Why is the sky blue?
Why is grass green?
I'll keep updating this blog over time, expect answers of 2-3 sentences to questions that may have crossed your mind many times before. Thanks, Adam King. X
The sky is blue due to the interaction of photons that have travelled the 8 minutes to the Earth from the Sun. They are being absorbed by the Oxygen in our atmosphere, however, the BLUE photons are being re-emitted/reflected and that is why the sky is blue.
You can take this fact and apply it to anything with colour!! If something is red, it is emitting/reflecting RED photons.
Grass/plants are GREEN because they use red and blue photons as energy for photosynthesis but reflect GREEN - this is probably due to the GREEN photons being of no use to them. I think they are spectacularly clever and GREEN is a nice colour - on a plant of course :-D. X
THE SUN IS WHITE! Yes, its true! It only appears yellow because we are observing it through our atmosphere. If you were to somehow view the Sun in a vacuum - it would be white. Why is it white? Well, visible light that has been "split" by a prism shows all the colours of the rainbow but if you use another prism the light essentially comes back together and when this happens - it is WHITE. All the colours of the rainbow together are WHITE. You look at the night sky when it's clear and you see many many stars and they are white. The Sun is a star and it's white too!! X
Why are Sunsets' RED? Well, if you've read the answer above as to why the sky is blue then this will make perfect sense. As the Sun sets on the horizon it appears to get lower in the sky because of the Earths spin and we are heading for night-time where we are on Earth at that time. Due to the Sun being lower on the horizon, the photons (light) will pass through more of the Earths atmosphere and encounter other gases such as pollution and perhaps water vapour. This results in the scattering of RED light predominantly, hints of orange are there too. So basically its all about YOUR position on the Earth and fundamentally, what is YOUR SUNSET is someone elses SUNRISE. X
Why are stars and planets spherical-shaped?
Gravity is the cause. Gravity is responsible for "building" every galaxy, star, planet, asteroid and comet. If I gave you a bunch of rocks and instructed you to "squash" them all together at the same time or told you that you had to make these rocks as small and compact as possible, you would proceed to wrap your hands around them and squeeze. You would form a sphere with your hands as you crushed the rocks. Gravity forms rocks into spheres because it is the only shape in which MASS can be evenly distributed. Think about it for a second.........you wouldn't see a square planet or a pentagon planet would you? It would have edges and be uneven. MASS is evenly distributed throughout a sphere and therefore it is BALANCED. If something is BALANCED it is in a suitable state. Stars are born due to gravity forcing atoms of Hydrogen together yet the resulting nuclear fusion causes outward pressure that is almost equal to the crunching of GRAVITY. The star is BALANCED. The Earth is actually referred to as an OBLATE SPHEROID - it isn't perfectly spherical - it BULGES at THE EQUATOR.
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