Ethan Siegel
@StartsWithABang
"Some blogger who doesn’t even write a single paper in a decade." #Cosmology Science writer, astrophysicist, author, communicator. He/him or they/them.
"Where can I buy Infinite Cosmos?" Yes!! Everywhere! Amazon: amzn.to/400384v Barnes & Noble: barnesandnoble.com/w/infinite-cos… Disney: books.disney.com/book/infinite-… Penguin/Random House: penguinrandomhouse.com/books/757535/i… Powell's city of books: powells.com/book/-97814262…

5 science facts that come from simply watching the Moon The Earth is round, the Moon's orbit is elliptical, the Moon's surface has high crater walls, and Earth reflects sunlight onto other bodies. Simply watching the Moon teaches us all this and more. bigthink.com/starts-with-a-…
Did our Universe really arise from nothing? #AskEthan Our Universe arose from a state of inflating, exponentially expanding, empty space. But is it really fair to say that this means our Universe came from "nothing?" bigthink.com/starts-with-a-…
Sure, we live in a quantum universe, where particles have inherently uncertain properties, like position, as part of their nature. But it's not just the particles that are quantum, the fields underlying them are quantum, too. bigthink.com/starts-with-a-…
"Whether you run the clock forward or backward, most of us expect the laws of physics to be the same. A 2012 experiment showed otherwise." by @StartsWithABang realclearscience.com/2025/07/23/uni…
The incredible physics of quantum levitation Quantum levitation isn't just a cool phenomenon, it's only possible when things are so cold that your material superconducts in a special (type II) way. Here's how to do it yourself. bigthink.com/starts-with-a-…
The Universe is not the same forward and backward in time In fundamental physics, it's only the weak interactions that aren't the same forwards and backwards in time. We observed it directly in 2012, but another discovery overshadowed this one. bigthink.com/starts-with-a-…
What we’ve learned after 35 years of NASA’s Hubble NASA's Hubble turned 35 this year. Even as funding threatens to end its operations, here are the highlights of what it's brought to our Universe. bigthink.com/starts-with-a-…
Could our whole Universe be a black hole’s interior? #AskEthan Could the Big Bang that our Universe emerged from be related to a black hole's interior from a previous Universe? The idea is wild, sure. But worth exploring? Definitely! bigthink.com/starts-with-a-…
Why is “F = ma” still the most important equation in physics? It's been over 300 years since Newton's laws were first written down, and we've learned so much more in all the time since. So, why does F = ma remain such an important equation? bigthink.com/starts-with-a-…
The single most amazing fact about the Universe The Universe is full of amazing facts, but the most amazing fact of all is that it exists in a way such that it can be understood. Everything else, literally everything, is built atop that foundation. bigthink.com/starts-with-a-…
LIGO’s heaviest black hole demands next-generation science LIGO (and Virgo, and KAGRA) have now detected more than 300 high-significance (plus ~4000+ tentative) gravitational wave events, with a new most-massive one. So why shut it down? bigthink.com/starts-with-a-…
How particle physics will continue after the last collider After the last collider gets built, particle physics won't come to an end. Instead, it will return to its roots: looking at rare, high-energy cosmic rays made elsewhere in space. bigthink.com/starts-with-a-…
The worst prediction in science? "The measured value of the cosmological constant is 120 orders of magnitude smaller than what’s predicted. How can this paradox be resolved?" via @StartsWithABang realclearscience.com/2025/07/12/can…
I just recently recorded an episode of the Roots of Reality podcast, where we talked about some foundational issues in physics and how our picture of the early Universe both succeeds and leaves us wanting more. A fun, deep, history-rich dive! soundcloud.com/ben-baumann-49…
Can we fix the worst prediction in all of science? #AskEthan The cosmological constant is the worst prediction in all of science, off by ~122 orders of magnitude from the observed value. Even worse: it's two unsolved problems in one. bigthink.com/starts-with-a-…
Jupiter endangers Earth, and may have extincted the dinosaurs Jupiter is often lauded as Earth's great cosmic shield and protector. But it's more foe than friend, and may have even triggered the great mass extinction that occurred 65 million years ago. bigthink.com/starts-with-a-…
The top quark isn’t a loner after all: “toponium” is real! The top quark is the most massive, shortest lived particle of all. But it isn't always a "bare quark" that just decays; the LHC just revealed that the bound state of "toponium" is real! bigthink.com/starts-with-a-…
Looking forward to The Grand Cosmic Story, partnering with @NatGeoBooks, coming out this fall? Preorder from Barnes & Noble, now through July 11, and get 25-35% off as a Rewards/Premium member! barnesandnoble.com/w/the-grand-co… #BNPreorder (Use coupon code PREORDER25 at checkout!)
Humanity’s third interstellar object, 3I/ATLAS, is arriving now Interstellar object 3I/ATLAS is now being measured and characterized for the first time. Here's what we've learned about it so far, including comparisons to 'Oumuamua and Borisov. bigthink.com/starts-with-a-…
Did JWST catch the Ring Nebula forming new planets? Planet formation normally happens when new stellar systems are forming: in protoplanetary disks. But when a Sun-like star dies, it makes new dusty debris. Do new planets arise from the ashes? bigthink.com/starts-with-a-…