Ethan Siegel+

Quantum fields carry energy. Does that prove that they’re real?

Are quantum fields real, or a mere calculational tool? 3 unique experiments show they carry energy. If energy’s real, so are quantum… Continue reading on Starts With A Bang! »

After the Sun devours both Venus and Mercury, Earth will be the hottest for a br

After the Sun devours both Venus and Mercury, Earth will be the hottest for a brief while.

Mercury lost its crown, and isn’t our Solar System’s hottest planet Mercury, as

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

AI makes its first meaningful breakthrough in theoretical physics

Making more complicated, more precise predictive calculations tells us what real experiments should deliver. AI just surpassed humans at… Continue reading on Starts With A Bang! »

Clawing its way to the TOP!

Clawing its way to the TOP!

IceCube, high-energy neutrinos, and Francis Halzen win 2026’s Physics Nobel A d

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

A revolution has come in the first of the Big Bang’s 4 cornerstones

The expanding Universe, CMB, and large-scale structure revealed the Big Bang. New nucleosynthesis advances deliver unprecedented precision. Continue reading on Starts With A Bang! »

Pure sulfur discovered on Mars, making Martian concrete possible 10 years ago,

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

18 pictures show how profoundly large our cosmos is

The observable Universe is 92 billion light-years in diameter. These pictures put just how large that is in perspective. Continue reading on Starts With A Bang! »

Is Olympus Mons really the Solar System’s highest mountain? Olympus Mons is not

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: If intelligent alien life exists, will we make contact?

We strongly suspect we aren’t alone in the Universe, but so far, we haven’t found anyone. What determines when we’ll finally make contact? Continue reading on Starts With A Bang! »

Ask Ethan: Do evaporating black holes ever lose their event horizons? When blac

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

“Donnie Darko” offers a time travel lesson you won’t find elsewhere

Most time travel stories involve changing the past to create a better future. Donnie Darko subverts that expectation, and a whole lot more. Continue reading on Starts With A Bang! »

Quantum fields carry energy. Does that prove that they’re real? In quantum phys

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

I don't think this, in and of itself, will lead to anything profound. But if we

I don't think this, in and of itself, will lead to anything profound. But if we can go to higher loop order in QED, we can test the standard model more precisely. Remember the muon g-2 experiment? This could improve the electron g-2 constraints, already the most stringent on the standard model.

The Higgs boson’s most important puzzle remains unsolved

Predicted back in the 1960s, 2012’s discovery of the Higgs boson completed the Standard Model. But the biggest Higgs puzzle still persists. Continue reading on Starts With A Bang! »

AI makes its first meaningful breakthrough in theoretical physics LLM-based AI

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

This discovery is why Einstein was history’s greatest physicist

Although many of Einstein’s papers revolutionized physics, there’s one Einsteinian advance, generally, that towers over all the rest. Continue reading on Starts With A Bang! »

A revolution has come in the first of the Big Bang’s 4 cornerstones The earlies

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

Most accurate cosmic clocks show unexpected instability

Millisecond pulsars are the Universe’s most accurate natural clocks. A pulse change, thought rare, just occurred twice in the closest one. Continue reading on Starts With A Bang! »

18 pictures show how profoundly large our cosmos is From planet Earth to the in

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: How did atoms come to be?

From a primordial soup of particles, atoms eventually emerged. What happened to make it so, and could things have worked out any other way? Continue reading on Starts With A Bang! »

Ask Ethan: If intelligent alien life exists, will we make contact? In the quest

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” 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

Do gravitational waves show evidence of wave-particle duality?

All matter particles can act as waves, and massless light waves show particle-like behavior. Can gravitational waves also be particle-like? Continue reading on Starts With A Bang! »

Depends. How do you feel doing service for the Nazi Science Foundation if you c

Depends. How do you feel doing service for the Nazi Science Foundation if you can help some of the "science" part while ignoring the rest of the "Nazi" part?

