This awesome (at first glance) photo titled "Sunset at the North Pole" is circulating on the internet.
Beautiful, no? Also bogus. Here are some reasons why this is a hoax, starting with the most obvious.
- The moon and the sun are no closer to an observer at the poles than to anybody else on earth. They’re about
240,000 and 93,000,000 miles away from all of us. So what we’re seeing here cannot be based on distance.
- The moon CAN appear unusually large when it's near the horizon due to the effect of the “moon illusion.”
Although this effect is difficult to describe and understand, most people still know that the same illusion applies to
the sun because they’ve observed it. In fact, the sun, being closer to the horizon in this “photo,” should appear larger
than the moon. So what we’re seeing here cannot be based on the moon illusion.
Most people know -- or should know -- that the sun and the moon are very similar in apparent size
in the sky (about a half a degree of apparent angle). That is how and why we can have both lunar
and solar eclipses. Why would they ever appear vastly different in size from any point on earth?
- At the poles, the sun and moon rise, set, and move across the sky at very low angles; further, a new or old
moon follows the sun’s path across the sky. The orientation shown, with the moon apparently following the sun
straight down on a vertical path, can occur only in the tropics. This fact may be harder to understand, but still,
most people have seen pictures of the sun’s path in the arctic sky and should know that neither the sun nor the
moon can ever get very high in the polar sky. So the sun-moon path we’re seeing here is impossible.
An experienced skywatcher would note other problems with the shot:
- The unlit side of the moon cannot be the same color as the twilight sky. A very new or old moon is lit to some
extent by “earthshine’, ie, sunlight reflected back from Earth. Rarely it appears blacker than the surrounding
sky, but under no circumstance does it take on the exact color and brightness as the sky and just disappear.
Earthshine is particularly bright when the moon is as new (or as old) as this very thin crescent suggests.
Here is a shot of an even older (less crescent) moon from Wikipedia -- see how much earthshine it reveals:
- The color and lighting gradient for the sky is not right for the sun at that elevation; more likely,
one of the photos used in this composite was made with the sun below the horizon.
More problems scream “fake” to the skilled Photoshopper and photographer of celestial objects:
- The moon’s reflection is too narrow; the creator should have used the Liquify filter to make the virtual reflection more diffuse.
- The moon shot required several seconds of exposure, likely by a camera with a motorized drive; this is especially true
because of the appearance of two stars. The sun shot, on the other hand, would have to have been made with a fast exposure,
only a fraction of a second -- stars never appear in such a shot. The solar and lunar images were absolutely not made with
the same exposure. (The stars might have been added separately, which still means it was Photoshopped.)
- The sun’s reflection is brighter than its primary image -- highly unlikely, and the mountains show lighting from
the observer’s side; a sunset shot from this position would reveal the mountains as a black silhouette. Try it and see.
This is an awe-inspiring picture, good work, but of course, fooling a scientifically illiterate public is not that hard to do.