0:00:17.479,0:00:20.063
"Hey, another atom.[br]I'm hydrogen, nice to meet you.

0:00:20.063,0:00:22.033
How are you feeling about the jump?"

0:00:22.033,0:00:24.955
"Hi there, I'm antihydrogen,[br]your antiatom,

0:00:24.955,0:00:27.119
and to be honest, I'm feeling[br]kind of neutral.

0:00:27.119,0:00:31.509
My positron and antiproton balance out,[br]just like your electron and proton, right?"

0:00:31.509,0:00:34.504
"Hey, yeah! You look just like me,[br]but different somehow."

0:00:34.504,0:00:38.498
"Whoa, be careful! If we get too close,[br]we'll disappear in a spark of energy.

0:00:38.498,0:00:40.256
I'd like to stay in one piece."

0:00:40.256,0:00:41.403
"Oh wow, sorry."

0:00:41.403,0:00:43.102
"It's okay. I was just thinking,

0:00:43.102,0:00:44.081
it's kind of weird for us to be

0:00:44.081,0:00:46.502
chatting like this before our [br]jump above CERN."

0:00:46.502,0:00:47.486
"Why's that?"

0:00:47.486,0:00:50.010
"Well, for starters, how do we know[br]we'll both fall?"

0:00:50.010,0:00:51.821
"Of course we'll fall. It's gravity,

0:00:51.821,0:00:54.224
you know, the force of attraction [br]between masses.

0:00:54.224,0:00:56.012
I even know how fast we should fall.

0:00:56.012,0:00:58.350
Galileo showed in that tower experiment

0:00:58.350,0:01:02.736
that all falling objects accelerate [br]at the same rate, regardless of mass."

0:01:02.736,0:01:04.535
"That's for bigger objects.

0:01:04.535,0:01:07.682
It's a different story [br]for small particles like us.

0:01:07.682,0:01:11.818
Our mass is so tiny that the gravitational[br]force we experience is miniscule,

0:01:11.818,0:01:16.526
and if the particles are charged, [br]like my antiproton or your proton,

0:01:16.526,0:01:18.697
then it becomes impossible to detect[br]

0:01:18.697,0:01:22.199
compared to the much greater[br]electromagnetic force acting on them."

0:01:22.199,0:01:25.468
"But that's only for charged particles.[br]You and I are both neutral.

0:01:25.468,0:01:29.029
Our charges balance out,[br]so the electromagnetic force is small

0:01:29.029,0:01:31.368
and the gravitational force[br]should be detectable.

0:01:31.368,0:01:32.921
I know mine's been measured."

0:01:32.921,0:01:36.019
"Because you're everywhere, [br]but I'm kind of hard to find."

0:01:36.019,0:01:37.757
"Why is that, anyway?

0:01:37.757,0:01:38.977
Shouldn't there have been an equal amount

0:01:38.977,0:01:41.359
of matter and antimatter created[br]in the Big Bang?"

0:01:41.359,0:01:43.845
"You'd think so, but then all of[br]those particles

0:01:43.845,0:01:46.833
would have annihilated [br]each other into energy, remember?

0:01:46.833,0:01:49.284
And the Universe is obviously[br]full of matter.

0:01:49.284,0:01:52.304
No one knows why there is more matter[br]than antimatter,

0:01:52.304,0:01:55.088
which is why scientists[br]are so interested in studying me."

0:01:55.088,0:01:56.924
"So where do they find you anyway?"

0:01:56.924,0:01:59.200
"Actually, I was made in that [br]lab down there.

0:01:59.200,0:02:03.875
They needed an accelerator to make[br]my antiproton because it's so heavy,

0:02:03.875,0:02:05.487
just as heavy as your proton.

0:02:05.487,0:02:07.329
Getting my positron was easier.

0:02:07.329,0:02:10.230
It's much lighter, like your electron,[br]and there are materials

0:02:10.230,0:02:12.732
that naturally decay by emitting one.

0:02:12.732,0:02:15.494
Then they just had to put the two together[br]and they got me.

0:02:15.494,0:02:16.558
But it's only recently

0:02:16.558,0:02:18.042
that they've been able to keep me[br]

0:02:18.042,0:02:20.306
around long enough[br]to study my properties."

0:02:20.306,0:02:24.305
"And now they've sent you on this[br]jump with me. Hey, wait a minute."

0:02:24.305,0:02:28.041
"That's right. We're reenacting[br]Galileo's experiment,

0:02:28.041,0:02:31.901
but with matter and antimatter[br]instead of two objects made of matter."

0:02:31.901,0:02:33.356
"So what's going to happen?

0:02:33.356,0:02:35.101
Are you going to fall [br]upwards or something?"

0:02:35.101,0:02:36.578
"Only one way to find out!"