Even though Parker Solar Probe's main task is to observe the Sun, it must complete seven gravitational maneuvers around Venus during its mission.
During one of these flights Parker made on July 11, 2020, the third in a row, when the probe was 12 thousand kilometers from Venus, the Wide-Field Imager for Solar Probe (WISPR) took a stunning picture of Venus. The WISPR camera is designed to capture the Sun in the visible range. NASA shared the photo with earthlings only now.
The surface of Venus cannot be seen in this image due to its dense atmosphere. But unexpectedly for scientists, it turned out that the device managed to capture two remarkable details. The first one is thermal radiation in the form of a bright glow on the edge of the planet. Scientists say it was caused by oxygen atoms on the night side of the planet.
“At Venus, the camera detected a bright rim around the edge of the planet that may be nightglow — light emitted by oxygen atoms high in the atmosphere that recombine into molecules in the nightside,” explained Michael Buckley, an astrophysicist at Johns Hopkins Applied Physics Laboratory.
The second remarkable detail captured by the probe is Aphrodite Terra, the largest highland region on the surface of Venus. It is colder than the rest, so it looks like a big dark spot in the center of the visible part of the disk. This means that WISPR could look through the atmosphere of Venus, which NASA scientists could not have expected.
“WISPR is tailored and tested for visible light observations. We expected to see clouds, but the camera peered right through to the surface,” NASA’s statement says.
Parker last flew around Venus on February 20. In the near future, scientists expect to receive new images and analyze them by the end of April.
Scientists said that they expected to see only clouds near the planet, but the camera was able to capture part of Venus. Astrophysicists have suggested that WISPR can work in the infrared range.
With the discovery of the new capabilities of Parker’s WISPR camera, scientists can expand the probe's research tasks. The probe has now been launched to study the Sun’s corona (the outermost atmosphere of plasma), but Parker could also contribute to the study of the surface of Venus, NASA says.