Galaxy Basics Quiz: Milky Way, Spiral Galaxies, and Elliptical Galaxies

Galaxies are vast gravitational systems of stars, gas, dust, dark matter, and other objects.

Galaxies are enormous systems with many stars, far larger than solar systems or star clusters.

Galaxies contain stars, gas, dust, dark matter, stellar remnants, and sometimes central black holes.

Gravity from stars, gas, dark matter, and other mass holds galaxies together.

Spiral, elliptical, and irregular are broad galaxy shape categories.

Galaxy morphology means a galaxy's shape and structure.

Stars form from cold gas and dust in dense interstellar regions.

Galaxy motions suggest unseen mass; dark matter is inferred from gravity.

The Local Group is our nearby galaxy neighborhood, including the Milky Way and Andromeda.

The Milky Way is one galaxy among many, not the whole universe.

Our Solar System belongs to the Milky Way, not Andromeda, Triangulum, or the Crab Nebula.

The Milky Way is commonly described as a barred spiral galaxy.

We map the Milky Way from inside, so we cannot directly photograph its full outside shape.

The Milky Way band is our view through the dense disk of our galaxy.

The Milky Way center includes a bulge, dense stars, gas, dust, and Sagittarius A*.

The Solar System is in the Milky Way's disk, far from the exact center.

The Solar System orbits the Milky Way's center within the galactic disk.

Interstellar dust absorbs and scatters visible light, but other wavelengths can reveal hidden regions.

Globular clusters are dense, old star groups often found in galactic halos.

Andromeda is a nearby large galaxy in the Local Group.

Spiral galaxies are associated with flattened disks and spiral arms.

Spiral arms are disk regions with stars, gas, dust, and star formation.

A barred spiral has a central bar-shaped stellar structure.

Blue regions often indicate hot young stars in star-forming areas.

A spiral galaxy disk is a flattened region with stars, gas, dust, and spiral structure.

A central bulge is a dense star-rich region near a spiral galaxy's center.

Many spirals contain cold gas and dust that can support star formation.

Rotation curves show star and gas motion and provide evidence for dark matter.

Face-on means viewing the disk broadly from above or below.

Edge-on means viewing a galaxy disk from the side.

Elliptical galaxies usually look round or oval and lack clear spiral arms.

Many ellipticals are dominated by older, redder stars, not newborn blue stars.

Many ellipticals have less cold gas and dust for new star formation.

Ellipticals generally lack the clear spiral arms seen in spiral galaxies.

Ellipticals range from dwarf to giant systems and vary widely in mass and brightness.

Galaxy mergers can disrupt disks and help form or grow some elliptical galaxies.

Many ellipticals look redder because older stellar populations dominate.

Many ellipticals form fewer new stars because they have less cold gas available.

Giant ellipticals are often found near the centers of galaxy clusters.

Spirals often have disks and arms; ellipticals are smoother and rounder or oval.