During a brief swing by Venus, NASA’s Parker Solar Probe detected a natural radio signal that revealed the spacecraft had flown through the planet’s upper atmosphere. This was the first direct measurement of the Venusian atmosphere in nearly 30 years — and it looks quite different from Venus past. A study published today confirms that Venus’ upper atmosphere undergoes puzzling changes over a solar cycle, the Sun’s 11-year activity cycle. This marks the latest clue to untangling how and why Venus and Earth are so different.
Born of similar processes, Earth and Venus are twins: both rocky, and of similar size and structure. But their paths diverged from birth. Venus lacks a magnetic field, and its surface broils at temperatures hot enough to melt lead. At most, spacecraft have only ever survived a couple hours there. Studying Venus, inhospitable as it is, helps scientists understand how these twins have evolved, and what makes Earth-like planets habitable or not.
On July 11, 2020, Parker Solar Probe swung by Venus in its third flyby. Each flyby is designed to leverage the planet’s gravity to fly the spacecraft closer and closer to the Sun. The mission — managed by Johns Hopkins Applied Physics Laboratory in Laurel, Maryland — made its closest flyby of Venus yet, passing just 517 miles (833 km) above the surface.
The data sonification in the video translates data from Parker Solar Probe’s FIELDS instrument into sound. FIELDS detected a natural, low-frequency radio emission as it moved through Venus’ atmosphere that helped scientists calculate the density of the planet’s electrically charged upper atmosphere, called the ionosphere. Credit: NASA’s Scientific Visualization Studio/Mark SubbaRao/Glyn Collinson
“I was just so excited to have new data from Venus,” said Glyn Collison of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the lead scientist on the study, published today (May 3, 2021) in Geophysical Research Letters. A Venus expert, Collinson has pored over all the Venus data available — from past missions like NASA’s Pioneer Venus Orbiter and ESA’s (the European Space Agency) Venus Express — several times.