Brown Dwarfs: Crash Course Astronomy #28

While Jupiter is nowhere near massive enough to initiate fusion in its core, there are even more massive objects out there that fall just short of that achievement called brown dwarfs. Brown dwarfs have a mass between giant planets and small stars. They were only recently discovered in the 1990s, but thousands are now known. More massive ones can fuse deuterium, and even lithium, but not hydrogen, distinguishing them from “normal” stars. Sort of.
Correction: In the illustration at 9:30, the numbers listed after the star names are the year of discovery, not distance.
Check out the Crash Course Astronomy solar system poster here: store.dftba.com/products/crash...
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Chapters:
Introduction: Brown Dwarfs 00:00
L Stars & The Lithium Test 2:50
Discovering the First Brown Dwarfs 4:14
What Color Are Brown Dwarfs? 6:24
Physical Characteristics of Brown Dwarfs 7:30
Small Stars vs. Big Planets 8:11
Review 10:17
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PBS Digital Studios: / pbsdigitalstudios
Follow Phil on Twitter: / badastronomer
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Facebook - / youtubecrashcourse
Twitter - / thecrashcourse
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Support CrashCourse on Patreon: / crashcourse
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PHOTOS/VIDEOS
The sun in extreme ultraviolet en.wikipedia.org/wiki/File:Th... [credit: NASA, ESA / Wikimedia Commons]
Jupiter www.spacetelescope.org/static/... [credit: NASA, ESA, and A. Simon (Goddard Space Flight Center)]
Forming a Planetary Gap www.spitzer.caltech.edu/video-... [credit: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)]
Exoplanet uanews.org/sites/default/files... [credit: NASA/JPL-Caltech]
A Trio of Brown Dwarfs (L/T/Y) www.nasa.gov/mission_pages/WIS... [credit: NASA/JPL-Caltech]
Artist's concept of a T-type brown dwarf en.wikipedia.org/wiki/Brown_d... [credit: NASA/JPL-Caltech]
Brown Dwarf Gliese 229B en.wikipedia.org/wiki/File:Br... [credit: NASA / Wikimedia Commons]
Gliese 229B Spectrum - image provided by Phil Plait [credit: NASA/ESA/Hubble/Al Schultz et al]
Artist's vision of a T-dwarf en.wikipedia.org/wiki/Brown_d... [credit: R. Hurt/NASA - R. Hurt/NASA, Wikimedia Commons]
First Ultra-Cool WISE Brown Dwarf wise.ssl.berkeley.edu/gallery_... [credit: NASA/JPL-Caltech/WISE Team]
Brown Dwarf Comparison www.nasa.gov/mission_pages/WIS... [credit: NASA/JPL-Caltech/UCB]
Storms Expected on Brown Dwarfs www.spitzer.caltech.edu/images... [credit: NASA/JPL-Caltech/T. Pyle (IPAC)]
Stars and brown dwarfs closest to the Sun en.wikipedia.org/wiki/Luhman_... [credit: NASA/Penn State University]

[@Bird_Dog00]

I think Phil's last sentence before the recap is a very important one. "Having to rewrite the books of sience - again." (not exactly what he said, but that's the message) is actualy what makes science so credible to me. Science isn't afraid of admiting and correcting mistakes and missinterpretations. Science, the accumulation of knowlege, is an ongoing process.

[@james4727]

best series on KZbin ever. I'm addicted

[@ksearcher4623]

James 😃😃😃😃👍👍

[@anuragkolla8295]

Me too

[@HeraldoS2]

0:42 Minecraft blocks converting Jupiter into a star, awesome.

[@MFahrulRozi]

I noticed that!

[@vladskiobi]

Funny how people who don't know what they're talking about call Jupiter a failed star, when not even 10 Jupiters is enough to amount to even a Brown Dwarf. It's not a failed Star, it's a very successful planet.

