Ethan Siegel

Ethan Siegel

Theoretical astrophysicist and science writer

Ethan Siegel Starts with a Bang!

Ethan Siegel is a Ph.D. astrophysicist and author of "Starts with a Bang!" He is a science communicator, who professes physics and astronomy at various colleges. He has won numerous awards for science writing since 2008 for his blog, including the award for best science blog by the Institute of Physics. His two books "Treknology: The Science of Star Trek from Tricorders to Warp Drive" and "Beyond the Galaxy: How humanity looked beyond our Milky Way and discovered the entire Universe" are available for purchase at Amazon. Follow him on Twitter @startswithabang.

A person sits in front of a white backdrop, surrounded by a cosmic map with galaxies and celestial objects.
2hr 18mins
"Asking the question of, "Where did the entire universe come from?" is no longer a question for poets and theologians and philosophers. This is a question for scientists, and we have some amazing scientific answers to this question."
lab leak SARS-CoV-2
In theory, scientists could've produced a deadly virus that accidentally infected lab workers. In practice, we know that didn't happen.
uranium oxide oklo nuclear reactor
Planets can create nuclear power on their own, naturally, without any intelligence or technology. Earth already did: 1.7 billion years ago.
The spiral galaxy, surrounded by dim stars and interstellar dust, stands out against a dark background, shining brighter than astronomers once imagined.
The most famous Hubble images show glittering stars and galaxies amidst the black backdrop of space. But more was captured than we realized.
Diagram of the universe's expansion with grid patterns and cosmic elements, framed by "Consensus or Crisis?" in white text on black background. This visual encapsulates how cosmology changed from 2000 to 2025, highlighting key theories and discoveries.
25 years ago, our concordance picture of cosmology, also known as ΛCDM, came into focus. 25 years later, are we about to break that model?
planetary nebulae
In around 7 billion years, we expect the Sun to run out of fuel, dying in a planetary nebula/white dwarf combination. Is that for certain?
A glowing orange planet casts a shadow in space amid a backdrop of stars.
Exoplanets can exist anywhere around their parent stars, even so close that they evaporate or disintegrate. Even the rocky ones.
Two visualizations map the cosmos, displaying color-coded cosmic microwave background radiation. Blue and orange patches indicate temperature variations across a spherical and an oval projection.
It's difficult to project a sphere onto a flat, two-dimensional surface. All maps of the Earth have flaws; the same is true for the cosmos.
Two colorful spiral galaxies interacting in space, with bright centers and swirling arms of red, blue, and white hues, set against a backdrop of stars.
The Kalam cosmological argument asserts that everything that exists must have a cause, and the "first" cause must be God. Is that valid?
We understand many things about our Universe, and our home within it, extremely well. The number of stars in the Milky Way isn't among them.
branching parallel universes
The Multiverse isn't just a staple of science fiction; there's real-life science behind it, too. Here are 10 facts to expand your mind.
A colorful, spinning galaxy with a bright orange core, existing for 12 billion years, is surrounded by smaller galaxies and star clusters against a black space background.
Large, massive, rotating galaxies like the Milky Way are common today. So how could one form a mere ~2 billion years after the Big Bang?
Over a century after we first unlocked the secrets of the quantum universe, people find it more puzzling than ever. Can we make sense of it?
globular cluster terzan 5
For centuries, even after we knew the Sun was a star like any other, we still didn't know what it was made of. Cecilia Payne changed that.
A cartoon of three cosmic phenomena (CMB, Baryon Acoustic Oscillations, Supernovae) pulling on a triangle. Text below reads: "Something has to give...
DESI, by mapping galaxies, has claimed they see evidence for dark energy evolving by getting weaker. But that's only one interpretation.
From the vastness of space, Earth at night reveals its exo-earth beauty, with illuminated continents showcasing a tapestry of lights across North and South America. Major cities and regions emerge from the glowing darkness, painting a vivid picture against the backdrop of oceans.
Even from a single pixel, multiwavelength data taken over time can reveal clouds, icecaps, oceans, continents, and even signs of life.
Colorful galaxy with dark dust lanes and bright stars, set against a deep space background.
Someday, we'll look back and see a young galaxy forming stars for the first time. JADES-GS-z14-0, the farthest ever, isn't early enough.
Einstein's general relativity has reigned supreme as our theory of gravity for over a century. Could we reduce it back down to Newton's law?
Two side-by-side images of the Pillars of Creation in the Eagle Nebula showcase different views with vibrant colors and star-filled backgrounds, embodying the great paradox of beauty within science.
Our scientific instruments are constantly improving, revealing nature's workings as never before. Without them, we'll remain in the dark.
round Earth messenger
All scientific theories are limited in scope, power, and application, being mere approximations of reality. That's why consensus is vital.