The lunar landings might unfortunately be some of the most vehemently denied occurrences of all time, with many bringing forward claims and conspiracy theories about how the landings were supposedly faked.

An example of an image perfectly exposed to view the Earth from the Moon, and the same image enhanced to over expose the brighter Earth and bring out stars in the background. Credit: NASA

What ought to be one of the proudest moments in human history has become riddled with ill-informed theories, fuelled by misinformation. One of the more common questions brought forward from lunar landing deniers is why there are no stars visible in the images taken by astronauts on the moon.

The explanation for this is clear to all those who have ever used a camera to capture images of the night sky. In order to capture light from fainter sources, like stars, a longer exposure time needs to be used – allowing more time for light from the fainter sources to hit the sensor.

On the lunar surface, such long exposures would have then over-exposed the much brighter lunar surface itself, which was in lunar daylight during the missions, bringing stars into view at the expense of capturing the lunar surface as a white, over-exposed blob with no detail. Since the aim of the missions was to land on the lunar surface and capture images of it, using long exposure photography made no sense there.