Hubble Telescope’s Annual ‘Grand Tour’ Tracks Changes in the Outer Solar System


Each year, NASA’s most venerable space telescope photographs the outer planets of the solar system.

And so this fall, as usual, the The Hubble Space Telescope in turn turned to each planet. Tradition allows astronomers to monitor how the atmospheres of these worlds – Jupiter, Saturn, Uranus and Neptune – change over time. But the photos are, of course, also stunning. NASA released footage from this year’s “grand tour” on November 18.

The images highlight the big differences between the four outer worlds and their inner, rocky counterparts: Mercury, Venus, Earth, and Mars. The outer gas giants are much larger and reside much further from the sun, up to 30 times further away than Earth, which means these worlds are also extremely cold, according to a NASA statement.

Related: The Solar System: A Guide to Things Orbiting Our Sun

New images from NASA’s Hubble Space Telescope capture breathtaking views of the outer planets Jupiter, Saturn, Uranus and Neptune, as part of this year’s “grand tour” of the solar system. (Image credit: NASA)

“Unlike rocky terrestrial planets like Earth and Mars which huddle near the warmth of the sun, these distant worlds are mostly made up of cold carbonated soups of hydrogen, helium, ammonia, methane and deep water. around a compact core, intensely hot and compact. “, according to the statement.

From the orbit of Hubble, above that of the International space station and up to 3 billion kilometers from the outer worlds, the space telescope has documented striking changes in the planets’ atmospheres from year to year, including dynamic weather patterns and seasonal variations. Each year, scientists working on the Outer Planets Atmospheres Legacy (OPAL) program turn Hubble images into annual maps of each planet that allow researchers to study the dynamic forces that cause planets’ unusual weather patterns.

Hubble’s view of Jupiter on September 4, 2021 captured a more reddish-than-expected equator and elongated bright red storms called “barges.” (Image credit: NASA, ESA, A. Simon (NASA-GSFC) and MH Wong (UC Berkeley); Image processing: J. DePasquale (STScI))

This year’s view of Jupiter’s ever-changing atmosphere shows several new storms and color differences near the planet’s equator. Taken on September 4, the image captured a darker, more reddish-than-expected equator and several elongated bright red storms called “barges”. The image also shows a smaller dot called “Red Spot Jr.”, under Jupiter’s famous big red spot.

“Whenever we get new data, the image quality and the detail of the cloud features always amaze me,” Amy Simon, planetologist at NASA’s Goddard Space Flight Center in Maryland, said in the statement. . “It hits me when I look at Jupiter, in the barges or in the red stripe just below you can see cloud structures that are clearly much deeper. We see a lot of structure here and variation in vertical depth.”

A new view of Saturn shows rapid and extreme color changes in the northern hemisphere bands of the planet, as seen on September 12, 2021. (Image credit: NASA, ESA, A. Simon (NASA-GSFC) and MH Wong (UC Berkeley); Image processing: A. Pagan (STScI))

Hubble’s last view on Saturn, taken on September 12, captures the planet’s northern hemisphere entering in early fall. The seasonal change triggers rapid and extreme color changes of the yellow and gold bands in the atmosphere, which are caused by ultra-fast winds.

Conversely, the south pole of the planet, which comes out of the winter season, gives off a bluish tint. The Hubble image also captured The iconic hexagonal storm of Saturn, which was not as visible last year, the statement said. The storm circles the planet’s north pole and was first spotted by the Voyager mission 30 years ago.

This view of Uranus, taken by Hubble on October 25, 2021, captures a brighter polar region, caused by an increase in ultraviolet radiation absorbed by the sun. (Image credit: NASA, ESA, A. Simon (NASA-GSFC) and MH Wong (UC Berkeley); Image processing: A. Pagan (STScI))

Likewise, Uranus and Neptune also show changes. An image of Uranus from October 25 highlights the planet’s bright north polar hood. It is spring in the northern hemisphere on Uranus, which means that the north pole of the planet is pointing towards the sun – and due to the dramatic tilt of the planet’s axis, almost 90 degrees, that’s a drastic change.

The increase in ultraviolet radiation absorbed by the sun in spring changes the concentration of methane and haze particles in the planet’s atmosphere, which in turn causes the polar region to brighten, the statement said.

On September 7, 2021, Hubble captured Neptune’s darkened northern hemisphere, along with its black dot storm, which has moved around the planet since it was first spotted by the Space Telescope in 2018. . (Image credit: NASA, ESA, A. Simon (NASA-GSFC) and MH Wong (UC Berkeley); Image processing: A. Pagan (STScI))

During this time, NeptuneThe northern hemisphere is darker than usual and shows a giant storm, represented by the dark spot in an image captured by Hubble on September 7. This dark storm – which scientists believe is wider than the Atlantic Ocean – has moved around the planet since it was first spotted by Hubble in 2018. In the new image, the storm has reversed its direction and move north.

The Hubble image also shows a black circle encompassing the planet’s south pole and a few bright clouds caused by red light being absorbed by the planet’s methane-rich atmosphere, the statement said.

On the four giant planets, the ability to track atmospheric changes over decades in such detail is only possible with a space telescope like Hubble.

“This is something we can do best with Hubble. With the high resolution of Hubble, we can determine which group is actually changing,” said Michael Wong, a planetary scientist at the University of California at Berkeley, in the communicated.

“If you were to look at this through a telescope on the ground, there is some blurring of our atmosphere, and you will lose some of those color variations,” Wong said. “Nothing on the ground will get visible light images as sharp. Like the one in Hubble.”

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Arline J. Mercier