Introduction to ASTR 1010L and the Solar System

Introduction to ASTR 1010L and the Solar System

Complete this lab before any other lab and ideally by 6/10/21

Object What are two main features or characteristics you observe on or about this object? What do you see that seems to be unique to this object?

Mercury It is rocky.

It is the smallest planet in the solar system. It is closest to the sun than any other planet.

Venus It is the hottest planet on the solar system.

It has a nearly round shape. It is covered with thick clouds.

Earth It is almost a sphere.

It has a solid surface. 70 percent of the earth’s surface is covered by water.

Mars It is rocky.

It has a thin atmosphere. Most of its surface is covered by red dust

Ceres It has a rocky inner core

It has a dusty outer crust It has an icy mantle.

Vesta It is almost spherical.

It is rocky and dense. It is separated into crust, mantle and core.

Mathilde It is very dark.

It has an albedo Not water or sign of hydrated features.

Gaspra It has several small craters.

Irregular in shape. Usually red and S-shaped.

Object Two observed features or characteristics Something unique

Jupiter Covered with clouds.

Has relatively low density. Its atmosphere is made up of mostly gases.

Saturn Less dense than all the planets.

It is covered by gases. Less dense than water.

Uranus Made up of water and other fluids.

It is blue in color because of the presence of methane in its atmosphere. It is the coldest planet.

Neptune It is dark and cold

It Is very windy It is the last planet.

Pluto It is rocky and icy.

It has a thin atmosphere It is heart-shaped

Earth’s Moon Its gravity influences the earth’s tides

Its bright at night. There is water in the moon.

Mars’ moons

Phobos and Deimos Irregular in shape.

Smaller compared to other moons. Look more like steroids than moons.

Jupiter’s moon

Io It has low density.

Crust mostly covered by ice It has its own magnetic field.


moon Ganymede It has a magnetosphere

Has a thin oxygen atmosphere. Largest moon in the solar system.

Saturn’s moon

Titan Covered by clouds

Crust with ice water. Contains largest seas


moon Mimas Ovoid shaped.

Mostly composed of ice water Smallest moon.

Saturn’s moon

Iapetus Full of craters

Saturn’s largest moon Bright hemisphere


moon Miranda Its rocky.

Its inner core surrounded by ice. Orbit is inclined.


moon Charon Large moon

Considered a dwarf moon. Its surfaces face each other.

Halley’s Comet Made of ice, gas and dust.

Bright and glowing appearance. It moves backward when orbiting.

Comet Hyakutake Long period comet

It passes close to the earth. It is the brightest comets.

Look at “The Planets To Scale” image. There are two really large planets, two medium sized, two small, and two very small!

Which FOUR planets are the terrestrial planets? (Terrestrial means Earth-like, which indicates that they have rocky surfaces and iron cores like the Earth – these planets do not have water on their surfaces or atmospheres like ours.)

Mercury, Venus, Earth and Mars.

Go back and look at the picture of Venus in the Solar System Bodies collection. What do you think you’re seeing instead of the rocky surface?

Craters, volcanoes, lava plains and mountains.

Which FOUR planets are the giant planets?

Jupiter, Saturn, Neptune and Uranus

What are some similarities and some differences you notice among these four planets? Similarities:

They have more than one moon.

Made up of rock and hydrogen compounds.


Main component of Neptune and Uranus is carbon, nitrogen and oxygen.

Main component of Jupiter and Saturn is Hydrogen and Helium.

Another great size comparison is seen in “Earth and Jupiter’s Great Red Spot To Scale”. We’ll study the Great Red Spot more in the Jupiter lab, but it’s basically a gigantic hurricane-like storm. Based on the pictures in the last few questions, how many times larger (across its equator) is Jupiter than the Earth?

Draw a sketch to help you remember. **If you are typing your answers, then sketch this on a piece of paper and either insert a photograph or scan of your sketch into this document or upload it separately.**

Jupiter is 11 times larger than earth

Look at “The Solar System As Seen From The Top”. Based on this diagram, what can you say is really different about asteroids and the comets (found in the Kuiper Belt) than the 8 planets?

While asteroids are made of metals and rock, comets are comprised ice and dust (Kanas, 2019). Asteroids and comets in the Kuiper Belt are larger than the asteroids and comets of the 8 other planets

What do you notice about the size of the planets relative to the amount of space in the solar system?

Inner planets including; Mercury, Venus, Earth and Mars are smaller while outer planets such as Jupiter, Saturn, Uranus and Pluto are larger.

