Feast your eyes on this breathtaking photo of Venus

Although its primary mission is to look at the Sun, NASA’s Parker solar probe will take any opportunity to send data back to Earth.

The planet Venus represents just such an opportunity, or rather seven of them. Seven times during its mission, the probe will swing around Venus for gravitational assistance, using the planet’s gravity as a slingshot for heading and speed corrections as it moves closer and closer to the Sun.

The solar probe performed the third of these maneuvers on July 11, 2020, and as it approached it took a glamorous photo of the night side of the planet using the Wide-field Imager for Parker Solar Probe (WISPR ).

Parker isn’t the only probe taking photos of Venus as she makes her way through the inner solar system. BepiColombo, a joint European and Japanese space agency Mercury probe, took a video of Venus while performing a gravity assist maneuver last year.

Flight over the Venus of BepiColombo. (ESA / BepiColombo / MTM)

These images show the planet as relatively smooth and featureless. This is not at all surprising – Venus is enveloped in a thick, toxic atmosphere with clouds of mostly sulfuric acid that reflect about 70% of the light that hits them. This is why Venus is one of the brightest objects in the night sky.

The Parker team expected to see a similar orb with no features – but that’s not what they saw when they processed the WISPR data.

If you look at the image, you can see a bright glow around the edge of the planet. This, according to the team, is nocturnal.

This is produced by atoms in the upper atmosphere. On the planet side, solar radiation splits carbon dioxide in the upper atmosphere into oxygen and carbon monoxide. When night falls, the atoms recombine into carbon dioxide, causing a glow.

This is something that also occurs on Earth and on Mars, and it has already been seen on Venus; its presence in the image of Parker is not surprising.

White streaks aren’t either – although the Parker team isn’t sure what they are, there are a number of candidates, including dust, cosmic rays, material ejected from the spacecraft. after being hit by dust, or a combination of all of them.

(NASA / Johns Hopkins APL / Naval Research Laboratory / Guillermo Stenborg and Brendan Gallagher)

What is surprising is this dark stain on the face of the planet. It is a region called Aphrodite Terra, the largest highland region on the surface of the planet.

WISPR, designed to image the solar corona and coronal ejections, is optimized for visible light observations – but it somehow scanned the clouds of Venus.

Scientists think they know what happened, however. Venus currently has an active mission, the Japanese Space Agency’s Akatsuki probe. It returns similar images, taken using its infrared camera, sensitive to temperature variations.

The Aphrodite Terra, with its higher altitude, is much cooler than the surrounding terrain, so in infrared or near infrared images of the planet it would be visible.

“WISPR effectively captured thermal emissions from the Venusian surface,” said Brian Wood, astrophysicist and member of the WISPR team at the US Naval Research Laboratory. “It is very similar to the images acquired by the Akatsuki spacecraft at near infrared wavelengths.”

This means that WISPR could be more sensitive to infrared light than it was designed to be – which, in turn, opens up new possibilities for Parker’s main mission of studying the Sun. The Parker team is now taking a closer look at the instrument’s specifications to determine exactly what it did.

“Either way,” said Angelos Vourlidas, WISPR Project Scientist, Johns Hopkins Applied Physics Laboratory, “exciting scientific opportunities lie ahead.”