Today, Mike Brown & his team from CalTech announced the discovery of a ninth major planet, which is just the third such discovery since the planets known from antiquity.
Just last year, we saw Ceres & Pluto up close for the first time, and it seemed like we maybe had the book on the solar system fairly well filled in - but now that book needs to be replaced with a new edition. And before we get close up pictures of Minerva (or whatever the ninth planet ends up being called), we'll probably need several, even many, new editions.
It might take five years to spot this new world; another 10 or more to decide to send a probe (perhaps many more, but here's hoping); perhaps 20 years to design a fast-enough probe that can communicate from such great distances; and maybe 40 years of travel time, for a total of 75 or more years to get that first picture.
So today's a good day to start thinking about it. :)
http://www.nytimes.com/2016/01/21/science/space/ninth-planet-solar-system-beyond-pluto.html