[@Depipro]

6:22 alternative - Oh Boy A Frickin' Giant Killing Machine Lumbers Towards You? Or perhaps you'd prefer: Our Best Approach For Gaining Knowledge Makes Little Toddlers Yawn?

[@ChrisBrengel]

3:43 So _THAT'S_ what the elements look like! I think kids would like the periodic table much more if you had these little graphics on them!

[@sion8]

I liked the part where he talks about his involvement in the science of Brown Dwarfs, it makes it even more interesting and authoritative as he is a part of how we knew about these celestial bodies!

[@MrLookatmyhat]

thought bubble periodic table poster please

[@crashcourse]

Samuel Kee As you wish: store.dftba.com/products/crashcourse-chemistry-periodic-table-of-the-elements

[@crashcourse]

***** It's from the Chemistry series -- we've had this poster for a while now :) -Nicole

[@MrLookatmyhat]

too... many... videos to watch... thanks. I'll go buy one :)

[@redcoat4348]

CrashCourse you are really in depth. a whole episode on BROWN DWARFS??????

[@crashcourse]

***** FAIR. I hesitated for a minute, trying to decide which speed you were referring to. Makes a lot more sense...

[@josephmatthews7698]

Elite Dangerous actually did a good job representing brown dwarfs. Weird, I thought they took a lot of artistic license with them. They are actually pretty darn beautiful.

[@hell_march6652]

I know im late but did ed bring ya here?

[@DuranmanX]

Updates to textbooks should just get patches

[@Buzzehxcx]

***** Like FIFA lol

[@Kneedragon1962]

***** Like the Hells Angels? Then you'd have to outlaw textbooks. Some people would thank you...

[@loupax]

***** All textbooks should become open source and being freely edited by the community. Wiki sounds like a good solution. Git can also work

[@cademock944]

+Κώστας Λουπασάκης It can also be terrible because of trolls

[@loupax]

Larry Whitebirch You are thinking of the way Wikipedia works. This is not the only collaboration model that exists. The way Github works is pretty much secure on trolls. Person makes a copy of the textbook, he makes any changes, requests for validation and review from the central source and after all that is done his changes get merged to the original book.

[@FruitSlice]

Phil's enthusiasm is so contagious, I love every episode.

[@androkguz]

"Oh Boy A Feral Giraffe Killed My Transparent Yeti!" That was so funny xD

[@headrockbeats]

Imagine the public outrage if they ever decide to reclassify Jupiter as a Dwarf Brown Dwarf. Or a Dwarfatoid.

[@synthena9776]

you mean sub brown dwarf?

[@nigelkendall5892]

yes a sort of nerdy outrage . a milder form of complaint i would imagine

[@pasijutaulietuviuesas9174]

@@nigelkendall5892 In this day and age, Twitter would consider it racist in some loosely connected way.

[@Dragrath1]

