Until about 10 years ago, the Planetary System looked like:
- But in 1992 the first Trans-Neptunian object found.
- It was 10% size of Pluto, so not a 'planet'.
- As equipment got better we started to find more and more of them.
- All were much smaller than Pluto, but it got people thinking.
- But, the largest was getting larger.
- Then a couple of weeks ago, we found one BIGGER than Pluto!