Ethan Siegel

Okay, it's late in the week so I probably won't have a piece out on K2-18b until early next week. Any astro pros (especially astrochemists/cosmochemists) have any statements you'd like me to quote you on? Reply to this or send a DM!

Is our Universe fundamentally unstable, and will it decay? Our dark energy-rich Universe has a positive amount of energy inherent to space. If that's not the lowest possible value, we may be in huge trouble someday, maybe even soon. https://t.co/Lxd7eaNesV

What's up, Charlottesville? I'm on my way to you right now. Looking forward to meeting the NSBP/Astro Club at 5 tomorrow. Then running astro bar trivia at 7 at Selvidge Taphouse. Then Friday at 3:30, giving the physics colloquium on JWST discoveries. Enjoy! Don't miss it!

Science’s value, unlike NASA, cannot be destroyed by politics Yes, NASA, and NASA science in particular, is facing its steepest cuts ever. But the value of science will persist, whether the USA reaps its benefits or not. https://t.co/ab0gDvZQRf

Have you ever lamented that people just aren't scientifically literate? It's true, but probably not for the reasons you've been taught. Here's what science literacy actually looks like, and why we need it now more than ever. https://t.co/D3xz5cUANJ

Science’s best answer to “where did the Universe come from?” For hundreds of thousands of years, humans have wondered what our Universe is and where it came from. Only now, in the 20th and 21st century, has science delivered the answers. https://t.co/cmNKZ8xpfE

See NASA’s most important image in space telescope history Do you need a reminder of what NASA science has done for humanity? 2025 marks the 30th anniversary of the first Hubble Deep Field: the most important image in space telescope history. https://t.co/FRXrd2CPoN

Couldn’t COVID-19 have originated in a Chinese lab? #AskEthan Still think it's possible that SARS-CoV-2 was engineered in a lab? And that COVID-19 originated from a lab leak? This is a must-read for anyone who cares about the truth. https://t.co/kyt70cjNb1 cc:@PhilippMarkolin

Why nuclear reactions on an exoplanet won’t imply alien life Someday, intelligent aliens will invent nuclear reactors, producing a characteristic antineutrino signature. But detecting those antineutrinos won't necessarily mean aliens. Here's why. https://t.co/3OF1l8Natv

The sky is brighter than astronomers imagined Those deep field images that show bright, compact galaxies amidst a black backdrop of emptiness? That's what happens when you oversubtract the overall sky. Here's what happens when we put that light back. https://t.co/XWmTlZTvIu

How has cosmology changed from 2000 to 2025? At the turn of the century, we had evidence for a dark energy and dark matter dominated Universe, as the Standard Model of cosmology came into focus. 25 years later, it's starting to crack. https://t.co/aq6ock8cgj

RT @AlbertEinstein: A scientist explains how the multiverse works https://t.co/mPc710mu9b @StartsWithABang

Will the Sun make a planetary nebula when it dies? Nearly every planetary nebula we prominently see is from a high-mass star in a multi-star system. So will the Sun make one? Almost certainly. Here's why. https://t.co/KEbIQ56Qu5

Starts With A Bang podcast #116 – Disintegrating exoplanets Exoplanets don't just have their atmospheres evaporate when they get too close to their parent stars, but can lose their crusts, mantles, and even cores. Meet our disintegrating exoplanets! https://t.co/69yhJHt9LB

Why are maps of the cosmos always oval-shaped? #AskEthan When astronomers show us maps of the Universe, they show the entire sky mapped onto an ellipsoid. Here's why, how, and what it sacrifices. https://t.co/adZ14EQju6

No, the “Kalam cosmological argument” doesn’t prove God’s existence No, you can't use what's known about the Universe to prove the existence of God. Whatever underlying assumptions you make aren't necessarily valid in our very weird Universe. https://t.co/2htDKgE3GA

Why we still don’t know how many stars are in the Milky Way We've nailed the total stellar mass of the Milky Way exquisitely: with an error of just ~10%. And yet, there could be 200, 300, or 400 billion stars, total. Here's why we don't know. https://t.co/bnKgBxeIcc