The Higgs boson’s most important puzzle remains unsolved We've found the Higgs

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

The information paradox at the heart of every black hole

The matter that creates black holes won’t be what comes out when they evaporate. Will the black hole information paradox ever be solved? Continue reading on Starts With A Bang! »

I mean, all of this is subjective, and the answer to "what was the greatest..."

I mean, all of this is subjective, and the answer to "what was the greatest..." or "who was the greatest..." has no better one than what Kareem Abdul-Jabbar gave when asked about the basketball GOAT: "We'll never know." But without Einstein and GR, we may only have ever reached EFTs for gravity.

This discovery is why Einstein was history’s greatest physicist Einstein made a

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

One blip isn’t enough to declare “dark matter has been detected”

In 1982, an experiment showed unprecedented evidence for exotic matter: magnetic monopoles. But without reproducibility, it didn’t hold up. Continue reading on Starts With A Bang! »

Thanks also to your collaborator Marcus Lower, who saw me conflate (before corre

Thanks also to your collaborator Marcus Lower, who saw me conflate (before correcting it while you were asleep) the processes of "glitch" and "pulse profile change." They are well-separated in the article as-is now!

Most accurate cosmic clocks show unexpected instability Millisecond pulsars are

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!

Only four days each year are actually 24 hours long

As the Earth spins and wobbles on its axis and revolves elliptically around the Sun, each day differs from the last. “24 hours” isn’t… Continue reading on Starts With A Bang! »

Ask Ethan: How did atoms come to be? The Universe made more quarks than antiqua

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

Ask Ethan: Do white holes, the opposite of black holes, physically exist?

In general relativity, white holes are just as mathematically plausible as black holes. Black holes are real; what about white holes? Continue reading on Starts With A Bang! »

Do gravitational waves show evidence of wave-particle duality? All particles, b

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

Does the expanding Universe stretch space or create new space?

The evidence that the Universe is expanding is overwhelming. But how? By stretching the existing space, or by creating new space itself? Continue reading on Starts With A Bang! »

Can we be certain that time really exists?

We experience time as real. But what if it’s only an illusion: an illusion that’s inherently relative? Does time fundamentally even exist? Continue reading on Starts With A Bang! »

The information paradox at the heart of every black hole Einstein's general rel

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

This physics trick allows you to beat the speed of light

There’s a speed limit to the Universe: the speed of light in a vacuum. But you can beat the speed of light. Just travel through a medium! Continue reading on Starts With A Bang! »

One blip isn’t enough to declare “dark matter has been detected” The LUX-ZEPLIN

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-chi

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-...

The “perfect cosmological principle” isn’t true for our Universe

Generations ago, cosmologists asserted that the Universe might not just be the same in all directions, but at all times. But is that true? Continue reading on Starts With A Bang! »

Only four days each year are actually 24 hours long "The day is 24 hours long"

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

Starts With A Bang podcast #133 — The Milky Way’s center

Today’s Milky Way only forms stars slowly. Our galactic center, where the star-forming rate is highest, gives a unique window into our… Continue reading on Starts With A Bang! »

Ask Ethan: Do white holes, the opposite of black holes, physically exist? Black

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

Ask Ethan: Are there really charm quarks inside the proton?

Every proton contains three quarks: two up and one down. But charm quarks, heavier than the proton itself, have been found inside. How? Continue reading on Starts With A Bang! »

Why mirrors flip left-to-right but not up-and-down

If you look into a mirror, you’ll notice that left-and-right are reversed, but up-and-down is preserved. The reason isn’t what you think. Continue reading on Starts With A Bang! »

Does the expanding Universe stretch space or create new space? The Universe exp

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

Time is a fundamentally different type of dimension than space

We live in a four-dimensional Universe, where matter and energy curve the fabric of spacetime. But time sure is different from space! Continue reading on Starts With A Bang! »

Can we be certain that time really exists? Some claim that time is merely a per

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

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 hon

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...

Do we live inside a baby universe that’s really a black hole on the outside?

