Galaxies, nebulae, and the cosmos beyond planets.
Test your knowledge with these top questions!
Which Milky Way feature contains the Sun?
The Sun occupies the Orion Spur, a smaller branch between the Milky Way's larger Sagittarius and Perseus arms.
What do the Whirlpool Galaxy's spiral arms help create?
The arms compress hydrogen gas into dense clouds that collapse into clusters of young stars.
What mainly powers the Orion Nebula's bright glow?
Hot young stars in the Trapezium flood hydrogen with ultraviolet light, making the gas emit M42's vivid colors.
What type of galaxy is the Milky Way?
A bar of stars crosses the Milky Way's center and can funnel gas inward toward the galactic core.
What are the Orion Nebula's proplyds?
A proplyd is a gas-and-dust disk around a newborn star, the raw material from which planets can form.
Which star cluster forms the bright core of the Orion Nebula?
The Trapezium name comes from four massive young stars arranged in a trapezoid at the nebula's center.
Why does the Milky Way appear as a pale band across the night sky?
Looking through the Milky Way's flat disk edge-on packs many distant stars into one bright strip.
What object anchors the center of the Milky Way?
Astronomers map fast stellar orbits around Sagittarius A* to weigh the otherwise invisible central mass.
Which region inside the Triangulum Galaxy is a giant stellar nursery?
NGC 604 is M33's largest star-forming region and one of the Local Group's biggest stellar nurseries.
Where does the Orion Nebula appear in the constellation Orion?
Under dark skies, M42 looks like a fuzzy patch in the Sword below Orion's Belt and can be seen without a telescope.