Ethan Siegel+

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

NASA’s Hubble opens the earliest window into the young Milky Way Studying our galactic center's globular clusters reveals evidence of the oldest merger in Milky Way history: 11.8 billion years ago. Hubble has now recovered our earliest relic ever. bigthink.com/starts-with-... #space #nasa #astro

“Dirty snowballs” have joined together since the planets formed

We’ve now found many “conjoined” objects in the asteroid and Kuiper belts, including the first contact trinary, Nysa. What does it all… Continue reading on Starts With A Bang! »

Ask Ethan: Does uneven cosmic expansion change our fate? Recent evidence, altho

Ask Ethan: Does uneven cosmic expansion change our fate? Recent evidence, although not yet a slam-dunk, claims our Universe is expanding differently in different directions. If that's true, what would that mean for our cosmic fate? bigthink.com/starts-with-... #space #astro #gravity #physics

Ask Ethan: Why are astronauts weightless while still in Earth’s gravity?

On Earth’s surface, we accelerate at 1g: 9.8m/s². In orbit, the acceleration is only slightly less. So why, then, are astronauts… Continue reading on Starts With A Bang! »

Earth’s oldest trees reveal history’s strongest solar storms The 1859 Carringto

Earth’s oldest trees reveal history’s strongest solar storms The 1859 Carrington event was our first recorded example of a solar storm. But over 1000 years earlier, we've forensically identified even bigger ones: imprinted in ancient trees. bigthink.com/starts-with-... #space #astro #sun #trees

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! »

Flying clocks in opposite directions around the world proved Einstein right If

Flying clocks in opposite directions around the world proved Einstein right If you fly a clock around the world, its time gets dilated. But if you fly 2 round-the-world clocks in opposite directions, they dilate differently from each other. Here's why. bigthink.com/starts-with-... $space $astro

The strongest experimental hint that gravity is quantum in nature

At a fundamental level, nobody knows whether gravity is truly quantum in nature. A novel experiment strongly hints that it is. Continue reading on Starts With A Bang! »

Cosmic birefringence: the signal that could upend cosmology The biggest observa

Cosmic birefringence: the signal that could upend cosmology The biggest observational anomaly in cosmology is the Hubble tension. But second-biggest is much less well-known: the cosmic birefringence signal in the CMB. (And yes, YOU can understand it!) bigthink.com/starts-with-... #space #astro

Why the world needs all three 30-meter class telescopes

Today, the world’s largest operating optical telescope is 10.4 meters in diameter. These 3 facilities will lead astronomy’s next… Continue reading on Starts With A Bang! »

"What is the future of American science?" From Kainaat studios, a conversation

"What is the future of American science?" From Kainaat studios, a conversation with me and Salman Hameed! www.youtube.com/watch?v=N_18...

“Dirty snowballs” have joined together since the planets formed Many objects fo

“Dirty snowballs” have joined together since the planets formed Many objects found in the Kuiper and asteroid belts are conjoined: with multiple "lobes" of distinct origin. The first contact trinary, Nysa, deepens the story even further. bigthink.com/starts-with-... #space #astro #asteroid #KBO

We caught an ocean of plasma waves “breaking” on the Sun

With the National Solar Observatory’s incredible DKIST, we see the Sun in the highest resolution ever. Its latest images blew us all away. Continue reading on Starts With A Bang! »

Not just you. It slow, yo.

Not just you. It slow, yo.

Starts With A Bang podcast #132 — Space in the ultraviolet

Few wavelengths of light reach Earth’s surface; the others require going to space. What can the ultraviolet ASPERA space telescope do? Continue reading on Starts With A Bang! »

Many physicists confuse many students with the definition that "W = mg." They t

Many physicists confuse many students with the definition that "W = mg." They themselves may not be confused, but their students usually are if that's the definition they use!

Ask Ethan: Why are astronauts weightless while still in Earth’s gravity? Astron

Ask Ethan: Why are astronauts weightless while still in Earth’s gravity? Astronauts in space, including on the ISS, are still heavily influenced by Earth's gravity, accelerating at ~90% their value on Earth's surface. So why, then, are they weightless? bigthink.com/starts-with-... #space #physics

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! »

Gravity can’t be an instantaneous force In Newton's gravity, the force was inst

Gravity can’t be an instantaneous force In Newton's gravity, the force was instantaneous and worked across infinite distances. According to Einstein, that can't be right. bigthink.com/starts-with-... #space #physics #astro #gravitationalwaves

Is the Universe truly infinite in size?

