NASA’s Parker Solar Probe peered through Venus’ cloud cover to take the first visible-light images (one shown) of the planet’s surface captured from space. The large dark splotch in the middle is Aphrodite Terra, a highland region. The streaks are caused by charged particles and dust grains striking the camera.
Image Credit: NASA, APL, NRL |
NASA’s Parker Solar Probe got a glimpse of the terrain during a couple of flybys
By
serendipity, scientists have photographed Venus’ surface from space for the
first time.
Though the
planet’s rocky body is concealed beneath a thick veil of clouds, telescopes
aboard NASA’s Parker Solar Probe managed to capture the first visible-light images
of the surface taken from space.
“We’ve
never actually seen the surface through the clouds at these wavelengths
before,” said Lori Glaze, Director of NASA’s Planetary Science Division.
Though the Parker Solar Probe was built to study the sun, it must make regular flybys of Venus. The planet’s gravity tugs on the probe, tightening its orbit and bringing it closer to the sun. Those assists from Venus helped the spacecraft make headlines when it became the first probe to enter the sun’s atmosphere.
It was
during two such flybys in July 2020 and February 2021 that the probe’s WISPR
telescopes captured the new images. While WISPR found Venus’ dayside too bright
to image, it was able to discern large-scale surface features, such as the vast
highland region called Aphrodite Terra, through the clouds on the nightside.
Clouds tend to scatter and absorb light. But some wavelengths of light get through, depending on the clouds’ chemical makeup, says Paul Byrne, a planetary scientist at Washington University in St. Louis who was not involved in the study.
Though scientists knew such spectral windows exist in Venus’ thick clouds of sulfuric acid, the researchers didn’t expect light visible to human eyes would break through so intensely. And while WISPR was designed to study the sun’s atmosphere, its construction also happens to allow it to detect this unanticipated window of light in Venus’ clouds. “It’s fortuitous that they happened to have an instrument that could see through the clouds,” Byrne says.
While
flying by Venus in February 2021, NASA’s Parker Solar Probe captured visible
light coming from the planet’s surface by using the probe’s two WISPR
telescopes — WISPR-0 (large box) and WISPR-1 (small box). Darker regions
represent cooler highlands, while lighter regions represent hotter lowlands.
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The photographs show a planet so hot that it glows, much like red-hot iron, said Brian Wood, an astrophysicist at the U.S. Naval Research Laboratory in Washington, D.C., and a coauthor of the paper, during the social media event.
“The pattern of bright and dark that you see is basically a temperature map,” he said — brighter regions are hotter and darker regions are cooler. This pattern correlates well with topographic maps previously produced from radar and infrared surveys. Highlands appear dark and lowlands appear bright, Wood said.
The images
come as NASA prepares to launch two missions to Venus (SN: 6/2/21). The new
photographs, Wood said, “may help in the interpretation of the observations
taken in the future from these new missions.”
References:
B.E. Wood
et al. Parker Solar Probe imaging of the night side of Venus. Geophysical
Research Letters. Vol. 49, February 16, 2022, e2021GL096302. doi: 10.1029/2021GL096302.
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