Ethan Siegel

The Universe is: Expanding, cooling, and dark. It starts with a bang! #Cosmology Science writer, astrophysicist, science communicator & NASA columnist.

The Physics of the Death Star

How to destroy an Alderaan-sized planet.

“What’s that star?
It’s the Death Star.
What does it do?
It does Death. It does Death

Mostly Mute Monday: Space turns green on 4/20

What sort of greenery are these galaxies smoking?

“The illegality of cannabis is outrageous, an impediment to…

Weekend Diversion: Zooming Into A Fractal

Just open your eyes, full-screen it, and watch.

Ask Ethan #84: Where did light first come from?

Before the first star ever formed, the Universe was filled with light. But how?

“Light thinks it travels faster than

Publications edited by Ethan Siegel

The Universe is out there, waiting for you to discover it.

Throwback Thursday: Is the Universe fine-tuned for us?

The Anthropic Principle is more limited than we like to believe.

“There is a voice inside of you

What the hell are Baryon Acoustic Oscillations?

They’re our best measurement of dark energy, even better than supernovae!

“If you think this Universe is bad, you

Einstein, Schrödinger, and the story you never heard

How “faith” in the Universe destroyed two brilliant men of genius.

“I don’t like it, and I’m sorry I ever…

Mostly Mute Monday: The Cosmic Sombrero

The closest, brightest edge-on galaxy gives us a view like nothing else.

“Since man, fragment of the universe, is governed

Weekend Diversion: The great yogurt tragedy

Sick of yogurt winding up stuck to the underside of the lid? Problem solved.

“My love for you would blot out the sun

Ask Ethan #83: What if dark energy isn’t real?

If our “standard candles” aren’t so standard, is dark energy still real?

Some say the world will end in fire,

Throwback Thursday: How Do Black Holes Get So Big, So Fast?

The Universe contains black holes billions of times as massive as our Sun.

“It is by going down into