Pluto’s atmosphere has been studied since the 1980s, using spectroscopy and stellar occultation (watching starlight flicker as Pluto passed in front of it). It wasn’t a surprise when New Horizons observed it.
I wasn’t thinking about the atmosphere. I meant in general, Pluto surprised more than other first fly-bys. Uranus is obviously extra weird in a lot of ways but who was expecting Pluto to be as interesting?
Short answer? Because it does. It doesn’t take much to be visible compared to space.
Oh wow that’s really cool! I didn’t know.
It’s about one millionth of the pressure of earth’s atmosphere at sea level.
I don’t think any planet1 has surprised us more than Pluto.
1 I know. If anyone gets pedantic, they’re reclassified as a dwarf clown.
Pluto’s atmosphere has been studied since the 1980s, using spectroscopy and stellar occultation (watching starlight flicker as Pluto passed in front of it). It wasn’t a surprise when New Horizons observed it.
I wasn’t thinking about the atmosphere. I meant in general, Pluto surprised more than other first fly-bys. Uranus is obviously extra weird in a lot of ways but who was expecting Pluto to be as interesting?