>> Well, today is Earth Day, it's an observance
that was originated in 1970
by then Wisconsin Senator Gaylord Nelson who wanted
to raise public consciousness about air and water pollution.
A lot of people look at that Earth Day as the start
of the modern environmental movement.
Well, since 1970, actually since before 1970,
NASA has had any number of missions that have been
up taking pictures of planet Earth.
One particular accomplishment has been the literally millions
of images that have been gathered by the men and women
who have had the rare opportunity
to be seeing the Earth from that unique point of view.
Joining us on this Earth Day is one of those astronauts to talk
about the point of view, Don Petit is a veteran
of almost more than year,
onboard the International Space Station, 161 days as a member
of Expedition 6, 193 days as a member of Expeditions 30 and 31,
plus another 16 days in space as a member
of Shuttle Mission STS126.
Just a guess, Don, how many photographs
of earth did you take in a year up there?
>> Oh gosh, as a crew on Expedition 30,
we took about a half a million pictures
and that doesn't count 20,000 some pictures we took
as a crew on STS126.
So in 16 days, we took over 20,000 pictures.
And then I think we took
about 50,000 pictures during Expedition 6 as a crew.
>> Did you have an interest in photography before you flew?
>> Oh, I've been interested in photography
since about the sixth grade when I got my first Brownie camera
that shot 120 film and I spent all my allowance doing film work
in a dark room so I could see these mysterious images appear
when you ran this film through the chemistry.
>> We've heard you and many of your colleagues try
to express what it is like to see earth
from that vantage point; I'm going to ask you to try to --
one more time, describe the view of earth that you get
from floating above it.
>> Okay, earth from space, you have the vantage point
of seeing detail on the length scale of half a continent
so you could be over Central Australia
and you could see both the East Coast and the West Coast
at the same time, that's the length scale that you could see.
You can't quite see that with the United States 'cause
that continent is stretched out a little bit more
but certainly the metaphor of being able to see structure
on the length scale of half a continent allows you
to see things that you can't see with your feet on the ground,
that you can't see from being in an airplane and from
that vantage point, you see different patterns,
different structure that is not visible when you get closer.
>> What parts of it, when you try to take all that in,
what are the parts of that view that attract your attention,
do you like to try to capture?
>> I like personally to use a wide angle lens on cameras
and do wide angle photography simply
because it takes advantage of being able to see earth
on the length scale of half a continent.
You can use our telephoto lenses, we've got a number
of them from 800 millimeters to 1200 millimeter telephoto lenses
and if you're really, really good, you can get pictures
that are almost as good as what you can get off of Google Earth.
And so from my perspective, I like to do the wide angle views
because I think that has the most
of what this particular view point has to offer.
>> Well, I asked you to share with us a couple
of your favorite shots so that we could share them
with everybody else and take a look at what they are.
The first of these, if I could get you
to describe what it is we're seeing;
I see a coastline and maybe a volcano.
>> Okay, this is in Guatemala and this is taken
with infrared photography, near infrared photography
and we have not been able to do this
since around 2002, 2003, after Columbia.
We quit flying film and we lost our ability
to do color infrared photography 'cause at that time,
it was all done with color infrared film
and now we have modified digital cameras
that give us back the color infrared capability
in digital form.
So this is an infrared picture
where plant material is bright red
and you can see there's jungles there
and there are volcanoes poking up
and this is a little different
than satellite infrared photography
in that it's oblique.
You're looking off axis and human beings
in station can take pictures of objects and at angles
that a preprogrammed satellite typically is outside the --
its event horizon for programming.
>> Let me move on to one other which is clouds of some kind
of way but framed by black on both sides.
>> Okay, this is an image
of polar mesonephric [assumed spelling] clouds or also known
as noctilucent clouds.
And these are clouds that are right on the fringes of space,
they are around 82 to 84 kilometers in altitude
and space is defined about at 100 kilometer altitudes
so they're right on that fringes of space and primarily seen
in polar regions during the summertime.
And they're allusive, they're the willow, the wisp
and we're trying to understand more about these clouds
and space is a great place to observe these.
>> And in this other, in this next image, we see a portion
of the station from where you do that.
>> Yes, this is a picture of what I like to call the view
of my view and it highlights the Cupola
which is this wonderful module filled with windows,
seven windows looking Nadir at earth and you can open
up the shutters and you can do marvelous photography
of daytime earth and nighttime earth and the transition
of day night terminator regions.
>> Now on your last trip, you also figured out a way
to take images that have come to be called star trails images
and we're going to show a couple
of them while you talk 'cause I want
to know what was your inspiration for doing this
and maybe more importantly,
how did you accomplish what we're about to see here?
>> Well, star trail pictures is something
that amateur astronomers do, you put a camera on a tripod,
you point it up at the sky and you open the shutter
and as earth turns, it makes the stars into streaks.
And you could do this on space station
and your orbital motion will make the --
not only the star streaks but the cities
down below will also be streaking
and if there are thunderstorms, they are flashing off
like flashbulbs in a dark room.
I first started doing this during Expedition 6,
back in 2002 with film 'cause the digital cameras back then
wouldn't allow a long enough exposure
without getting a write error to disk and you don't like that
when you're taking a picture but film would allow us
to take these star trail pictures and then I continued
that on STS126 and then I really had the time to zero
in on this during Expedition 30, 31.
>> Those are some remarkable images;
they're really, really quite special.
From the time you first flew
on Expedition 6 till the time you came home
from Expedition 31 is about 10 years in between,
from your [inaudible] personal view, can you see a difference
in the earth over that 10 year hunk of time?
>> The basic earth looks the same and earth is happy to go
on with or without us as human beings
and I think it's important for us to realize this and make sure
that earth goes on with us as riders.
One of the more obvious effects
over the last 10 years has been the display of cities at night,
how we sprinkle as human beings the lights from our cities
and there's this amazing display of lights that are dictated
by geography, by cultural choice of lighting
and by the technology used.
And just as an example, if you're next to a coastline,
you'll see all these lights
and then it gets dark really quick right at the coastline.
Some cultures use mercury vapor lighting and there are cities
that have this blue green cast from the mercury vapor.
Others use sodium vapor lighting and you can see that.
Some cities, the older parts of town are blue green
and the new burrows are the yellow orange
and so you can see the extent of technology.
You can see the extent of geography
and you can see the extent of cultural choice.
Sometimes the lighting produce less light pollution
and you can see the countries
that don't have any light pollution technology
and their cities are lit up in a different way than cities
where they follow a light pollution doctrine.
>> That's fascinating and on behalf of everybody
who hasn't had the opportunity to see what you've seen,
thanks for telling us about it.
Thanks for sharing some of these great pictures.
>> It's my pleasure.
Recording what we see as astronauts from space
of earth is one way of sharing this experience to folks
on earth that don't get a chance to get into space.
>> Another way of sharing it is
that there are astronaut photographs of earth
that are posted on a special website
at earthobservatory.nasa.gov and for Earth Day
at this special URL right down here, you can see images
of the day, maps and features
that will excite the geography enthusiast.
There are tens and tens of thousands of photographs
that you can see special for Earth Day right here every day
at earthobservatory.nasa.gov.