Thursday, August 6, 2015

Moon passing earth

At first I thought it is a photo-montage, later I though it is an hoax but finally I understood that it is real and that gave me a lot to thought about. Not everyday you see something from such a new point of view. So what is it?

The far (and illuminated) side of the moon. NASA
The far (and illuminated) side of the moon. NASA
Clearly we see the Earth in the photo but what is the other orb? The first impression was that it is another of the photos which shows Pluto and Earth, but that's not Pluto. It is our own moon.

- But the moon doesn't look like that at all!

You are right, the near side of the moon, the only side that we can see from Earth doesn't look like that, but the unseen FAR side of the moon is what we see in this photo. Lets remind that the FAR side is the half of the moon that we can't see from Earth. The moon has a dark and light side but they are changing as the moon rotates around its axis (Just like day and night on Earth). A new moon is when the NEAR side that we see is also the dark side (All the sunlight is on the far side). A full moon is when the near side is fully illuminated. In between we see part of the lighted-side and part of the dark side.

DSCOVR spaceship which is between the Earth and the sun captured that image. The camera nickname is EPIC and the photo is epic indeed. Never before did we saw such a thing. DSCOVR is about 1.5 Million KM from earth at a point where the Earth and Sun gravitational force is balanced making the spaceship more or less "float" there.

DSCOVR's orbit. Nasa
DSCOVR's orbit. Nasa
The moon is very grey. This is the real color of the moon, it seems white to us only because it s so bright in the skies. Photos from the moon surface are also grey.
DSCOVR took many photos and NASA combined them to a stunning video

This is a totally new way to observe new moon (Which is a full moon on the far side). Usually you can see an 18 hours old moon. during solar eclipse you can get a hint of the new moon (you don't see the moon, but you see that it is there blocking the sun).
Everything is relative. Just change your point of view and a new moon becomes full. It is also another demonstration that you can always see new sides in familiar objects, and that Earth indeed is not the center of the solar system, the universe, or anything. It gives new perception about our little world. We see such photos of Earth back from Apollo and before and the "Earthrise" famous photo of Apollo 8 was mind-breaking. I was not around here at that time, but maybe this photo makes me feel similar feelings.

We will have other chances to see the familiar near side when it is almost half a lunar moon. We will see it goes BEHIND the Earth, and since it will be much further away from DSCOVR (1.9m KM and not 1.1m) it will be much smaller than the moon in this picture. It will be interesting to see the opposite as well. Full moon on earth and from 1.5m km a big black circle occultating Earth. Maybe in time that will happen as well.
Another theoretical possibility is to put a spaceship 15m KM from Earth and covering a whole cycle of a lunar moon. However there is no scientific value for such photos so I guess we will have to do with simulations.

More information about the photo at NASA site

To DSCOVR mission page