The Solar System, Stars, and Galaxies

Flashcards covering cosmic hierarchy, inner and outer planets, properties of the Sun and stars, and types of galaxies.

What is the hierarchical structure of the universe from largest to smallest leading to Earth?

Universe $\rightarrow$ Milky Way Galaxy $\rightarrow$ Solar System $\rightarrow$ Earth

What are the physical characteristics of the inner planets compared to the outer planets?

The inner planets are closer to the Sun, smaller, and rockier.

Which group of planets is shown in this image, and what are their names in order from closest to furthest from the Sun?

The inner planets: Mercury, Venus, Earth, and Mars.

What are the physical characteristics of the outer planets?

The outer planets are further away from the Sun, larger, and made up mostly of gas.

Which group of planets is shown in this image, and what are their names in order from closest to furthest from the Sun?

The outer planets: Jupiter, Saturn, Uranus, and Neptune.

Why is the Sun at the center of our solar system?

It is the biggest object and has a greater mass than anything else in the solar system, which gives it the greatest gravitational pull.

How does the size of our Sun compare to other stars in the universe?

Even though it is huge compared to us, it is actually a lot smaller than many other stars.

What is the relationship between the mass of a star and its temperature?

As mass increases, so does the temperature (the greater the mass, the greater the temperature).

How does the mass of a star affect its expected lifespan?

As the mass of a star increases, the expected lifespan of that star decreases; smaller stars live longer.

Why are there more stars located at the center of the Milky Way?

Because the largest stars in the galaxy have the greatest amount of gravitational pull.

What is the definition of a galaxy?

A huge collection of stars, gas, and dust.

What are the defining characteristics of a spiral galaxy?

It is shaped like a disk and contains dust, gas, and young blueish stars.

What are the defining characteristics of an elliptical galaxy?

It is shaped like a basketball or football and contains older redder stars and little dust.

What are the defining characteristics of an irregular galaxy?

It is oddly shaped, has no bright center, and contains a large amount of gas and dust as well as lots of young stars.