they're all impossible.  They either require the universe to be rotating (it isn't), they require infinitely large systems (we can't make them), they require negative-mass matter (no such matter exists), or they require you perform your time travel within the interior event horizon of a Kerr black hole (which is fine, but then you can't leave).

This situation is worse than merely having a concept of physics that excludes time travel, or that merely says that time travel is impossible.  For if time travel was excluded by theory, then we could always say the theory was incomplete.  What we have instead is a system that fully allows time travel possibilities without prejudice, as long as we're able to break some other law of physics to get there.  It's not just the stubborn "no" of a parental figure; it's like having your parents describe step-by-step exactly what you can do to eat chocolate cake for breakfast, and one of those steps is "eat infinite broccoli".

Physics also knows how to effect FTL travel.  The speed of light puts a prohibitive barrier on
our ability to explore the stars, but a number of work-arounds have been proposed.  Technically, relativity only prohibits local FTL movement, but says nothing of global FTL travel.  So if you can distort space and time in just the right way, you can move however fast you want.  One of the more frequently explored proposals is wormhole travel.    Wormholes produce a kind of "short cut" in spacetime, and it is actually a Federal Law that when you want to discuss how wormholes work you must draw two dots on a sheet of paper, "A" and "B", draw the straight line connecting them, then fold your paper so "A" and "B" touch and jab a pencil through it.  While going along the line you draw may take billions of years, going through the wormhole may take minutes.
My lawyers also recommend I show you this diagram

Sadly, you can't make a wormhole.  And even if you made a wormhole, the throat collapses when you try to travel inside of it, so you can't even use the wormhole for travel anyway.

Another proposal is the Alcubierre warpdrive.  This contracts spacetime in the front and expands it in the back, producing what some call a "wave" of spacetime contraction that "tips over" the light cones inside the warp bubble.  Locally, you're moving slower than light, but globally you may be moving, in theory anyway, as fast as you want.

But you can't make the Alcubierre warp drive either.  If you took the mass of the universe and made it negative, the Alcubierre warp drive requires ten times that number in negative-mass matter to move a standard-sized spaceship.   To clarify, we haven't even found one single particle of negative-mass matter.

Science knows how to make a Bag of Holding, and can even make a Bag of Holding that slows down time (see chapter 3 here).  You can store a lifetime supply of hot pies and ice cream in the same box, and whenever you take them out the pie is still oven-fresh and the ice cream still ice cold, and so even twenty years later you can serve yourself delicious pie a la mode.  But, like so many awesome things, it requires either negative mass or impossible mater distributions and can't be made.

I just made a post about how the Bag of Holding (aka, Van den Broeck Bubble) can be exploited to, potentially, travel to parallel worlds (if any even exist).  This one is a lot more speculative, requiring ideas way beyond established science, but is at least partially based in what we already know about general relativity and curved-space geometry.  It isn't really scientific, but if we wanted to know if there were other universes, this has potential to actually find them.  But it also requires not only negative mass, but infinitely much of it.  So we won't ever be able to try.

Pictured: A guy wearing a green screen.
Not Pictured: An invisibility cloak 
Science has pretty recently discovered (less than ten years ago) how to make a literal cloak of invisibility.  It involves bending light in just the right way.  We know what that just-the-right-way way is, and we even know how to make materials that bend light in just that way.  Sadly, it only works for a single frequency (i.e. color) of light at a time.  There's no way to be completely invisible, because there don't exist materials with  the right optical properties naturally.  So you can be green-invisible, but you'll still be perfectly visible in red and blue.  I guess you'll just look slightly more purple?

I recently calculated (as part of my research) how to make a slightly different kind of cloak, namely a shadow cloak.  Also something you'd read about in fantasy books, the shadow cloak works on the same spacetime distortion principle as for a black hole, but now modified to work with optical materials (so not requiring it be made of actual black holes).  A perfect realization  would allow light to enter, but trap it there.  If you were wearing it, you would appear to be not just covered in a black garment, but actually swathed in shadows.  (Look at a black object, then look at an unlit hole; there's a big visual difference)  You'd also probably heat up a lot (since all the energy is trapped), which would make this kind of material perfect for solar panels, increasing their efficiency probably to near 100%.  But you can't make the shadow cloak, because it requires material parameters that are both infinite and negatively infinite.  Like with the invisibility cloak, you can only realize this (if at all) for a single color of light at a time.  Which vastly diminishes its coolness.

You can probably see where my knowledge tends to specialize, but physics knows a lot more cool things in the quantum domain, such as teleportation devices and solutions to the P=NP problem.  All of which, we know how it would work, and only minor technicalities render it impossible.  Things like wavefunction collapse, quantum decoherence, and the no-cloning theorem.

