All around US is associate invisible mixture of gases we tend to decision air. It contains concerning fifteen completely different gases, though most of it’s simply two-nitrogen and element. The precise content of air varies from place to position. For instance, damp air has additional vapour than dry air. Hazy air contains additional floating mud particles than clean air. The blanket of air around Earth is understood because the atmosphere and this can be wherever weather happens.

As the Earth and its atmosphere spin once every day, the sun warms different areas by different amounts. Warm air is lighter and rises, therefore cooler air flows on to require its place. This moving air is wind and it’s a kind of energy. we tend to catch and use wind energy in many ways, from ancient windmills that grind grain and elevate water, to the most recent wind turbines manufacturing electricity.

Almost all of air—about ninety nine percent—is nitrogen.

The sounds we tend to hear is created by vibrations within the air. These travel into our ears, wherever nerves develop the vibrations and send signals to our brains. Our voices, musical instruments, and horns and sirens all go by inflicting vibrations within the air.

Smog could be a mixture of smoke and fog. It forms in settled areas wherever mud, smoke, fumes, and chemicals from cars and different vehicles, factories, and power plants all create the air hazy. Air pollution is worse once there’s no wind, or once hotter air flows over the impure air and traps it close to the bottom. It will cause respiration issues and different health hazards.

All the air within the atmosphere weighs half dozen.1 quadrillion tons. Concerning 1/millionth of Earth’s weight.


Like islands in a vast sea of space, most galaxies are millions of light-years apart. However, some galaxies are close enough to be pulled by gravity into clusters. Members of galaxy clusters can pull on each other so strongly that they collide.

Stephan’s Quintet is a group of galaxies that appear to be smashing into each other. Four of them are about 280 million light-years away from Earth, but the fifth is closer to us. NGC 7318b is passing through the main group at nearly 200 million mph (320 million km/h). This creates a shock wave that causes the gas between the galaxies to heat up and give out X-rays (the light blue region in the middle).

Cluster collision
The ultimate crashes occur when several clusters of galaxies collide. The biggest collision astronomers have seen so far is a pile-up of four clusters called MACS J0717. This filament (stream) of galaxies, gas, and dark matter is 13 million light-years long. It is moving into an area already packed with matter, causing repeated collisions. When the gas in two or more clusters collides, the hot gas slows down. Galaxies don’t slow down as much, so they end up moving ahead of the gas.

A distorted view
Some galaxy clusters act as magnifying glasses in the sky. Their powerful gravity distorts the space around them. This means that light from more distant galaxies or quasars is bent on its way to us. We see multiple arcs and distorted images of the distant object, like a mirage in space.