How Do We Know What Stars Are Made Of?

Pin-pricks in the celestial sphere, through which shines the light of heaven? Or gods and heroes looking down from their constellations? Or lights kindled above middle earth by Varda Elbereth and brightened with the dew of the trees of Valinor? Science has long pondered the mysteries of the stars. This is how we finally figured them out.

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Hosted by Matt O'Dowd
Written by Matt O'Dowd
Graphics by Leonardo Scholzer, Yago Ballarini, & Pedro Osinski
Directed by: Andrew Kornhaber
Camera Operator: Setare Gholipour
Executive Producers: Eric Brown & Andrew Kornhaber

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[vedatonurylmaz]

Congrats Matt!
"Lehman Associate Professor Matthew O’Dowd was awarded a five-year, $2.94 million grant by Schmidt Futures to study the structure and evolution of the universe, black holes, quasars and dark energy"

[BaconAndPotatoCorp]

Seeing a doctor in physics wearing a "Periodic Table of Minecraft" shirt is just hilarious, lmao

[nneeerrrd]

0:54 I tip my hat to video editor for highlighting Matt's right side when he's "close to the star". You're true pro, sir/madam.

[swampdonky]

This man is a hero: wearing a Minecraft periodic table shirt while referencing the silmarillion and segwaying into stellar physics.

[hellegennes]

Fun fact: the first person to postulate that the other stars are heavenly objects like the Sun, rather than just shiny dots fixed on the heavens was Aristarchus of Samos (3rd century BC). He was also the first to propose the heliocentric model, but his peers mostly rejected the idea because they posited that if the Earth revolved around the Sun, the background stars whould change positions (parallax). Aristarchus' counterargument was that they were too bloody far away for a measurable effect on parallax to be observed. Since you need a telescope to observe a parallax angle, he was right. He was also the first to try and measure the distance to the Moon and the size of the Moon (with results very close to their actual values), using the newly calculated circumference of the Earth, which Eratosthenes measured just a couple of years prior. He then used those measurements to try and find the distance to the Sun and its size. It turns out though that it's impossible to do that measurement with the naked eye, and so he calculated the Sun to be just 20 times bigger than the Moon and 20 times farther away. In reality it's more like 400 times as distant and 400 times as big as the Moon.

[jarehelt]

"They're fireflies! Fireflies that, uh... got stuck up on that big bluish-black thing."

"Oh, gee. I always thought they were balls of gas burning billions of miles away."

"Pumbaa, with you, everything's gas."

[rohannalawade]

Cecilia Payne
Annie Jump Cannon
Henrietta Swan Leavitt
Lisa Meitner
Rosalind Franklin
And many more. Thank you.
You deserved more.

[constantchanger]

Kudos for emphasizing contributions from women in physics who have historically gone under-acknowledged.

[thingsiplay]

10:32 I really thought this was the time you say "Space Time". You really got me off guard with this one.

[thesinofpride]

Gotta love the Silmarillion version, tho

[qwerty_and_azerty]

Imagine being a stellar core photon, travelling for ten thousand years to the surface of the star, only to be halted at the last possible instant by an unfortunately placed atom.

Of course, if you really were a photon, you wouldn’t notice those ten thousand years passing you by, so I guess it’s not as devastating as it sounds to us time-locked entities.

Edit: spelling

[LordSplittawig]

Fun fact:

Helium was discovered on the sun before it was discovered on Earth.

[jongutierrez]

A photon checks into a hotel. The bellhop asks, “Can I help you with your luggage?” The photon replies, “I don’t have any. I’m traveling light!”

[shahman]

A Silmarillion reference in my Space Time? *Happy Noises*

[messyhair]

How topical, I'm currently in the middle of reading The Glass Universe, about the Harvard Observatory cataloging of hundreds of thousands of stars and Cecelia Payne has come up already.

[SciFactsYT]

Completely random fact:

Since the moment Pluto was discovered and until the moment when it lost its status of a planet, this celestial body has not completed a single full revolution around the Sun.

-SciFacts

[nzuckman]

Yay, a video about spectroscopy! This is exactly the sort of research I've been doing. If anyone's interested, I've got a video on my channel about a project I did over the spring to analyze the absorption/emission spectrum of Fe II - a particularly useful ion for determining the compositions of stars due to its dense spectrum. I'll have another video coming up soon(-ish) for some software I've written to enable researchers anywhere to precisely study NIST's archive atomic spectrum photoplates (once the archive has been scanned and is available online). Come and check out what atomic spectroscopy research is like firsthand! :D

[Locuts]

It’s absolutely astounding the progress we have made in the past 100 years in understanding... everything. We tend to think of a hundred years as a long time by human time scales but these days by modern life spans it’s only about a decade longer than a 1st world “long” life span. And by historical measures it’s a drop in the bucket. Thousands of years passed with only small advancements in our collective understanding of the universe, the world around us, and ourselves. Then in the span of 100 years or so we seem to have witnessed an exponential explosion in our understanding of everything.

[magics]

Thank you for constantly going back to point out Professor Payne's importance. There are a lot of women glossed over during that time period. It's a shame we don't know her more. But you do a great job of highlighting her this whole video.

[DepthInfinite]

I appreciate the time taken to share such important (and sadly lesser known) history of women in STEM! I also love the Minecraft shirt!

These are such great videos to deeper understanding of our universe! Thanks for taking the time to share your knowledge with everyone! :)