@@nigelkendall5892 technically Jupiter can be classified on that scale as a Y dwarf just no one really does since we now are quite sure Jupiter formed as a "planet". Of course it gets messy since we also now know of at least one true star that likely formed as a planet given the extreme mass ratio difference between it and its "parent star" and a significant number of "brown dwarfs" around more massive A type stars almost certainly based on population dynamics formed as planets becoming massive enough to fuse deuterium and there is even evidence for some sub Jupiter mass objects probably having formed like brown dwarfs. Really just like the iffy boundaries between planets, moons, and dwarf planets we will either need to give up our discrete orderly categorization schemes for a spectrum probably based on mass and density separate from orbital parameters i.e. whether its free floating orbiting a star or another body that itself is orbiting a planet making the latter a separate categorical identifier. If up to me I would probably start with redoing the classifications of asteroids and comets separating out rubble piles from "real" asteroids like Psyche, Hygiea, Pallas, and Vesta (or similarly massed Moons like Mimas, Enceladus )or from the smaller gravitationally differentiated dwarf planets like Ceres Sedna Orcus, Haumea, Makemake in addition to similarly massed Moons Charon Dysnomia, Tethys Then the order of magnitude larger dwarf planets and major Moons that are able to support internal dynamics or even atmospheres but aren't quite massive enough to be able to support a dense enough atmosphere to support surface oceans; Pluto, Eris, Triton, Europa, Moon/Luna, Io, Callisto, Titan and Ganymede, the latter 3 are very close to the limit for the next category hence why it is really a spectrum. Next would come a category for the true terrestrial planets with well defined surfaces able to theoretically support liquid water(i.e. even Mercury if it wasn't so close to the Sun were it given an atmosphere and water should be able to hold onto it). Then would come sub giant planets(no solar system examples), ice giants gas giants, brown dwarfs and the spectral classes of stars with an additional extension to cover the WNh stars which never appear on the main sequence proper as currently defined as the vigorous CNO cycle fusion stirs up their interiors allowing them to become fully convective again and thus allowing them to fuse all their hydrogen examples including R136a1 the most massive star known at 315 Msun which is still fusing hydrogen but more than half of its way through Hydrogen burning as it's spectrum shows it is about 40% Hydrogen and 60%Helium+trace Metals. A system based off Mass and radius and thus average density using readily observable properties seems more appropriate such that at some point something like it will come into existence.

[@demonking86420]

Failed star

[@K_i_t_t_y84]

Can y'all do a video about Rogue Planets soon? Thank you!

[@headrockbeats]

Megan Rivera I have a pretty strong feeling that you don't need to ask.

[@K_i_t_t_y84]

Headrock I *LOVE* this series so it would be amazing to see! ^_^

[@getefix3]

Megan Rivera i wanna know if its possible for rogue planets to be geologicaly active and maybe warm enough under the surface for liquid water :P something tells me ill be disapointed though

[@OmegaMegalodon]

Megan Rivera you mean Rogue Nation? Need to check with Tom Cruise :P

[@Bardun_]

+Zurt maybe not hot enough on the surface, but maybe some are like Europe... have some warmth generated in the center, so that there is liquid water beneath many kilometers of ice

[@RetroSnoop]

I always liked reading about the planets and stars when I was a child and this channel is resparking my interest in astronomy. Loving the videos, keep making them!

[@RubenJMorenoMusic]

This has so far been my favorite video. I have loved astronomy since I took it in college to fulfill a science credit. Thank you so much for making these videos and supplementing my astronomical education.

[@mysryuza]

I love that there are hot stars, but also cool stars, which not many regular people outside space-related interests talk about. The brown dwarfs made me so intrigued that such a thing would exist

[@dryzalizer]

This episode was sub-stellar, and I mean that in the best possible way ;)

[@vahnn0]

In a free-roaming spaceship simulator game, called Elite: Dangerous, you can use a "fuel scoop" to orbit around stars and gather fuel to power your ship. The acronym for the classes of stars which can be scooped is KGB FOAM. Just thought that was somewhat interesting. Have to plan your route carefully to make sure there are scoopable stars on your path or you'll get stuck in a sea of dwarf stars and be stranded. The game boasts a 1:1 scale galaxy (really! there are around 400 billion star systems!) it could take a long, long time before another player could bring you fuel. At that point it's almost better to self-destruct!

[@RubberDuckyLabel]

vahnn0 I was just wondering if there was an easy way to remember which stars in elite are scoopable. Thanks :D

[@koffieslikkersenior]

vahnn0 I got refueled once. When I tried to cross one of the more empty regions of the Milky Way. It's awesome!

[@SV67943]

vahnn0 I need to get back into game. Ripping through the upper atmosphere in super-cruise, to dredge the atmosphere of a star for fuel, is a pretty unique gaming experience, as far as I'm concerned. Even better when someone tries to intercept you, and your escape vector goes directly into the star itself. Have you made a pilgrimage to Sag A* yet?

[@vahnn0]

koffieslikkersenior Call the Fuel Rats!

