In what year was Pluto reclassified as a dwarf planet?

1996 2006 2016 1986

According to the IAU definition, a full planet must do all of the following EXCEPT:

Orbit the Sun Have enough gravity to be nearly round Have cleared its orbital neighborhood of other debris Have at least one moon

Which condition does Pluto fail that prevents it from being classified as a full planet?

It does not orbit the Sun It is not round enough It has not cleared its orbital neighborhood — it shares its orbit with many Kuiper Belt objects It is too small to be seen from Earth

Which dwarf planet is found in the asteroid belt (not in the outer solar system)?

Pluto Eris Ceres Haumea

Which dwarf planet's discovery in 2005 directly triggered the reclassification of Pluto?

Makemake Eris Haumea Sedna

How many dwarf planets are officially recognized by the IAU?

2 5 9 25

Which of the following correctly lists all five officially recognized dwarf planets?

Pluto, Eris, Ceres, Vesta, and Titan Pluto, Eris, Ceres, Makemake, and Haumea Pluto, Eris, Ceres, Sedna, and Quaoar Pluto, Charon, Ceres, Eris, and Makemake

Where are Pluto, Eris, Makemake, and Haumea located?

In the asteroid belt between Mars and Jupiter In the Oort Cloud far beyond the solar system In the Kuiper Belt, a region of icy bodies beyond the orbit of Neptune In orbit around Jupiter

Which dwarf planet is slightly more massive than Pluto?

Ceres Makemake Haumea Eris

Could there be more dwarf planets in our solar system that have not yet been officially recognized?

No — astronomers have catalogued every object in the solar system Yes — scientists estimate there could be hundreds or even thousands of dwarf planets in the outer solar system No — the IAU has confirmed there are exactly 5 No — dwarf planets can only form in the asteroid belt