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
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The flimsy case for evolving dark energy
Is dark energy evolving with at least 99.99% confidence? Despite the quality of recent data, scientists have every reason to be skeptical.

Ethan Siegel

A colorful map shows the distribution of nearby galaxies, with distances and redshift factors labeled, created by DESI; NSF, NOIRLab, and Kitt Peak logos are visible.
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We’ve populated low-Earth orbit with satellites in record time — now we have to figure out how to keep it safe.
logarithmic history of universe
In a 13.8 billion year old Universe, a few seconds hardly seems like it matters. But these minuscule changes sure do add up over time.
Two peculiar galaxies collide in deep space, forming bright clusters and swirling dust clouds—a striking scene that reveals the beauty and violence of the cosmos against a dark background.
Most massive galaxies are spiral or elliptical shaped. But peculiar galaxies showcase the beautiful violence that helps explain our cosmos.
Illustration of multiple spiral galaxies and stars being pulled toward a central black hole in deep space, with blue and purple light streaks tracing the motion along a dark energy curve that shapes the universe.
Early on, the Universe needed near-perfect flatness, or atoms, stars, and galaxies couldn't form. What happens once dark energy takes over?
bok globule barnard 68 dust wavelength
The image you're seeing isn't a hole in the Universe, and the cosmic voids that do exist aren't hole-like at all.
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While LooksMaxxing often headlines the news, the idea of BrainMaxxing deserves real attention. Growing your mind never goes out of style.
We have two descriptions of the Universe that work perfectly well: general relativity and quantum physics. Too bad they don't work together.
Looking up at the night sky gives us a glimpse of the Universe beyond our terrestrial concerns. Here's the science of what's out there.
No matter what physical system we consider, nature always obeys the same fundamental laws. Must it be this way, and if so, why?
color charge color anticolor
When what we predict and what we measure don't add up, that's a sign there's something new to learn. Could it be a new fundamental force?
Standard Model particles symmetry
The combination of charge conjugation, parity, and time-reversal symmetry is known as CPT. And it must never be broken. Ever.
travel straight line
In theory, the fabric of space could have been curved in any way imaginable. So why is the Universe flat when we measure it?
Binary black holes eventually inspiral and merge. That's why the OJ 287 system is destined for the most energetic event in history.
M81 Group
Over billions of years, fewer stars form, galaxies mutually recede, and the Universe becomes ever darker. Here's how fast it all happens.
wormholes
Nothing lives forever, at least, not in the known Universe. But relativity allows us to get closer than ever: from a physics perspective.
A satellite with large solar panels orbits above Earth against a colorful space background, where the cosmic clouds resemble the Hand of God carved by a dead star.
The path to exploring the high-energy Universe was clear and compelling. Here's how 2025's cuts are still causing NASA casualties in 2026.
Millikan Lemaitre and Einstein
Not everyone accepts the scientific consensus; some even make careers out of challenging it. But only a select few do it the right way.
Side-by-side images of a nebula in space, showing colorful, wispy gas and dust shells surrounding a bright central region with numerous stars in the background.
Resembling a cosmic brain, the Exposed Cranium Nebula instead shows a dying, massive star, as JWST reveals. Its fate remains uncertain.
Digital illustration of Earth showing a large amount of space debris and satellites orbiting the planet, highlighting the issue of space junk.
What goes up into low-Earth orbit will eventually come down, bringing huge consequences with it. Be informed, not surprised!
warm-hot intergalactic medium sculptor wall
In traveling through the expanding Universe, particles slow down while light and gravitational waves redshift. What degrades and what won't?