Astronomy 101

01 The Solar System

Our solar system includes everything affected by sun’s gravity. By the way, sol comes from the Latin meaning sun.  So that’s where solar  comes from. You could even think of our solar system as being our “sun system.” Humans and life forms on earth continue to exist because of the healthy presence of our sun. At some point, the sun will die.

But that’s a long time away, so don’t stress too much. Also, a lot of smart people believe the universe is expanding, so that could possibly be good and give humanity time to find somewhere else to support life. Think of it as a race between the sun dying and the universe expanding enough to find us another home. But don’t think of it right now. Don’t let the looming extinction of our planet and all life forms in our solar system be at the top of your list of concerns. Your first concern should be: did I make my bed this morning?

If you didn’t, no worries. I didn’t either. Moving on from total annihilation of our species and basic morning chores to the fundamentals of our sun system: here we go.

The sun is approximately 93 million miles away. That is a fairly accurate number, as I believe smart people have actually used a measuring tape to arrive at that exact number. Or radio telescopes and such. More on those later. That number of 93 million miles is significant, because it’s such a big number that it was decided to invent a new measurement for gauging distances in the universe: an astronomical unit (AU).

One astronomical unit (AU) equals 93 million miles

So the solar system has a bunch of planets and other stuff orbiting around it, like moons and asteroids.

Inner planets

There are four planets closer the sun than the others, and they’re known as terrestrial planets, because - and of course you know this because you’ve studied Greek - terra refers to earth. So they’re terrestrial planets because they have iron cores and are made up of rocks, similar to Earth.

The terrestrial inner planets are (in order from the sun):


Earth is the only one known to support life. It has several things that make it unique, such as liquid water, an atmosphere, an an ozone layer.

Mars is known as the red planet and has a book series written about it by Pierce Brown. I highly recommend it.

Outer planets

The outer planets are farther from the sun than the inner planets. They are not terrestrial, they are gas giants because they’re basically made up of gas and sludge. A sludgy gas. They’re way bigger than the terrestrial planets. Jupiter is the biggest of them all. But Uranus has the coolest name. But Neptune has rings.

Dwarf planets

Pluto is the most well-known of the dwarf planets, probably because it used to be an actual full-fledged planet. Did it change, in any significant physical or chemical manner? No. It got demoted. Suddenly and ignominiously. Imagine being a king, a good and mild-mannered, yet competent king, and then suddenly someone decides your kingdom isn’t big enough so they change your listing on the map so now you’re a mayor of a town instead of the king of a kingdom. That’s Pluto.

Is a dwarf planet bigger or smaller than a regular planet? Figure it out. Use the contextual clues to figure this one out.

Dwarf planets still orbit the sun like their big siblings, but their gravity isn’t strong enough to suck in planetary debris and keep the neighborhood clean.

So you’re wondering what happened to Pluto. Pluto’s narrative really is the Macbeth of planet stories, except poor Pluto didn’t really do anything wrong at all, so it’s not really like Macbeth at all, besides a *spoiler alert* tragic ending. Also, Pluto gets demoted, rather than dying. *spoiler alert* Macbeth dies. But then again, we all must die, including the sun, someday. Memento mori.

What happened is this: in 2005, scientists discovered a dwarf planet called Eris. This discovery made them rethink the definition of planet, as Eris was almost as big as Pluto. Rather than adding Eris as a tenth planet, they subtracted Pluto from the major leagues and made him a dwarf. But ideally Pluto is happy now having some playmates his own size. Pluto, Eris, and Ceres. A happy trio of dwarves.


Guess what?! There’s other stuff floating in the solar system besides planets and dwarf planets! The largest are asteroids. Asteroids are large chunks of rock that get hurled around and mostly hang out between Mars and Jupiter in a sweet spot called the Asteroid Belt.

Comets are pretty cool too, in the sense that yellow snow is cool. Kind of icky gross cool. The best way to describe comets is analogous to the famous Charles Chaplin quote:

Life is a tragedy when seen in close-up, but a comedy in long-shot.

Comets are beautiful when seen from afar; that beautiful light trail of white streaking through the night sky. That’s the fun comedy part; the pretty part. But up close, they’re basically made out of dust and rock particles, frozen gases, ice, that sort of stuff as they do their big giant clunky orbits. So enjoy from afar.

At first guess, you might think that meteroids, meteors, and meteorites have nothing to do with one another. After all, they all have totally different suffixes. But guess what?! They’re all related!

