Venus may be the second planet from the Sun but its thick atmosphere prevents us from getting a good look at its surface. Thankfully, NASA’s Parker Solar Probe had a chance to get up-close and personal with the Planet of Love in July 2020. The NASA probe, which was launched in 2018 to study the Sun’s outer layer or corona, will rendezvous with Venus a total of seven times during its seven-year mission.
Each time the probe swings around Venus, the planet’s gravity will bend the spacecraft’s orbit, pushing the spacecraft closer and closer to the Sun.
But the close flybys have another major advantage – they give NASA’s probe a chance to photograph the planet in crisp detail.
On July 11, 2020, the Parker probe made its third flyby of Venus, coming within 7,693 miles of the planet.
The probe engaged its Wide-field Imager for Parker Solar Probe, or WISPR, capturing a breathtaking view of the planet’s nightside.
At first glance, the image looks incredibly dusty or scratched up like an old 35mm film negative.
But these faint white streaks are a combination of sunlight reflected by space dust, solar radiation and particles ejected from the spacecraft itself.
The amount of streaks present in the images varies, depending on the spacecraft’s speed and orbit.
Another thing you will notice is a clear and bright highlight running around the edge of the planet.
This highlight is known as nightglow and is caused by oxygen atoms high in the atmosphere emitting light when they recombine into molecules.
There is also a dark patch running across the central portion of the planet, which astronomers have identified as the Aphrodite Terra.
This geographic feature is the third-largest highland feature on Venus.
According to NASA, it appears darker compared to its surroundings, because it is about 30C (85F) cooler.
Angelos Vourlidas, WISPR project scientist from the Johns Hopkins Applied Physics Laboratory (APL), was surprised to see this come up on the image.
WISPR was designed to photograph the Sun’s corona and inner heliosphere – a region of space surrounding the Sun and planets that is affected by solar winds and charged particles.
Dr Vourlidas said: “WISPR is tailored and tested for visible light observations.
“We expected to see clouds, but the camera peered right through to the surface.”
Brian Wood, an astrophysicist from the Naval Research Laboratory in Washington DC, added: “WISPR effectively captured the thermal emission of the Venusian surface.
“It’s very similar to images acquired by the Akatsuki spacecraft at near-infrared wavelengths.”
NASA’s Parker probe made its last flyby of Venus’s nightside on February 20, and the WISPRS team is looking forward to analysing the next set of images.
But the photos will not arrive back on Earth until the end of April.
Planetary scientist Javier Peralta who was on the team that proposed the Parker probe in 2015, said: “We are really looking forward to these new images.
“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.”