Astronomy
Today we will be learning about nebulas, or nebulae. Nebulae are clouds of dust and gas in the universe.
Nebulae are important objects for astronomers to study because they provide insights into the processes of star and planet formation, as well as the evolution of galaxies.
Stars are made from nebulae. What causes a nebula to form? The matter, or stuff, from dying stars, causes nebulas to form. Nebulae are typically very large, spanning many light-years, and they can take on a wide variety of shapes and colors.
Even though nebulas form from dying stars, they are also where new stars are made. Nebulae are made of dust and gases—mostly hydrogen and helium. The dust and gases in a nebula are very spread out, but gravity can slowly begin to pull together clumps of dust and gas. As these clumps get bigger and bigger, their gravity gets stronger and stronger.
The Helix nebula is the closest nebula to Earth. It is 700 light years away.
Astronomy is the science of the universe.
If you like outer space, the planets, and the solar system, astronomy is for you!
Since the universe is so big, how do we measure things?
You can use two measurements, AU and lightyears.
AU (say each letter) , is the distance from the Earth to the Sun.
This is 93 million miles!
If you go to the Sun at highway speed, it would take 177 years!
Another unit is lightyear.
This is how far light travels in one year.
Light travels too fast for us to catch it, but it does take time for light to shine from one place to another.
One lightyear is 5.88 trillion miles, or 5,880,000,000,000 miles!