As far as we can tell, there’s no limit to how far it goes on; only a limit to how far we can see. Could the Universe truly be infinite? Continue reading on Starts With A Bang! »

May or may not have been interviewed by the author. 😅

May or may not have been interviewed by the author. 😅

The strongest experimental hint that gravity is quantum in nature We still don'

The strongest experimental hint that gravity is quantum in nature We still don't know whether #gravity is truly quantum or classical in nature. But the purely #quantum Aharanov-Bohm effect doesn't just work for electromagnetism. Gravity activates it, too. bigthink.com/starts-with-... #physics

Where is gravity the strongest and weakest on Earth?

The Earth is a massive planet, but doesn’t form a truly perfect sphere. Here’s how to understand our strongest and weakest gravity points. Continue reading on Starts With A Bang! »

Why the world needs all three 30-meter class telescopes The leap from the 10 me

Why the world needs all three 30-meter class telescopes The leap from the 10 meter class of ground-based optical telescopes to the 30 meter class will be scientifically profound. Here's why we need all 3 of them, and how to get there. bigthink.com/starts-with-... #space #astro #GMT #TMT #ELT

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! »

We caught an ocean of plasma waves “breaking” on the Sun You've seen the newest

We caught an ocean of plasma waves “breaking” on the Sun You've seen the newest pictures from DKIST: of fluid instabilities on the Sun. Now watch the animations, and see how exquisitely observations and simulations match! bigthink.com/starts-with-... #sun #heliophysics #DKIST #astro #space

Which 10 atmospheres are the Solar System’s thickest?

Obviously, the gas giants all top this list. But the fall-off is rapid after that, and the final two spots in the top 10 are truly… Continue reading on Starts With A Bang! »

My dude and colleague, I am here to give you credit for all you did. Life is me

My dude and colleague, I am here to give you credit for all you did. Life is menacing and relentless and full of pressures, and yet here you are, fighting the unwinnable fight against entropy, expending your life force to locally increase order. You deserve praise for every incremental step taken!

Starts With A Bang podcast #132 – Space in the ultraviolet From Earth, we only

Starts With A Bang podcast #132 – Space in the ultraviolet From Earth, we only see the Universe in a few wavelengths of light; the rest require going to space. The ASPERA mission launches soon; here's what awaits in the ultraviolet! bigthink.com/starts-with-... #space #uv #aspera #astro

And when Harry Turtledove calls bullshit on your claim, it's definitely bullshit

And when Harry Turtledove calls bullshit on your claim, it's definitely bullshit.

It surprised me too when I first learned it. But one of the most important less

It surprised me too when I first learned it. But one of the most important lessons is that when we have equations that describe reality, we should take their predictions seriously, even if those predictions seem surprising, absurd, or inconceivable!

Ask Ethan: Can “following the science” save the Earth? There are so many proble

Ask Ethan: Can “following the science” save the Earth? There are so many problems our world is facing, posing several existential threats to humanity. Following the science isn't just a smart move. It's the only sensible one. bigthink.com/starts-with-... #space #science #astro #earth

I hope the link and further explanation help you understand why!

I hope the link and further explanation help you understand why!

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! »

If there's a boundary because there's a limit to where the universe "Big Banged"

If there's a boundary because there's a limit to where the universe "Big Banged" versus where inflation took place, then there's likely inflating space at the edge of that boundary. Yikes! If there's a surface because of topological connectedness, you're stuck, and must remain on the surface!

Oh right! ICYMI (5 years old but still relevant): bigthink.com/starts-with-...

Oh right! ICYMI (5 years old but still relevant): bigthink.com/starts-with-...

I sure hope I wrote 46 billion and not million!

I sure hope I wrote 46 billion and not million!