[@vahnn0]

SV67943 I actually got rather bored of the game and the Power Play update wasn't all I'd hoped it would be. And ramming tactics and disconnects are still painfully common in PVP which drains a lot of the fun for me. I doooooo have enough cash on hand to buy and Asp and fit it for exploration, but I decided to hang on to that money and wait for the "next big update" and see what it brings to the table. Visiting the center of the Milky Way sounds like a hell of an adventure, though, and one I'll definitely have to make at some point before it's too late!

[@AndrewJGaming]

I've actually met Jill Tarter. I went to a talk she gave about searching for exoplanets at Fermilab in Chicago.

[@atruv2089]

OH BOY!!!!! A FERAL GIRAFFE KILLED MY LITTLE TRANSPARENT YETI!!!!!

[@AMoistBum]

Bertú sending this to NASA

[@j3tt436]

I was momentarily confused

[@zbstof]

I was very interested in astronomy since i was 10. Read countless books, wiki articles, been tracking news on Internet for the last 7 years. Most educational videos about astronomy is just entertainment for me - I already know 99% of the facts. But this episode is different. It was really exciting for me to learn something new. Thanks, guys for creating something so wonderful and sharing your passion about astronomy)

[@vtron9832]

I love astronomy too, loved it since kinder

[@jamesdungan4426]

Стас Бицько ñ

[@discoreapor8154]

“I already know 99% of the facts.” ikr? I'm wondering where can I find more complicated videos about astronomy on the internet

[@jetblack742]

"99% of the facts." Uh-huh. Yeah, but apparently not the Dunning-Kruger effect.

[@jetblack742]

And really, dude. How can you say you know 99% of the facts without having studied brown dwarfs?

[@bw6603]

Thank you for making the series!

[@procrastinator99]

I love this series SO much. More, please.

[@BeepDerpify]

this show is amazing!!!

[@Jawjawjaw3]

I want a black dwarf episode now.

[@marcino457]

From what I remember Black Dwarfs are objects that are, in theory, formed after a white dwarf radiates away all its heat. They cannot exist yet, because it would take dozens of bilions of years in order for one to form.

[@benaaronmusic]

marcino457 Great info. Thanks for teaching me something about our universe.

[@MarcelloSevero]

marcino457 If I recall it might take over a quadrillion (10^15) years for a black dwarf to form.

[@crunkdwscrew]

marcino457 Whats a white dwarf?

[@marcino457]

crunkdwscrew Dude can't you seriously type it in Wikipedia? I answered to jawjawjaw because making a whole episode about black dwarfs would be pointless lol

[@mrx4022]

So you're telling me that brown dwarves are equivalent of that uncle nobody invites to family gatherings?

[@idiotninja]

Every CC Astronomy ep is FANTASTIC.

[@PastPerspectives3]

This guy worked on Hubble?! This teacher is awesome.

[@azlib77]

"My god, it's full of stars."

[@lordkenzington]

Fascinating! Something I knew very little about until now. Thanks again crash course team!

[@OnTheWhistle]

it's really cool that this is stuff Phil has personally taken the time to study and work on. you can tell he has some very strong opinions on this topic.

[@Christopher4700]

Oh Boy A Feral Giraffe Killed My Little Transparent Yeti!!

[@TheGoldSheepTGN]

has anyone ever wondered if there is a solar system where there is a planet or planets bigger in size than the star they're orbiting?

[@MikeRosoftJH]

Could be. A white dwarf is about as large as the Earth (but has a mass comparable to the Sun). I believe that the more distant planets will survive the star's transformation to a red giant and then to a white dwarf (though the star loses a part of its mass in the process, so their orbits will change accordingly). There were even planets found orbiting pulsars (neutron stars)!

[@lanceheaps581]

Bloodbath Warrior 20% larger in diameter correct?

[@megustalostacos1993]

love your videos! ive learned so much already! you should do a series on the environmental sciences!(plant biology, geology, geography, topography, etc) that would be so cool!

