What is a star?
An object that produces its own energy, including heat and light.
What is a nebula?
A huge cloud of gases and dust (mostly hydrogen atoms).
Name three of the five stages of a normal star's life cycle.
Nebula, protostar, star, red giant, white dwarf.
At 10 million degrees Celsius, hydrogen atoms combine together to form what?
Helium.
At 600 million degrees Celsius, hydrogen atoms combine together to form what?
Iron.
What's an exploding star called?
A supernova.
What do supernovas form?
New nebulas.
How might a massive star end its life cycle?
As a black hole.
What is a black hole?
An object so dense with such powerful gravity that nothing can escape from it, not even light.
How can astronomers discover planets around distant stars that they cannot see?
By looking at stars with irregular motions and making an inference.
