We have learned about the rocks on Earth, the water on Earth, and the air on Earth. Now it is time to learn about the rest of the universe...
How did the universe begin?
The current accepted theory is called the Big Bang:
As some of that energy cooled simple matter appeared in massive clouds. These are called nebulae:
That matter (gas and dust--mostly hydrogen) started to condense under the effects of gravity until...
...the force of gravity fuses atoms together and a sun is born.
Any other matter floating in the area gets caught by this sun's gravity and form planets.
A whole bunch of these solar systems formed and clumped together by gravity into galaxies:
Galaxies come in spiral, elliptical, and irregular varieties.
The Milky Way (our galaxy) is a spiral with our solar system on one of the arms.
Stars do not live forever.
As the hydrogen in the sun fuses to helium, the sun runs out of fuel.
This makes it cool off (and swell) into a red giant.
When all the fuel runs out, it may successfully fuse helium.
If so, it will become a white dwarf (tiny and very bright due to fusing the new fuel).
If not, it may fade out.
Or, in the attempt to fuse helium, it could nova (explode).
If it enjoys a second life as a white dwarf or if it were larger to begin with, when it dies, it could supernova or collapse into a black hole.
The sun's magnetic lines get twisted by the uneven rotation. This makes chaotic flares, cooler areas, and arcs.
Every 11 years the sun's magnetic lines are so tangled that they simply realign and the sun calms back down again for a while.
The sun's surface is only about 5,500 degrees celcius, but the corona is about 2 million degrees celcius.
Sometimes there are bursts coming from the sun. Those ions travel from the sun at 400 km / second! And when they hit planets, they interact with ions in the ionosphere (outer layer of the atmosphere). The ions get excited and give off light ==> Auroras
Each planet has cool things to know about it.
There are more "planets" that keep getting discovered:
Out beyond Neptune, there are other planetoid objects. These include: Pluto and its moon Charon, Ixion, Quaoar, Eris, Sedna, Orcus, Haumea, Varuna, Makemake, and 2002 TC 302
Planets are not the only things in our solar system. Meteors:
Luna, our moon:
Since the moon rises 50 minutes later each night, there is 24 hours and 50 minutes between direct high tides. That means 12 hours and 25 minutes between high tides. That means 6 hours and 12.5 minutes between high and low tide.
Solar eclipses touch down about once a year for a few minutes and is visible in a small swath on Earth.
Lunar eclipses occur also about once each year, but are visible to about half of the Earth and for a few hours.