Foundational Concepts
Stars
Planets + Galaxies
Cosmology
Random Trivia
100
The displacement of spectral lines toward longer wavelengths (the red end of the spectrum) in radiation from distant galaxies and celestial objects. This is interpreted as a Doppler shift that is proportional to the velocity of recession and thus to distance.


What is redshift?

100

The stellar remnant left behind after a supernova explosion of the most high-mass stars. 

What is a black hole?

100
A large planet of relatively low density consisting predominantly of hydrogen and helium, such as Jupiter, Saturn, Uranus, or Neptune.


What is a gas giant?

100
The rapid expansion of matter from a state of extremely high density and temperature that according to current cosmological theories marked the origin of the universe.


What is the big bang?
100

The closest non-satellite galaxy of the Milky Way that is set to collide with the Milky Way. 

What is Andromeda?

200
the branch of science concerned with the investigation and measurement of spectra produced when matter interacts with or emits electromagnetic radiation.


What is spectroscopy?

200

A very young star that is still gathering mass from its parent molecular cloud.

What is a protostar?

200

A galaxy type primarily formed due to gravitational interactions and collisions between two galaxies. 

What is an irregular galaxy?

200

A mysterious form of matter that makes up around 85% of the universe.

What is dark matter?

200

What is the star referred to as the "North Star"?

What is Polaris?

300
A great circle on the celestial sphere representing the sun's apparent path during the year, so called because lunar and solar eclipses can occur only when the moon crosses it.


What is the ecliptic?

300

The stellar remnant left behind after a low-mass star sheds off its outer layers. 

What is a white dwarf?

300

A planet outside of our solar system.

What is an exoplanet?

300

The faint, pervasive glow of microwave radiation that fills the entire universe, representing the residual heat from the Big Bang.

What is the Cosmic Microwave Background?

300

The name for a process that occurs as an object travels into a black hole (or other high-mass object) due to extreme tidal forces, stretching the object vertically while compressing it horizontally. 

What is spaghettification? 

400

The apparent shift in a nearby star's position relative to distant background stars as Earth orbits the Sun, a perspective effect used to measure stellar distances via trigonometry.

What is parallax? 

400

A commonly-used plot that shows the relationship between a star's luminosity (or absolute magnitude) and its temperature (or color).

What is an H-R Diagram?

400

The most common method of galaxy classification.

What is the Hubble Galaxies Classification/Hubble Sequence?
400

The characteristic of the wide-scale universe represented by lambda (Λ) which represents the constant energy density of the vacuum which acts as a repulsive force driving the accelerated expansion of the universe. 

What is the cosmological constant?

400

The largest moon in our Solar System. 

What is Ganymede?

500

One of two common examples of a "standard candle".

What is a type 1a supernova OR cepheid variable?

500

Created when a low-mass star sheds its outer layers in a relatively peaceful process. 

What is a planetary nebula?

500

A galaxy type that has a disc shape without defined spiral arms. 

What is a lenticular galaxy?

500
One of two characteristics of the universe assumed the cosmological principle. 

What is homogenous OR isotropic?

500

One of the most famous supernova remnants and the first supernova remnant with a recorded supernova observation in multiple different cultures (~1054 AD). This object has a pulsar at its center and serves as a standard unit for measuring X-ray and gamma-ray sources. 

What is the Crab Nebula?

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