Any time there's something cool in physics, there's something else that renders it impossible.

Again, this isn't the situation of wanting to do something incredible and merely lacking a theoretical model to describe it.  Our formulations of physics account for it exactly.

It's just that all the cool stuff is impossible.

More and more, it just seems like the Universe comes equipped with fail-safes against our ever doing the cool things of science fiction.

Tuesday, January 14, 2014

Sailing Away to Narnia

I stumbled upon an article a few months ago that I've been meaning to blog for a while and never got around to.

The original article is by Chris van den Broeck, and deals with the subject of warp drives.

Yes, warp drives.  The Alcubierre warp drive engine is a device that stretches the spacetime around a spaceship, forming what is known in scientific literature as the "warp bubble" (really, that's what we call it).  Within the warp bubble, the ship is moving at "normal speeds", but outside of the bubble, the ship is moving faster than the speed of light.  The geometry for this is known and well understood, and the means of producing it are also fully understood.

You're probably wondering, if we know how to make a warp drive, why we haven't actually... you know... made a warp drive.  And that's a wonderful question.  We haven't made a warp drive because it requires a lot of stuff that probably doesn't exist, namely negative energy mass.  It requires a whole lot of it.  Like, ten times the positive mass of the entire universe in negative mass.

Van den Broeck proposed an idea to get around this, one elegant in both its simplicity and apparent absurdity.

Here's what you do: Take a bag.  Distort space, so that the inside of the bag is bigger than the outside of the bag.  The inside is big enough to hold a spaceship, and the outside if around the Planck length.  Now stick your spaceship inside of the bag, and then put a warp bubble around the bag.   It requires a lot less negative energy.  Voila!  Crisis averted.
Schematic from original article.
Region II is the bag.
Region I is where the ship is.
Region IV is the warp bubble
Now, warp drives are cool of themselves, but what I really want to talk about is the device that distorts space so the inside of the bag is bigger than the outside of the bag.  This is sometimes called a "van den Brocek bubble", or, somewhat more appropriately, a Bag of Holding.

We've gone from warp drives to the bag of holding, and we're not even done yet.  We're going all the way to Narnia.

Tuesday, January 1, 2013

Why Travel to Hyperspace Would Instantly Kill You

So, I've wondered a lot about a way to construct a "system of magic" (as often appear in modern fantasy works) from a collection of physical laws.  And until I got carried up in classes last semester, that was one of my main focuses of attention.

I was thinking that, in an alternative universe, there's no reason why they should have the same number of spatial dimensions as us.  So why not four, or five, or ten?

Because if you traveled to four-dimensional space, then you would find your skin insufficient to contain all of the air, blood, half-digested food, and maybe even internal organs that now find an extra degree of freedom within which to diffuse.

Five and higher dimensions makes it worse; the many things inside of you that keep you alive would disperse and splatter even faster.

So far I have discovered that to have any sort of meaningful adventure in a parallel universe, it must have the same number of spatial dimensions as we do (namely 3), it must have at least one time-like dimension, the electromagnetic interaction must exist and must recognize and interact with your electrons and protons.  Gravity would be nice, and I don't know enough about weak and strong interactions to know if they would be necessary.

There are most likely other limitations and dangers in such fantastic travel that have not yet come to mind.

In short, the inter-universe questing of children from our universe can never be to any world truly alien from our own.  Which is very sad.

Thursday, August 23, 2012

The Berenstein Bears: We Are Living in Our Own Parallel Universe

if only facebook would make this the preview photoWhen I was growing up, all through elementary school we would watch movies and read books about the Berenstein Bears.  I still even remember the theme song for the TV show, mostly, which wasn't a song so much as a guy in a gruff bear voice speaking in rhyming couplets.  If you don't know who the Berenstein Bears are, they were nuclear family of anthropomorphic bears who lived in a tree out in Bear Country and had family-based situational comedy and taught life lessons.  And Ma Bear always wore a blue shower cap.

These bears appeared in a series of children books by the married Stan and Jan Berenstein, that later became a TV series, that got beamed to 3rd grade classrooms all over the country.  Anyone between the ages of 23-30, and maybe more, will know who the Berenstein Bears are.  And they will remember the flashy cursive bubble-letters on the front of every single book and in the opening credits of the show.  The bubble letters that spelled out "Berenstein Bears".

About a year ago, Jan Berenstein passed on, as had Stan some time before.  And appearing in headlines across the internet, I saw "Jan Berenstain Dies at 88".


They misspelled her name.  In her obituary.  Gosh, that's really just morbidly embarrassing.  "Berenstain" doesn't even make sense.