Astronomy Koan

Astronomy Koan – Definition

A family views the visible orbit path of the earth.
A family views the visible orbit path of the earth.

An astronomy koan is a short, easy-to-memorize phrase that distills a key teaching about astronomy (especially physical astronomy).

The words are simple enough for a child to learn, but they carry complex insights about scientific observations.

The astronomy koan is a mnemonic that has layers of meaning or presents an ambiguous or challenging observation in a pithy phrase.

Try memorizing one of these – you can bring these with you everywhere.

Four Physical Astronomy Koans


That star rose earlier today.

The moon moves toward the dawn.

Night is where you are.

Same Sun all night. Dusk to the left, dawn to the right.


What do you think about these?

Do you know any astronomy koans?

Share your ideas in the comments section.

Merry-Go-Round Earth shows Seasonal Constellations

Welcome Starry Night event visitors! We built this fun, interactive model of the merry-go-round Earth on the evening of March 3rd, 2018 around a real campfire. Read on for the background and teaching method.

The Earth is like a Merry-Go-Round

Merry-Go-Round Earth model demonstrating how the seasonal constellations work
A Merry-Go-Round is a good model of daily Earth rotation.

The Earth is like a merry-go-round showing us seasonal constellations

That iconic childhood ride. Round and round each day we go, round and round each year we go, where we stop nobody knows! When we look out from the edge of the ride we can see the space beyond. Sometimes the Sun occupies that space, and sometimes that space is the night sky filled with stars.Click here to continue reading…

Quiz – Can we see the Sun at midnight? Where is the Sun?

Can we see the Sun at midnight?

Yes. We can see the Sun at midnight. But, only if we are at one of the polar regions during the Summer season.

Image of the Sun's rays hitting the Earth. The Earth is tilted 23.4 degrees. Summer is when the northern hemisphere is titled toward the Sun. The summer Sun never sets - not even at midnight - if you are north of the Arctic Circle.
You can see the Sun at midnight! If you are at the North Pole in summer.

A quiz – seeing the Sun at midnight – don’t scroll til you try to answer!

When you see the Sun “rising” in the morning at dawn you are facing the east.

When you see the Sun “setting” at the end of the day you are facing the west.

Assuming you are not above the Arctic circle and not too close to the equator… if you could look right at the Sun (when the night is exactly half over) – by looking through the Earth – which cardinal direction would you be facing? East, West, North, or South?

Looking north or south to see the Sun at midnight?
A compass rose showing the cardinal directions.

Click here to continue reading…

Galaxy Rise

Physical Astronomy by Daniel Cummings

A still more glorious dawn awaits Not a sunrise, but a galaxy rise A morning filled with 400 billion suns The rising of the milky way.

The Sun rises. The Moon rises. Stars rise. The Galaxy rises – twice.

Each day the Earth rotates and sky objects (seem to) rise in the Eastern sky. The Sun, the Moon, the Stars, and the Galaxy rise at various times.

The Sun “rises” once-a-day at the start of the day.

The Moon “rises” once-a-day at different times of the day and night depending on the moon’s orbit around the Earth (its phase).

The Stars “rise” once-a-day – all night long, one after another and in groups.

The Milky Way Galaxy “rises” twice a day – once on its bright (center) side and then 12 hours later on its dim (outer arm) side.

We can orient our bodies to the rising of the Milky Way. And we can experience our daily movement as “plunging through” this flat disk of stars.

Click here to continue reading…

Walk to Mintaka

Physical Astronomy by Daniel Cummings
Mistakable rises toward the zenith as you walk toward the equator
As you walk toward the equator, Mintaka appears to rise higher in the sky.

In this post we will learn how to use one bright star of Orion’s belt to visualize the Earth’s equator.

Mintaka is a Star in Orion’s Belt

When you look up at the winter sky in the northern hemisphere, Orion and his famous belt are impossible to miss. The belt is made up of three stars of equal brightness.

One of these stars is called Mintaka and it is a guidepost for finding the Earth’s equator in space. Click here to continue reading…

Tilt Head to Tilt Earth

Physical Astronomy by Daniel CummingsTilt your head to tilt the earth and experi nice the seasons

Seasons are caused by a tilted Earth

Use this technique to understand how seasons happen on the Earth. The Earth is tilted. When the northern part (your forehead and eyes) tilts away from the Sun the season is winter. When the northern part tilts toward the Sun the season is summer.

The Earth is tilted as it spins daily – it is not straight up and down like a top, but more like the Leaning Tower of Pisa (if the tower could spin!). As it goes through its yearly orbit, the Sun hits the northern and then the southern parts of the Earth.

Tilt your head to tilt the Earth

In this model, when the northern part (your forehead and eyes) tilts away from the Sun the season is winter. When the northern part tilts toward the Sun the season is summer.

Did you like this season model? Any questions? Type in the comments to send me a message.

Arms around the ecliptic

Learn to see the ecliptic

Physical Astronomy by Daniel Cummings

Ecliptic Arms

The sun follows the same path through the sky every day.

Sun up. Noon. Sun down.

The sun starts the day in the east in the morning, rises high in the sky at noon, and settles down again in the west for a nap at night.

See the ecliptic

Here is an exercise to discover that path – the ecliptic.

