７ Solar System

７　Solar System

○The Solar System is located in the Orion Arm, 26,000 light-years from the center of the Milky Way (100,000 light years in diameter).
○There are 200 billion stars in the Milky Way galaxy.
○The solar system is orbiting in the galaxy at a speed of 220km / s, for about one orbiting of the galaxy about 225-250 million years. [1]
○Revolution speed of the Earth is 30km per second.

○The brightness of the sun was only about 70% of the current in 4.6 billion years ago when the solar system was born, that has been increasing the brightness gradually thereafter. 
○The sun continues to increase the brightness at a rate of 1% in about 100 million years now. [2]

Zooming out the Solar System [1]

○The earth revolves in Milky Way Galaxy while drawing a spiral.＜You Tube [3]＞

【References】
1. Wikipedia：Solar System
2. Wikipedia：スノーボールアース
3. You Tube：The helical model - our Galaxy is a vortex
https://www.youtube.com/watch?v=C4V-ooITrws&ebc=ANyPxKpN2IVUNbkZQH_I0UWh1cGk_Yz4d3Xz4-vd2Np7c1cYC4gBbdYbCEsT_5Fo-V1zZCgSF1PALLZyeq041CWHdx1_PTFDdA