Ethan Siegel
A theoretical astrophysicist and science writer, host of popular podcast "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.
First ‘Oumuamua, then Borisov, and now ATLAS have shown us that interstellar interlopers are real. Here’s what the newest one teaches us.
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?
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.
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.
Originally, the abundance of bright, early galaxies shocked astronomers. After 3 years of JWST, we now know what’s really going on.
Looking at a dark, night sky has filled humans with a sense of awe and wonder since prehistoric times. But appearances can be deceiving.
In just its first 10 hours of observations, the Vera Rubin observatory discovered more than 2000 new asteroids. What else will it teach us?
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.
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.
Here in 2025, many of us claim to come to our own conclusions by doing our own research. Here’s why we’re mostly deluding ourselves.
Massive galaxy cluster Abell S1063, 4.5 billion light-years away, bends and distorts the space nearby. Here’s what a JWST deep field shows.
Is the Universe’s expansion rate 67 km/s/Mpc, 73 km/s/Mpc, or somewhere in between? The Hubble tension is real and not so easy to resolve.
The ANITA experiment found cosmic rays shooting out of Antarctica. One interpretation claims “parallel Universes,” but is that right?
Different methods of measuring the Universe’s expansion rate yield high-precision, incompatible answers. But is the problem robustly real?
Launched in March, the PUNCH mission has viewed two incredible coronal mass ejections, tracking them farther from the Sun than ever before.
The tiniest galaxies of all are the most severely dominated by dark matter. Could black holes be the cause of the extra gravity instead?
A few physical quantities, in all laboratory experiments, are always conserved: including energy. But for the entire Universe? Not so much.
If you want to understand the Universe, cosmologically, you just can’t do it without the Friedmann equation. With it, the cosmos is yours.
Viewing Uranus’s largest moons with Hubble, astronomers hoped to find darkening on the trailing side. They found the exact opposite instead.
On Earth, our particle accelerators can reach tera-electron-volt (TeV) energies. Particles from space are thousands of times as energetic.
The first galaxies were irregular blobs of gas and stars. But modern features, like spiral arms and bars, appeared earlier than expected.
The hunt for extraterrestrial life begins with planets like Earth. But our inhabited Earth once looked very different than Earth does today.
If the Universe is 13.8 billion years old today, but different ages the farther we look back, what does it mean for a star to be the first?
The COSMOS-Web has just finalized their release of their full field: larger and deeper than any other JWST program. Here’s what’s inside.
When theory and experiment disagree, it could mean new physics. This time, they solved the muon g-2 puzzle, and saved the Standard Model.
For decades, astronomers have claimed the Milky Way will merge with Andromeda in ~4 billion years. Here’s why, in 2025, that seems unlikely.
As US science faces record cuts to funding, jobs, and facilities, these 10 quotes help remind us how science brings value to us all.
In our Universe, dark matter outmasses normal matter by a 5-to-1 ratio, shaping the Universe as we know it. What if it simply weren’t there?
It rotates on its axis, revolves around the Sun, moves throughout the Milky Way, and gets carried by our galaxy all throughout space.