NASA recently released another image of Pluto, and it’s one of the most stunning yet.
It looks like a frozen pond, doesn’t it? New data from the New Horizons spacecraft points to just that and hints that liquid may have flowed across the dwarf planet’s surface.
Did you know: Pluto has tropic and arctic regions. ‘Tropic’ isn’t exactly a word we think of with Pluto, but the dwarf planet has seasons just like those on Earth. Like Earth, Pluto also contends with Milankovitch cycles. These are long-term orbit variations that cause changes in climate over hundreds of thousands of years.
For Pluto, these Milankovitch cycles cause the arctic and tropical regions to push and pull back over time. Here’s an image showing how these regions advance and recede over time.
You can also see just how much more titled it is compared to Earth in the image. That means its arctic zones stretch to nearly the equator sometimes. Right now, Pluto sits in an intermediate climate, resting between two extreme climate states.
The climates of Pluto point to another intriguing feature. Note the dark band spanning nearly the entire planet.
Richard Binzel, from MIT, says this zone is the only region on Pluto that is always tropical. It always gets a day/night cycle and never has to deal with a long, cold arctic winter. If there’s one spot to be on Pluto, this is it. Better bring your jacket, though – it’s still chilly.
The way Pluto’s seasons work could also explain the dark appearance of the equatorial band. Ice and volatiles don’t build up here like they do everywhere else on Pluto.
A thicker atmosphere = liquid nitrogen
The New Horizons team also noted these Milankovitch cycles (climate cycles) can produce stunning atmospheric effects. According to data from New Horizons, atmospheric pressure has undergone dramatic changes in Pluto’s history. How big are we talking? New Horizons’ Alan Stern says pressure changes could have varied by four orders of magnitude.
We are talking about pressures that could have exceeded those seen on Mars by factors of 4 to 40 times. Unfortunately for us, the current atmospheric pressure is low compared to past levels.
“In extreme cases the pressure and temperature can exceed the triple point of nitrogen, allowing it to be stable even as a liquid on Pluto’s surface,” reads their conclusion. Pluto may have had flowing liquids on its surface in the past. This little dwarf planet never ceases to amaze. Here’s one slide showing two other features that suggest flowing liquids.
I can’t recommend the press briefing video below enough. If you want to learn what’s going on with Pluto alongside researchers, check it out.
And the crazy part? New Horizons is still downlinking data. Who knows what other surprises the dwarf planet and its moons have in store for us.
Image credits: NASA