Knowledge N Fact4u

Why doesn't the planet Uranus explode if it contains so much hydrogen and methane ? •The planet Uranus indeed contains a significant amount of hydrogen and methane, both highly flammable gases. •However, the burning of methane or hydrogen requires oxygen. Simply but, there is no free oxygen on the planet Uranus.  •On earth, we are so immersed in oxygen that we tend to take it for granted. Many chemical reactions that require oxygen seem to just happen automatically on earth: metals rust, forests catch fire, and candles burn. •We may be tempted to ignore oxygen's role in a chemical reaction since it seems to be always there.  •But oxygen is not always present. If I place metal in a jar containing only argon, it will not rust. If I place a lit candle in a jar with no oxygen, its flame will go out.  •There is an easy demonstration you can do at home to convince yourself of this fact.  •Get a bowl and fill it about a quarter full with bakin...

Why is the sky not blue as seen from space ? •The daytime sky is indeed blue as seen from space. Look closely at any color-accurate photograph of earth taken from space and the blue tint of everything on the day side is unmistakable. This blue tint is the sky. •The daytime sky as viewed from space is not a solid, uniform blob of blue for two reasons: (1) there are white clouds in the sky which can be seen just as well from space as from earth's surface, and (2) the sky is not opaque. •Earth's atmosphere consists mostly of nitrogen molecules and oxygen molecules bouncing around as a gas.  •Air is close to perfectly transparent. It's a good thing, because the transparency of air is what allows you to see your computer screen and breath at the same time.  •However, air is not perfectly transparent. A very small amount of the light that passes through air is scattered in all directions instead of being allowed to continue traveling on in the forward directi...