Ethan Siegel

Do the three quantum forces all unify together? We have three forces that we know are quantum in nature: the strong, weak, and electromagnetic forces. We know that the weak and electromagnetic forces unify. What about all three? bigthink.com/starts-with-... #physics #space #GUTs #theory

How long does it take to travel through the Universe at 1g? If you had a spacecraft that could continuously accelerate at 1g forever, you could reach anywhere within the observable Universe. A one-way trip would take just 25 years, max. bigthink.com/starts-with-... #space #astro #physics

Listen: Stellar streams and the dark Universe Only the surviving stars and gas guide us when it comes to our Milky Way's history. Stellar streams may not just unlock hidden parts of that history, but the nature of dark matter as well. bigthink.com/starts-with-... #space #astro #physics #darkmatter

Ask Ethan: Can we solve the mysteries of the largest black holes? In 2004, black hole TON 618 was announced: with a mass of 66 billion Suns, just 3 billion years after the Big Bang. The theoretical limit was 50 billion Suns by today. So what gives? bigthink.com/starts-with-... #space #astro

The sci-fi inspired “cloaking device” makes invisibility possible Becoming invisible has long be a human aspiration, with Star Trek's "cloaking device" taking it mainstream. The combination of metamaterials and metalenses could soon make it a reality. bigthink.com/starts-with-... #space #physics

Are we asking the wrong questions about dark matter? People often bring up dark matter and wonder whether it exists or not. But nearly every astrophysicist has moved on to ask, "what is dark matter?" Here's how we'll find out. bigthink.com/starts-with-... #space #astro #cosmo #darkmatter

MMX mission to reveal the origins of the Martian moons The MMX mission has successfully launched, and is on its way to Mars's Phobos. Here's what it's going to do, and how it will reveal the origins and history of the Martian moons. bigthink.com/starts-with-... #space #astro #Mars #MMX #JAXA

The ultimate key to unlocking the heart of the Milky Way For millennia, light-blocking dust prevented us from seeing the heart of the Milky Way. Today, we've reached our galactic center, its supermassive black hole, and now, the event horizon. bigthink.com/starts-with-... #space #astro #blackhole

Ask Ethan: What should humanity’s message to the Universe be? We often complain that no intelligent aliens have ever tried to contact us, but we've never sent out an appropriate announcement that "we're here." Here's what one would look like. bigthink.com/starts-with-... #space #astro #SETI #METI

Einstein’s general relativity equations: explained in plain English The #Einstein field equations are incredibly complex and general. Even the best physicists can only solve them for a few special cases. In plain English, here's what they mean. bigthink.com/starts-with-... #physics #space #GR

Naturalness: a useful principle, but not an absolute rule Naturalness means something very special to physicists, and "naturalness arguments" are often used to motivate theoretical explorations. It's often a useful guide, but it's no law. bigthink.com/starts-with-... #space #physics #astro

Will the #Hubble “constant” ever become an actual constant? The cosmic expansion rate changes with time, but we call it "the Hubble constant." If one specific condition is true, it will, one day, become a constant. But no one will be able to tell. bigthink.com/starts-with-... #space #astro

7 mind-bending comparisons between the Universe and the human body The Universe is too vast for our minds to comprehend, while the cellular, molecular, and atomic world within us is mind-numbingly small. These 7 comparisons help bridge that gap. bigthink.com/starts-with-... #space #astro #human

Ask Ethan: Can a Kevlar tether create artificial gravity in space? The cheapest way to create artificial gravity in space is to rotate two massive, tethered capsules together. But how to control for both angular momentum and Coriolis forces? bigthink.com/starts-with-... #space #astro #physics

Mercury lost its crown, and isn’t our Solar System’s hottest planet Mercury, as the closest planet to the Sun and the most absorptive planet in the Solar System, should be the hottest, too. Maybe it was at one point. But Venus is #1 now, and by a lot. bigthink.com/starts-with-... #space #astro

IceCube, high-energy neutrinos, and Francis Halzen win 2026’s Physics Nobel A deep dive on the history and development of high-energy neutrino astrophysics. Francis Halzen thoroughly deserves to be physics' first solo Nobel Laureate since 1992! bigthink.com/starts-with-... #space #physics #astro

