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.

A jellyfish galaxy with a bright white and yellow core is surrounded by red clouds of gas, set against a dark background filled with stars.
Weird-looking galaxies, with tentacle-like tails or prominent dual streams, appear like jellyfish or bunny ears. But that’s just the start.
A vast starry sky showcases a spinning galaxy, a relic from 12 billion years ago, among countless stars of varying brightness on a dark background.
For over 10 billion years, the cosmic star-formation rate has been dropping and dropping. Someday, the final star in the Universe will die.
gravity probe b
We first measured G, the gravitational constant, back in the 18th century. As the least well-known fundamental constant, can it be improved?
In 2017, a kilonova sent light and gravitational waves across the Universe. Here on Earth, there was a 1.7 second signal arrival delay. Why?
A detailed image of the Eta Carinae star system could trick science headlines with its bright, colorful clouds of gas and dust in blue, red, and purple hues swirling around a luminous central region.
Dark matter, dark energy, and the Big Bang are all part of a solid scientific foundation. Here's why popular media often claims otherwise.
A bright, circular object with concentric rings and a surrounding halo set against a dark background, resembling a gap-clearing planet or other astronomical phenomena.
Planets grow from protostellar material in disks, leading to full-grown planetary systems in time. At last, the final gap has been filled.
A wavy line, one meter long, transitions from dark red to bright yellow above a ruler, set against a magenta oval with a blue background featuring drawn human figures.
Until the late 20th century, there wasn't a truly universal standard. Under our current definition, everyone agrees on what "one meter" is.
Book cover of "Do Aliens Speak Physics?" by Daniel Whiteson and Andy Warner, featuring a blue background, yellow and white text, and an illustration of a robot and people interacting.
Do aliens speak the same physics that we do, with similar laws, observables, and underlying mathematics. Maybe not, argues Daniel Whiteson.
gravitational wave effects on spacetime
We've now detected hundreds of gravitational waves with LIGO, Virgo, and KAGRA. What if we tried Weber's original method in the modern day?
terraforming
The first world beyond Earth for human habitability should be the Moon, not Mars. This is why we should terraform our lunar neighbor first.
two particles different wavelength speed of light
Times dilate and lengths contract near the speed of light. Bizarre and confusing? Sure. But under relativity, it can't be any other way.
A field of galaxies in deep space, featuring a bright spiral galaxy at the lower right with a stellar stream escaping the galaxy, and a large, bright red star at the upper left.
Stellar streams are faint trails of stars that appear to "stream" out of galaxies. A new one, escaping galaxy M61, may point to many others.
Three side-by-side images show different views of the Red Spider Nebula in space, captured by JWST, with a bright center and colorful gases in orange, green, and blue against a backdrop of stars.
When dying, Sun-like stars have binary companions, spectacular sights arise from the ionization. JWST spots the Red Spider Nebula in action!
big crunch
There's some, but not overwhelming, evidence that dark energy is evolving. What would it take for a "Big Crunch" to be our cosmic fate?
solar system model
Scientists are notoriously resistant to new ideas. Are they falling prey to groupthink? Or are our current theories just that successful?
ufo lights liverpool
Physicist Daniel Whiteson challenges the notion that all intelligent species would eventually uncover the same laws of nature. Do you agree?
DUNE neutrino detectors
Nearly 100 years after being theorized, the strange behavior of the neutrino still mystifies us. They could be even stranger than we know.
An image of El Gordo, a massive galaxy cluster captured by Hubble
The planet, the Solar System, and the galaxy aren't expanding. But the whole Universe is. So where does the dividing line begin?
big bang
For 13.8 billion years, the Universe has been expanding. But that couldn't have been the case for an eternity, and science has proven it.
dark matter
Dark matter has never been directly detected, but the astronomical evidence for its existence is overwhelming. Here's what to know.