Friday , December 3 2021

The moon shines brighter than the sun in NASA Fermi's fiery images


NASA Fermi's Fermi Space Telescope has been observing the moon for 10 years. Although our eyes cannot see gamma rays, the space telescope shows us what it is like to "look" at the moon from a high-energy radiation perspective. In Fermi's new images, the moon shines brighter than the sun and is a fiery sight.

Gamma-ray observations are not sensitive enough to clearly observe the lunar surface characteristics or the lunar disk shape, but Fermi's large-area telescope (LAT) detects a strong glow focusing on the position of the moon in the sky, it is said in a NASA announcement. By studying Fermi images, NASA can help protect astronauts from dangerous conditions, including high-energy gamma radiation when they visit the moon.

Francesco Loparco and Mario Nicolas Mazotita, who are at the National Institute of Nuclear Physics of Bari, study the moon's moonlight to better understand cosmic rays, fast moving particles that are another type of radiation from space.

Because these particles are electrically charged, they are highly affected by magnetic fields that the moon does not have. Low-energy cosmic rays can reach the moon's surface and turn the moon into a "space particle detector," according to NASA. When cosmic rays hit the surface, they interact with regolith (dusty moon surface) to generate gamma radiation. The moon absorbs most of these gamma rays, but some of them escape in the process.

Loparco and Mazziotta analyzed the Fermi LAT lunar observations to demonstrate how this view improved during the mission. The duo has collected data on gamma rays with energy of more than 31 million electron volts, more than 10 million times the energy of visible light, and organized them in a timely fashion, showing how longer exposures help improve perspective.

These images show Fermi's enhanced view of the intense luminosity of the moon. (Photo Credit: NASA / DOE / Fermi LAT Collaboration)

The luminescence of gamma rays is impressive, but the sun shines brighter in gamma rays with energy higher than one billion electron volts. The lower-energy cosmic rays do not reach the Sun because its strong magnetic field acts as a shield against them. Vigorous cosmic rays can move through this magnetic screen and strike the atmosphere of the sun, which produces a gamma ray that can reach the Fermi Gamma ray cosmic telescope.

The gamma ray moon does not show phases in a monthly cycle, but its brightness changes over time. According to Fermi LAT, the moon's brightness varies by about 20 percent over the 11-year solar cycle. NASA claims that varying in the intensity of the sun's magnetic field during the cycle can change the velocity of cosmic rays reaching the moon and change the production of gamma rays.

As NASA prepares to send humans to the moon by 2024 through the Artemis program, it is important to understand how the lunar environment can influence future missions. These gamma-ray observations demonstrate that astronauts on the moon will need protection from the same cosmic rays that generate this high-energy gamma radiation. With these observations, NASA can improve the design of space suits and train future astronauts about the dangers of gamma radiation in the coming years.

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