Earth's Moon
Why Do We Have Tides?
Tides
![](/sites/default/files/waves.jpg)
Credit: Ron Porter @ Pixabay.com
The level of the sea rises and falls about two times each day. We call these changes tides.
Phases of the Moon
![Lunar cycle](/sites/default/files/astro/lunarcycle.jpg)
Credit: www.moonconnection.com with permission.
The Moon is the brightest object in the night sky when its whole face is showing. This only happens at full Moon. Why isn't it always full Moon?
Moon's Orbit
![](/sites/default/files/astro/moon_orbit.jpg)
Credit: Apollo 17; NASA
An orbit is the path an object takes in space around another. The Moon makes one complete orbit of the Earth every 27.3 days. It travels around the Earth at about 4,000 kilometres an hour.