Is the Universe truly infinite in size? The observable Universe is "only" 13.8

Is the Universe truly infinite in size? The observable Universe is "only" 13.8 billion years old, extending for 46 billion light-years in all directions. But what about the unobservable Universe? It could still be infinite! bigthink.com/starts-with-... #space #astro #physics #universe #math

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! »

Where is gravity the strongest and weakest on Earth? The acceleration due to gr

Where is gravity the strongest and weakest on Earth? The acceleration due to gravity isn't constant at Earth's surface, but varies with latitude, altitude, and crustal composition. The differences are small, but they matter! bigthink.com/starts-with-... #space #earth #physics #astro

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! »

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

3 forgotten keys to a real scientific golden age for the USA Instead of pouring money into "integrating AI into everything," we should follow the proven roadmap for science in America. These 3 keys were what previously made us great. bigthink.com/starts-with-... #space #physics #science #usa

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! »

Moar astronomy Merediths!! Yeah!!

Moar astronomy Merediths!! Yeah!!

I just wanted an excuse to post the song for getting it, lol.

I just wanted an excuse to post the song for getting it, lol.

The song exists, you just need to Weird Al (Weird Sarah? Weird Mike?) the lyrics

The song exists, you just need to Weird Al (Weird Sarah? Weird Mike?) the lyrics: www.youtube.com/watch?v=HMUD...

Which 10 atmospheres are the Solar System’s thickest? Only a few worlds in the

Which 10 atmospheres are the Solar System’s thickest? Only a few worlds in the Solar System have substantial atmospheres of any type. This top 10 list goes from hero to almost-zero faster than you might've imagined. bigthink.com/starts-with-... #space #astro #planets #science

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: What would “first life” see in their night sky? Our night sky reveal

Ask Ethan: What would “first life” see in their night sky? Our night sky reveals the Universe as it is today: 13.8 billion years after the Big Bang. What would first life, just 1 or 2 billion years into cosmic history, have seen instead? bigthink.com/starts-with-... #space #astro #physics

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! »

Here's an example: en.wikipedia.org/wiki/Monetae...

Here's an example: en.wikipedia.org/wiki/Monetae...

If you read Dava Sobel's biography of Copernicus, it's the focus of roughly 90 p

If you read Dava Sobel's biography of Copernicus, it's the focus of roughly 90 pages of that book. It was what Copernicus made a career out of for all of his public life.

You can from many others! But for me, Brahe was too dogmatic, was unwilling to

You can from many others! But for me, Brahe was too dogmatic, was unwilling to share the spotlight, and held back others who were coming up behind him. Copernicus was too timid to publish his results while he was alive, and spent most of his public efforts fighting coin-shaving. So, pass from me.

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

Johannes Kepler, not Newton or Einstein, is science’s best role model People often look to Einstein or Newton as a scientist's best role model. But Kepler did something more important: he changed his mind when the evidence demanded it. bigthink.com/starts-with-... #space #astro #kepler #science

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! »

An honest look inside the “Science: A New Golden Age” report In a 100+ page rep

An honest look inside the “Science: A New Golden Age” report In a 100+ page report, OSTP director Michael Kratsios, with help from Trump and Vought, outlined a path for American science. I read through the whole thing so you don't have to. bigthink.com/starts-with-... #space #science #physics

2026’s Perseids, lousy this July, will peak at the perfect time

Although the Geminids have rivaled the Perseids recently, in 2026, the Perseids should win at their peak. Here’s why, plus how to see them. Continue reading on Starts With A Bang! »

Not really of "cosmic" importance in the same way to me, but we are all entitled

Not really of "cosmic" importance in the same way to me, but we are all entitled to our own choices and preferences and I would never begrudge you that one!

The 20 biggest cosmic discoveries of the last 20 decades 200 years ago, we didn

The 20 biggest cosmic discoveries of the last 20 decades 200 years ago, we didn't even know what the stars were, much less what the Universe was. These 20 big steps, one per decade, help illustrate exactly how we got here. bigthink.com/starts-with-... #space #astro #cosmology

A cosmic first: separated sibling stars reunited by supernovae

We’ve never witnessed a system of binary stars both go supernova before. A once-hidden source of gamma rays just revealed the first one. Continue reading on Starts With A Bang! »

The rare quantum reason that neutral atoms are possible If atoms only de-excite

The rare quantum reason that neutral atoms are possible If atoms only de-excited conventionally, emitting ultraviolet photons when they dropped into the lowest-energy state, the Universe would have become neutral when it did. Here's how it happened. bigthink.com/starts-with-... #space #physics

Sugar in space: another step towards life’s origins

In a gas cloud 26,000 light-years away, a 4-carbon sugar, erythrulose, has just been found. Here’s what it means for life in the Milky Way. Continue reading on Starts With A Bang! »

If you see this, quote skeet a pic of yourself in sunglasses.