Click here to continue reading…

Groundhog Day Shadow Tracker

Physical Astronomy Tool by Daniel Cummings

Groundhog Day Shadow Tracker Lesson Plan
It’s Groundhog Day!

What better way to celebrate Groundhog Day than to Build your own Groundhog Day Shadow Tracker

Let’s do some Physical Astronomy. The experience will help you to understand the movement of the earth and sun through the seasons. You will build a scientific instrument that is also a fun garden decoration and you will be able to track the Groundhog’s Shadow all Spring!

Click here to continue reading…

A new star will appear in the sky in 2022

Binary star merge to form a new star - a star in a starAn amazing thing is about to happen! A Star in a Star will be born.

You  can witness the birth of a new star in the night sky.  The new Star already has a birthday: 2022!

According to scientists, the new star will form when two stars that are orbiting each other grow so close that they merge into one.

The new star will appear in the constellation Cygnus. You can see the approximate location marked by a red circle in the Stellarium screenshot here:

A screenshot of Stellarium showing the new star location under the constellation Cygnus's left wing

The image of the two blue stars on the home page of this Star in a Star site shows what scientists think it looks like now. This impressive video shows an artist’s rendering of the star merge.

In the pair, one star is larger than the other so in the end, there will be a new star…  A Star in a Star.

The Moon Dance – Learn Moon Phases

PHYSICAL ASTRONOMY BY DANIEL CUMMINGS

The moon dance helps you learn and understand the phases of the moonAt sunset.

Face the sun.

Point your right hand toward the Sun.

Now point your left hand toward the Sun.

Both hands should be pointing at the sun.

Now, turn a little bit to the left, keeping both hands pointing at the sun.

Swing your left arm out until it is pointing in the opposite direction from the sunset. Bring your hands together again and repeat this swinging motion.

Bring your hands together again and point them both at the sun. This time, instead of swinging, bounce your left hand, leftward, some number of times… (14 is perfect if you can do it) …until it is pointing in the completely opposite direction from the Sun at sunset. Your left hand should now be pointing East.

Was the moon at any one of those 14 hand bounce spots? That is the age of the moon in days.

Please post your questions in the comments!

Stellarium – a Gift to Humanity

Hello! Find out more about Stellarium in this tutorial that introduces several of the cool and clever things this astronomy software can do.

An image of the winter sky showing the Full Moon near the constellations Orion, Taurus, the Big Dog (with the bright star Sirius), and the Little Dog (with the bright star Procyon).
An image of the winter sky showing the Full Moon near the constellations Orion, Taurus, the Big Dog (with the bright star Sirius), and the Little Dog (with the bright star Procyon).

Stellarium – a glorious gift to Humanity in software form – gives you super powers. And best of all … It’s FREE!

Superpowers!

Always wanted to know the names of the stars and constellations? You can search, play, pan and zoom, examine, compare and anchor your knowledge.

It’s a cloudy night? No problem. You can see through the clouds! 

Wished that the sky had labels on everything? Stellarium has 10 different label types.

Stop time? Move time by day, by week? Do you want to see what will happen in 2 months? Or look at the sky during the Pharoah’s reign? You can time travel.

You can easily drag and zoom, stop time, go in reverse, make a timelapse, follow the moon through its phases. You have a tool to help you understand the ecliptic and sidereal time and retrograde motion. You can see the great orbital swing of Venus as it circles the Sun.

Ok! I’m convinced by your Stellarium review. What should I do now? What’s my call to action?

Get a copy of Stellarium.

You can download it here.

Stellarium is a free, easy to use, and powerful tool – and best of all (did I mention this already?) it’s FREE and easy to use.

I will write some specific tutorials about my favorite parts of Stellarium in 2017, but for now… go get it and play!

You will be able to see things about sky objects and movements that are impossible to see live. But, once you have seen them with the help of Stellarium, the sky will open up for you – like a gift.

What Looks Like Sunset

English: The sunset seen from Shwesandaw Pagoda in Bagan, Myanmar. Date 9 December 2014, 17:23:27 Source Own work Author Jacklee Camera location 21° 09′ 49.23″ N, 94° 51′ 58.11″ E Heading=76.098113207547° Is what looks like sunset really the sun – “setting”?

What is that thing that happens every day that makes it look like sunset?

Can you change your mind easily? Are you flexible enough to understand that the same set of observations and facts can lead two different people to two different conclusions?

For a long time, everyone on the Earth thought the Sun was moving and the Earth was staying still. This is just what it looks like and anyone who dared to suggest a different view might easily be considered odd, or worse, dangerous. Having the benefit of hundreds of years of scientific evidence and wisdom to back up my observations, I now have the luxury of believing that it is the Earth that is moving and that the Sun is the one standing still.

It is fun to imagine being carried through space on the surface of a giant ball. Definitely better than staying still while the sun careens through the sky each day. With this image in my mind, I feel the Earth is carrying me away from the view of the Sun.

Sunset should be called “away sun” and not “sun set” because it is me moving, not the sun. It is me being carried away into the shadows forming behind the bulge of the Earth, not the Sun setting. I am riding the Earth with its great round bulk between me and the Sun.

It’s NOT a sunset but me… rushing backwards… at 1000 mph as the bulge of the earth grows in between.

I propose “awaysun” as the new name for sunset and “towardsun” as the name for sunrise. These new names help solidify the idea that we are the ones moving.

What do you think?