1
00:00:00,000 --> 00:00:06,720
How do aerosols affect our health?

2
00:00:06,720 --> 00:00:08,240
What is remote sensing?

3
00:00:08,240 --> 00:00:12,840
Name and describe the two types of remote sensing and give examples of each.

4
00:00:12,840 --> 00:00:17,680
How are aerosols in the atmosphere measured?

5
00:00:17,680 --> 00:00:20,760
Studying the atmosphere is a fairly new science.

6
00:00:20,760 --> 00:00:25,160
In the chemistry and dynamics branch of NASA Langley Research Center, atmospheric scientists

7
00:00:25,160 --> 00:00:31,120
are trying to determine how many aerosols there are and where they are in the atmosphere.

8
00:00:31,120 --> 00:00:34,920
Now these aerosols are important because they affect our health.

9
00:00:34,920 --> 00:00:38,900
Small aerosols can enter our lungs as we breathe polluted air.

10
00:00:38,900 --> 00:00:44,120
These aerosols can be deposited deep in our lungs, blocking the lungs' ability to exchange

11
00:00:44,120 --> 00:00:46,560
oxygen and carbon dioxide.

12
00:00:46,560 --> 00:00:49,400
Over time, this makes it hard to breathe.

13
00:00:49,400 --> 00:00:54,960
Here at NASA Langley, we measure aerosols using a technique called remote sensing.

14
00:00:54,960 --> 00:00:57,160
What is remote sensing?

15
00:00:57,160 --> 00:01:00,640
Remote sensing is collecting information about an object without physically touching the

16
00:01:00,640 --> 00:01:01,640
object.

17
00:01:01,640 --> 00:01:04,000
It's learning without touching.

18
00:01:04,000 --> 00:01:09,720
The most familiar kind of remote sensing is the use of our eyes to detect a distant object.

19
00:01:09,720 --> 00:01:12,560
We also learn without touching when we hear.

20
00:01:12,560 --> 00:01:18,360
For example, when a car beeps its horn, we hear it from a distance and sense we're in

21
00:01:18,360 --> 00:01:19,360
danger.

22
00:01:19,360 --> 00:01:20,680
Get out of the street!

23
00:01:20,680 --> 00:01:25,400
So now, there are two types of remote sensing, active and passive.

24
00:01:25,400 --> 00:01:29,400
An early example of passive remote sensing involved the use of a camera.

25
00:01:29,400 --> 00:01:35,520
In 1858, the first aerial photograph of land was taken from a balloon floating over Paris,

26
00:01:35,520 --> 00:01:36,520
France.

27
00:01:36,520 --> 00:01:40,640
This is called passive because the camera uses only the light from the sun to record

28
00:01:40,640 --> 00:01:42,560
the image on film.

29
00:01:42,560 --> 00:01:46,680
On the other hand, active remote sensing uses its own light source.

30
00:01:46,680 --> 00:01:51,200
Put a flash on the camera and you've made it active because the light from the flash

31
00:01:51,200 --> 00:01:54,720
reflects off the distant object being photographed.

32
00:01:54,720 --> 00:01:58,560
Using active remote sensing, you can take pictures whenever you want because you don't

33
00:01:58,560 --> 00:02:00,720
have to depend on the sun to give you light.