On the night-side, where atoms are transported by a vigorous diurnal circulation, the glow can be seen with appropriate instruments, such as VIRTIS.
A nitric oxide nightglow in the infrared has never been observed in the atmospheres of Mars or Earth, although it is known that the necessary nitric oxide molecules are present because they have been observed in ultraviolet.
The nightglow on Venus has been seen at infrared wavelengths before, betraying oxygen molecules and the hydroxyl radical, but this is the first detection of nitric oxide at those wavelengths.
It offers data about the atmosphere of Venus that lies above the cloud tops at around 70 km. The oxygen and hydroxyl emissions come from 90-100 km, whereas the nitric oxide comes from 110-120 km altitude. Yet, even VIRTIS cannot see the nitric oxide nightglow all the time because it is often just too faint.
"Luckily for us, Venus has a temperamental atmosphere. Packets of oxygen and nitrogen atoms are blown around."
Sometimes, these become dense enough to boost the brightness of the nightglow, making it visible to VIRTIS.The VIRTIS team plans to continue monitoring the planet, building up a database of this fascinating phenomenon. (ANI)
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