For Earth Day, We’re Inviting You To Take A Moment To Celebrate Our Wonderful Water World, Earth. As

Free Online Language Courses

Here is a masterpost of MOOCs (massive open online courses) that are available, archived, or starting soon. I think they will help those that like to learn with a teacher or with videos.  You can always check the audit course or no certificate option so that you can learn for free.

American Sign Language

ASL University

Sign Language Structure, Learning, and Change

Arabic

Arabic Without Walls

Madinah Arabic

Moroccan Arabic

Armenian

Depi Hayk

Bengali

Learn Bangla (Register to see course)

Catalan

Parla.Cat

Speak Cat

Chinese (Mandarin)

Beginner

Chinese for Beginners

Chinese Characters for Beginners

Chinese for HSK 1

Chinese for HSK 2

Chinese for HSK 3 I & II

Chinese for HSK 4

Chinese for HSK 5

Mandarin Chinese Level I

Mandarin Chinese Essentials

Mandarin Chinese for Business

More Chinese for Beginners

Start Talking Mandarin Chinese

UT Gateway to Chinese

Intermediate

Intermediate Business Chinese

Intermediate Chinese Grammar

Mandarin for Intermediate Learners I

Dutch

Introduction to Dutch

English

Online Courses here

Resources Here

Faroese

Faroese Course

Finnish

A Taste of Finnish

French

Beginner

AP French Language and Culture

Elementary French I & II

Français Interactif

Vivre en France - A1

Vivre en France- A2

Intermediate & Advanced

French Intermediate course B1-B2

Passe-Partout

Travailler en France A2-B1                    

Vivre en France - B1  

German

Beginner

Deutsch im Blick

German Project

German at Work

Goethe Institute

Gwich’in

Introduction to Gwich’in Language

Hebrew

Biblical Hebrew

UT Austin

Hindi

A Door into Hindi

Virtual Hindi

Icelandic

Icelandic 1-5

Indonesian

Learn Indonesian

Irish

Irish 101, 102, 103, 104, 105, 106, 107

Italian

Beginner

Beginner’s Italian I

Introduction to Italian

Intermediate & Advanced

AP Italian Language and Culture

Intermediate Italian I

Advanced Italian I

Japanese

Genki

Japanese JOSHU

Japanese Pronunciation

Marugoto Courses

Tufs JpLang

Korean

Beginner

First Step Korean

How to Study Korean

Introduction to Korean

Learn to Speak Korean

Pathway to Spoken Korean

Intermediate

Intermediate Korean

Norwegian

Introduction to Norwegian I, Norwegian II

Norwegian on the Web

Persian

Easy Persian

PersianDee

Polish

Online Course

Portuguese

Pluralidades em Português Brasileiro

Russian

Beginner

A1 Course

I speak Russian

Intermediate

B1 Course

B1+ Course

B2.1 Course

B2.2 Course

Spanish

Beginner

AP Spanish Language & Culture

Basic Spanish I, Spanish II

Spanish for beginners  

Spanish for Beginners 1, 2, 3, 4, 5, 6

Spanish Vocabulary

Advanced

Corrección, Estilo y Variaciones 

Leer a Macondo

Swahili

Online Course

Turkish

Online Course

Ukrainian

Read Ukrainian

Speak Ukrainian

Welsh

Beginner’s Welsh

Discovering Wales

Yoruba

Yorùbá Yé Mi

Multiple Languages

Ancient Languages

More Language Learning Resources & Websites!

Last updated: May 2019

Stars Make Firework Supplies!

The next time you see fireworks, take a moment to celebrate the cosmic pyrotechnics that made them possible. From the oxygen and potassium that help fireworks burn to the aluminum that makes sparklers sparkle, most of the elements in the universe wouldn’t be here without stars.

From the time the universe was only a few minutes old until it was about 400 million years old, the cosmos was made of just hydrogen, helium and a teensy bit of lithium. It took some stellar activity to produce the rest of the elements!

Stars are element factories

Even after more than 13 billion years, the hydrogen and helium that formed soon after the big bang still make up over 90 percent of the atoms in the cosmos. Most of the other elements come from stars.

