Ethan Siegel

Ethan Siegel

A theoretical astrophysicist and science writer, host of popular podcast “Starts with a Bang!”

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.

Silhouetted quiver trees under a starry night sky, with the Milky Way forming a bright arc above the horizon—perfect for fans of stunning 2025 night sky images.
Across planet Earth, dark and pristine night skies are an increasingly rare resource. These photos showcase the best of what we still have.
The Universe was born incredibly hot, and has expanded and cooled ever since. Could life have begun back when space was "room temperature?"
space expanding
Just 13.8 billion years after the hot Big Bang, we can see 46.1 billion light-years away in all directions. Doesn't that violate...something?
A person in a suit holds up a NOAA map showing the forecast track and intensity of Hurricane Dorian, reminding us that, unlike Einstein, we can't change the facts—only prepare for them—in an office setting.
Einstein is credited with saying, "If the facts don't fit the theory, change the facts." What he actually said has a very different meaning.
An image of an ancient black hole
At the center of Hubble's famous "cosmic horseshoe," a very heavy supermassive black hole has been robustly measured. How is it possible?
A person inspects a large, cylindrical section of a Higgs factory tunnel lined with metal pipes, cables, and equipment—a crucial site for particle physics research.
A next-generation collider is required for studying particle physics at the frontiers. Here's the fastest, cheapest way to get it done.
A dark, rocky planet orbits in space with the sun illuminating its edge, surrounded by stars and distant cosmic clouds.
In the search for life in the Universe, the ultimate goal is to find an inhabited planet beyond Earth. How will we know when we've made it?
parallel universe
Parallel universes are among the most profound notions in all of quantum physics. It's a compelling and fascinating idea, but is it true?
Amplifying the energy within a laser, over and over, won't get you an infinite amount of energy. There's a fundamental limit due to physics.
Two tall, rectangular scientific instruments, including a NASA nuclear reactor prototype, stand on the rocky lunar surface with Earth visible in the background against the blackness of space.
There are real concerns with long-term power generation on the Moon; nuclear could be the answer. But for NASA, will the cost be too high?
A hexagonal telescope with a gold exterior and an open, black interior is shown against a black background, highlighting NASA habitable worlds observatory science.
At the end of July, hundreds of scientists convened to plan NASA's upcoming astrophysics flagship mission. Will the US allow it to happen?
Two supermassive black holes on an inevitable death spiral push the limits of Einstein's relativity. New observations reveal even more.
creation of adam sistine
When it comes to our Universe's origins, scientists discuss the Big Bang, cosmic inflation, and other theories. Why doesn't "God" come up?
laniakea
On the largest scales, galaxies don't simply clump together, but form superclusters. Too bad they don't remain bound together.
Abstract digital artwork featuring concentric blue circles, lines, and green geometric shapes over a dark blue and black textured background, evoking a sense of vibe physics within its captivating composition.
The conversation you're having with an LLM about groundbreaking new ideas in theoretical physics is completely meritless. Here's why.
5000 exoplanets
Somewhere, at some point in the history of our Universe, life arose. We're evidence of that here on Earth, but many big puzzles remain.
Full moon over a city skyline at night, high-rise buildings aglow and lights reflecting on the calm water—a scene that inspires 5 science lessons about the moon's impact on our world.
Even just by examining the Moon with the unaided eye, we can learn an incredible amount about the Moon, Earth, and more.
The Big Bang was hot, dense, uniform, and filled with matter and energy. Before that? There was nothing. Here's how that's possible.
quantum particles
Realizing that matter and energy are quantized is important, but quantum particles aren't the full story; quantum fields are needed, too.
levitation
With the right material at the right temperature and a magnetic track, physics really does allow perpetual motion without energy loss.