Fermi LAT data shows that the Moon’s brightness varies by about 20% over the Sun’s 11-year activity cycle. Variations in the intensity of the Sun’s magnetic field during the cycle change the rate of cosmic ray (Photo: NASA/DOE/Fermi LAT Collaboration)
- Look what NASA found; Moon glows brighter than Sun in images from the Fermi telescope, and there is science behind this magic
- If our eyes could see high-energy radiation called gamma rays, the Moon would appear brighter than the Sun to our eyes
- NASA’s Fermi Gamma-ray Space Telescope has 10 years of data on our nearest celestial neighbour on that theory
What if our eyes could see high-energy radiation called gamma rays, teases NASA. It says the Moon would appear brighter than the Sun to our eyes. NASA’s Fermi Gamma-ray Space Telescope has 10 years+ of data on our nearest celestial neighbour on that theory. So why don’t we see the Moon in that light? NASA explains that the gamma-ray observations are not sensitive enough to clearly see the shape of the Moon’s disk or any surface features. But, Fermi’s Large Area Telescope (LAT) detects a prominent glow centred on the Moon’s position in the sky.
What is the Fermi Gamma-ray Space Telescope?
NASA says the Fermi Gamma-ray Space Telescope that was launched on June 11, 2008, observes the cosmos using the highest-energy form of light. “Mapping the entire sky every three hours, Fermi provides an important window into the most extreme phenomena of the universe, from gamma-ray bursts and black-hole jets to pulsars, supernova remnants and the origin of cosmic rays,” says the NASA website.
Two scientists from Italy’s National Institute of Nuclear Physics in Bari – Mario Nicola Mazziotta and Francesco Loparco – have been analyzing the Moon’s gamma-ray glow as a way of better understanding another type of radiation from space: fast-moving particles called cosmic rays.
“Cosmic rays are mostly protons accelerated by some of the most energetic phenomena in the universe, like the blast waves of exploding stars and jets produced when matter falls into black holes,” Mazziotta reportedly told NASA.
So how do the gamma rays make the Moon’s surface glow?
The particles are electrically charged, and therefore, they’re strongly affected by magnetic fields. But as we know, the Moon lacks a magnetic field and therefore, even low-energy cosmic rays can reach the surface. NASA says that this is why the Moon turns into a handy space-based particle detector. “When cosmic rays strike, they interact with the powdery surface of the Moon, called the regolith, to produce gamma-ray emission. The Moon absorbs most of these gamma rays, but some of them escape,” claims Francis Reddy of NASA’s Goddard Space Flight Center, Greenbelt, Maryland.
Mazziotta and Loparco have assembled and collated data from the Fermi-LAT lunar observations for gamma rays with energies above 31 million electron volts — more than 10 million times greater than the energy of visible light — and organized them over time, showing how longer exposures improve the view. “Seen at these energies, the Moon would never go through its monthly cycle of phases and would always look full,” is Loparco’s belief as shared with NASA.
Astronauts & gamma-ray radiation during the trip to the Moon:
Man has always been intrigued by space and space travel. As NASA sets its sights on sending humans to the Moon by 2024 through the Artemis program, with the eventual goal of sending astronauts to Mars, understanding various aspects of the lunar environment take on new importance. Possibly, these details were not available during the Apollo missions. These gamma-ray observations are a reminder that astronauts on the Moon will require protection from the same cosmic rays that produce this high-energy gamma radiation.
So will it turn us into superheroes?
Gamma-ray exposure and humans? Does that ring a bell? Oh, yes! The Marvel comics superhero Bruce Banner aka The Hulk. Different versions of The Hulk give us different reasons for his transformation, but one thing common to all of them is the theory that a high dose of gamma rays mutated Bruce Banner’s DNA such that it causes him to be transformed into The Hulk whenever he’s angry. Awww! So are gamma rays good for humans? Maybe in comics, certainly not in the real world! Gamma rays are a type of high-energy radiation such that when humans are exposed to high doses of gamma rays, our cell DNA would be mutated or even destroyed. This could kill. Remember, Nobel laureate Marie Curie died from illnesses caused by gamma radiation poisoning.
So if gamma rays come from the Sun, why does it glow duller than the Moon on the images?
When only gamma rays are filtered to observe the two celestial objects from Earth, why is it that the Moon’s gamma-ray glow is surprising and impressive, and the Sun – which actually shines brighter in gamma rays with energies higher than 1 billion electron volts – does not seem so to our telescope? That is explained by NASA. It says that it is so because cosmic rays with lower energies do not reach the Sun as its powerful magnetic field screens them out. But it is not like all gamma radiation from the Sun is undetected by Fermi. NASA says that much more energetic cosmic rays can penetrate this magnetic shield and strike the Sun’s denser atmosphere, producing gamma rays that can reach Fermi.
Do the lunar phases as seen from the Earth make any difference to the gamma-ray radiation caught by Fermi’s LAT from the Pale Blue Dot? NASA explains that the gamma-ray Moon doesn’t show a monthly cycle of phases, though its brightness does change over time. The Fermi-LAT data show that the Moon’s brightness varies by about 20% over the Sun’s 11-year activity cycle. Variations in the intensity of the Sun’s magnetic field during the cycle change the rate of cosmic rays reaching the Moon, altering the production of gamma rays.
The views expressed by the author are personal and do not in any way represent those of Times Network.