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In
In December 1968, the 
In March 2011, NASA released an image of Mercury's Spitteler and Holberg craters taken by the 
In the image on the left of the Tin Bider Crater, Algeria from the NASA Earth Observatory
retrieved September 12, 2015
The Dome Illusion!Lunar Craters inverting Illusion
{{DEFAULTSORT:Optical illusion Optical illusions Impact craters Space photography and videography
astronomical imaging
Astrophotography, also known as astronomical imaging, is the photography or imaging of astronomical objects, celestial events, or areas of the night sky. The first photograph of an astronomical object (the Moon) was taken in 1840, but it was no ...
and Earth imaging
Satellite images (also Earth observation imagery, spaceborne photography, or simply satellite photo) are images of Earth collected by imaging satellites operated by governments and businesses around the world. Satellite imaging companies sell ima ...
, the crater illusion, also known as the dome illusion or crater/dome illusion, is an optical illusion
Within visual perception, an optical illusion (also called a visual illusion) is an illusion caused by the visual system and characterized by a visual perception, percept that arguably appears to differ from reality. Illusions come in a wide v ...
which causes impact craters and other depressions to appear raised as domes
A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...
or mountains
A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher th ...
. It is believed to be caused by our being accustomed to seeing light from overhead. When some images are taken from orbit, the light from the sun is nearly horizontal. This is the only time shadows are seen. Our brains are tricked into thinking that the interior of the crater is above the surrounding terrain instead of below it.
Examples
In September 2015,NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
released an image from the space probe Dawn
Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the appearance of indirect sunlight being scattered in Earth's atmosphere, when the centre of the Sun's disc has reached 18° below the observer's horizo ...
of the crater Occator on dwarf planet Ceres
Ceres most commonly refers to:
* Ceres (dwarf planet), the largest asteroid
* Ceres (mythology), the Roman goddess of agriculture
Ceres may also refer to:
Places
Brazil
* Ceres, Goiás, Brazil
* Ceres Microregion, in north-central Goiás st ...
. Because of the position of the Sun at the time the image was taken, the walls of the crater may appear to be convex instead of concave. On the right is the same image rotated 180 degrees to change the position of the shadows and eliminate the illusion. In December 1968, the Apollo 8
Apollo 8 (December 21–27, 1968) was the first crewed spacecraft to leave low Earth orbit and the first human spaceflight to reach the Moon. The crew orbited the Moon ten times without landing, and then departed safely back to Earth. These ...
mission took the photograph on the right of the Moon's crater Goclenius Goclenius may refer to:
* Conrad Goclenius (1490-1539), German humanist
* Rudolf Goclenius the Elder (1547–1628), German scholastic philosopher
* Rudolf Goclenius, Jr. (1572–1621), German physician and professor of physics, medicine and mathema ...
. On the left is the same image rotated in an attempt to create the illusion.
In March 2011, NASA released an image of Mercury's Spitteler and Holberg craters taken by the MESSENGER
''MESSENGER'' was a NASA robotic space probe that orbited the planet Mercury between 2011 and 2015, studying Mercury's chemical composition, geology, and magnetic field. The name is a backronym for "Mercury Surface, Space Environment, Geoche ...
spacecraft. The image on the left is the original image and the image on the right is the same image rotated in an attempt to remove the illusion.
In the image on the left of the Tin Bider crater
Tin Bider ( ar, تين بيدر) is an impact crater that sits in dry, rugged terrain in Algeria. The crater was formed in the last 70 million years, perhaps in the late Cretaceous or early Tertiary Period. Spanning 6 kilometres, the crater sits at ...
produced by NASA Earth Observatory's EO-1-based Advanced Land Imager produces a reverse illusion. The crater rises above the surrounding terrain, however the position of the sun makes it appear to be below it.retrieved September 12, 2015
References
External links
The Dome Illusion!
{{DEFAULTSORT:Optical illusion Optical illusions Impact craters Space photography and videography