© 2026 LearnInShort
Why Records Beat Theory Here
Solar system questions are almost never about orbital mechanics. They are about records — which planet is largest, hottest, densest, farthest — and about a handful of fixed facts. Learn the record table and you clear this chapter in one sitting.
Start with the order. Eight planets, Sun outward:
> Mercury · Venus · Earth · Mars · Jupiter · Saturn · Uranus · Neptune
> Mnemonic: My Very Educated Mother Just Served Us Noodles.
The first four are inner or terrestrial planets — small, rocky, dense, few or no moons. The last four are outer or Jovian planets — huge, gaseous, ringed, many moons. The asteroid belt sits between Mars and Jupiter and is the boundary between the two groups.
Pluto was demoted from planet to dwarf planet by the International Astronomical Union in 2006, because it has not cleared its orbital neighbourhood. That year is asked directly.
1. Which is the hottest planet in the solar system?
2. Which planet has a density lower than that of water, so that it would float if placed in a large enough ocean?
3. In which year was Pluto reclassified from a planet to a dwarf planet by the International Astronomical Union?
4. The asteroid belt of the solar system lies between the orbits of:
5. Approximately how long does sunlight take to reach the Earth?
6. Which is the largest natural satellite in the solar system?
7. Which planet is tilted at about 98 degrees on its axis, so that it appears to roll along its orbit on its side?
8. A solar eclipse can occur only when the Moon is in which phase?