NASA Fermi Images See The Moon As Brighter Than The Sun

We all know that in visible light, the moon in much, much dimmer than the Sun. If you look at the Sun directly, you risk harming your vision permanently from its brightness. We all stare at the moon, and no one has ever gone blind from the brightness of the moon. However, if humans were able to see gamma rays, the moon would look brighter than the Sun in images.

NASA's Fermi spacecraft sees gamma rays, and in its digital eyes, the moon is brighter than the Sun. The image here shows what Fermi sees when it looks at the moon. The gamma-ray observations aren't sensitive enough to clearly see the moon's shape or surface features.

What Fermi sees is a glow in the position of the moon in the sky. Researchers are studying the moon's gamma-ray glow as a way to study another type of radiation consisting of fast-moving particles called cosmic rays. Cosmic rays are some of the most energetic phenomena in the universe, and since they are electrically charged, they are strongly affected by magnetic fields.

The moon has no magnetic field, and as a result, even low energy cosmic rays can reach the moon's surface. The interaction of the cosmic rays with the surface of the moon produces gamma-ray emissions. The moon absorbs most of the gamma rays, but some escape.

The scientists analyzed the Fermi LET lunar observations to gather data on gamma rays with energies above 31 million electron volts. The team says that when viewed at those energies, the moon never goes through its monthly cycles of phases and would always look full. The team notes that learning about these waves is important because astronauts going back to the moon in future missions will need protection from the gamma rays.