1
00:00:00,333 --> 00:00:02,369
It's called the ambipolar field

2
00:00:02,369 --> 00:00:04,671
and it's an agent of chaos.

3
00:00:04,671 --> 00:00:06,573
It's an electrical field.

4
00:00:06,573 --> 00:00:09,542
It begins at about 250km
above your head

5
00:00:09,542 --> 00:00:11,011
and it keeps going.

6
00:00:11,011 --> 00:00:14,614
The atmosphere up there is different
than the atmosphere down here.

7
00:00:14,614 --> 00:00:16,249
Thinner, right? There’s less of it.

8
00:00:16,249 --> 00:00:18,485
So, think about just one atom

9
00:00:18,485 --> 00:00:19,285
– here it is –

10
00:00:19,285 --> 00:00:21,721
the Sun shines on it
and it breaks off this electron.

11
00:00:21,721 --> 00:00:26,459
So, now we have this negatively charged
electron and this positively charged ion,

12
00:00:26,459 --> 00:00:29,195
and the two are attracted
towards each other.

13
00:00:29,195 --> 00:00:32,165
The electron would happily
escape all by itself,

14
00:00:32,165 --> 00:00:35,435
but the ion still feels
that big tug of gravity.

15
00:00:35,435 --> 00:00:38,138
So, as the electron tries to pull away,

16
00:00:38,138 --> 00:00:43,276
the electric force forms between the two
to restrain it to keep it from escaping.

17
00:00:43,276 --> 00:00:46,346
And it also helps pull the ion upwards.

18
00:00:46,346 --> 00:00:48,615
The field works in both directions,

19
00:00:48,615 --> 00:00:50,650
it is ambipolar.

20
00:00:50,650 --> 00:00:52,419
Imagine you're walking a dog

21
00:00:52,419 --> 00:00:55,422
and you've got a tiny tiny little dog
and it's pulling on a leash.

22
00:00:55,422 --> 00:00:57,424
That dog is going nowhere.

23
00:00:57,424 --> 00:01:00,427
This ion an electron pair
that you've been thinking about,

24
00:01:00,427 --> 00:01:03,963
they are only one in an
enormous sea of the ionosphere.

25
00:01:03,963 --> 00:01:08,101
But, overall, because gravity is
pulling down on the ions, it adds up.

26
00:01:08,101 --> 00:01:11,604
And over a large distance,
you get this field forming.

27
00:01:11,604 --> 00:01:14,808
It's like this conveyor belt that's
countering gravity

28
00:01:14,808 --> 00:01:18,078
and lifting the ions up
so they can escape to space.

29
00:01:18,078 --> 00:01:21,281
Which is why it may have had an impact
on the evolution of the atmosphere.