Jupiter is not only the biggest planet in the universe, but it is also home to the biggest storm known as the Great Red Spot that has been swirling for centuries and is even bigger than Earth. But scientists only knew a little about it not until NASA launched a spacecraft a decade ago to look into this enormous vortex.

Juno arrived at Jupiter in 2016, five years since it was launched, but it slightly changed its course in 2019 and passed over the Great Red Spot twice. As Science Times previously reported, Juno used its microwave sensors to measure the storm's depth, which is much thicker than expected and different than how Earth's atmosphere works.

Great Red Spot: NASA's Juno Mission Measures the Storm's Gravity to Better Understand Gas Giants Like Jupiter
(Photo : Wikimedia Commons)
Jupiter's Great Red Spot Region

Juno Measures Great Red Spot's Gravity

In 2019, Juno was traveling at 130,000 miles per hour as it changed its course and observed the Great Red Spot. According to NPR, the massive size of the storm has jostled the spacecraft during its flyby because of its gravity.

Juno scientist Marzia Parisi from NASA's Jet Propulsion Laboratory (JPL) in Southern California explains that the local gravity tends to pull and push away Juno as it flies over the enormous vortex, creating some sort of bumps in the road for the spacecraft.

Scientists noted that they could indeed see from Earth that Juno seems to be passing through the gravitational bumps because every time that the gravity jostles the spacecraft, it is nudged either closer to or farther to Earth.

They explained that these observations in the changes of distance have caused radio waves to be sent back to Earth which is about 400 million miles away, to be subtly squeezed and stretched. This phenomenon is called the Doppler shift or the change of frequency of the wave in relation to the observer moving closer to the source.

Juno could pick up tiny jostles of about 0.01 millimeters per second because of this effect. Parisi said that the findings from the gravity observations complemented the recent microwave measurements that concluded the depth of Great Red Spot could be at 300 miles into Jupiter's atmosphere.

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Is the Great Red Spot Shrinking?

Observations of the Great Red Spot from Earth show that the biggest storm in the Solar System has been slowly shrinking since it was discovered nearly a century and a half, and scientists do not exactly know how long it will last.

Reta Beebe, an emeritus professor at New Mexico State University, told NASA in an interview that there is evidence that the |Great Red Spot has grown and shrunk over the years. However, recent observations suggest that the storm is quite smaller now and it has already been so long since it last grew.

Scientists said that the storm has been contracting and is expected to become even stronger like an ice skater who spins faster as she pulls her arms closer. In other words, the Great Red Spot is stretching up but is getting smaller.

Furthermore, its color has been deepening too and becoming intensely orange since 2014, although scientists do not know why. But they hypothesized that the chemicals, which add color to the storm, are being carried higher into the atmosphere as the spot stretches up. The higher UV radiation must have deepened the color of these chemicals.

As of now, scientists are still not sure whether the Great Red Spot will shrink, stabilize, or completely break apart. Through the help of Juno spacecraft, scientists hope to gain more insights into the planet and make much more sophisticated models to simulate conditions on Jupiter and make predictions of what might happen in the future.

 RELATED ARTICLE: First 3D View of Jupiter's Atmosphere Shows the Great Red Spot is Deeper Than Expected, NASA's Juno Reveals

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