Stars began popping into the universe about 400 million years after the big bang. That sounds like a long time, but it’s only about 3% of the universe’s current age!

Our Nancy Grace Roman Space Telescope will study the universe’s early days to help us learn more about how we went from a hot, soupy sea of atoms to the bigger cosmic structures we see today. We know hydrogen and helium atoms gravitated together to form stars, where atoms could fuse together to make new elements, but we're not sure when it began happening. Roman will help us find out.

The central parts of atoms, called nuclei, are super antisocial – it takes a lot of heat and pressure to force them close together. Strong gravity in the fiery cores of the first stars provided just the right conditions for hydrogen and helium atoms to combine to form more elements and generate energy. The same process continues today in stars like our Sun and provides some special firework supplies.

Carbon makes fireworks explode, helps launch them into the sky, and is even an ingredient in the “black snakes” that seem to grow out of tiny pellets. Fireworks glow pink with help from the element lithium. Both of these elements are created by average, Sun-like stars as they cycle from normal stars to red giants to white dwarfs.

Eventually stars release their elements into the cosmos, where they can be recycled into later generations of stars and planets. Sometimes they encounter cosmic rays, which are nuclei that have been boosted to high speed by the most energetic events in the universe. When cosmic rays collide with atoms, the impact can break them apart, forming simpler elements. That’s how we get boron, which can make fireworks green, and beryllium, which can make them silver or white!

Since massive stars have even stronger gravity in their cores, they can fuse more elements – all the way up to iron. (The process stops there because instead of producing energy, fusing iron is so hard to do that it uses up energy.)

That means the sodium that makes fireworks yellow, the aluminum that produces silver sparks (like in sparklers), and even the oxygen that helps fireworks ignite were all first made in stars, too! A lot of these more complex elements that we take for granted are actually pretty rare throughout the cosmos, adding up to less than 10 percent of the atoms in the universe combined!

Fusion in stars only got us through iron on the periodic table, so where do the rest of our elements come from? It’s what happens next in massive stars that produces some of the even more exotic elements.

Dying stars make elements too!

Once a star many times the Sun’s mass burns through its fuel, gravity is no longer held in check, and its core collapses under its own weight. There, atoms are crushed extremely close together – and they don’t like that! Eventually it reaches a breaking point and the star explodes as a brilliant supernova. Talk about fireworks! These exploding stars make elements like copper, which makes fireworks blue, and zinc, which creates a smoky effect.

Something similar can happen when a white dwarf star – the small, dense core left behind after a Sun-like star runs out of fuel – steals material from a neighboring star. These white dwarfs can explode as supernovae too, spewing elements like the calcium that makes fireworks orange into the cosmos.

When stars collide

White dwarfs aren’t the only “dead” stars that can shower their surroundings with new elements. Stars that are too massive to leave behind white dwarfs but not massive enough to create black holes end up as neutron stars.

If two of these extremely dense stellar skeletons collide, they can produce all kinds of elements, including the barium that makes fireworks bright green and the antimony that creates a glitter effect. Reading this on a phone or computer? You can thank crashing dead stars for some of the metals that make up your device, too!

As for most of the remaining elements we know of, we've only seen them in labs on Earth so far.

Sounds like we’ve got it all figured out, right? But there are still lots of open questions. Our Roman Space Telescope will help us learn more about how elements were created and distributed throughout galaxies. That’s important because the right materials had to come together to form the air we breathe, our bodies, the planet we live on, and yes – even fireworks!

So when you’re watching fireworks, think about their cosmic origins!

Learn more about the Roman Space Telescope at: https://roman.gsfc.nasa.gov/

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Psyche by Auguste Barthélémy Glaize (1856)

Se "Biblical Hebrew Short Lessons - http://www.eTeacherBiblical.com" på YouTube

Happy New Year 2024 from Korea.

Year of the 🐲🐉!

Édouard Debat-Ponsan, La fille de Jephté. 1876, oil on canvas. 

Musée des Beaux-Arts

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