[@FatmasterKY3]

Enjoying this series a lot

[@tungster24]

This video made me love brown dwarves '._.

[@Robert08010]

Enter Your Title Well, you know what they say. Once you go brown, you never will frown.

[@LucasHaither]

nice touch with the Minecraft icons. great video as always!!

[@heoTheo]

so entertaining and also informative! Amazing work!

[@362sara]

I look forward to every Thursday to see the new astronomy video CrashCourse has put out. Thank you CrashCourse for making Thursdays exciting.

[@brianp2038]

When i saw this pop up in my sub box it made my break from work fly by! I love this channel.

[@robertandersson1128]

Thank you very much for making this video, Phil Plait and the others at _CrashCourse_ Astronomy! Yeah, brown dwarfs are also very interesting. A cross between giant gas giant and small, cool stars. I have one question for you: do stars and brown dwarfs have clouds and a surface? In this video, we clearly saw a picture depicting a brown dwarf with rain clouds and an obvious surface was seen. Is this just beautiful art or is it reality?

[@rcender]

Thank you for all of you great educational videos.

[@jootoobert]

Thank you again Phil, very interesting topic!

[@DjMoelder]

Quite funny the way this guy reminds me of Adam Savage's looks, voice and enthusiastic ways of explaining things.

[@paulpennington2239]

Wow how does he talk for that long without hurting his throat?.He is amazing 😄👍

[@rubicunduseratiudas1264]

Loved the way you explained this and the mental order you have.

[@nariminator8337]

i love this series!

[@squabungus7310]

All I can think of is the ending to 2010: odyssey 2

[@davidpalozzolo6940]

Did Anybody else notice the Darth Vader on the Millennium Falcon?

[@giantcarlo1785]

David Palozzolo OMG YOU'RE RIGHT! THIS IS AN OUTRAGE!

[@headrockbeats]

David Palozzolo He's been there since episode #1...

[@andrewmacmillanjr4675]

David Palozzolo hgg

[@dwightgoad6281]

I always look forward to this guy's presentation.

[@danielgoodwin7679]

Thank you for your contribution to humanity. Having a better understanding of this reality has improved my quality of life.

[@edittheory]

Wait, you worked on the HST?! WOW! :D And by the way.. is there any way we can listen to the full intro/outro?

[@MrNeutross]

Hah! 0:39 - minecraft blocks

[@MrNeutross]

MrNeutross first

[@nono7918]

+MrNeutross right

[@joycerodriguez7582]

ye

[@kennethbowen8441]

That was funny

[@void2509]

dump diamond ore into Jupiter

[@Maegrol]

Love this series! Keep it up.

[@laurellielee]

Phil, Another great episode. I have been enjoying these every week. I would love to learn about the space race, astronauts and space missions, maybe after your get through objects. I would really be interested in learning about that. Thanks!

[@IWasAlwaysNeverAnywhere]

9:49 wait so let me get this straight yall would know if theres a dwarf star near or within our solar system yet nibiru is still seemingly a mystery? IM NOT SAYING NIBIRU IS GONNA KILL US ALL but you gotta wonder why theres no real confirmation whether it exists or not. and our equipment is apparently super good so?

[@savitrrakatamatah7256]

Yeah it might be real. If it is constantly moving it might be very hard to detect it and maybe only certain satellites are able to detect it and not ground based at all times. Maybe be able to catch it once in a while from ground but highly unlikely to find it again if you do.

[@WheezingCheetah]

I see a brown dwarf whenever look back into my toilet bowl

[@mattcero1]

Awesome video Phil. You're very quick and intellectually efficient! Bet few minutes of science so far this year here on KZbin.

[@giovannidallas]

Your videos are amazing! Always a great job! :)

[@myersa80]

Please tell me we'll get to neutron stars and maybe even magnetars.

[@crashcourse]

Sigh Neutron stars & magnetars are coming up in episode 32 :)

[@myersa80]

CrashCourse Awesome! Magnetars are my absolute favorite interstellar objects, they can practically vaporize a person through sheer magnetism up to 1000 KM away!

