Fermi Gamma-ray Space Telescope images the Moon, but not as we know it

Optical light isn't the only way to observe our Moon. Viewing in different wavelengths often tells a completely different story.

Published: October 6, 2019 at 1:39 am
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Gamma ray observations of the Moon by the Fermi Gamma-ray Space Telescope. Credit: NASA/DOE/Fermi LAT Collaboration

The object in these images may look like a bright star, but it is in fact our Moon, as seen by the Fermi Gamma-ray Space Telescope.


The Fermi science team have been observing our planet’s satellite to study cosmic rays: charged particles generated by violent phenomena such as exploding stars.

While the top left image shows the scale of the Moon in optical light, the following sequence of images show how cosmic rays hit the lunar surface to produce a gamma ray glow, seen in exposures ranging from 2 months (second from top left) to 128 months (bottom right).

At these energies, our Moon is brighter than the Sun.

If you'd like to have a go at imaging the Moon - although you shouldn't expect to replicate what you can see here! - read our guide on how to photograph the Moon.


Credit: NASA/DOE/Fermi LAT Collaboration


Iain Todd, BBC Sky at Night Magazine
Iain ToddScience journalist

Iain Todd is BBC Sky at Night Magazine's Staff Writer. He fell in love with the night sky when he caught his first glimpse of Orion, aged 10.

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