These are enormous, cold clouds of dust and gas that will eventually form stars.
What are giant molecular clouds?
100
The source of power for stars on the main sequence.
What is fusing hydrogen into helium?
100
Stars moving through this region of the H-R diagram become unstable and pulsate.
What is the instability strip?
100
As it ages, the Sun will eventually begin to fuse helium into these elements.
What are carbon and oxygen?
100
The "edge" of a black hole, past which nothing can escape.
What is the event horizon?
200
Dense, dark blobs of dust and gas that represent an early stage in the collapse of a cloud to form a star.
What is a Bok globule?
200
Compared to our Sun, the average lifetime we might expect for a low-mass M-type red dwarf.
What is hundreds of billions of years or more?
200
These are low-mass pulsating variable stars with short periods.
What are RR Lyrae variables?
200
A massive star will eventually form this element in its core, signalling its doom in this kind of event.
What are iron and a supernova?
200
A super-luminous, star-like object that was more common in the early universe and which is powered by the super-massive black hole in a galaxy.
What is a quasar?
300
Compared to our Sun, the time a very massive star needs to contract and reach the main sequence.
What is much less time?
300
When the Sun runs out of hydrogen in its core, hydrogen fusion still takes place here.
What is in a shell around the core?
300
These variable stars have a direct correlation between their average luminosity and the period of their pulsations.
What is a Cepheid variable?
300
Our Sun, after it becomes a red giant, will puff off its outer layers and form this kind of structure.
What is a planetary nebula?
300
Two pieces of evidence we have for the existence of black holes, despite the fact that we can't see them directly.
What are the orbital motions of nearby objects and the emission of x-rays from the accretion disk?
400
A not-quite star that is starting to heat up due to gravitational contraction but which is not yet fusing hydrogen.
What is a proto-star?
400
The lifespan of a massive star compared to our Sun.
What is very much shorter (tens to hundreds of millions of years)?
400
Cepheid variables are useful in astronomy for determining this.
What is the distance to other galaxies?
400
The two general classes of objects left behind after a massive star explodes.
What are a neutron star or a black hole?
400
The three quantities used to describe a black hole.
What are its mass, spin (angular momentum) and charge?
500
The stage of stellar evolution where a young star, not quite to the main sequence, ejects lots of gas due to vigorous activity in its chromosphere.
What is the T-Tauri stage?
500
Over time, this happens to the stars in an open cluster, a group of stars formed from the same giant molecular cloud at approximately the same time.
What is the cluster drifts apart and scatters?
500
The name for a pair of stars that orbit each other so that they pass in front of each other from our line of sight and produce regular dips in the system's brightness.
What is an eclipsing binary?
500
A neutron star that rotates and produces a beam of radio energy that periodically sweeps over the Earth describes this.
What is a pulsar?
500
The process by which black holes will eventually evaporate and dissipate.