Pure sulfur discovered on Mars, making Martian concrete possible 10 years ago, the recipe for making effective concrete with Martian sand was discovered. The key ingredient: molten elemental sulfur. Guess what the Curiosity rover just found? bigthink.com/starts-with-... #space #mars #astro

Is Olympus Mons really the Solar System’s highest mountain? Olympus Mons is notorious for being the highest mountain, base-to-peak, in the Solar System. But Vesta's Rheasilvia may yet be larger, and many other planetary candidates remain unexplored. bigthink.com/starts-with-... #space #astro

Ask Ethan: Do evaporating black holes ever lose their event horizons? When black holes evaporate, their event horizons shrink. If those horizons get small enough, could they possibly reveal some object other than a singularity at their cores? bigthink.com/starts-with-... #space #astro #physics

Quantum fields carry energy. Does that prove that they’re real? In quantum physics, we often argue over "what is real?" Is the wavefunction? Are eigenstates? Quantum fields have a compelling argument for their reality: they carry energy. bigthink.com/starts-with-... #physics #quantum #energy

AI makes its first meaningful breakthrough in theoretical physics LLM-based AI just computed a specific nine-loop order calculation in theoretical physics: going well beyond what humans, alone, could do. May we hope that QED loops are next! bigthink.com/starts-with-... #physics #theory #llm #AI

A revolution has come in the first of the Big Bang’s 4 cornerstones The earliest of the Big Bang's four cornerstones is nucleosynthesis: the primeval creation of the light elements. It has now entered the era of precision cosmology, too: to 0.5%! bigthink.com/starts-with-... #space #astro #cosmo

18 pictures show how profoundly large our cosmos is From planet Earth to the inflationary multiverse, our conception of the Universe spans an enormous range of cosmic scales. This photo tour takes us from here to eternity. bigthink.com/starts-with-... #physics #space #cosmology #multiverse

Ask Ethan: If intelligent alien life exists, will we make contact? In the quest to find alien life, sure, luck plays a role in terms of how common it is. But just as important, and vastly underrated, is how much we invest in the endeavor. bigthink.com/starts-with-... #space #astro #aliens #SETI

“Donnie Darko” offers a time travel lesson you won’t find elsewhere The movie "Donnie Darko" first came out 25 years ago. How does the time travel in the story stack up against what physics actually understands? bigthink.com/starts-with-... #space #astro #physics #timetravel #movies

The Higgs boson’s most important puzzle remains unsolved We've found the Higgs boson, measured its mass, and confirmed the Standard Model. But does the Higgs field have a 1st or 2nd order phase transition? The origin of matter depends on it bigthink.com/starts-with-... #space #physics #higgs

This discovery is why Einstein was history’s greatest physicist Einstein made a whole lot of discoveries in his life, with many others very close to many of his breakthroughs. But without Einstein, General Relativity may never have come about at all. bigthink.com/starts-with-... #space #astro

Most accurate cosmic clocks show unexpected instability Millisecond pulsars are the Universe's most accurate natural clocks. Not only do they glitch, changing their period, but their pulse profiles change. By quite a lot, too. #space bigthink.com/starts-with-... Cc: @rami.spaceaustralia.com!

Ask Ethan: How did atoms come to be? The Universe made more quarks than antiquarks, hadronized, created protons and neutrons (plus an electron asymmetry), and underwent nucleosynthesis before making atoms. Did it have to? bigthink.com/starts-with-... #physics #space #astro #atoms

Do gravitational waves show evidence of wave-particle duality? All particles, both fundamental and composite, exhibit wave-particle duality at some level. If gravitational waves do, too, then gravity can be proven to be quantum in nature. bigthink.com/starts-with-... #space #astro #gravity

The information paradox at the heart of every black hole Einstein's general relativity gives us black holes with zero entropy. That can't be right, according to quantum physics. How will the black hole information paradox be resolved? bigthink.com/starts-with-... #physics #astro #math #blackhole

One blip isn’t enough to declare “dark matter has been detected” The LUX-ZEPLIN dark matter candidate event is the most interesting experimental physics result in years. But one event does not a detection make. Just ask Blas Cabrera about 1982. bigthink.com/starts-with-... #physics #particle

Congratulations to Emily Levesque on becoming the new AAS journals editor-in-chief! Emily succeeds Ethan Vishniac, who is awesome and did a wonderful job. Emily is also awesome and I'm sure will also do a wonderful job! Great choices by AAS! aas.org/press/emily-...