If you see this, quote skeet a pic of yourself in sunglasses.

You don't resolve from 6 to 3, but you certainly do ease it. I think if you get

You don't resolve from 6 to 3, but you certainly do ease it. I think if you get it to below 2 you can say resolved.

Truly fantastic. Keep an eye on that CATRA instrument next. (That's what you ca

Truly fantastic. Keep an eye on that CATRA instrument next. (That's what you call your photometer, with blue and yellow filters, right?)

Ask Ethan: Should we stop worrying about vacuum decay? Vacuum decay is one of t

Ask Ethan: Should we stop worrying about vacuum decay? Vacuum decay is one of the most frightening, and undetectable-until-it-happens, possibilities for how this will all end. But if we learn enough, there could be a way to stop it. bigthink.com/starts-with-... #space #physics #cosmology

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! »

I mean, that whole movie could just be...

I mean, that whole movie could just be...

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

4 myths cause us to abandon science. Here’s the path back. Four myths about how "science is flawed" cause people to choose conspiratorial thinking instead. That's the path to fraud, grift, and misinformation. Here's the way back. bigthink.com/starts-with-... #science #information #lies #myths

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! »

So many great publications, with so many important writers who focus on deep, tr

So many great publications, with so many important writers who focus on deep, truthful stories about reality, are being sold off and scrapped for parts. Goodbye, National Geographic, Scientific American, Spektrum de Wissenschaft, Research Professional News, and more...

Has Subir Sarkar, Oxford cosmologist, published anything about dark energy, or c

Has Subir Sarkar, Oxford cosmologist, published anything about dark energy, or cosmology in general, that isn't absurdly wrong since the last good paper I'm aware of that he wrote: back in 1996? Along with Madhu and Loeb, the clown show is really intensifying over here.

2026’s Perseids, lousy this July, will peak at the perfect time The #Perseids h

2026’s Perseids, lousy this July, will peak at the perfect time The #Perseids have begun here on Earth, but conditions are lousy for it right now. On the night of the peak, however, conditions will be just about ideal. Here's how to best see them. bigthink.com/starts-with-... #space #astro

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! »

A cosmic first: separated sibling stars reunited by supernovae We've never witn

A cosmic first: separated sibling stars reunited by supernovae We've never witnessed a pair of massive, binary stars both go supernova before. Opposite the galactic center, we just might have spotted the ultimate family reunion: in death. bigthink.com/starts-with-... #space #astro #supernova

99% of a core-collapse supernova’s energy is invisible

Despite the brilliance of these cosmic beacons, only 1% of a core-collapse supernova’s energy is observable. The other 99% is in neutrinos. Continue reading on Starts With A Bang! »

Sugar in space: another step towards life’s origins With the discovery of our f

Sugar in space: another step towards life’s origins With the discovery of our first sugar, the four-carbon molecule erythrulose, in an interstellar gas cloud, the raw ingredients for life are more abundant than ever. One big step to go! bigthink.com/starts-with-... #space #chemistry #astro

Big evidence for “second generation” black hole mergers

With nearly 400 black hole events from gravitational waves, we can begin to infer their origins. At least two different populations emerge. 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! »

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

Ask Ethan: Does Mars’s gravity prohibit human colonization? Human bodies decay in the microgravity environment of interplanetary space, but recover on planet Earth. The low gravity of Mars will be a challenge, but maybe not a dealbreaker. bigthink.com/starts-with-... #mars #humans #astro #space

Ask Ethan: What sets the size of the observable Universe?

For all we know, the cosmos could truly be infinite in scale. But the observable part of our Universe? It’s finite, and its size is known. 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! »

Forget seeing the Universe’s beginning. It’s already been erased

We used to think the Big Bang started it all. Then we realized that something else came before it, erasing everything that existed prior. 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! »