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.

Astronomers see spiral and elliptical nebulae nearly everywhere, except by the Milky Way’s plane. We didn’t know why until the 20th century.
We’ve wasted our time and resources ideologically policing and punishing each other for far too long. Here’s a better route to prosperity.
From the tiniest subatomic scales to the grandest cosmic structures of all, everything that exists depends on two things: charge and mass.
The CMB gives us critical information about our cosmic past. But it doesn’t give us everything, and galaxy mapping can fill in a key gap.
The full extent of the Andromeda galaxy, the nearest large galaxy to our own, has been entirely imaged with Hubble’s exquisite cameras.
Dark matter doesn’t absorb or emit light, but it gravitates. Instead of something exotic and novel, could it just be dark, normal matter?
We’re all entitled to our own opinions, no matter how ill-informed they are. But facts are facts; we can’t just choose the ones we prefer.
Asteroid 2024 YR4, which could devastate a city’s worth of humans, has gone from 1.2% to 2.3% to 2.6% to 3.1% chances of impact. Here’s why.
At extremely close distances to their stars, even rocky planets can be completely disintegrated. We’ve just caught our first one in action.
Ring galaxies are rare, but we think we know how they form. A new, early-stage version, the Bullseye galaxy, provides a new testing ground.
Here in our Solar System, terrestrial bodies get moons from gravitational capture or collisions. The Pluto-Charon system? It was both.
Only 5% of the Universe is made of normal “stuff” like we are. Could there be dark matter or dark energy life, or even aliens, out there?
When we divide matter into its fundamental, indivisible components, are those particles truly point-like, or is there a finite minimum size?
The primary causes of global climate change are all due to human activity. Adding aerosols to our atmosphere only exacerbates the problem.
The ultimate multi-messenger astronomy event would have gravitational waves, particles, and light arriving all at once. Did that just occur?
A young, nearby, massive star, whose protoplanetary disk appears perfectly edge-on, was just viewed by JWST, with staggering implications.
If we wish to tackle the very real problems society faces, we require expert-level knowledge. Valuing it starts earlier than we realize.
Seeking life beyond the Solar System, we first look to the closest star systems with Earth-like planets. Here’s why that’s not good enough.
Our Moon is full of craters, basins, and ancient lava flows. But two large lunar Grand Canyons have the same origin: a single, giant impact.
There are only four super star clusters in all the Local Group: rarities today. Here’s what the youngest, the just-discovered N79, shows us.
Here in our Universe, both normal and dark matter can be measured astrophysically. But only normal matter can collapse. Why is that?
With a flurry of threats to scientists, science funding, and health policy, the USA now faces a crisis reminiscent of Soviet-era Lysenkoism.
First discovered in the mid-1960s, no cosmic signal has taught us more about the Universe, or spurred more controversy, than the CMB.
From LIGO, there weren’t enough neutron star-neutron star mergers to account for our heavy elements. With a JWST surprise, maybe they can.
It’s the ultimate game of cosmic “cover up,” as the dimming occurs when a circumbinary disk from a nearby star passes in front of T Tauri North.
Matter is made up largely of atoms, where atomic nuclei can contain up to 100 protons or more. But how were the heaviest elements made?
Cosmic inflation, proposed back in 1980, is a theory that precedes and sets up the hot Big Bang. After thorough testing, is it still valid?
Scientists just viewed one of the tiniest, most isolated, lowest-mass galaxies ever found with JWST. Despite all odds, it’s still growing.
New telescopes, radio dishes, and gravitational wave detectors are needed for next-generation science. Will the USA lead the way?
The Ring Nebula, a bright, circular planetary nebula, is created by a dying Sun-like star. After centuries, we finally know its true shape.