While its main mission is to look at the sun, NASA’s Parker Solar Probe will take any opportunity to send data back home to Earth.
The planet Venus represents just such an opportunity, or rather, seven of them. Seven times during its mission, the probe moves around Venus to aid gravity, using the planet’s gravity as a slingshot to correct course and speed as it gets closer and closer to the Sun.
The solar probe made a third of these movements on July 11, 2020, and as it approached, it captured a glamorous view of the planet’s night side using the Wide-field Imager instrument for Parker Solar Probe ( WISPR).
Parker is not the only probe that takes pictures of Venus as it moves through the Internal Solar System. BepiColombo, Mercury’s European and Japanese space exploration joint venture, took a video of Venus while it made a mission-oriented motion last year.
Venus BepiColombo flyby. (ESA / BepiColombo / MTM)
These images show the planet as something smooth and featureless. That’s no surprise – Venus is surrounded by a thick, poisonous atmosphere with clouds of mostly sulfuric acid that reflect about 70 percent of the light they hit. That is why Venus is one of the brightest objects in the night sky.
Parker ‘s team expected to see an orb without a similar feature – but that’ s not what they saw when processing WISPR data.
If you look at the image, you can see a clear cry around the edge of the planet. That, the team believes, is a nightmare.
This is done by atoms in the upper atmosphere. On the planet’s day, solar radiation converts atmospheric carbon dioxide into oxygen and carbon monoxide. When night falls, the atoms turn into carbon dioxide, causing a cry.
This is something that is also happening on Earth, and on Mars, and has been seen before on Venus; his presence in Parker’s image is not surprising.
And the streaks aren’t white – while Parker’s team isn’t sure what they are, there are a number of candidates, including dust, cosmic rays, material extracted from the spacecraft after they flew. beaten with dust, or a combination of all these.
(NASA / Johns Hopkins APL / Naval Research Laboratory / Guillermo Stenborg and Brendan Gallagher)
What is surprising is that there is a dark smear on the face of the planet. It is an area known as the Aphrodite Terra, the largest Highland region on the planet’s surface.
WISPR, designed to image solar corona and coronal ejections, is optimized for visible light scenes – but somehow it showed through the clouds of Venus.
The scientists believe they know what happened, however. Venus currently has one operational mission, the Akatsuki probe of the Japan Space Agency. It captures similar images, taken using its infrared camera, sensitive to temperature changes.
The Terra Aphrodite, with its higher altitude, is much colder than the surrounding earth, so in infrared or near-infrared images of the planet, it would be visible.
“WISPR effectively captured Venusian surface thermal emissions,” said astrophysicist and WISPR team member Brian Wood of the U.S. Naval Research Laboratory. “It’s very similar to images obtained by the Akatsuki spacecraft at near-infrared waves.”
This means that WISPR could be more sensitive to infrared light than it was designed to be – which, in turn, opens up new opportunities for Parker’s main mission to study the sun. . Parker’s team is currently taking a closer look at the instrument’s specs to find out exactly what, it did.
“Similarly,” said WISPR project scientist Angelos Vourlidas of the Johns Hopkins Applied Physics Laboratory, “some exciting science opportunities await us.”