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.
Flying clocks in opposite directions around the world proved Einstein right
Time isn't the same for everyone, even on Earth. Flying around the world gave Einstein the ultimate test. No one is immune from relativity.

Ethan Siegel

unreachable
We live on Earth, orbiting the Sun, part of our Solar System, within the Milky Way. But what's our membership status on even larger scales?
ivy mike nuclear test
Einstein's most famous equation is E = mc², which describes the rest mass energy inherent to particles. But motion matters for energy, too.
A diagram illustrating one of the biggest mysteries: the origin of the universe, from the Big Bang and inflation to today, showing the formation of atoms, stars, galaxies, and the ongoing expansion of space.
When it comes to the big question of our cosmic origins, inflation is our leading theory. But did string theory ultimately cause inflation?
A grainy black and white image shows SPHEREx comet 3I/ATLAS gleaming at the center, surrounded by stars appearing as streaks due to long exposure.
Interstellar comet 3I/ATLAS has an ancient age, but not for the reason most commonly touted. These three lines of evidence are far stronger.
A dense globular cluster of stars with varying brightness in deep space, some showing blue and orange hues, appears concentrated toward the center—possibly an imposter resembling Terzan 5.
Globular clusters are some of the most ancient cosmic relics that still survive in our Milky Way today. Famed Terzan 5 isn't one of them.
JWST deep field vs hubble
With targets from all across the Universe, focusing a space telescope — with so many moving parts — is challenging, but doable. Here's how.
atoms
By probing the Universe on atomic scales and smaller, we can reveal the entirety of the Standard Model, and with it, the quantum Universe.
A large planet orbits a bright blue star, with swirling rings of gas and dust—rich in boron and beryllium—surrounding both objects against the distant glow of white dwarfs in space.
Despite their rarity, boron and beryllium can both be detected within white dwarf atmospheres. What does their presence and abundance imply?
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.
When JWST opened its eyes, it spied a huge number of Little Red Dots. What we saw inside was a puzzle, but what's missing could solve it.
Illustration of the universe’s timeline from the Big Bang to the present, showing key events in cosmic evolution with labeled galaxies, stars, and cosmic structures.
After a period of cosmic inflation came to an end, the hot Big Bang commenced. 13.8 billion years later, we arrived. Here's how we got here.
A supermassive black hole caught turning on reveals a mesmerizing cosmic dance, with bright streams of light and colorful gases swirling around it against a starry backdrop.
Once you cross over to the inside of an event horizon, you can never come out again. But then, how do black holes emit all sorts of things?
Oort cloud object Bernardinelli–Bernstein has the largest known cometary nucleus: 119 km wide. An impact with Earth would be catastrophic.
transit spectroscopy PLATO
The Universe took a great many steps to create not just life, but intelligent life, here at home. What can we say about life beyond Earth?
The anthropic principle has fascinating scientific uses, where the simple fact of our existence holds deep physical lessons. Don't abuse it!
warm-hot intergalactic medium sculptor wall
Vast arrays of planets, stars, black holes, galaxies, and more populate our Universe. Within each category, differences can be astounding.
A high-resolution image of the Eagle Nebula shows a bright star cluster, pink nebula clouds, and dark dust columns scattered throughout a star-filled background.
Contracting gas clouds don't just make a single star, but a spectrum, with all different masses. Early on, that spectrum differed. But why?
proton internal structure
Protons and neutrons are composite structures: made of quarks and gluons. But knowing they had substructure goes back long before that.
black hole central singularity
Yes, "the laws of physics break down" at singularities. But relativity itself would have to be wrong for black holes to not possess them.
Image of a galaxy cluster with three marked regions labeled A, B, and C; the right side shows JWST zoomed-in views of red objects, hinting at possible black holes before galaxies—labeled QSO1A, QSO1B, and QSO1C.
It's the Universe's ultimate chicken-and-egg question: what came first, the galaxy or the black hole? One Little Red Dot proves the answer.
A chart showing the masses of black holes and neutron stars detected by LIGO-Virgo-KAGRA, highlighting how gravitational wave astronomy has become a mature science. Masses are plotted in solar masses on a logarithmic scale.
In 2016, humanity announced our first successful gravitational wave detection. 10 years and 389 events later, here's how far we've come.