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.

Diagram showing light from a distant galaxy bending around a red-hued massive object, reaching telescopes on Earth via different paths and at different times.
With the observation of SN 2025wny, a lensed superluminous supernova, astronomy's future comes into sharp, exciting focus.
Illustration of various carbon molecules, including buckyballs and graphene sheets, floating in space near a bright cosmic background with stars and nebulae.
It takes a wide variety of processes in the Universe to make all the elements that populate space today. We're still discovering new ones!
A row of black and blue server racks in a data center, where LLMs power chatbot solutions, with illuminated green lights and a white tile floor with black circular vents.
As technology advances, more opportunities for cheating arise. Large language models aren't posing a new problem; they're how students cheat themselves.
existence of God
Science isn't absolute. Its truths and discoveries enable us to approximate reality, but we must always remain open-minded to revisions.
A grid of six astronomical images shows different examples of gravitationally lensed quasars, each labeled with its unique identification code and relevant to studies addressing Hubble tension.
The method you use to measure the expanding Universe determines which of two answers you'll get. Lensed supernovae can't resolve that issue.
satellites
Scientific truths remain true regardless of belief. These 10, despite contrary claims, remain vitally important as 2025 draws to a close.
A large group of people stands together inside a spacious, industrial facility—likely the LHC—surrounded by tall machinery, pipes, and metal structures, celebrating the best 2025 discovery in particle physics.
Some vital, key ingredients must be in place for the Universe to make more matter than antimatter. The LHC took us one step closer in 2025.
An Ishihara color blindness test with colored dots, showing letters “u” and “d” in black, and a magnified section highlighting the dot pattern—inviting viewers to observe proton decay through subtle visual cues.
As the lightest baryon in the Universe, the proton is thought by many to be eternally stable. But if it isn't, can we observe it decaying?
Two space telescopes with solar panel arrays are shown against a plain, dark background. NASA's Habitable Worlds Observatory is represented by one with a hexagonal mirror, highlighting its role in advancing space science.
Finding alien Earths requires seeing Earth-sized planets at Earth-like distances from Sun-like stars. A new discovery completes the roadmap.
A mesmerizing starry sky with shooting stars and a majestic tree.
With a waning Moon and a denser-than-ever debris trail, 2025's Geminids might be the year's best meteor shower, and 2026's could be amazing.
millennium simulation cosmic web slice
We have a picture of how and when it will all come to an end. These three big ideas could still profoundly change how our cosmos evolves.
Illustration depicting cosmic evolution from the Big Bang, through inflation and CMB, to the large-scale cosmic web. As time advances from 0 to 13.8 billion years, SPHEREx's mapping of galaxies teaches what CMB can't about our universe's development.
Science has assembled an incredible story outlining our Universe's whole history. Despite its unrivaled success, 9 profound gaps remain.
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.
There are so many problems, all across planet Earth, that harm and threaten humanity. Why invest in researching the Universe?
el gordo JWST rotated cropped
Although American Thanksgiving only comes once a year, the scientific rules that make our Universe possible are always worth appreciating.
moon two faces
The far side of the Moon is incredibly different from the Earth-facing side. 66 years later, we know why the Moon's faces are not alike.
supermassive black holes
Such massive, early supermassive black holes have puzzled astronomers for decades. At last, we've finally figured out how they form.
A telescope beneath a colorful, abstract visualization of the universe, with a starry night sky in the background.
Every observation out into deep space is also a look back in time.
One side of the Moon always faces us: the near side. The "dark side" of the Moon began as a mere metaphor, but today, science can weigh in.
hoag's object
Spirals, ellipticals, and irregulars are all more common than ring galaxies. At last, we know how these ultra-rare objects are made.
flight through universe CEERS JWST NASA
Wavelengths stretch, distances grow, and temperatures cool as the Universe expands with time. How are the various cosmic parameters related?