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Ethan Siegel
Theoretical astrophysicist and science writer
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.
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Only nearby objects appear to the naked eye. With telescopes of all types, especially in space, we've smashed those records many times over.
Triton is Neptune's largest moon today, but it was once the undisputed king of the Kuiper belt. Here's why the outer solar system matters.
There's a lot of room in interplanetary, interstellar, and intergalactic space, but just how low the densities go is truly mind-boggling.
Contrary to common experience, not everything needs a medium to travel through. Overcoming that assumption removes the need for an aether.
Newton's gravitational constant, G, is still known to just 3 significant figures in 2026. New measurements merely highlight our uncertainty.
In 2006, the IAU defined "planet" for the first time, excluding Pluto and all other dwarf planets. In 2026, is it now time for a change?
From within our own galaxy to behemoths billions of light-years away, supermassive black holes create jets like nothing else in the cosmos.
It takes incredible energies to accelerate masses near the speed of light. So how do the farthest galaxies speed away from us so quickly?
In 2006, Pluto was controversially demoted to "dwarf planet" by the IAU. Unless you ignore most of astrophysics, it won't ever be one again.
The first colliding galaxy cluster to reveal dark matter, empirically, turns 20 this year. Here's why it cements dark matter's existence.
NASA has just sent astronauts back to the Moon for the first time since 1972 with Artemis II. So why would we cut NASA and NSF science now?
Today, we have the Standard Model of particles with four fundamental forces governing them. But things weren't always the way they are now.
Many facts are well-known to professionals, but are unappreciated or even rejected outright by the public. "How stars work" takes the cake.
For decades, theorists have been cooking up "theories of everything" to explain our Universe. Are all of them completely off-track?
Our dream of journeying to other star systems has a big obstacle to overcome: the vast interstellar distances. Can antimatter get us there?
On cosmic scales, only dark matter (or something equivalent) gives us the Universe we observe. Now, the Sunyaev-Zel'dovich effect agrees.
Although a star's "birth" is well-defined, it doesn't correspond to an ignition event in its core. Here's how stars are actually born.
Every time a new star forms, there's an opportunity to form planets alongside and around it. How does it happen, and how long does it take?
"Color" with respect to the strong force is just an analogy. Here's how to understand it without colors, group theory, or any advanced math.
From 2004 through 2017, Saturn was imaged many times and from many angles up close by Cassini. This new viral image isn't real; it's AI.