According to the International Astronomical Union (IAU) there are currently five planets classified and accepted as dwarf planets: Ceres, Pluto, Makemake, Haumea, and Eris.
These dwarf planets are much smaller than the Earth.
Here is Pluto compared to the Earth.
Except for Ceres, which is found in the main asteroid belt, these dwarf planets are located beyond Neptune in the Kuiper Belt.
How is a dwarf planet different from a planet?
According to the IAU International Astronomical Union
A planet must meet these three guidelines.
1. Orbit the Sun
2. Have enough mass to assume a hydrostatic equilibrium.
In other words, have a round shape.
3 Have enough mass to have cleared the neighborhood around its orbit.
A dwarf planet has satisfied 1 and 2 of the qualifications but does not have the mass to clear its neighborhood of all objects in its orbit by either collision, capture, or gravitational disturbance.
Ceres which is found in the asteroid belt and is smaller than Earth's Moon. Ceres is heavily cratered with large amounts of ice underground. Ceres does not have a moon.
Pluto is the first large object discovered in the Kuiper belt and was considered a planet for many years. Pluto is 39 Astronomical units from the sun compared to Ceres which is only 2.8 au away from the sun.
Pluto has 5 moons to revolve around it.
Here is the size of Pluto compared to the Earth.
Haumea is located in the Kuiper belt. This dwarf planet has a distinctive egg shape because it rotates rapidly. Haumea has two moons.
Eris has a diameter slightly smaller than pluto but is the most massive of the dwarf planets. It is found on the edge of the Kuiper belt. At times Eris will be almost three times further away from the sun as Pluto.
Eris was considered the tenth planet by NASA until August of 2006 when the IAU defined dwarf planets
Eris has one moon.When a line is cut into two and we know one angle, we can always find the other one.
The two angles are supplementary, which means they add to 180 degrees.
For example, if one angle is 40 degrees we know the other angle is 140 degree.
or if one angle is 80 degrees we know the other angle will be 100 degrees.
Angle a equals 180° - 80° = 100°
This method can be used for several angles on one side of a straight line.
Example: What is angle "b" in the picture above?
