A huge sphere surrounding and rotating around the earth on whose surface the stars and constellations were firmly embedded.
What is a celestial sphere?
100
This planet has 16 moons.
What is Jupiter?
200
The remnant of a white dwarf after it has cooled down. It has very low luminosity.
What is a black dwarf?
200
This dwarf is no longer considered to be a planet.
What is Pluto?
200
A small body orbiting the sun in an elliptical orbit.
What is a comet?
200
The star that is right on the celestial north pole and so appears not to move at all.
What is Polaris?
200
A region of space between the orbits of Mars and Jupiter.
What is the asteroid belt?
300
A normal star that is undergoing nuclear fusion of hudrogen into helium.
What is a main sequence star?
300
5.98*10^24 kg
What is the mass of Earth?
300
The generic name for matter in galaxies and clusters of galaxies that is too cold to radiate. Its existence is inferred from techniques other than direct visual observation.
What is dark matter?
300
In 12,000 years' time, this will point to the star Vega.
What is the axis of rotation that now points to Polaris?
300
This unit is properly defined as 3.26 ly.
What is a parsec (pc)?
400
Gas and dust that did not reach high enough temperatures to initiate fusion. These objects continue to compact and cool down.
What is a brown dwarf?
400
163.7 years
What is the orbital period of Neptune?
400
Powerful energy emitter. They are very active cores of young galaxies.
What is a quasar?
400
During December, the Earth's night hemisphere points to this constellation.
What is Gemini?
400
The most famous comet.
What is Halley's comet?
500
A red giant at the end stage of its evolution will throw off mass and leave behind a very small, dense star in which no nuclear reactions take place. It is very hot but its small size gives it a very low luminosity.
What is a white dwarf?
500
This planet was visited by only one spacecraft, Voyager 2 on Jan 24 1986.
What is Uranus?
500
A group of stars that are physically near each other in space, created by the collapse of the same gas cloud.
What is a stellar cluster?
500
During this month, Earth's night hemisphere points to Capricorn.
What is June?
500
These two planets do not have moons orbiting them.