NASA’s Parker Solar Probe will soon become the closest human-made object to get to the Sun. To get there, it’s helped by Venus and some creative orbital designs. During a flyby in July 2020, using the planet's gravity to bend its orbit close to the Sun, it snapped some pictures of the planet. One of these photos shows something unexpected: the surface of Venus.
Why is this unexpected? Unlike Earth, Venus is covered in a thick blanket of clouds. To peer through them, previous spacecraft, including Japan’s Akatsuki, have used radar and infrared cameras. The Parker Solar Probe is not equipped with either. Its Wide-field Imager (WISPR) is designed to take visible images of the solar corona and the Sun's inner heliosphere in visible light.
“WISPR is tailored and tested for visible-light observations. We expected to see clouds, but the camera peered right through to the surface,” Angelos Vourlidas, WISPR project scientist from the Johns Hopkins Applied Physics Laboratory, said in a statement.
“WISPR effectively captured the thermal emission of the Venusian surface,” said Brian Wood, an astrophysicist and WISPR team member from the US Naval Research Laboratory in Washington, D.C. “It’s very similar to images acquired by the Akatsuki spacecraft at near-infrared wavelengths.”
These observations of Venus might have a huge impact on the mission. If WISPR can see more than visible light, it will provide even more insight in the inner workings of the Sun. Planetary scientists who study Venus are also excited given that with these observations they got more than was expected from the Parker Solar Probe.
The images show the night glow of the planet and the vast Aphrodite Terra, the largest highland region on the planet.
“We are really looking forward to these new images,” said Javier Peralta, a planetary scientist from the Akatsuki team who organized the Parker Solar Probe collaboration with Akatsuki, which has been orbiting Venus since 2015. “If WISPR can sense the thermal emission from the surface of Venus and nightglow — most likely from oxygen — at the limb of the planet, it can make valuable contributions to studies of the Venusian surface.”
The latest pass near Venus by the Probe was just last week, on February 20, so there should be some more exciting science coming soon.