On September 23, 1846, atronomer Johann Galle discoverd another planet in our solar system. The eighth planet of our solar system was named Neptune shortly after discovery. Neptune is much larger than Earth. While Earth is nearly 8000 miles across, Neptune is 31,000 miles across! The gas giant orbits roughly 2.8 billion miles from the sun (about 30 times as far as Earth is from the sun).  Here are some books about the mighty gas giant!