A photon walks into a hotel and the clerk asks if he needs help with luggage. "No thanks," says the photon. "I'm traveling light."

Flat Earthers have nothing to fear but sphere itself.

I love a good joke. Worse, I love puns. I scoured the web and my social circles in search of more astronomy jokes to beef up my original humor blog created several years ago. I hope something here will bring you a smile. If I missed a favorite of yours, please share it with us. In a few obscure jokes I provide an explanation so you can better appreciate the inside humor.

I wanted to include the work of my favorite science cartoonist, Sidney Harris but can't because his material is copyrighted. Instead, I encourage you to visit his page Science Cartoons Plus.

Without further ado:

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A neutron goes into a bar and asks the bartender: "How much for a beer?" The bartender replies: "For you, no charge."

I was up all night wondering where the sun had gone ... then it dawned on me.

Variation: Did you hear about the man who stayed up all night looking for the sun to come up? Yes, it finally dawned on him!

The rotation of the Earth makes my day.

Why do rocks from space taste better than Earth rocks?

They're a little meteor!

What's a nuclear physicist's favorite meal?

Fission chips

A seminar on time travel will be held last Tuesday.


Two astrophysicists are discussing their research in a bar one evening. An inebriated patron overhears them in the next seat, turns around and says in a very worried voice: "What was that you just said?"

"We were discussion stellar evolution, and I said to my colleague here that the sun would run out of nuclear fuel and turn into a red giant star in about 5 billion years, possibly melting the Earth."

"Whew!" says the drinker. "You really had me worried. I thought you said 5 million."


Scientists watched the Earth rotate. After 24 hours they were bored, so they called it a day.

How many balls of string would it take to reach the moon?

One. A very large one.

Never trust an atom because they make up everything.

"Are you a string theorist?" asked the physics student of a speaker at the astronomy conference.

"No, I'm a frayed knot," the professor answered.

Heisenberg is out for a drive when he's stopped for speeding. The policeman says: "Do you know how fast you were going?" Heisenberg says: "No, but I know where I am." (Note: The gist here rests on the Heisenberg uncertainty principle that says that at the subatomic level it's not possible to measure both the position and speed of a particle simultaneously. The more precisely you measure one, the less you know about the other.)

After his first meal on the moon, the astronaut commented that the food was good, but the place lacked atmosphere.

How do you know when the moon is going broke?

When it's down to its last quarter.

Two atoms bump into each other. One says: "I've lost an electron." "Are you sure?" "Yes, I'm positive."

What did Mars say to Saturn?

Give me a ring sometime.

How does the man in the moon cut his hair? Eclipse it.

How are false teeth like stars?

Both only come out at night.

Orion's Belt is just a big waist of space!

What's the difference between a good burger and a shooting star?

The burger is very meaty, but the other is a little meteor.

A Higgs boson goes into a church and the priest says: "We don't allow Higgs bosons here." And the Higgs boson says: "But without me there is no mass." (Note: The Higgs boson is a particle (or field) responsible for giving matter its mass.)

Black holes are most commonly found in black socks.

The professor tried giving a serious talk about black holes, but no one appreciated the gravity of the situation.

An astronomy major had a part-time job working in the university's off-campus housing office. One day, a fellow student, upon entering the office in thought about the morning lecture, asked: "What's an astronomical unit?" To which the astronomy major replied: "One heck of a big apartment." (Note: An astronomical unit is the Earth's distance from the sun or 93 million miles.)

Why didn't the Dog Star laugh at the joke?

It was too Sirius

What kind of songs do the planets like to sing?


When do astronauts eat lunch?

At launch time

Where does an astronaut park her spaceship?

A parking meteor

What happens in a black hole stays in a black hole.

Why didn't the sun go to school?

Because it already has 27 million degrees!

"Copernicus, when are you going to realize that the world doesn't revolve around you?" asked his ex-girlfriend.

A neutrino walks into a bar ... and keeps right on going.

Did you hear about the claustrophobic astronaut?

He just needed a little space.

What did the astronaut cook for lunch?

An unidentified frying object

My sibling kept asking me about the orbits of planets and the amount of area swept in any given time. I had to ask him: "Am I my brother's Kepler?"

Entropy isn't what it used to be.

Einstein developed a theory about space... and it was about time too!

How far can you see on a clear day? 93 million miles — from here to the sun.

Other names for the Big Bang

The Bottom Turtle

The Grand Opening Sale

OK, Fine (my personal favorite)

Why couldn't the astronaut book a room on the moon?

Because it was full

First star I see tonight

I wish I may, I wish I might

Oh wait, it's just a satellite

"There's just one thing I can promise you about the outer space program — your tax dollar will go further." — Wernher von Braun

The speed of time is one second per second.

If athletes get "Athlete's Foot" What do astronauts get?

Missile toe

How do astronomers see in the dark?

They use standard candles (Note: "Standard candles" are another way to describe variable stars called Cepheids that astronomers use to determine the distances to galaxies.)

How many absolute relativists does it take to change a light bulb?

Two. One to hold the bulb and the other to rotate the universe.

What does an astronomer blow with gum?


What do you get if you cross Santa with an alien spaceship?

A UF-ho-ho-ho!


Sherlock Holmes and Dr. Watson go on a camping trip. After a good dinner and bottle of wine, they retire for the night and go to sleep. Some hours later, Holmes wakes up and nudges his faithful friend.

"Watson, look up at the sky and tell me what you see."

"I see millions and millions of stars, Holmes," Watson replied.

"And what do you deduce from that?"

Watson ponders for a minute.

"Well, astronomically, it tells me that there are millions of galaxies and potentially billions of planets. Astrologically, I observe that Saturn is in Leo. Horologically, I deduce that the time is approximately a quarter past three. Meteorologically, I suspect that we will have a beautiful day tomorrow. Theologically, I can see that God is all powerful, and that we are a small and insignificant part of the universe. What does it tell you, Holmes?"

Holmes is silent for a moment. "Watson, you idiot!" he says. "Someone has stolen our tent!"

"Astro" Bob King is a freelance writer for the Duluth News Tribune. Read more of his work at duluthnewstribune.com/astrobob.