Define planets
What Is a Planet? The International Astronomical Union (IAU) defined a planet as having the following three essential criteria:
- A celestial object that orbits a star
- Is large enough that its gravity pulls it into the shape of a sphere
- Has cleared other objects in its orbital neighborhood
The word planet comes from the Greek word planetes, which means 'wanderer.' This is because the planets appear to wander amongst the fixed stars in the night sky as they orbit the sun. As of June 2013, approximately 900 planets have been identified in the universe. However, it's estimated that there are trillions of them out there. Scientists believe it's very likely that one of these trillions of planets is capable of supporting life.
In our solar system, there are eight official planets. Listed in order of proximity to the sun, they are:
- Mercury
- Venus
- Earth
- Mars
- Jupiter
- Saturn
- Uranus
- Neptune
A great way to remember the order is to use the acronym: My Very Eager Mother Just Served Us Nachos.
The International Astronomical Union (IAU) defined a planet as having the following three essential criteria:
- A celestial object that orbits a star
- Is large enough that its gravity pulls it into the shape of a sphere
- Has cleared other objects in its orbital neighborhood
The word planet comes from the Greek word planetes, which means 'wanderer.' This is because the planets appear to wander amongst the fixed stars in the night sky as they orbit the sun. As of June 2013, approximately 900 planets have been identified in the universe. However, it's estimated that there are trillions of them out there. Scientists believe it's very likely that one of these trillions of planets is capable of supporting life.
In our solar system, there are eight official planets. Listed in order of proximity to the sun, they are:
- Mercury
- Venus
- Earth
- Mars
- Jupiter
- Saturn
- Uranus
- Neptune
A great way to remember the order is to use the acronym: My Very Eager Mother Just Served Us Nachos.