If you choose to do the Solar System Model Bonus Project, you will see that even those little dots are actually too big!

To compare to the moons, asteroids, and Pluto, look at both “The 15 Largest Objects in Our Solar System” and “The Not-Planets”.

Make observations about the sizes of the smaller terrestrial planets compared with the larger moons.

Smaller terrestrial planets such as Mars and Venus are quite smaller than other larger moons (Singer et al., 2021). The smallest terrestrial planet, mercury is 4879 km while the largest moon, Jupiter’s Ganymede is 5,268 km.

Make observations about the sizes of the smaller terrestrial planets compared with Pluto.

Pluto is larger than smaller terrestrial planets. They have larger number of satellites compared to terrestrial planets (Kanas, 2019). Unlike terrestrial planets which have solid surfaces, Pluto has no solid surface.

Make observations about the sizes of the asteroids Ceres and Vesta compared with the terrestrial planets and larger moons.

Some of the asteroids such as Ceres and Vesta are larger than terrestrial planets such as Mercury. They are quite similar to larger moons because of their size (Kanas, 2019). Some asteroids such as Vesta are larger than some moons such as Mathilde.

In comparison, Vesta is about 10 times the diameter of Mathilde (not in these diagrams but in the Solar System Objects), and most asteroids are even smaller!

The Kuiper Belt is the region of space around the Sun that holds the comets and Kuiper Belt objects. (Kuiper Belt objects are essentially just really big comets; Pluto is one of the two largest known Kuiper Belt objects.) Because they are so far from the Sun, comets and Kuiper Belt objects are made of not only rock and metal but also significant quantities of ice.

Look back at the pictures of the comets in the Solar System Objects. The photograph of Halley’s Comet shows its nucleus, which is the small icy/rocky part of the comet that is the responsible for the fuzzy coma (the round part in the lower left) and tail that you can see in the picture of Comet Hyakutake.

The nuclei of most comets are very small – Halley’s is pretty typical at 10 miles along its long axis, less than 1/3 the size of Mathilde – and yet the tails of a comet can easily stretch well over a million miles. The photograph of Halley’s Comet was taken by a spacecraft when the comet was close to its closest approach to the Sun. What do you think is happening to the comet to make the jets you can see in the left side of the picture?

The comet is orbiting round the sun hence making it stretch miles away and appear larger (Singer et al., 2021). However, when the comets are static, they appear smaller as they do not stretch (Kanas, 2019). As the comet orbits, it is drawn close to the sun and hence appears closer when captured by a spacecraft.

This is the kind of thing we will be doing for some of our labs – looking at pictures, learning about the objects, and then seeing what we can learn when we apply our knowledge to photographs of planetary surfaces.

Finally, to get a little feel for the rest of the universe, answer the following questions. You can do research online or in your lecture textbook.

What is a galaxy?

A galaxy is a system comprising of gas, dust, stars and their solar systems being held up by gravity.

What name do we give the galaxy we live in?

Milky Way Galaxy

Roughly sketch what a galaxy like ours looks like. **If you are typing your answers, then sketch this on a piece of paper and either insert a photograph or scan of your sketch into this document or upload it separately.**

Milky Way Galaxy

Approximately how many stars are in a galaxy like ours?

There are over 10 million stars scattered over our galaxy.

What is a light year?

It is the distance that light travels in vacuum in one year

How many light years away are we from the center of our galaxy?

We are 25,000 light years away from the center of our galaxy.

Show where the solar system is located (very roughly!) on your sketch of our galaxy (part c).

It located about 27,000 light years from the center of the galaxy.

Approximately how many galaxies are in our Local Group of Galaxies?

30 Galaxies.

What is the name of the other large spiral galaxy in the Local Group?

The Milky Way and the Andromeda Galaxy

How many light years away is that galaxy?

Over 70 million light years away.

Approximately how many galaxies are in our universe?

Over a trillion galaxies

How many light years away are the most distant galaxies?

13.4 billion light years.

How does this all make you feel!?

Our galaxy is complex and difficult to comprehend. It will take us several years to understand our galaxy.


Kanas, N. (2019). Our expanding solar system: Planets and moons. Solar System Maps, 141-192., K. N., Grundy, W. M., White, O. L., & Binzel, R. P. (2021). Introduction to Icarus special issue “Pluto system, Kuiper belt, and Kuiper belt objects”. Icarus, 356, 114269.