Classification and Characteristics of Galaxies

The video explains Edwin Hubble's classification scheme for galaxies, categorizing them into elliptical, spiral, and irregular types. It details the characteristics of these galaxies, including their shapes, star formation activities, and spectral types. The video also discusses the concept of dwarf galaxies, which are classified by mass rather than size, and highlights the interactions between different galaxy types.

What is the primary basis for Hubble's classification of galaxies?

• Their distance from Earth

• Their color

• Their size

• Their shape and structure

Which type of galaxy is known for actively forming new stars?

• Elliptical galaxies

• Spiral galaxies

• Irregular galaxies

• Dwarf galaxies

Which type of galaxy is most likely to have a bar structure?

• Elliptical galaxies

• Irregular galaxies

• Spiral galaxies

• Dwarf galaxies

What is a key characteristic of elliptical galaxies?

• They are mostly blue in color

• They are actively forming new stars

• They are featureless and massive

• They have prominent spiral arms

Why do elliptical galaxies appear yellowish or red?

• They have a lot of gas and dust

• They contain many young stars

• They are dominated by older stars

• They are closer to the sun

What typically causes irregular galaxies to form?

• Lack of star formation

• Interactions with other galaxies

• Being isolated in space

• Having a high mass-to-light ratio

What does the 'P' in Hubble's classification scheme stand for?

• Parallel

• Primary

• Prominent

• Peculiar

How are dwarf galaxies primarily classified?

• By their distance from Earth

• By their shape

• By their mass

• By their color

What is a common characteristic of dwarf galaxies?

• They are easy to observe

• They are mostly elliptical

• They have high surface brightness

• They are very bright

What is a significant challenge in observing dwarf galaxies?

• Their high luminosity

• Their large size

• Their rapid movement

• Their low surface brightness