The radio signal in the ionosphere provides clues about the effects of the solar cycle

The Parker Solar Probe was launched in 2018 with the aim of closely studying the sun, and approached Venus to perform a maneuver known as “gravitational buoyancy”. In order to reach the sun, the spacecraft must use the eruption of a planet like Venus to change its orbit, reducing the perihelion in each of the passages around the sun, until it reaches its maximum approach. Parker made the third flight there in July 2020 and surprised the scientists with the radio noise.

Although the signal was normal, the researchers didn’t exactly wait for it. Glenn Collison, of the Goddard Space Flight Center at NASA When Solar Parker FIELDS detected a low-frequency signal for seven minutes, he says, it wasn’t able to recognize it right away. However, the sudden change in data frequency caught Collinson’s attention because the signal was somehow familiar to him. He said, “So, the next day, I woke up, and I thought, Oh my God, I know what this is!”

Collinson knew the signal because he had worked extensively with atmospheric data from Venus before – enough to be recognized as an expert on the planet. He has already analyzed all of the Venus data from previous missions, such as NASA’s Venus Venus Orbiter and the European Space Agency’s Venus Express (European Space Agency). many times. Then, when faced with the frequency captured by the solar probe, he realized that the probe had passed through the upper atmosphere of Venus. A good surprise will allow us to study the effects of solar activities on the climate of Venus.

In terms of size and structure, Venus is not much different from Earth, and some researchers believe it was once a suitable place for liquid water in the past. Today, however, our neighbor is known as the “Infernal Planet,” and the reason is easy to imagine – Venus is hot and poisonous, not only for the life forms we know of, but also for our scientific instruments. None of Sensors sent to Venus to this day He survived for more than a few minutes.

Fortunately, you don’t have to be on Venus to know a little about its atmosphere. On passing, the Parker probe collected a lot of useful information, especially about the thickness of the upper atmosphere. This was the first direct measurement of Venus’ atmosphere in nearly 30 years, and the data can now be used for comparison with older ones. Has Venus changed? Well, the captured signals look very different now, and a study confirmed that the planet’s upper atmosphere is undergoing changes during the current solar cycle.

The solar cycle indicates the activity of the Sun and corresponds to 11 years. During this time, our star reaches the alleged minimum of the sun, advances to the maximum of the sun, and then returns to its lowest activity. For us, it is essential to understand the effects of the Sun’s Maximum in Earth’s atmosphere and in the entire Solar System, which of course includes Venus. However, without direct monitoring it wouldn’t be possible to detect much, and this is where the radio signal becomes important.

The last time direct measurements of the ionosphere of Venus were obtained in 1992, when the Sun was close to the Sun’s maximum. In the years that followed, as the sun was on its way to a minimum, ground-based telescopes suggested changes in the ionosphere – it became at the top, making the escape of gases into space easier. But it was necessary to confirm this, and with Solar Parker’s flight and the “occasional” set of ionospheric signals on Venus, researchers can trust this hypothesis. In fact, they concluded that Venus’ ionosphere is much thinner compared to previous measurements made during the solar peak.

This new understanding will help researchers better understand what happened to the climate of Venus. But for that, they’ll have to figure out why the ionosphere of Venus thins during the solar minimum, and that’s especially interesting because, if Venus is really very similar to Earth, we want to avoid what happened there so that the planet could make it unusual. If it is true that the ionosphere of Venus experiences leaks of energized gases into space during minimal solar energy, the next step should be to collect data about the changes that will take place there in the later stages of the solar cycle.

Source: NASA