Posts by 

Christopher Crockett

What is the zodiac?

Maybe you associate the word "zodiac" with astrology, but it has an honored place in astronomy, too. It's defined by the annual path of the sun across our sky.

What do redshifts tell astronomers?

Redshifts reveal how an object is moving in space, showing otherwise-invisible planets and the movements of galaxies, and the beginnings of our universe.

What are coronal mass ejections?

Coronal mass ejections - CMEs - are powerful eruptions on the sun that ripple through space and can interfere with satellites and power grids on Earth.

What are white dwarf stars?

White dwarfs are dead stars. A single white dwarf contains roughly the mass of our sun in a volume no bigger than our planet. Our sun will become a white dwarf someday.

What is a parsec?

Why do professional astronomers speak of distances in the universe not in terms of light-years, but in terms of parsecs, a distance of 3.26 light-years? Explanation here.

The ecliptic is the path of the sun

The ecliptic is an imaginary line that marks the path of the sun. You can also find the planets and moon near this line, tracing the plane of our solar system.

What are gamma ray bursts?

Only the most powerful explosions in the universe.

What is a light-year?

Hint: A light-year is a unit of distance, not time.

What are elliptical galaxies?

Elliptical galaxies are among the largest single star systems in the universe and are built by the collisions of many smaller galaxies.

What lives between the stars?

The interstellar medium is the stuff between the stars. Made up mostly of hydrogen and helium gas, it contains all the material needed to make stars and planets. It is shaped by stellar winds, dying stars, galactic magnetic fields, and supernova explosions.