NASA’s Parker Solar Probe main job is to study the sun, however, in order to get there the probe needed to perform a close flyby of Venus first, which it did back in July 2020. During that close flyby, the probe managed to capture a spectacular image of Venus, which NASA recently released to the public.
In order to get to its final destination, the Parker Solar Probe flew by Venus a total of seven times over the course of its seven-year mission, using the planet’s gravity to bend the spacecraft’s orbit and propel it towards the Sun. These ‘Venus gravity assists’ allow the probe to fly closer and closer to the Sun, where it is able to closely study the dynamics of the solar wind close to its source.
While these close flybys are a critical element in getting the probe closer to the sun, they also provide some unique and even unexpected views of the inner solar system. During the mission’s third Venus gravity assist, which took place on 11 July 2020, the onboard Wide-field Imager for Parker Solar Probe (WISPR), captured a striking image of the planet’s nightside from 12,380 kilometres away.
Take a look at the image below:
During its latest flyby, the WISPR camera managed to pick up a bright rim around the edge of the venus. NASA believes this might be a phenomenon known as nightglow, which is essentially light emitted by oxygen atoms high in the atmosphere that recombine into molecules in the nightside.
In terms of what the prominent dark feature in the centre of the image is, this is a section of Venus known as Aphrodite Terra, which is the largest highland region on the planet’s surface. The feature appears dark because of its lower temperature, about 30 degrees Celsius cooler than its surroundings.
“WISPR effectively captured the thermal emission of the Venusian surface,” said Brian Wood, an astrophysicist and WISPR team member from the U.S. Naval Research Laboratory in Washington, D.C. “It’s very similar to images acquired by the Akatsuki spacecraft at near-infrared wavelengths.”