|NASA photo of Pluto|
It has been an exciting week for space nuts. In some respects the biggest news-grabber was the discovery of “Earth 2.0”, a planet orbiting a yellow dwarf star a little larger than our sun, in the Goldilocks zone. It's fourteen hundred light years away, so we won't be visiting soon, but although I'm not quite as excited as some, the discovery adds weight to the already impressive argument that we can't possibly alone.
Personally, I'm much more excited about the data from Pluto.
I'm not a scientist, just an interested spectator. I was expecting a barren, frozen rock rather like our own moon, swinging around the distant sun in its wildly eccentric orbit that sometimes means Pluto is closer to the sun than Neptune. I was wrong. Frozen, sure. But just a rock? Uh-uh. Pluto has an atmosphere. Pluto is not covered in impact craters – which means it is geologically active. Pluto has canyons, and Pluto has solid, water ice mountains as high as the Rockies. All this on a sphere smaller than Earth's moon. Exactly what size is one of the many things NASA's New Horizon probe has been able to calculate, as reported here. And that's one of the things that interests me. Our moon has negligible atmosphere; Pluto's can be measured. It seems that heart-shaped thing is a glacier. There may be organic molecules on the surface. This article on Space.com gives a great, potted explanation of what has been discovered so far.
The reason I find all this so fascinating is mainly because of the water ice, and the organic molecules. It has been speculated that Earth's water came from asteroids. Pluto is the largest known object in the Kuiper belt, the source of comets and asteroids. Perhaps just such a body collided with the early Earth, contributing its water and its organic molecules to the primordial mix?
I watched and rewatched the footage which Voyager sent back to Earth during its encounters with Jupiter, Saturn, Uranus and Neptune back in the eighties and nineties. Until now, that data was all the scientists had to play with. They learned so much about the outer planets from that data and it still forms the basis of many of their theories. The New Horizons mission has answered some questions and raised many others. The Dawn comet mission is set to send back more data as the host comet plunges towards the sun. And Kepler continues to discover more exoplanets. Meanwhile, work is proceeding on the James Webb space telescope, set to replace Kepler. Who knows what it will discover?
It's an exciting time to be alive.