She’s the closest planet to Earth, yet she hides her secrets behind a veil of cloud.
Venus and Earth have often been described as twins because they’re close in size and share complex weather systems, but they’re very different.
- Venus is the hottest planet in our solar system and the second closest to the sun.
- She shines the brightest due to the cloud covering her surface. The atmosphere is so dense that it traps heat in a greenhouse-like effect.
- Temperatures on Venus reach 880 degrees Fahrenheit (471 degrees Celsius), hot enough to melt lead.
Observations from various sources on Earth have provided us with a lot of information, and probes have been sent to gather data over the years.
Orbiters have had the most success, being able to map the surface of Venus, sending images back to Earth for analysis.
We used to send targeted probes to Venus.
Many orbited the planet and gathered measurements and data. Several landed, and a few lasted long enough to send information back.
Most spacecraft survived only a few hours after landing before being destroyed by the intense heat. They were costly lessons, providing little return.
Because of that, we don’t fund missions with the sole purpose of landing on Venus anymore.
Instead, we make do with the data collected as probes fly by on other missions.
In July 2020, NASA sent the Parker Solar Probe on a trajectory toward Venus.
An interesting new observation has recently come from this probe, which was launched in 2018.
Its mission was to touch the Sun.
“The Parker Solar Probe will make 24 orbits of the star before swooping into the outermost part of the solar atmosphere, known as the corona, to study the sun up close and personal. At its closest approach, Parker Solar probe will fly within 3.7 million miles (6 million kilometers) of the sun’s surface — more than eight times closer than any other spacecraft and more than eight times closer than Mercury.” Space.com
Scientists consider any of this probe’s observations of Venus a bonus, as the official mission is to study the sun.
The Parker Solar Probe used Venus to steer closer to the sun.
They planned seven fly-bys, which were considered ideal opportunities to gather data.
The purpose of these orbits is to slow down the spacecraft so that Parker Solar Probe can get closer to the sun.
In July 2020, during one of these fly-bys, the probe collected information that supported an intriguing idea.
Venus’ upper atmosphere is reacting to the activity of the sun.
In the past, data from ground-based telescopes had suggested big changes occurred in Venus’s atmosphere as the Sun moved through different phases.
It was believed that during solar minimums, most of the atmosphere remained the same. But the ionosphere, at the top, where gases can escape to space, was much thinner.
Without direct measurements, this theory was impossible to confirm.
The most recent observation confirms that a layer in the upper atmosphere has more charged plasma particles when the sun is more active and fewer when the sun is less active.
It’s exciting because it confirmed something that was previously unverified.
The ionosphere on Venus is thinner when solar activity is at a minimum.
On Earth, the ionosphere is a layer of the atmosphere that grows and shrinks depending on the energy it absorbs from the Sun. The name ‘Ionosphere’ comes from how the gases in this layer are excited by solar radiation to form ions, which have an electrical charge.
This sea of gases emits radio waves that were detected by the Parker Solar Probe. They used the waves to calculate density.
The last time they were able to do that, was in 1992 when the Pioneer Venus Orbiter flew through. That was during a solar maximum and the ionosphere was denser during that time.
Comparing the two measurements gave them the first opportunity to verify what they suspected all along.
This data moves researchers one step along the path to understanding what causes changes in the nightside plasma density.
There are two main hypotheses that try to explain what causes these changes on the nightside.
Understanding what causes these changes would help us understand how and why the atmosphere of Venus is slipping away from the planet into space.
Scientists are very hungry for any information from the planet so this new data is very exciting.
“I was just so excited to have new data from Venus,” Glyn Collinson, an instrument scientist at NASA’s Goddard Space Flight Center in Maryland.
These fly-bys are ‘missions of opportunity.’
When any probe or craft draws near Venus, we gather and record as much data as we can. Any data collected is mined as an unexpected treasure. It would be a missed opportunity otherwise.
During an interview with Space.com, Shannon Curry, a planetary physicist at the University of California, Berkeley, spoke about gathering data on Venus.
“The Venus flybys are like, if you have like a 48-hour layover in Paris, not leaving the airport,” Shannon Curry, told Space.com.
“It would be crazy not to turn on [the instruments].”
At this time, only one spacecraft is currently orbiting Earth’s strange twin, Japan’s Akatsuki mission. NASA has no plans to send a targeted mission to Venus but is evaluating its options.