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.

bounce ball
Whether you run the clock forward or backward, most of us expect the laws of physics to be the same. A 2012 experiment showed otherwise.
every square degree
When the Hubble Space Telescope first launched in 1990, there was so much we didn't know. Here's how far we've come.
Green abstract image with floating, glowing funnel-shaped objects and spherical wireframe shapes evokes a black hole universe, all set against a misty green background with ethereal light streaks.
Once you cross a black hole's event horizon, there's no going back. But inside, could creating a singularity give birth to a new Universe?
F = ma fall up
From high school through the professional ranks, physicists still take incredible lessons away from Newton's second law.
A colorful, abstract scientific illustration with a central glowing sphere, circular patterns, and various lines and circles suggesting quantum connections or uncertainty data points, on a dark background with blue accents.
No matter what it is that we discover about reality, the fact that reality itself can be understood remains the most amazing fact of all.
gravitational wave effects on spacetime
With over 300 high-significance gravitational wave detections, we now have a huge unsolved puzzle. Will we invest in finding the solution?
Two glowing spheres, one red and one green, face each other in space with a wavy line of light—like a particle physics collision—connecting them against a speckled dark background reminiscent of the last collider’s discoveries.
Will we build a successor collider to the LHC? Someday, we'll reach the true limit of what experiments can probe. But that won't be the end.
A visual simulation of two objects orbiting and merging, distorting a red-orange grid representing spacetime—illustrating gravitational waves once thought to be the worst prediction in science.
The measured value of the cosmological constant is 120 orders of magnitude smaller than what's predicted. How can this paradox be resolved?
comet collide with earth
65 million years ago, a massive asteroid struck Earth. Not only did Jupiter not stop it, but it most likely caused the impact itself.
Two colorful, semi-transparent spheres, one blue and one red, represent a possible top quark bound state, toponium, surrounded by small particles inside a cloudy, circular enclosure.
Can the top quark, the shortest-lived particle of all, bind with anything else? Yes it can! New results at the LHC demonstrate toponium exists.
Black and white image of a star field with one bright object in the center, indicated by a red arrow, believed to be the third interstellar object detected passing through our solar system.
First 'Oumuamua, then Borisov, and now ATLAS have shown us that interstellar interlopers are real. Here's what the newest one teaches us.
A crane lifts a large metal structure onto a white building at a construction site in a mountainous, arid area under clear blue sky.
The relic signal that first proved the Big Bang has been known and analyzed for 60 years. Join us at the frontiers of modern cosmology!
The CMB has long been considered the Big Bang's "smoking gun" evidence. But after what JWST saw, might it come from early galaxies instead?
Images show the planet Uranus. The left image highlights its bright rings, while the right image, captured by the James Webb Space Telescope, depicts surprising details of glowing rings and a cloudy atmosphere. Discover more wonders in our solar system with these stunning visuals.
Once every 12 years, Earth, Jupiter, Uranus, and Neptune all line up, opening a window for a joint mission. Our next chance arrives in 2034.
Infographic displays spacecraft names and missions around the Sun, planets, and moons, illustrating the current and planned science fleet exploring the Solar System.
Over the first half of 2025, the US has cut science as never before. This disaster for American science may be a gift to the rest of the world.
A dense field of distant galaxies and bright stars against a black background, as captured in a JWST early galaxies deep space telescope image.
Originally, the abundance of bright, early galaxies shocked astronomers. After 3 years of JWST, we now know what's really going on.
the night sky with stars and trees in the foreground.
Looking at a dark, night sky has filled humans with a sense of awe and wonder since prehistoric times. But appearances can be deceiving.
The Vera Rubin Observatory is situated on a rocky hilltop under a clear, star-filled night sky, with distant mountains and a bright planet visible on the horizon, inspiring astronomers to solve puzzles of the universe.
In just its first 10 hours of observations, the Vera Rubin observatory discovered more than 2000 new asteroids. What else will it teach us?
An image of a sphere with stars in it.
For over 50 years, it’s been the scientifically accepted theory describing the origin of the Universe. It’s time we all learned its truths.
A dense star field and distant galaxies with bright galaxy clusters and several white squares highlighting specific points in the image.
For hundreds of millions of years, a cosmic fog blocked all signs of starlight. At last, JWST found the galaxies that cleared that fog away.