When I was in elementary school we thought of the solar system as being the Sun and nine planets including: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Mercury. We also learned that there was a mysterious ring of asteroids between Mercury and Jupiter called the Asteroid Belt. We also knew that there were some moons out there around some of the planets. We never discussed yet another belt, the Kuiper Belt.
The Kuiper Belt is no secret but there was no thought of it existing until after Pluto was identified in 1930. In my own mind the Kuiper Belt is like the asteroid belt but further away and of necessity bigger as it surrounds the solar system starting about 30 AU from the Sun (an AU is the astronomical unit of measure of the average distance of the Earth from the Sun). Putting this in perspective, our fastest man-made probe travels at roughly 430,000 miles per hour. At that speed it would take nine days to reach the Earth from the Sun. It would take that same ship 9 months to travel to the edge of the Kuiper Belt.
So what’s in the Kuiper Belt? Again something I wasn’t aware of when I was younger was that the Kuiper Belt might seem to be a good sized junk yard if it was on Earth. It has trillions of objects, but thinking in terms of something of size, it is estimated that there are over 100,000 objects over 62 miles (100 km) in diameter. In our Asteroid Belt they have discovered about 200 objects of that size. Of course the Kuiper Belt covers a lot of ground. Remember AU? It is about 100 AU in diameter.
So what we know so far about the solar system is pretty limited, with knowledge of the Kuiper Belt only being in our history for less than a hundred years. Now they have discovered a second Kuiper Belt even further out. What do we know about it? Not much yet, other than it is out there. We know there is a sizable gap between Kuiper Belt 1 and Kuiper Belt 2.0 and it is between 70 and 90 AU from the Sun. The number of sizable objects, if we extrapolate from Asteroid Belt to Kuiper 1 Belt, would suggest millions of sizable objects and even more icy objects.