Ethan Siegel
@startswithabang.bsky.social
Cosmologist, science communicator, author, speaker, and longtime writer of Starts With A Bang.
Not the next Carl Sagan; the first Ethan Siegel.
Not the next Carl Sagan; the first Ethan Siegel.
You probably haven't said this in 30 years but...
November 10, 2025 at 8:27 PM
You probably haven't said this in 30 years but...
Happy Halloween 2025 everyone, from your old pal Zorak!
October 31, 2025 at 5:16 PM
Happy Halloween 2025 everyone, from your old pal Zorak!
Today is the day!
The Grand Cosmic Story, my newest book (with Jon Lomberg, Mark Garlick, and Will Lidwell), from National Geographic, is released!
Get the history of the whole Universe, one page and 100 Myr at a time, today!
amzn.to/46GsS9d
www.penguinrandomhouse.com/books/789623...
#space #book
The Grand Cosmic Story, my newest book (with Jon Lomberg, Mark Garlick, and Will Lidwell), from National Geographic, is released!
Get the history of the whole Universe, one page and 100 Myr at a time, today!
amzn.to/46GsS9d
www.penguinrandomhouse.com/books/789623...
#space #book
October 7, 2025 at 4:20 PM
Today is the day!
The Grand Cosmic Story, my newest book (with Jon Lomberg, Mark Garlick, and Will Lidwell), from National Geographic, is released!
Get the history of the whole Universe, one page and 100 Myr at a time, today!
amzn.to/46GsS9d
www.penguinrandomhouse.com/books/789623...
#space #book
The Grand Cosmic Story, my newest book (with Jon Lomberg, Mark Garlick, and Will Lidwell), from National Geographic, is released!
Get the history of the whole Universe, one page and 100 Myr at a time, today!
amzn.to/46GsS9d
www.penguinrandomhouse.com/books/789623...
#space #book
Now is absolutely the perfect time to preorder my newest book, The Grand Cosmic Story from National Geographic, coming out in just 2 weeks!
Do it now at this link - promo.porchlightbooks.com/pages/promot... - and get a FREE bonus frameable print of the unique artwork in the book!
Do it now at this link - promo.porchlightbooks.com/pages/promot... - and get a FREE bonus frameable print of the unique artwork in the book!
September 25, 2025 at 10:06 PM
Now is absolutely the perfect time to preorder my newest book, The Grand Cosmic Story from National Geographic, coming out in just 2 weeks!
Do it now at this link - promo.porchlightbooks.com/pages/promot... - and get a FREE bonus frameable print of the unique artwork in the book!
Do it now at this link - promo.porchlightbooks.com/pages/promot... - and get a FREE bonus frameable print of the unique artwork in the book!
This is gonna age like
August 24, 2025 at 8:48 PM
This is gonna age like
Hey space/astronomy fans, what are you doing this Thursday?
Come join me and this all-star lineup for a virtual one-day extravaganza hosted by the Astronomical Society of the Pacific.
astrosociety.org/get-involved...
Get up early and catch me and more; it'll be worth it!
#space #astro
Come join me and this all-star lineup for a virtual one-day extravaganza hosted by the Astronomical Society of the Pacific.
astrosociety.org/get-involved...
Get up early and catch me and more; it'll be worth it!
#space #astro
August 19, 2025 at 4:46 PM
Hey space/astronomy fans, what are you doing this Thursday?
Come join me and this all-star lineup for a virtual one-day extravaganza hosted by the Astronomical Society of the Pacific.
astrosociety.org/get-involved...
Get up early and catch me and more; it'll be worth it!
#space #astro
Come join me and this all-star lineup for a virtual one-day extravaganza hosted by the Astronomical Society of the Pacific.
astrosociety.org/get-involved...
Get up early and catch me and more; it'll be worth it!
#space #astro
TFW when you're only the second scariest "White Party" around...
July 6, 2025 at 4:22 PM
TFW when you're only the second scariest "White Party" around...
Also, if you're wondering what the results are from #AAS246, it turns out the Sun does set in Anchorage near the solstice. It happens very late, but it's worth it!
June 11, 2025 at 4:58 PM
Also, if you're wondering what the results are from #AAS246, it turns out the Sun does set in Anchorage near the solstice. It happens very late, but it's worth it!
For those of you who don't understand what needs to happen to Elon Musk and the other fascist tech-bro oligarchs, I have some recommended reading for you.
In fact, I can sum up the whole book in one panel:
In fact, I can sum up the whole book in one panel:
May 21, 2025 at 4:01 PM
For those of you who don't understand what needs to happen to Elon Musk and the other fascist tech-bro oligarchs, I have some recommended reading for you.