The inside of every black hole leads to the birth of a new Universe. Could our Universe have arisen from one? Continue reading on Starts With A Bang! »

The few benign ones are of the "you're missing out" variety. Most get angry: ei

The few benign ones are of the "you're missing out" variety. Most get angry: either because you told them what was true, or because you didn't respond and _how dare you_ be so rude! Some of them escalate to what I can only gently describe as "threats" of some type. Many are quite unsettling.

Yes, the Sun is a star, but it’s far from typical

Most of us have heard that the Sun is an ordinary, typical, unremarkable star. But science shows we’re actually anything but average. Continue reading on Starts With A Bang! »

The “perfect cosmological principle” isn’t true for our Universe On the largest

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

Lucky you. My experience is the opposite, and the ones I get more frequently co

Lucky you. My experience is the opposite, and the ones I get more frequently come with a heightened sense of entitlement to "seeing the beauty and power of their ways" than ever before.

New podcast! Starts With A Bang #133: The Milky Way's center All at once, the

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

Is it a bad thing to have an illusion shattered? It's hard when you're a teache

Is it a bad thing to have an illusion shattered? It's hard when you're a teacher, and the illusion was the primary motivation.

The worst thing about the age of AI is how evident it's become that so many peop

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 ther

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...

Ask Ethan: Can someone possibly see the edge of spacetime?

Our Big Bang could be just one region within an infinite, inflating multiverse. If we were born close to the cosmic edge, what would we… Continue reading on Starts With A Bang! »

Why mirrors flip left-to-right but not up-and-down Wave at yourself in a mirror

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

The act of measuring reality alters what you’ll observe

The double-slit experiment, hundreds of years after it was first performed, still holds the key mystery at the heart of quantum physics. Continue reading on Starts With A Bang! »

The sky is blue. The ocean is, too. But the reasons why are very different.

The sky and oceans are both blue. It’s not because one reflects the other. Science explains them both, but for very different reasons. Continue reading on Starts With A Bang! »

Time is a fundamentally different type of dimension than space We have more tha

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

New video: Largest-scale cosmic test ever favors dark matter over MOND

There are two rival ideas to try and make sense of the Universe: dark matter or modified gravity. Can a new cosmic test settle the issue? Continue reading on Starts With A Bang! »

Do we live inside a baby universe that’s really a black hole on the outside? Ou

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

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

NASA’s Hubble opens the earliest window into the young Milky Way

The newest find recovers the earliest merger in galactic history: just 2 billion years after the Big Bang. Here’s what we know today. Continue reading on Starts With A Bang! »

Ask Ethan: Can someone possibly see the edge of spacetime? In all directions, t

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

Ask Ethan: Does uneven cosmic expansion change our fate?

Recent evidence could indicate the Universe doesn’t expand evenly. Does that change our expected fate: Big Rip, Big Crunch, or Heat Death? Continue reading on Starts With A Bang! »

The act of measuring reality alters what you’ll observe The most annoying part

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

Earth’s oldest trees reveal history’s strongest solar storms

1859’s Carrington event gave us a preview of how catastrophic the Sun could be for humanity. But it could get even worse than we imagined. Continue reading on Starts With A Bang! »

The sky is blue. The ocean is, too. But the reasons why are very different. The

The sky is blue. The ocean is, too. But the reasons why are very different. The sky is blue, and the oceans are blue. But the reason for each one is very different, and has nothing to do with "one reflecting the other" like you might've heard. bigthink.com/starts-with-... #physics #science #blue

Flying clocks in opposite directions around the world proved Einstein right

Time isn’t the same for everyone, even on Earth. Flying around the world gave Einstein the ultimate test. No one is immune from relativity. Continue reading on Starts With A Bang! »

Video: Largest-scale cosmic test ever favors dark matter over MOND If you can m

Video: Largest-scale cosmic test ever favors dark matter over MOND If you can measure the kinetic Sunyaev-Zel'dovich from the CMB plus large-scale structure, you can test the law of gravity on giant cosmic scales. Who's right: Einstein or MOND? bigthink.com/starts-with-... #space #astro #cosmology

Cosmic birefringence: the signal that could upend cosmology

We assume there’s no preferred frame of reference in the Universe, and that light behaves the same in all directions. What if we’re wrong? Continue reading on Starts With A Bang! »

Gravity can’t be an instantaneous force

Newton thought that gravitation would happen instantly, propagating at infinite speeds. Einstein showed otherwise; gravity isn’t instant. Continue reading on Starts With A Bang! »

Ask Ethan: Can “following the science” save the Earth?