Only four days each year are actually 24 hours long "The day is 24 hours long" is something we all say, but however you measure it, it's only precisely true for four days out of the year. Planetary motion is complicated! bigthink.com/starts-with-... #space #astro #time #physics

Ask Ethan: Do white holes, the opposite of black holes, physically exist? Black holes definitively exist, and hundreds have now been directly detected. Mathematically, white holes are just as permissible. So where are they? bigthink.com/starts-with-... #space #astro #blackholes #spacetime

Does the expanding Universe stretch space or create new space? The Universe expands. Does that mean space itself is stretching, that new space is getting created, or some other option for which our conventional understanding breaks down? bigthink.com/starts-with-... #space #physics #astro #cosmo

Can we be certain that time really exists? Some claim that time is merely a persistent illusion. But there are good reasons, physically, to believe that it really does exist in a meaningful way. bigthink.com/starts-with-... #space #time #physics #astro

This physics trick allows you to beat the speed of light The speed of light in a vacuum is the ultimate speed limit for any information-carrying signal through spacetime. But not everything is a vacuum, and that's the key to defeating it! bigthink.com/starts-with-... #physics #light #einstein

It's hard to believe, but the 60th anniversary of Star Trek is upon us! In honor of that, I just did an interview with Kieran Mulvaney about Star Trek, Technology, and hope. Here in 2026, it's the message we need to heed more than ever. www.history.com/articles/inv...

The “perfect cosmological principle” isn’t true for our Universe On the largest scales, the Universe is the same everywhere in space. Could it also be the same everywhere in time? That's the Perfect Cosmological Principle: fascinating, but untrue. bigthink.com/starts-with-... #space #astro

New podcast! Starts With A Bang #133: The Milky Way's center All at once, the galactic center is the most evolved part of our galaxy, and also our window into its most primitive stages. Listen to Cara Battersby and I discuss this amazing place in space! bigthink.com/starts-with-... #space #astro

The worst thing about the age of AI is how evident it's become that so many people have no interest in or passion for learning or understanding topics that have fascinated me my whole life. Who cares about "getting the right answer" if you don't know how to get there yourself?

Ask Ethan: Are there really charm quarks inside the proton? Everyone knows there are two up quarks and one down quark inside a proton. But when we smash things into them, we suddenly can find evidence for charm quarks inside them, too. bigthink.com/wp-content/u...

Why mirrors flip left-to-right but not up-and-down Wave at yourself in a mirror and the mirror's reflection waves back, but using the opposite hand from you. Mirrors swap left-and-right, but not up-and-down. Do you know why? bigthink.com/starts-with-... #physics #mirrors #light #optics

Time is a fundamentally different type of dimension than space We have more than three dimensions in our Universe, because time (the fourth) is also one. But it has some fundamental differences from the spatial dimensions, and oh, do they matter. bigthink.com/starts-with-... #space #time #physics

Do we live inside a baby universe that’s really a black hole on the outside? Our Universe consists of everything we know of. But might it simply be the interior of a black hole that formed as part of a larger, grander structure than we can perceive? bigthink.com/starts-with-... #cosmology #astro

Yes, the Sun is a star, but it’s far from typical It's a remarkable scientific fact that our Sun is a star: just like all the ones we see in the night sky. But it's perhaps equally remarkable how atypical we are. Find out by how much! bigthink.com/starts-with-... #space #astro #sun #stars

Ask Ethan: Can someone possibly see the edge of spacetime? In all directions, the Universe goes on, almost perfectly uniform, as far as we can see. But if we had been born close to the edge of our hot Big Bang's bubble, what would the edge reveal? bigthink.com/starts-with-... #space #astro #cosmo

The act of measuring reality alters what you’ll observe The most annoying part of quantum mechanics is that masuring a system doesn't just "determine" its state, but alters the experimental outcome. The double slit setup reveals how. bigthink.com/starts-with-... #physics #quantum