Venus is so hot that its surface glows clearly at night through its thick clouds.
That’s what images captured by NASA’s Parker Space Probe have revealed.
The planet’s average temperature hovers around 860 degrees Fahrenheit, and dense clouds of sulfuric acid obscure visibility. To date, the only images of the surface of Venus have been taken by four Soviet spacecraft that successfully landed there in the 1970s and 1980s, briefly operating before succumbing. before the hell environment.
During the transit of Venus, the Parker spacecraft pointed its cameras at the night side of Venus. It can see visible light wavelengths, including the reddish hues emitted by infrared that can penetrate clouds.
“It’s a new way of looking at Venus that we haven’t tried before – in fact, it’s not even possible,” said Lori Glaze, director of NASA’s planetary division. “.
In Parker’s images, hotter areas such as the low volcanic plains appear brighter while those at higher elevations such as Aphrodite Terra, one of three continent-sized regions on Venus, are cold. about 85 degrees darker and darker.
Brian Wood, a physicist at the Naval Research Laboratory in Washington, DC, and lead author of a study published this month in Geophysical Research Letters described the findings. “It starts to glow a little bit at a very red wavelength. And that’s what we’re seeing: the surface of Venus glows at very red wavelengths, because it’s so hot.”
The photos also show a luminescent oxygen halo in the atmosphere.
“We were able to capture really, really, really, really beautiful images,” said Nicola Fox, director of NASA’s astrophysics division.
For Dr. Wood and the other scientists working on the mission, the study was a course in planetary science. Dr Wood said: “I have never studied planets. “We are all solar physicists. We are experts on the sun, not the planet. “
As its name suggests, the Parker Solar Probe’s mission is to probe the sun, withstanding the extreme temperatures as it dives through the sun’s outer atmosphere. By design, the Parker spacecraft’s orbit creates a number of pieces flying close to Venus, using the planet’s gravity as a braking force to allow it to get closer and closer to the sun.
The single camera instrument, called the Wide Field Imager for Parker Solar Probe, or WISPR, is not designed to look directly at the sun where it is too bright, especially at close range. Instead, WISPR is on a par with charged particles known as the solar wind that emanate from the sun at a speed of one million miles per hour.
Prior to the launch of the Parker Solar Probe in 2018, Dr Glaze and Dr Fox, then project scientists for the mission, discussed the possibility of turning the instruments on during the flight. over the flight of Venus. But no definite plans are made until after launch and the Parker Space Probe is running smoothly.
“It was just because of safety concerns,” Dr. Fox said. “Until you get to orbit, you don’t really know how your spacecraft is going.”
Designed to capture faint solar wind particles, WISPR turned out to be very adept at creating the faint glow on Venus’ night face.
It took a bit of trial and error to figure that out. In July 2020, on the maiden flight where the camera was turned on, scientists discovered that if any part of Venus’s day was in the field of view, the photo would be overexposed.
“We didn’t really know what we were doing,” says Dr. Wood. “We quickly learned that led to the image being completely unusable.”
But there are two images pointing towards the night. “It’s the images that reveal to us, ‘Wow, OK, so now we’re seeing something,’ Dr Wood said.
The scientists were better prepared when their spacecraft made another flight last February, capturing enough images to stitch into a movie.
Other orbiting spacecraft, including Japan’s Akatsuki and the European Space Agency’s Venus Express, have observed similar patterns at longer infrared wavelengths, invisible to the human eye. Okay. (Dr. Wood said whether an astronaut in orbit above the sun of Venus would see the light that Parker detected is still unclear because the human eye can barely detect the wavelengths. this).
Because different materials glow at different intensities at different wavelengths, the Parker data can be combined with infrared observations from other spacecraft to help identify certain minerals on the surface. face.
“This is where we’d like to get access to these data, but we’re not there yet,” said Dr Wood.
The data will also help future Venus missions like NASA’s DAVINCI+, which will launch at the end of the decade and bring a parachute probe to the surface. “I think it will James Garvin, principal investigator for DAVINCI+, said. “Venus will come alive.”
The Parker Space Probe won’t get another good look at the night side of Venus until its final flight in November 2024.
Dr. Wood noted a historic symmetry to his Venus discoveries. In 1962, the first successful interplanetary probe, NASA’s Mariner 2 mission to Venus, confirmed the existence of the solar wind. That is the prediction of Eugene Parker, an astrophysicist who shares the same name as the mission he is on.
“I just find it interesting that the connection between studying Venus and studying the solar wind has been around since the beginning,” said Dr. Wood.
https://www.nytimes.com/2022/02/25/science/venus-photos-nasa.html Venus shows its Hot, Cloudy Side