The Juno spacecraft of the National Aeronautics and Space Administration (NASA) has dispelled the misconceptions about the origin of zodiacal light or ‘false positives’.
The zodiacal light is like sunlight reflected by dust particles between the sun and the Earth and is best seen near sunrise or sunset. As the name implies, this cloudy call appears in a constella ring called the zodiac. These are found on the ecliptic, which is the east-like “path” for the sun to cross the Earth’s sky.
Astronomers have believed that zodiacal light has been introduced into the inner solar system by a few of the asteroid and comet families that enter from afar.
A machine that was aboard the spacecraft Juno serendipitously found fragments of dust entering the spacecraft as it traveled from Earth to Jupiter.
The effects provided important information about the origin and evolution of the dust mites, unraveling some mysterious variations of the zodiacal light. This finding is very influential.
John Leif Jørgensen, a professor at the Danish Technical University, said “I never expected to look for interplanetary dust. ”
He designed the four-pointed star that is part of Juno’s magnetometer study. These on-board cameras shoot images of the sky every quarter of a second to confirm Juno’s direction in space by recognizing star patterns in his images – an engineering task that is essential for the accuracy of the magnetometer.
It was not until the researchers measured the apparent size and distance of the objects in the images that they finally realized something: Juno dust particles had broken into at about 10,000 miles (or 16,000 kilometers) per hour, slicing submillimeter pieces. “Even though we’re talking about low-mass items, they pack a medium punch,” said Jack Connerney, Juno’s magnetometer research director and deputy chief investigator of the mission , based at NASA ‘s Goddard Space Flight Center in Greenbelt, Maryland.
As it turned out, the debris from the solar panels came from Juno’s wide-angle solar panels – the largest and most sensitive unusual dust detector ever built.
“Every piece of debris we find records the impact of interplanetary dust material, allowing us to build up a dust circulation on Juno’s path,” Connerney said. Juno was launched in 2011. After moving deep space into the asteroid belt in 2012, it returned to the inner solar system for Earth gravity assistance in 2013, which captured the spacecraft that towards Jupiter.
Connerney and Jørgensen observed that the majority of dust effects were recorded between the Earth and the asteroid belt, with gaps in the distribution associated with the gravitational impact of Jupiter.
According to scientists, this was a radical revelation. Prior to this, scientists had not been able to quantify the orbit of these dust particles. Dedicated dust detectors have very few collection points and therefore sensitivity to a small amount of dust.
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They usually count the more abundant and much smaller dust grains from an intercropping place. In comparison, Juno’s wide range of solar panels have 1,000 times more collection space than most dust detectors.
Juno scientists concluded that the cloud of dust will end at the Earth because the pressure of the Earth sucks the nearby dust. “That is the dust we see as zodiacal light,” Jørgensen said.
As for the outer edge, about 2 celestial units (AU) from the Sun (1 AU is the distance between the Earth and the Sun), it ends a little further than Mars. At that point, the scientists report, the gravitational effect of Jupiter acts as a barrier, preventing dust particles from crossing from the inner solar system into a deep space. This same phenomenon, called orbital repositioning, also works the other way, where it blocks dust coming from deep space from entering the inner solar system.
The deep impact of the gravity barrier indicates that the dust grains are in an almost circular orbit around the sun, Jørgensen said. “And Mars is the only thing we know in an almost orbital orbit around 2 AU, so the natural thought is that Mars is the source of this dust,” he said.
“The dust emission we measure will be better consistent with the difference in zodiacal light observed,” Connerney said. The researchers developed a computer model to predict the light emitted by the dust cloud, scattered by a gravity interaction with Jupiter that disperses the dust into a thicker disk. The scattering depends on only two measures: the ecliptic’s dustiness and its magnitude. When the researchers entered the orbital elements of Mars, the emission definitely predicted the signature of the change of zodiacal light change near the ecliptic. “That, I think, is proof that we know for sure how these grains are breaking down in our solar system,” Connerney said, “and where they came from. ”
Although there is now good evidence that Mars, the most dusty planet we know of, is the source of zodiacal light, Jørgensen and his colleagues still cannot explain how the dust could have been overcoming a Martian seizure. They hope other scientists will help them.
Meanwhile, the researchers note that finding the true dispersion and density of dust particles in the solar system will help engineers design spacecraft products that can withstand prefer dust effects. Knowing the real dust that can guide flight path design for future spacecraft to avoid the highest density of grains. Tiny particles that travel at such high speeds can pick up to 1,000 hours from a spaceship.
Juno solar arrays escaped damage because the solar cells are well protected from impact behind or the dark side of the row by the supporting structure.