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.

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.
The long-elusive neutrino was shown to have a bizarre property no one expected: mass. New, tightest-ever limits have profound implications.
Many were hoping that JWST would find the first stars of all. Despite many hopeful claims, it hasn’t, and probably can’t. Here’s how we can.
Here in our Universe, time passes at a fixed rate for all observers: one second-per-second. Before the Big Bang, things were very different.
If it weren’t for the intricate rules of quantum physics, we wouldn’t have formed neutral atoms “only” ~380,000 years after the Big Bang.
Coming from just 280 million years after the Big Bang, or 98% of cosmic history ago, this new, massive galaxy is a puzzle, but not a mirage.
If all massive objects emit Hawking radiation, not just black holes alone, then everything is unstable, even the Universe. Can that be true?
There’s an old saying that “what you see is what you get.” When it comes to the Universe, however, there’s often more to the full story.
The surface and atmosphere is colored by ferric oxides. Beneath a very thin layer, mere millimeters deep in places, it’s not red anymore.
Many, from neuroscientists to philosophers to anesthesiologists, have claimed to understand consciousness. Do physicists? Does anyone?
With stars, gas, and dark matter, galaxies come in a great array of sizes. This new one, Ursa Major III/UNIONS 1, is the smallest by far.
NASA astrophysics, which gave us Hubble, JWST, and so much more, faces its greatest budget cut in history. All future missions are at risk.
Just 10 years ago, humanity had never directly detected a single gravitational wave. We’re closing in on 300 now, with so much more to come!
The fact that our Universe’s expansion is accelerating implies that dark energy exists. But could it be even weirder than we’ve imagined?
The laws of physics obey certain symmetries and defy others. It’s theoretically tempting to add new ones, but reality doesn’t agree.
For centuries, vaccines have been the top life-saving, expert medical intervention known to humans. How can individuals make the right call?
It took nearly 400,000 years, after the Big Bang, to first form neutral atoms. The imprints from that early time can now be seen everywhere.
The COSMOS-Web survey is now complete, combining JWST and Hubble infrared data. Its spectacular views show us the Universe as never before.
Since 1998, we’ve known our Universe isn’t just expanding, but the expansion is accelerating. Could the Big Bang itself be the reason why?
For millennia, diamonds were the hardest known material, but they only rank at #7 on the current list. Can you guess which material is #1?
As democracy recedes and fascism rises in the USA and around the world in 2025, history provides a lesson in how science can fight fascism.
The laws of nature are almost perfectly symmetric between matter and antimatter, and yet our Universe is made ~100% of matter only. But why?
There are limits to where physics makes meaningful predictions: beyond the Planck length, time, or energy. Here’s why we can’t go further.
All stars shine due to an internal source of energy. Usually, it’s nuclear fusion: converting mass into energy. What makes them most bright?
Photons come in every wavelength you can imagine. But one particular quantum transition makes light at precisely 21 cm, and it’s magical.