Triton’s Atmosphere More Mysterious Than Previously Thought

The first ever infrared analysis of the atmosphere of Neptune’s moon Triton revealed the presence carbon monoxide and methane. As summer hit the moon’s southern hemisphere, observations made at the Very Large Telescope (VLT) based at the European Southern Observatory (ESO) showed the thin atmosphere to vary with seasons.

triton atmosphere
Artist’s impression of how Triton, Neptune’s largest moon, might look from high above its surface. The distant Sun appears at the upper-left and the blue crescent of Neptune right of center – Credit: ESO/L. Calçada

“We have found real evidence that the Sun still makes its presence felt on Triton, even from so far away. This icy moon actually has seasons just as we do on Earth, but they change far more slowly,” says Emmanuel Lellouch, the lead author of the paper reporting these results in Astronomy & Astrophysics.

On Triton, where the average surface temperature is about minus 235 degrees Celsius, it is currently summer in the southern hemisphere and winter in the northern. As Triton’s southern hemisphere warms up, a thin layer of frozen nitrogen, methane, and carbon monoxide on Triton’s surface sublimates into gas, thickening the icy atmosphere as the season progresses during Neptune’s 165-year orbit around the Sun. A season on Triton lasts a little over 40 years, and Triton passed the southern summer solstice in 2000.

Based on the amount of gas measured, Lellouch and his colleagues estimate that Triton’s atmospheric pressure may have risen by a factor of four compared to the measurements made by Voyager 2 in 1989, when it was still spring on the giant moon.

Carbon monoxide was known to be present as ice on the surface, but Lellouch and his team discovered that Triton’s upper surface layer is enriched with carbon monoxide ice by about a factor of ten compared to the deeper layers, and that it is this upper “film” that feeds the atmosphere. While the majority of Triton’s atmosphere is nitrogen (much like on Earth), the methane in the atmosphere, first detected by Voyager 2, and only now confirmed in this study from Earth, plays an important role as well.

triton moon
Voyager 2 raw image of Neptune’s satellite Triton taken from roughly 500,000 km. Evidence of complex surface features can be seen from this distance – Credit: NASA

Of Neptune’s 13 moons, Triton is by far the largest, and, at 2700 kilometers in diameter (or three quarters the Earth’s Moon), is the seventh largest moon in the whole Solar System. Since its discovery in 1846, Triton has fascinated astronomers thanks to its geologic activity, the many different types of surface ices, such as frozen nitrogen as well as water and dry ice (frozen carbon dioxide), and its unique retrograde motion.

Observing the atmosphere of Triton, which is roughly 30 times further from the Sun than Earth, is not easy. In the 1980s, astronomers theorised that the atmosphere on Neptune’s moon might be as thick as that of Mars (7 millibars). It wasn’t until Voyager 2 passed the planet in 1989 that the atmosphere of nitrogen and methane, at an actual pressure of 14 microbars, 70 000 times less dense than the atmosphere on Earth, was measured. Since then, ground-based observations have been limited. Observations of stellar occultations (a phenomenon that occurs when a Solar System body passes in front of a star and blocks its light) indicated that Triton’s surface pressure was increasing in the 1990′s. It took the development of the Cryogenic High-Resolution Infrared Echelle Spectrograph (CRIRES) at the Very Large Telescope (VLT) to provide the team the chance to perform a far more detailed study of Triton’s atmosphere.

Aliens Found on Mars: A Brief History

A Short and Quick History of NASA Finding Life on the Martian Planet.

The red planet has held a special place in humanity’s collective imagination for centuries. However, since the Viking landers actually travelled to the red planet, the question of whether there is life on Mars has taken several sharp turns. Just in the past few years, there has been some major controversies and developments. We’ll explore the major ones, from most recent all the way back to the ‘Martian Face’ that NASA photographed in the 90’s.

July 2018: NASA Accused of Burning Evidence of Life on Mars

viking lander nasas

This controversy comes from an actual NASA report, but it has been wildly misinterpreted. Here’s how it goes: researchers discovered data from an old test of Martian soil done by the Viking landers back in the 1970’s. The Viking landers found no evidence of organic molecules, which was puzzling since we did find evidence of them when the two Martian rovers sampled Martian soil.
Now, the soil contained a compound called perchlorate, which is very flammable. There’s very little oxygen or heat on Mars, so it normally doesn’t burn. But the NASA report suggests that the Landers accidentally burned evidence of the Martian organic compounds by burning it with the perchlorate.
The controversy is a whole lot of nothing. We know now that organic compounds do exist on Mars, so whether the Viking landers messed up the first tests doesn’t really matter.

Remember that these are organic compounds, which are the building blocks of life, but aren’t evidence of life itself.

June 2018: Organic Matter Found on Mars

NASA announced that they had discovered organic matter preserved in mudstones that are over 3 billion years old (Earth is 4.5 billion years old, for reference). The announcement also mentioned the fact that we see methane being released into the atmosphere of Mars. Methane is evidence of some kind of organic matter being released into the atmosphere. It’s not clear what this organic matter is, however.

Well, at least that’s what UFO spotters looking at this NASA Mars Rover picture saw:

aliens found on mars
What according to some appears to be a skull with eye sockets and a nose – Source: BARCROFT/NASA

I, personally, am more inclined towards a bowling ball, which would definitely indicate the presence of intelligent life on Mars, unlike here, on Earth.

mars face
The “famous” Face on Mars – part of the Cydonia region, taken by the Viking 1 orbiter and released by NASA/JPL on July 25, 1976. – Source: NASA/JPL
female figure mars
A photo of what appears to be a “female” figure taken on the red planet by the Spirit rover. – Source: NASA