[@MackBXIII]

I have a crush on this guy for some reason. Yes,talk more science to me baby! Oh yeah! Fill my mind with your theories!!

[@nathanpen1031]

Love these videos ... keep them coming!

[@liesbethtatjana2794]

I am always so happy when these show up in my feed!

[@kimpeater1]

Can brown dwarves have planet systems?

[@davidk1308]

Peter K Yes, if they have disk material left over from their formation, than they could have planets.

[@manabouttongue]

David K not planets, moons.

[@davidk1308]

manabouttongue Since brown dwarfs fuse material like stars, and are too big to be planets (Like stars), I'm pretty sure any big enough object orbiting the brown dwarf would be classified as a planet, not a moon.

[@loupax]

Peter K Every massive object can have "satellites" or become a "satellite" of another massive object. Technically it is even possible to have a small star orbit a bigger star in the same fashion a planet does even though in most cases two starts orbit around the center of mass of their system. So to answer your question, yes they can. The only problem is whether these objects should be called "planets", "moons", "satellites" or even something else

[@annoythefish]

+manabouttongue uh oh here comes the completely arbitrary argument about nonemclature

[@Dj4Life777]

9:15 maybe we should call them, Puns'?

[@quito787]

Awesome episode! Learned a lot today!

[@thestormypoet]

This...right here....is why I loved KZbin. Every day you can come and learn awesomeness. Every...single...day.

[@millermonsterair]

i remember the first time i saw this guy on tv. looks exactly like an uncle of mine and just as nerdy. lol.... but yeah, this dude is pretty cool

[@gremice31]

erm.. can I have my brain back and what makes a star a star again!?

[@Kneedragon1962]

Gregory Barber A star is a star, one of the bright spots in the sky. Stars normally have atomic fusion reactions going on, mostly with hydrogen fusing into helium. What we're learning is you need a certain amount of mass to fuse hydrogen. Oddly, you need somewhat less mass to fuse helium into something else. It seems some of these small borderline objects have enough mass to fuse helium, and get rather hotter than if they were just planets, but not enough to start fusing hydrogen. Physically, I gather, they're about half as big again as Jupiter, and weigh (let's say) between 50 ~ 100 times as much.

[@JamesLewis007]

Gregory Barber I DO!!!! I am BOB Lord of Space! Tremble before my astronomical might!!!!!

[@Kneedragon1962]

James Lewis LOL. I hear and obey. All praise be unto Bob.

[@natnew32]

...Helium Fusion requires even more mass than Hydrogen-1 fusion; He said it was Lithium fusion which requires less mass than Hydrogen-1, but not even much. Lithium requires roughly 65x as much as Jupiter to fuse, with Hydrogen-1 needing ~75x as much. Out star will have about 8 times that amount once Helium Fusion starts. Ditrogen, also known as Hydrogen-2, reuires only 13x as much mass as Jupiter, so... maybe that's what you mean?

[@meghanscarlott7029]

Please do Crash Course Physics! It would help so much this year! And I bet a lot of people would agree. Thanks!

[@brentknickerbocker6023]

This was the most interesting episode yet. I didn't realize how much there was to know about brown dwarfs.

[@Sarruji]

This is why I hate these things. Your like oh it's a gas giant so you don't mind getting closer. Then you get the warning your ship is over heating. Damn you brown dwarf damn you.

[@fatimashafiq7129]

Markus Orison It's like everyone has a iship x nowadays except for me, excuse me while I go complain to mum, get rejected and weep in my bedroom.

[@ilikeceral3]

Captain Kirk wrote this comment

[@jeanosorio1]

dafuq happened to vsauce?

[@captaincomrade8056]

IKR

[@GuiiBrazil]

=/

[@nwashugu273]

+kurama feel old yet ?

