why is sky blue what is black hole
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Answer:
❀Why is sky blue?
Gases and particles in Earth's atmosphere scatter sunlight in all directions. Blue light is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.
❀What is black hole?
A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying. Because no light can get out, people can't see black holes.
Explanation:
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Answer:
Why is sky blue?
Gases and particles in Earth's atmosphere scatter sunlight in all directions. Blue light is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.
Like most curious people, you have probably asked at some time, “Why is the sky blue?” Or if you saw a beautiful sunset or sunrise, you might have asked, “Why is the sky red?”
It’s so obvious that the sky is blue, you might think the reasons would be just as obvious. They aren’t! Of all the colors of the rainbow, why blue?
Couldn’t the sky just as easily be green? Or yellow? When we see a rainbow, we do see green and yellow in the sky, as well as blue, violet, orange, yellow, red, and everything in between.
The white light coming from the Sun is really made up of all the colors of the rainbow. We see all those colors when we look at rainbows. Raindrops act as tiny prisms when lit by the Sun, bending light and separating it into its different colors.
But why are there different colors? The light you see is just one tiny bit of all the kinds of light energy beaming around the Universe - and around you! Like energy passing through the ocean, light energy travels in waves, too. What makes one kind of light different from others is its wavelength - or range of wavelengths. Visible light includes the wavelengths our eyes can see. The longest wavelengths we can see look red to us. The shortest wavelengths we can see look blue or violet.
The wavelengths in this picture are not to scale. A red light wave is about 750 nanometers, while a blue or violet wave is about 400 nanometers. A nanometer is one-billionth of a meter. A human hair is about 50,000 nanometers thick! So these visible light wavelengths are very, very tiny.
Another important thing to know about light is that it travels in a straight line unless something gets in the way to:
●reflect it (like a mirror)
●bend it (like a prism)
●or scatter it (like molecules of the gases in the atmosphere)
As the white light from the Sun enters Earth’s atmosphere, much of the red, yellow, and green wavelengths of light (mixed together and still nearly white) pass straight through the atmosphere to our eyes. The blue and violet waves, however, are just the right size to hit and bounce off of the molecules of gas in the atmosphere. This causes the blue and violet waves to be separated from the rest of the light and become scattered in every direction for all to see. The other wavelengths stick together as a group, and therefore remain white.
What is black hole?
A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.
Because no light can get out, people can't see black holes. They are invisible. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently than other stars.
Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the mass of a large mountain. Mass is the amount of matter, or "stuff," in an object.
Another kind of black hole is called "stellar." Its mass can be up to 20 times more than the mass of the sun. There may be many, many stellar mass black holes in Earth's galaxy. Earth's galaxy is called the Milky Way.
The largest black holes are called "supermassive." These black holes have masses that are more than 1 million suns together. Scientists have found proof that every large galaxy contains a supermassive black hole at its center. The supermassive black hole at the center of the Milky Way galaxy is called Sagittarius A. It has a mass equal to about 4 million suns and would fit inside a very large ball that could hold a few million Earths.