This is the reason that stars in a cluster have similar composition.
What is formed from the same nebula?
This type of reaction produces energy in a star.
What is nuclear fusion?
These two things make up interstellar medium.
What are dust and gas?
Stars will remain on the Main Sequence until they run out of this fuel.
What is hydrogen?
This type of star cluster has 100's to 1000's of stars.
What is open?
Hydrogen atoms are fusing into this atom.
What is helium?
This type of star cluster has millions of stars.
What is globular?
This property of stars increases toward the upper left of the main sequence.
What is mass?
A globular cluster has many of this type of star.
What is red giant?
This force slowly pulls together particles within a protostar.
What is gravity?
What does "interstellar" mean?
What is "among/between the stars"?
What does OBAFGKM represent?
What are the spectral classes of stars?
What is open?
This equation developed by Einstein calculates the amount of energy released from a fusion reaction.
What is E=mc2?