Yes, Pluto is warming as well. Surprised? I mean, really…
Pluto has a very eccentric orbit. On its closest approach to the sun, its distance to the sun is 4,436,824,613 km. When it is the farthes away from the sun, its distance is 7,375,927,931 km, and even for the metric impaired it should be clear that that is quite a difference. It needs 248.09 years to complete one orbit. Near perihelion (that is when it is closest to the sun), it is even nearer to the sun than Neptun. Last time that happened was from February 7, 1979 through February 11, 1999. It is now farther away, and still receding from the sun – but the ‘close’ encounter had consequences.
Pluto’s atmospheric pressure has tripled over the past 14 years, indicating a stark temperature rise, the researchers said. The change is likely a seasonal event, much as seasons on Earth change as the hemispheres alter their inclination to the Sun during the planet’s annual orbit.
They suspect the average surface temperature increased about 3.5 degrees Fahrenheit, or slightly less than 2 degrees Celsius.
The increasing temperatures are more likely explained by two simple facts: Pluto’s highly elliptical orbit significantly changes the planet’s distance from the Sun during its long “year,” which lasts 248 Earth years; and unlike most of the planets, Pluto’s axis is nearly in line with the orbital plane, tipped 122 degrees. Earth’s axis is tilted 23.5 degrees.
Though Pluto was closest to the Sun in 1989, a warming trend 13 years later does not surprise David Tholen, a University of Hawaii astronomer involved in the discovery.
“It takes time for materials to warm up and cool off, which is why the hottest part of the day on Earth is usually around 2 or 3 p.m. rather than local noon,” Tholen said. “This warming trend on Pluto could easily last for another 13 years.”
The article also mentions the possibility of vulcanos.
So, we do have a very simple explanation.
New data will be available soon, when Pluto will eclipse a star, and this event will be visible (with powerful telescopes) in the southwestern US.
Image is from the wikipedia.