I went to the museum of natural history last saturday. The Universe was born 15 billion years ago, and the earth was formed 4.6 billion years ago. I saw the 8 planets of solar systems, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Originally, there was 9 planets including Pluto, but actually it was too far from the sun and small than the other planets, so Pluto got out of the solar system.

I also saw some dinosours, and one of those, there was the troodon. Troodon weighed about 22.7kg, and the brain weighed about 37~45g.

It was an interesting time in the museum.