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.

Lecturer standing in front of a classroom, teaching college admissions students seated at desks with sunlight casting shadows.
There are many problems with relying on SAT and ACT scores for college admissions. But removing them entirely creates less opportunity.
Illustration of the solar system's planets and their predicted fates, with some being swallowed by the sun as it dies and others stripped of their atmospheres or ejected.
For now, our Solar System's eight planets are all safe, and relatively stable. Billions of years from now, everything will be different.
Planets in varying sizes orbiting around a bright central star in a purple-hued cosmos, where life persists.
There are plenty of life-friendly stellar systems in the Universe today. But at some point in the far future, life's final extinction will occur.
A blue t-shirt with a yellow circle and arrow, representing the universe.
The second law of thermodynamics tells us that entropy always increases. But that doesn't mean it was zero at the start of the Big Bang.
An image of a yellow and purple wave with an unclear origin.
Everything acts like a wave while it propagates, but behaves like a particle whenever it interacts. The origins of this duality go way back.
nasa merge black hole
So far, gravitational waves have revealed stellar mass black holes and neutron stars, plus a cosmic background. So much more is coming.
An image of a spiral galaxy taken by the JWST in space.
Almost every large structure in the Universe displays a 5:1 dark matter-to-normal matter ratio. Here's how some galaxies defy that rule.
A choropleth map of the united states displaying median age by county with a color gradient from light to dark blue indicating increasing age ranges following a natural bell curve distribution.
Almost everything we can observe and measure follows what's known as a normal distribution, or a Bell curve. There's a profound reason why.
Comparison of early Mars with abundant water and a thicker atmosphere versus the dry and arid Mars of today, much like Venus, which also died in terms of its potential to support life.
In the early stages of our Solar System, there were three life-friendly planets: Venus, Earth, and Mars. Only Earth thrived. Here's why.
gaia ESA milky way
For thousands of years, humanity had no idea how far away the stars were. In the 1600s, Newton, Huygens, and Hooke all claimed to get there.
Einstein field equations
Although many of Einstein's papers revolutionized physics, there's one Einsteinian advance, generally, that towers over all the rest.
A cluster of galaxies with a star in the middle.
Beyond the planets, stars, and Milky Way lie ultra-distant objects: galaxies and quasars. Here's how far back we've seen throughout history.
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.
An abstract composite image depicting where life began with mountainous terrain, chemical structures, and a monochrome inset of a cloudy sky.
Although early Earth was a molten hellscape, once it cooled, life arose almost immediately. That original chain of life remains unbroken.
A digitally enhanced view of a crescent planet Earth with a galaxy in the background.
The Earth that exists today wasn't formed simultaneously with the Sun and the other planets. In some ways, we're quite a latecomer.
A diagram showing the structure of a galaxy.
The Universe didn't begin with a bang, but with an inflationary "whoosh" that came before. Here are the biggest questions that still remain.
A view of jupiter from space.
NASA's Juno mission, in orbit around Jupiter, occasionally flies past its innermost large moon: Io. The volcanic activity is unbelievable.
A bright light in the sky.
As planets with too many volatiles and too little mass orbit their parent stars, their atmospheres photoevaporate, spelling doom for some.
wormhole nasa illustration
Without wormholes, warp drive, or some type of new matter, energy, or physics, everyone is limited by the speed of light. Or are they?
A computer-generated image of a bright celestial object with an accretion disk, possibly representing what the sun looked like when it was born.
It took 9.2 billion years of cosmic evolution before our Sun and Solar System even began to form. Such a small event has led to so much.