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.

Two bright celestial objects, including the brightest planet, shine in the night sky, partially obscured by clouds and surrounded by smaller, faint stars.
Even at its faintest, Venus always outshines every other star and planet that's visible from Earth, and then some!
A dense field of distant galaxies and bright stars against a black background, as captured in a JWST early galaxies deep space telescope image.
Many collaborations have used JWST to take deep-field images: some wider and some deeper than others. Here's how it can surpass them all.
connected entangled pair
A century ago, quantum physics overthrew our view of a deterministic Universe. A profound 21st century theorem closes the door even further.
Image of a star field with numerous galaxies; several objects are circled in white, and one object is marked with an “X” near the center.
The Universe formed stars, galaxies, and even galaxy clusters extremely early on in our cosmos. This new marvel is one more JWST surprise.
cosmic rays
At the upper limits of what's energetically possible, cosmic rays still persist. What happens if a human gets hit by the most energetic one?
Our great hope is that today's indirect, astrophysical evidence will someday lead to successful direct detection. What if that's impossible?
A deep space image showing a field of distant galaxies with several regions zoomed in to highlight faint, small JWST objects.
Just like animals, galaxies often have bizarre, unusual, or even unique properties. But finding many, all at once, really does raise alarms.
moon landing Apollo 11
Our view of the world, the Universe, and ourselves can change with just one glimpse of what's out there. It's happened many times before.
venus jupiter earth iss
Outer space begins just over 100 kilometers up, but what we can see extends for billions of light-years. Here's what all of it looks like.
Raisin bread expanding Universe
Even in an expanding Universe, we expect both redshifted and blueshifted galaxies. But nearly every one we see is redshifted. Here's why.
An elderly woman wearing glasses, a black hat, and a patterned scarf smiles while seated indoors—reminiscent of Gladys West, the Einstein behind GPS technology.
Two main contributors enabled our modern global positioning system (GPS): Albert Einstein and Gladys West. Here's how she made it happen.
Green and red aurora borealis lights, sparked by a recent solar radiation storm, arc across the night sky and reflect over a calm lake with a rocky shoreline.
The Sun often produces solar flares and coronal mass ejections, but a rare solar radiation storm made the 2026's first great auroral show.
Many view the development of fringe, alternative theories as a useless waste of time. But when they can be tested, it shows what reality is.
A vivid image of a galaxy with bright blue and red nebulous clouds, set against a black star-filled background in deep space.
With unprecedented resolution, wavelength sensitivity, and light-gathering power, JWST reveals our cosmos like no other observatory ever.
A deep space image shows numerous distant galaxies and stars against a dark background, including several bright spots shaped by a gravitational lens cross, with diffuse light sources scattered throughout.
Gravitational lenses arise when foreground masses and background light sources properly align. Einstein rings are rare, but crosses abound.
black hole
It's not about particle-antiparticle pairs falling into or escaping from a black hole. A deeper explanation alters our view of reality.
Diagram showing light from a distant galaxy bending around a red-hued massive object, reaching telescopes on Earth via different paths and at different times.
The VENUS survey isn't about planets at all, but about finding multiply-lensed supernovae. The ambition? To save the expanding Universe.
Astro2020
US science is worth fighting for, but so are the science projects and scientists denied opportunities. Here are 4 paths all worth exploring.
Five panels show NASA Chandra images of Kepler's supernova remnant as it expands over 25 years, with increasingly diffuse blue filaments against a starry background; a composite is shown in the last panel.
Back in 1604, Johannes Kepler discovered the Milky Way's last naked-eye supernova. Here's how NASA's Chandra sees it over the 21st century.
A colorful map shows the distribution of nearby galaxies, with distances and redshift factors labeled, created by DESI; NSF, NOIRLab, and Kitt Peak logos are visible.
The seeds of cosmic structure that were planted back during the Big Bang grew into the cosmic web we see today. What is it telling us?