In fact, I can sum up the whole book in one panel:
In fact, I can sum up the whole book in one panel:
I believe the answer is yes: if you could fly "above" what we call galactic north (which is arbitrary!), you'd see that the galaxy was rotating exactly as Jon Lomberg illustrated back in, I believe, the 1980s:
April 30, 2025 at 4:13 PM
I believe the answer is yes: if you could fly "above" what we call galactic north (which is arbitrary!), you'd see that the galaxy was rotating exactly as Jon Lomberg illustrated back in, I believe, the 1980s:
Repost with your favorite James Bond (wrong answers only)
April 13, 2025 at 7:31 PM
Repost with your favorite James Bond (wrong answers only)
When I read this part, at the end, I thought instantly that Elon Musk ticked every single box on the "who goes Nazi?" Bingo card.
March 17, 2025 at 3:54 PM
When I read this part, at the end, I thought instantly that Elon Musk ticked every single box on the "who goes Nazi?" Bingo card.
No cheating. Post the last photo of your pet.
March 15, 2025 at 4:51 AM
No cheating. Post the last photo of your pet.
You may recognize yourself and/or others in this:
February 24, 2025 at 7:03 PM
You may recognize yourself and/or others in this:
Every time I read that the DOGE team is going to some government agency, I keep hoping they'll be led to the "server room" where they can get full access, which turns out to just be an unfinished basement.
Then the government agents leave the room.
Then they go the way of FMA's General Raven.
Then the government agents leave the room.
Then they go the way of FMA's General Raven.
February 19, 2025 at 9:12 PM
Every time I read that the DOGE team is going to some government agency, I keep hoping they'll be led to the "server room" where they can get full access, which turns out to just be an unfinished basement.
Then the government agents leave the room.
Then they go the way of FMA's General Raven.
Then the government agents leave the room.
Then they go the way of FMA's General Raven.
Okay, but like, you "get a distance," but there are huge uncertainties on that distance due to those degeneracies, right?
Like "348 Mpc" still has a tremendous (~30%) uncertainty on it for this event, right?
Like "348 Mpc" still has a tremendous (~30%) uncertainty on it for this event, right?
February 11, 2025 at 6:57 PM
Okay, but like, you "get a distance," but there are huge uncertainties on that distance due to those degeneracies, right?
Like "348 Mpc" still has a tremendous (~30%) uncertainty on it for this event, right?
Like "348 Mpc" still has a tremendous (~30%) uncertainty on it for this event, right?
Have you been reading articles from Important Harvard Professors (sic) about how the US is ultimately fine because the Constitution, judges, and checks and balances will protect us?
There's a great piece by Jay Willis on ballsandstrikes where he nails why that take overlooks what's happening.q
FTA
There's a great piece by Jay Willis on ballsandstrikes where he nails why that take overlooks what's happening.q
FTA
February 7, 2025 at 10:39 PM
Have you been reading articles from Important Harvard Professors (sic) about how the US is ultimately fine because the Constitution, judges, and checks and balances will protect us?
There's a great piece by Jay Willis on ballsandstrikes where he nails why that take overlooks what's happening.q
FTA
There's a great piece by Jay Willis on ballsandstrikes where he nails why that take overlooks what's happening.q
FTA
It was us.
The plan was always us.
The plan was always us.
February 4, 2025 at 4:53 PM
It was us.
The plan was always us.
The plan was always us.
Oh please oh please oh please...
January 30, 2025 at 12:34 AM
Oh please oh please oh please...
Found a photo of me from the American Astronomical Society's gallery this week at #aas245.
Even from the back, there's no doubt that's me.
Even from the back, there's no doubt that's me.
January 19, 2025 at 3:31 AM
Found a photo of me from the American Astronomical Society's gallery this week at #aas245.
Even from the back, there's no doubt that's me.
Even from the back, there's no doubt that's me.
Portland, OR!
Come see me, live and in person, talking about the James Webb Space Telescope Monday night!
11/18, 8 PM at the OMSI Planetarium, I'm speaking to the Rose City Astronomers (general meeting starts 7:30).
The event is free and open to the public! That means you!!
Come see me, live and in person, talking about the James Webb Space Telescope Monday night!
11/18, 8 PM at the OMSI Planetarium, I'm speaking to the Rose City Astronomers (general meeting starts 7:30).
The event is free and open to the public! That means you!!
November 17, 2024 at 6:22 PM
Portland, OR!
Come see me, live and in person, talking about the James Webb Space Telescope Monday night!
11/18, 8 PM at the OMSI Planetarium, I'm speaking to the Rose City Astronomers (general meeting starts 7:30).
The event is free and open to the public! That means you!!
Come see me, live and in person, talking about the James Webb Space Telescope Monday night!
11/18, 8 PM at the OMSI Planetarium, I'm speaking to the Rose City Astronomers (general meeting starts 7:30).
The event is free and open to the public! That means you!!