Here's one of the most famous images in history, clicked on by the first man on the moon.
Neil Armstrong inducts the Apollo-11 astronaut Buzz Aldrin on July 20, 1969 using the passive seismic experiment. Image courtesy of NASA
The next image of the planet Jupiter is a contemporary legend, clicked on by the NASA spacecraft Juno.
In this image from May 2018, the Great Red Spot is portrayed by the extraordinary view of Jupiter from the south as if it were in the northern area. Courtesy of: NASA
This is from the only laboratory humans have built in space.
Astronaut James Newman waves during a spacewalk in front of the International Space Station. With the kind permission of NASA
And finally the Earth seen from the Moon
In contrast to the barren, frosted lunar surface, the earth in this image of December 24, 1968, is seen above the moon. Image courtesy of NASA
These were four of the most famous images ever captured in space. But do you notice something missing in them?
The one thing common to all of them is the lack of stars in the background. Given the crowded skies seen from Earth on a clear night, this absence of stars in the background has led several conspiracy theorists to question the legitimacy of these images – and sometimes even historical events such as the moon landing of 19459011
So, the governments of the world have conspired against us to hide the fact that no one ever went into space? Because without an atmosphere in the room that blocks the view of the stars, we do not see Vincent van Gogh-esque Images when astronomers click on images of celestial objects
The answer must be more to do with photography have as astrophysics.
In space, astronomers can actually see stars – and maybe only stars, when they look away from the sun. But these stars are extremely dark compared to the light reflected by the image subject (that is the earth in the case of the last image and Buzz Aldrin in the case of the first image). In order to capture this bright subject, the camera must be set to a very short exposure and fast shutter speed – settings that even the dark stars can not detect.
Without Atmosphere is the Light That Comes from the Sun A planet (or the International Space Station in the third picture) is at least as bright as the sunlight we receive on a clear afternoon on Earth. This forces space cameras to be set to settings that we would use on a bright lunch here on Earth. And that leaves the weak stars in distant galaxies no chance to appear in these pictures.
Unlike their cameras, however, astronomers can see stars and a planet in the foreground at the same time as they look out of their spaceships. This is because the human eye is much more sensitive to light than a photographic film or sensor.
This effect of stars disappearing in the background in space photography can also be seen on Earth. On a full moon night, the number of stars visible in the sky is much lower than on a new moon night – and this because the dark stars are washed out by the bright sunlight reflected by the moon. The same reason applies to pictures of sports events at night and pictures of bright night markets in cities around the world.
This does not mean, however, that stars can not be captured by cameras in space. We've parked telescopes like the Hubble Telescope in space to capture star systems and galaxies in our universe. To summarize, here is a picture taken by the Hubble to demonstrate just that:
The "Hubble Ultra Deep Field" shows the galaxies furthest from Earth. Image courtesy of NASA
