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.

A large telescope observatory under construction at dusk with a visible moon and stars in the sky. Cranes and construction equipment are present around the structure.
Comet A3, also known as Comet Tsuchinshan-ATLAS, has sprung to life since 2024's last equinox. Here's how to catch the show for yourself.
dark matter substructure intracluster light
In theory, dark matter is cold, collisionless, and only interacts via gravity. What we see in ultra-diffuse galaxies indicates otherwise.
A spacecraft travels at the fastest spacecraft speed record through bright, yellow-orange streaks of plasma and solar wind near the Sun.
The Parker Solar Probe is about to undergo its seventh encounter with Venus on its journey toward the Sun. Here's how fast it'll go.
Lockman hole galaxy cluster herschel
In all directions, at great distances, the Universe looks younger, more uniform, and less evolved. Does that mean Earth must be the center?
time dilation
Time is relative, not absolute, as gravity and motion both cause time to dilate. Your head and feet, therefore, don't age at the same rate.
A deep-space image captured by the JWST showcases numerous galaxies of various shapes, sizes, and colors scattered across a dark background, potentially setting a new cosmic distance record.
Despite many ultra-distant galaxy candidates found with JWST, we still haven't seen anything from the Universe's first 250 million years.
A large, intricate machine with metallic components and blue scaffolding in a laboratory setting. Numerous cables and pipes are connected to the central structure.
LHC scientists just showed that spooky quantum entanglement applies to the highest-energy, shortest-lived particles of all: top quarks.
Two views of the same celestial object: the fiery orange-blue image on the left and a cooler blue-pink image on the right, showcasing an hourglass-shaped cloud of gas and dust in space.
Just 460 light-years away, the closest newborn protostars are forming in the Taurus molecular cloud. Here are JWST's astonishing insights.
entanglement across space
It's possible to remove all forms of matter, radiation, and curvature from space. When you do, dark energy still remains. Is this mandatory?
spooky action quantum
Do we actually live in a deterministic Universe, despite quantum physics? An alternative, non-spooky interpretation has now been ruled out.
A vivid depiction of a cosmic event showing a jet of orange and red energy extending from a bright source in the vastness of space, surrounded by stars and interstellar matter.
With the discovery of Porphyrion, we've now seen black hole jets spanning 24 million light-years: the scale of the cosmic web.
Parker Solar Probe
It would get rid of our hazardous, radioactive, and pollutive waste for good, but physics tells us it's a losing strategy for elimination.
A dense cluster of young stars and bright blue-white spots set against a dark reddish-brown background, with scattered sparkles of light from numerous stars in the outer Milky Way, captured stunningly by JWST.
Almost all of the stars, planets, and interesting physics happens in the inner portions of galaxies. Is that conventional wisdom all wrong?
Rows of identical Earth-like planets stretch out into the vast copy multiverse, with a dark starry background visible between them.
Within our observable Universe, there's only one Earth and one "you." But in a vast multiverse, so much more becomes possible.
Satellite image showing a dense cloud mass over the southeastern United States and the Gulf of Mexico, with an inset graph from NOAA depicting hurricane frequency peaking around mid-August to late September, a trend exacerbated by global warming.
The laws of physics aren't changing. But the Earth's conditions are different than what they used to be, and so are hurricanes as a result.
atom illustration
Most fundamental constants could be a little larger or smaller, and our Universe would still be similar. But not the mass of the electron.
Two breathtaking pictures of a galaxy and a star taken by the Hubble telescope, highlighting the beauty and cosmic magnitude that fuels the Hubble tension.
In the expanding Universe, different ways of measuring its rate give incompatible answers. Nobel Laureate Adam Riess explains what it means.
The image shows a bright spot labeled "JADES-GS-z13-1-LA," seemingly an impossible light captured by the JWST, surrounded by measurement markers, including a scale bar for 1 kpc and 0.28 arcsec. Filters and colors are listed at the bottom.
The Lyman-α emission line has never been seen earlier than 550 million years after the Big Bang. So why does JADES-GS-z13-1-LA have one?
A detailed image of two galaxies in space, one with spiral arms on the left and the other, more elliptical, on the right, surrounded by distant stars.
Galactic activity doesn't just arrive when supermassive black holes feast on matter. Before, during, and after all create fascinating signs.
uap ufo UAPs UFOs
Although a great many unidentified sights have been seen in the skies, none have conclusively demonstrated the presence of aliens. So far.