Galaxies

Grade 8

What type of galaxy is the milky way?

Spiral Galaxy

At what speed does the sun orbit?

828,000 km/h

How long does it take for the sun to complete 1 orbit?

225-250 million years

At what speed does the galaxy rotate??

270 km/s

What is intergalactic space mostly composed of?​

Almost nothing, making it a near vacuum​

The term used for planets orbiting stars other than the Sun is….

exoplanets

What is stellar dust, and where does it come from?​

Stellar dust, also called interstellar or cosmic dust, is made up of tiny solid particles produced by stars. It consists of small molecules or rocky particles that help in the formation of gas clouds in galaxies​

What is the estimated amount of matter in one cubic meter of intergalactic space?

1 atom of hydrogen

What is the approximate size range of stellar dust particles?

A few molecules to 0.1 µm across

What are the main components of the huge clouds inside galaxies?

gases and cosmic dust

How r asteroids formed?

They formed from leftover cosmic dust that did not become planets

Planets orbiting a star form a….

planetary system

A planetary system includes:

A central star

Planets (some with moons)

Dwarf planets, asteroids, and comets

By 2020, scientists had discovered….

3163 planetary systems and 701 systems with multiple exoplanets

Who was Ernest Hubble?

He was an American astronomer who discovered that some gas clouds were vast groups of stars far outside the Milky Way

What are the 3 types of galaxies??

Spiral galaxies, elliptical galaxies, and irregular galaxies