Between war, disease, environmental destruction, and resource overconsumption, our civilization’s future is uncertain. Can science save us? Continue reading on Starts With A Bang! »

3 forgotten keys to a real scientific golden age for the USA

Neither Vannevar Bush’s “Science: the Endless Frontier” nor OSTP’s “Science: A New Golden Age” got it fully right. Here’s what they missed. Continue reading on Starts With A Bang! »

Ask Ethan: What would “first life” see in their night sky?

Human beings only see the Universe now: 13.8 billion years after the Big Bang. What would the earliest life, anywhere, have seen instead? Continue reading on Starts With A Bang! »

Johannes Kepler, not Newton or Einstein, is science’s best role model

When people choose the greatest scientist of all, Newton and Einstein always come up. Here’s why they should pick Johannes Kepler instead. Continue reading on Starts With A Bang! »

An honest look inside the “Science: A New Golden Age” report

Scientists are livid over the OSTP director’s official report to the President. Will it lead to a new golden age for US science, or end it? Continue reading on Starts With A Bang! »

The 20 biggest cosmic discoveries of the last 20 decades

200 years ago, we hardly knew anything about our Universe on cosmic scales. Today, there’s so much that we know. Here’s how we arrived. Continue reading on Starts With A Bang! »

The rare quantum reason that neutral atoms are possible

Early on, the entire Universe was ionized. Without the forbidden two-photon transition, it would have remained that way for far too long. Continue reading on Starts With A Bang! »

Ask Ethan: Should we stop worrying about vacuum decay?

Our Universe has a positive, non-zero value to the energy within empty space. Can we potentially save ourselves by considering vacuum… Continue reading on Starts With A Bang! »

4 myths cause us to abandon science. Here’s the path back.

It’s not a gambit. It’s not fraud. It’s not driven by opinion, prejudice, or bias. It’s not unchallengeable. And it’s more than facts… Continue reading on Starts With A Bang! »

Ask Ethan: Does Mars’s gravity prohibit human colonization?

Mars is very different than Earth: smaller, drier, colder, etc. But the biggest long-term challenge, for human colonies, is its low… Continue reading on Starts With A Bang! »

The physical Universe isn’t made of pure mathematics alone

Mathematics is our language for quantitatively describing reality, but it can also take us to worlds that never were. Physics needs more. Continue reading on Starts With A Bang! »

The big reason Einstein would never have used AI

Many think that intelligence can be outsourced to AI. Einstein wouldn’t have used it. If he had, he never would have become Einstein. Continue reading on Starts With A Bang! »

Starts With A Bang podcast #131 — The baryon life cycle

The history of atoms in the Universe is our own history: without them, there would be no us. So how do we piece their cosmic story… Continue reading on Starts With A Bang! »

America pioneered gravitational wave research. Now it may leave it behind.

The LIGO facilities in the U.S. are the most sensitive gravitational wave detectors in the world. Their future remains uncertain. Continue reading on Starts With A Bang! »

Famous study in error: the Universe isn’t anisotropic

Using the newest large-scale structure data, a team of researchers announced a huge cosmic anisotropy in Nature. Too bad it’s wrong. Continue reading on Starts With A Bang! »

Is it finally time to take dark matter-free galaxies seriously?

The first one, NGC 1052-DF2, was mired in controversy. With four examples now, there only remains one possible escape. What does nature… Continue reading on Starts With A Bang! »