Galaxies and Their Characteristics

The video explores the differences between elliptical and spiral galaxies, including their shapes, star formation, and content. It discusses the origin of the term 'galaxy' and Hubble's classification system. The video highlights the characteristics of elliptical and spiral galaxies, such as their halo, bulge, and star populations. It also covers the distribution of galaxies in galactic fields and the potential future collision between the Milky Way and Andromeda galaxies.

What is the origin of the term 'Galaxy'?

• It is named after the Roman god of the sky.

• It comes from the Greek word 'Galax', meaning 'milky'.

• It originates from the ancient Egyptian word for 'universe'.

• It is derived from the Latin word for 'star'.

How many galaxies are estimated to exist in the universe?

• 300-400 billion

• 200-300 billion

• 100-200 billion

• 50-100 billion

Who developed the morphological classification scheme for galaxies?

• Edwin Hubble

• Albert Einstein

• Isaac Newton

• Galileo Galilei

Which of the following is NOT a type of galaxy in Hubble's classification?

• Lenticulars

• Spirals

• Irregulars

• Ellipticals

What is a key structural difference between elliptical and spiral galaxies?

• Ellipticals have swirling arms, spirals do not.

• Ellipticals are round to oval, spirals have a disc shape.

• Ellipticals are brighter than spirals.

• Ellipticals contain more cool gas than spirals.

Why is star formation virtually absent in elliptical galaxies?

• They lack a central bulge.

• They have an abundance of cool gas.

• They do not contain cool gas necessary for star formation.

• They are too bright for new stars to form.

What type of stars predominantly make up elliptical galaxies?

• Young blue stars

• Old red stars

• Newly formed stars

• Massive blue stars

Where are spiral galaxies typically found?

• In high-density galactic fields

• Near black holes

• In the center of the universe

• In low-density galactic fields

What is expected to happen between the Milky Way and the Andromeda galaxy?

• They will collide and distort each other.

• They will pass by each other without interaction.

• They will remain in their current positions.

• They will merge into a single galaxy.

Why might we have found more spiral galaxies than elliptical ones?

• Spirals are more common in the universe.

• Ellipticals are only found in distant galaxies.

• Spirals are easier to spot.

• Ellipticals are too small to detect.