[@aputoy9627]

lmao

[@Siliziumwesen]

He matured out of his larval form

[@rashisti]

This is the best Crash Course series. PBS makes some amazing content.

[@MayorOfTown]

great video; I liked the summary at the end

[@billyjoeparker8054]

OH BOY A FERAL GIRAFFE KILLED MY LITTLE TRANSPARENT YETI

[@XxRAPTORxX23]

How can someone dislike this? Oh except creationists...

[@TheLightStudios356]

I'm a creationist and I don't have a problem with this

[@RhapsodicXStyle07]

TheLightStudios Same here

[@eggslicer2399]

THE RAPTOR GOTTEM!!!!!

[@yeahoh2222]

Cough Christians cough

[@razorfett147]

I think you need to be more worried about the conspiracy nuts than Christians at this point. Ive never met a Christian that disbelieved in astronomy

[@turki_wz]

6:30 Absolutely mind blowing!

[@jameswright7375]

Superb work!

[@Gregsplays]

now imagine a habitable planet orbiting a brown dwarf, that would be really really wierd

[@hooflepoof1593]

Wow, that would be a dark planet xD

[@Gregsplays]

XD, but it would also have to be super close to the star, like one of Jupiter's moons, and when you see the sun rise and see, you just see this magenta-glowing ball moving across the sky with swirls of darker and lighter colours, and flecks of much brighter material as the clouds part in places and let through light from further inside the star.

[@MarkOffenberg]

Wouldn't radiation be a problem at that distance then?

[@CrossWindsPat]

+Bayonetta Is My Goddess "might be harmful or harmless" I see you covered all your basis there :D

[@Enzo012]

The habitable zone if they can have one would probably be well within the Brown Dwarfs roache limit so any planet that that close would be torn apart and create a ring system around the brown dwarf.

[@fact5567]

Do you think space is scary or crazy? If not, then my new fact video might change that... >:)

[@zacharielgovad9623]

Thanks so much for the amazing video, learned something new today.

[@CorwynGC]

Thank you for clearing up the whole brown dwarf vs planet thing. Astronomers have been frustratingly vague on the issue for a while.

[@jabelltulsa]

Your videos are so interesting. Great format, easy to digest, engaging topics; I could go on. Thanks!!

[@DDCrob]

Not going to go into much detail here but thanks so much for posting this video. It answered some big questions I had for a while now.

[@ElloBoppit]

This series is great.

[@DanielFenandes]

this is the best crash course séries ever

[@renatobritto4096]

omg this video was so good, really thanks for the awesome job

[@Tourian]

I love these videos so much. 😭

[@romero1337]

That was very informative! I never knew about Brown Dwarfs

[@gsyamsri8122]

Wow that course is starting to become REALLY good.

[@pedrojorge1912]

This episode is so amazing, one of the best of the course. We've studied the planets and then the stars, but then Phil opens questioning _if we have an object far more massive than a planet, but not quite massive enough to become a true star? What sort of thing would we have?_ Then you can feel all his enthusiasm with _what indeed!_ and you instantly get more excited to learn further, how the heck would something in-between look like? During the episode we find not just about it, but that he has worked on brown dwarfs in the Hubble Telescope, and himself actually discovered and produced part of the knowledge he's teaching about now! And finally, at the end we conclude that this lesson isn't just about Astronomy, but how categorization, our view of the universe and science in general work, as we _have to rewrite the book of science - again_

[@shuura]

Thanks for this Phil!!!

[@emilycooper1121]

Though I respect his vast knowledge, my astronomy professor lectures dryly for an hour and a half with no visuals and little humor. Our final exam is tomorrow and this is helping me so much!!!! Thank you!!!!!!

[@Devillionaire]

Sick video. Well done.

[@skpjoecoursegold366]

thanks for the recaps.

[@patriciacanada8282]

Excellent teacher !

[@reidstrr]

The best guy on Crash Course atm, cmon Stan!

[@samirbatta502]

I'm so addicted to this