Starts With A Bang

A field of stars and colorful cosmic dust clouds scattered across the dark expanse of space.
The Universe is out there, waiting to be discovered

Our mission is to answer the biggest questions of all, scientifically.

What is the Universe made of? How did it become the way it is today? Where did everything come from? What is the ultimate fate of the cosmos?

For most of human history, these questions had no clear answers. Today, they do. Starts With a Bang, written by Dr. Ethan Siegel, explores what we know about the universe and how we came to know it, bringing the latest discoveries in cosmology and astrophysics directly to you.

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Ethan Siegel is an award-winning PhD astrophysicist and the author of four books, including The Grand Cosmic Story, published by National Geographic.

Full Profile
A bald man with a long beard and handlebar mustache gestures with his hands against a backdrop of an upside-down cityscape wearing a purple shirt.
Ask Ethan: What would “first life” see in their night sky?
Human beings only see the Universe now: 13.8 billion years after the Big Bang. What would the earliest life, anywhere, have seen instead?

Ethan Siegel

the night sky with stars and trees in the foreground.
When people choose the greatest scientist of all, Newton and Einstein always come up. Here's why they should pick Johannes Kepler instead.
Scientists are livid over the OSTP director's official report to the President. Will it lead to a new golden age for US science, or end it?
The grid features 15 images of distant galaxies, each labeled with identifiers and redshift values from z=4.75 to z=8.92. Captured by JWST, these celestial wonders include intriguing little red dots scattered across the vast cosmos.
200 years ago, we hardly knew anything about our Universe on cosmic scales. Today, there's so much that we know. Here's how we arrived.
heavy neutral atom
Early on, the entire Universe was ionized. Without the forbidden two-photon transition, it would have remained that way for far too long.
big crunch
Our Universe has a positive, non-zero value to the energy within empty space. Can we potentially save ourselves by considering vacuum decay?
pulse polio day india
It’s not a gambit. It’s not fraud. It’s not driven by opinion, prejudice, or bias. It's not unchallengeable. And it's more than facts alone.
A shot of the Perseid meteor shower
Although the Geminids have rivaled the Perseids recently, in 2026, the Perseids should win at their peak. Here's why, plus how to see them.
Colorful nebula with red and blue gas clouds, two bright stars—once separated stars now reunited after distant supernovae—and a rocky object, set against a star-filled background in space.
We've never witnessed a system of binary stars both go supernova before. A once-hidden source of gamma rays just revealed the first one.
A molecular cloud labeled G+0.693-0.027 is shown in space, with an inset displaying a 3D model of the erythulose molecule—a sugar that may provide clues about the origin of life—found within the cloud.
In a gas cloud 26,000 light-years away, a 4-carbon sugar, erythrulose, has just been found. Here's what it means for life in the Milky Way.
Mars is very different than Earth: smaller, drier, colder, etc. But the biggest long-term challenge, for human colonies, is its low gravity.
universe bulk volume brane dimension
Mathematics is our language for quantitatively describing reality, but it can also take us to worlds that never were. Physics needs more.
Einstein
Many think that intelligence can be outsourced to AI. Einstein wouldn't have used it. If he had, he never would have become Einstein.
elements Cas A remnant Chandra X-ray
Despite the brilliance of these cosmic beacons, only 1% of a core-collapse supernova's energy is observable. The other 99% is in neutrinos.
Illustration of black holes merging, showing spiraling paths and arrows indicating movement and direction, set against a dark, starry background.
With nearly 400 black hole events from gravitational waves, we can begin to infer their origins. At least two different populations emerge.
A barred spiral galaxy is shown with a bright central bar, curved arms, and scattered blue regions indicating star formation, against a dark background.
The history of atoms in the Universe is our own history: without them, there would be no us. So how do we piece their cosmic story together?
observable universe size
For all we know, the cosmos could truly be infinite in scale. But the observable part of our Universe? It's finite, and its size is known.
An aerial view of LIGO Hanford, showing two long, perpendicular arms extending across a flat, brown landscape with a few buildings at the intersection.
The LIGO facilities in the U.S. are the most sensitive gravitational wave detectors in the world. Their future remains uncertain.
cosmic inflation
We used to think the Big Bang started it all. Then we realized that something else came before it, erasing everything that existed prior.
A large, circular structure—destined to become the world's best and smallest giant telescope—is under construction inside a spacious industrial facility with scaffolding and bright overhead lighting.
At "only" 25 meters in diameter, the Giant Magellan Telescope is the smallest of three current projects. That might make all the difference.
Using the newest large-scale structure data, a team of researchers announced a huge cosmic anisotropy in Nature. Too bad it's wrong.