Galaxy Formation and Characteristics

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Questions and Answers

What is a galaxy?

An isolated planet with its own orbit
A single massive star in the universe
A collection of stars, planets, nebulae, gases, dust, and other cosmic matter bound together by gravity (correct)
A group of comets and asteroids in space

How do galaxies form according to the most widely accepted model?

From clouds of dust and cosmic matter coming together and rotating around a central axis (correct)
By fusing multiple stars into one massive celestial body
Through the collision of comets and asteroids in space
From isolated planets that merge with each other

What is the approximate number of galaxies estimated to exist in the universe?

Exactly 100 billion galaxies
Over 200 billion galaxies (correct)
Less than 10 billion galaxies
Around 50 billion galaxies

What does gravity do in relation to galaxies?

Attracts matter towards the center of a mass or an object (B) Signup and view all the answers

How are light-years defined?

The distance traveled by light in one year (B) Signup and view all the answers

What distinguishes irregular galaxies from elliptical and spiral galaxies?

Lack of a distinct shape (B) Signup and view all the answers

How do elliptical galaxies differ from spiral galaxies in terms of star composition?

Predominantly composed of older, dimmer stars (B) Signup and view all the answers

Which feature distinguishes spiral galaxies from elliptical and irregular galaxies?

Central disk surrounded by spiral arms (D) Signup and view all the answers

What is a common characteristic between elliptical and irregular galaxies?

Older, dimmer stars (A) Signup and view all the answers

How do irregular galaxies differ from elliptical galaxies in terms of dust content?

Characterized by significant amounts of interstellar gases (C) Signup and view all the answers

What is the main difference between elliptical and spiral galaxies?

Elliptical galaxies are older and have stars rotating in random orbits, while spiral galaxies are younger and have stars forming actively. (D) Signup and view all the answers