Why is the Rubik's Cube so Hard -- Episode 2


Uploaded by redkb on 19.11.2011

Transcript:
Hi! My name's Kenneth...
Here are some more thoughts I had on the Rubik's Cube.
Last time we looked at how many possible positions or permutations a Rubik's Cube could be twisted.
We found out that the answer is 43 quintillion.
We also found, that 43 quintillion is quite large.
Many people asked about the V-Cube 7. They wanted to know how many more positions are
in a 7x7.
Well let's compare the two.
First we'll start with a Rubik's Cube.
Last time we used a sheet of paper to represent a Rubik's Cube. This time we'll go smaller.
A standard Rubik's Cube is 57mm on each side.
Currently the smallest 3x3 in the world is the Elemental Cube. It's 8mm on each side.
But we need smaller for our calculations.
Let's imagine we have a machine that can shrink a Rubik's Cube down to the size of this....
A carbon atom.
Now we will see what 43 quintillion carbon atom sized Rubik's Cubes would look like.
Using high school chemistry we can calculate the mass of 43 quintillion carbon atoms. Remember,
even though 43 quintillion is a big number, atoms are small...
43 quintillion carbon atoms weighs in at .85 mg. That's about 1/7000th of my elemental
cube, or some shavings off of my pencil.
Now lets look at the V-Cube 7.
Lets do the same thing, only this time we'll use any atom, not just carbon.
The 7x7 has 19 duoquinquagintillion possible positions or permutations.
So what does 19 duoquinquagintillion atoms look like??
Well, it's more atoms than you would find in a Pencil.
More atoms than you would find in your house.
More atoms than you would find in the tallest building in the world.
More atoms than all the atoms in all the oceans of the earth.
More atoms than the earth and moon combined.
More atoms than our solar system.
More than our galaxy..
Even more atoms than all the atoms in the visible universe!!
If I were to stop here... I would be doing you a disservice.
If I stop now I will have failed at making an accurate comparison.
In fact to say there are more possible positions in a 7x7x7 than atoms in our universe would
be a vast understatement!!
You wouldn't need 2 or 3 universes full of atoms...
Not even 1,000 or a million would be enough.
You would need 10 to the power of 80 universes full of atoms...
That's a universe for each atom in this universe.
Remember that in all of these universes full of atoms, there is only 1 atom in 1 universe
that represents a solved 7x7. It's your job to find that atom.
So... What does this tell us?
This tells us that the difficulty of a puzzle is not determined solely on the number of
possible permutations.
If it were so, the V-cube 7 would be impossible.
I hope you enjoyed my video. It was a lot of fun to make.
If you like it you can click the like button or share it with a friend.
I do come out with new videos every other weekend so stay tuned for the next video.
Thanks guys for watching.
And of course have a great day!