A meteoroid is a chunk of rock that breaks off from a bigger interplanetary rock and then makes a beeline for Earth and its mesmerizing gravity. Then…

…that meteoroid becomes a meteor when it enters earth’s atmosphere and start to burn up from all the friction. This turns them into a bright streak that some like to gleefully call a shooting star. So basically meteors are not so much the chunk of rock itself, but the flash of light we see as it’s self-immolating. They’re like the rainbows of the night. Only they usually die.

If - and this is a big IF - they make it to Earth without burning up, they’re called a meteorite. So the life cycle is kind of like that of a butterfly that started off as a millipede, or ant, or whatever they start off as.

A surprising number of meteors have actually hit the Earth. If you need one more thing to worry about, then think on this, but find comfort in knowing that if you get hit by a meteorite, you will die instantly. Even if it’s a small one. However, if you’re standing at your mailbox, and your mailbox is a ways from your house, and a meteorite hits your home, then you might survive, but your house will likely not, and the resulting destruction may or may not be covered by your homeowners insurance, at which point you may wish you had been struck dead instead. But the point is, try to be aware at all times that you could get struck by a meteorite and take appropriate actions to protect yourself and your loved ones. There’s really nothing you can do, except worry and hope that it doesn’t happen.

Have you ever heard someone ponder the idea that too much knowledge can sometimes be a bad thing?. This might be a good example. You probably don’t need to know anything about meteorites, including the fact that they exist and could instantly annihilate you without any warning. On the other hand, if you own a large piece of property and it landed a safe distance from your house in a pasture where there wasn’t any cattle, you might have a good-sized swimming hole excavated for you without having to rent any earthmoving equipment.

So there’s definite upsides to meteorites as well. Just remember to try and avoid being underneath one if possible. It’s not possible to avoid them, so just avoid ever looking up. If you’re going to get hit, you’re going to get hit and there’s really no way you could move in time to avoid one. Just know that they’re real, and they have sad lives too. Remember, they once belonged to a comet before they ripped themselves free.

Studying and observing

There are a lot of of ways to study the universe. The easiest is to read a book about it that somebody smart has written. Also, it would be great to study the universe in a time-hopping, wormhole-slithering spacecraft. But there’s other ways too. Like telescopes.

Pretty much most objects in space emit electromagnetic radiation. Examples of these include radio waves and visible light. Thanks to Galileo Galilei and others, we can use telescopes to help us observe this emitted radiation and therefore understand space better. More understanding is good. Cosmic empathy.

chapter two - earth >

Footnotes to chapter 2

  • There’s a great song by a band I call the Fuzzy Buttons entitled Surf Solar. It’s 13 minutes long and filled with atmospheric and electronic bleeps and cool sounds but it’s still poppy.

  • By a long time, I mean billions of years until the Sun croaks and Earth gets vaporized.. There are projects that involve such things as using the gravitational slingshot pull of thousands of asteroids to pull Earth out of orbit so when the Sun sets for the final time, our descendants will have a chance in a separate but equal solar system.. But unless cryogenics gets significantly better in our lifetime, we probably won’t be around to find out whether that works or not.

  • Have you seen the Christopher Nolan film Interstellar? See it. One of his Top Five films among a stellar lineup. And it will make you think heavily about existence and the nature of love. Also, there is a Russian filmmaker, Andrei Tarkovsky, who made some very interesting space-themed films about existence and such, but they don’t zip along quite like Interstellar. Start with that.

  • There’s a good chance you haven’t studied Greek because it’s no longer taught as a core subject in most schools. I have an opinion on that. But I won’t share it here. But I will just say that yes, of COURSE KIDS SHOULD STILL BE LEARNING GREEK AND LATIN! But I won’t tell you why here. And I have no opinion on learning cursive. None. Well...maybe a small opinion. But when have I ever been opinionated?

  • Memento mori is a wonderful Latin phrase (aren’t they all?) that basically means: we all must die. It’s just one reason that A Series of Unfortunate Events is one of the most wonderful series of all time: if you read the 13-book series or watch the delightful 3-season Netflix adaptation, you’ll learn some Latin phrases such as this that will be enormously beneficial to your life education and ability to pull out a good classic phrase or two in an apropos situation, should you ever need to. Also, if you’re trying to understand good humor, or figure out exactly what irony is, then you should certainly educate yourself more by reading this series.

  • Chances are they’ve been reading about the Tower of Babel in the Biblical book of the Bible entitled Genesis chapter 11