Friday, October 23, 2015

A FAKE picture of the REAL Earth and REAL stars

Today, I discovered a new NASA web site that provides daily images of the Earth taken by the Deep Space Climate Observatory (DSCOVR) satellite, which is in an orbit around the Sun, 924,777 miles away from the earth.  The satellite is in orbit around a Lagrange point where the Earth's gravity is exactly the same as the Sun's gravity.  So, the satellite is, in effect, orbiting the Sun just inside the Earth's orbit, moving in sync with the Earth, and it can continually take pictures of the side of the Earth that faces the Sun as the Earth spins on its axis.

Because the exposure time to take a picture of the Earth from that satellite is much faster than an exposure time that would be needed to take pictures of the stars, the pictures do not show stars.  They show the Earth and a black background. 

I wondered what the Earth would look like with a starry background, and I created this FAKE image of the REAL Earth (from HERE) and REAL stars (from HERE):

You can click on the image to view a much larger (and more spectacular) version.

The images were combined using

Someone advised me of a REAL picture that does show the Earth and stars.  Here it is:

Of course, the only reason you can see both the Earth and background stars in the picture is because the Earth is so small and isn't significantly brighter than a star in the picture.  As a result, the same exposure time will capture the Earth, the moon and some of the brighter background stars.   

Looking around the Internet, I found a picture HERE taken by US astronaut Reid Wiseman on the International Space Station (ISS) that shows part of the earth and plenty of stars:

The problem with it, is that he had to use a 3-second time exposure from the moving ISS, so the stars are blurred and so is anything else that moved relative to the ISS. 

And the fact that the above picture was a time exposure reminded me of the time (about 60 years ago) when I went down to the shore of Lake Michigan to take a time exposure photo of the moon over the lake.  Here it is:

There are no stars visible in the photograph, yet it was a beautiful night and the sky was full of stars.  (That white dot just above the horizon on the right could be Venus, or it could be a blemish on the color slide.) The time exposure just wasn't long enough to make the stars visible.  If I would have left the shutter open longer to capture the stars, the moon would have moved and turned into an oblong shape.  


  1. Here is a link to a great photo of the earth and moon with a background of stars taken from the NASA Messenger probe. Maybe not a fake.

    1. Great! Thanks. I'll add the picture to the thread comment. It helps explain why it's difficult to get the Earth (as a large image) and stars in the same photograph.