So I can't promise I'll do the tutorial unless there is interest, but even if I do but you can't wait, here's the Zooniverse citizen science project: www.zooniverse.org/projects/marckuchner/backyard-worlds-planet-9

New Horizons, the only probe sent to explore a planet that was no longer a planet by the time it got there.

Pluto didnt lose planet status in our hearts

The cautionary tale of "Vulcan" should be mentioned with this however. The idea that math was so precise that it could be used to predict a planet due to perturbations within a planets orbit, it convinced a great many scientists that there was in fact a planet within the orbit of Mercury. Of course we now know there is no planet "Vulcan" (within our solar system at least!) and Mercury's orbit was explained through Einstein's determination of how gravity truly works within space-time.

Fun fact: The planets were called "wandering stars" at various points in history because unlike other stars they would move around the night sky. Various cultures believed they were the homes of or outright were gods. It is one reason they are named the way they are.

no matter how many times I hear the story of Neptune's discovery it doesn't get any less fantastic. to be able to predict something's existence simply because of an incongruence in another body's movement, and for the maths to be so precise? incredible! if Planet X does actually exist I really hope I'm around to hear about its discovery :)

Personally I hope Planet 9 exists just because it would be cool to have such a distant extreme planet in the sol system and maybe one of the agencies will decide to send a probe so far out

One of the coolest ideas (and most terrifying, I guess) I have heard about planet 9 is that it is not a planet that we haven't observed, but rather a primordial black hole. These are very small black holes that are predicted to possibly exist with our current understanding of astrophysics. Crazy thing is, if they do exist, they would be completely undetectable due to only having diameters in the range of an average apple or human fist... It probably isn't a black hole, but again, we do not know if these exist or not.

than you Alex for your excellent explanation about the solar system, I have love astronomy since I was six years old ( am now 62 yrs ).

A small correction. The Babylonians did not determine which objects moved around the Sun. They determined which "stars" were moving irregularly. It was quite some time before people figured out that they were planets, and not just weird stars. It's actually quite easy to look at the sky every night and see every star in the same place as every other night except for a handful.

It's amazing to me just how smart these early astronomers were.

Congratulations on 1mill subscribers!! Been an amazing journey, much more to come!!!

I absolutely adore your videos about how early astronomers found planets and learned about this stuff! Going backwards is so fascinating!

I really like how you briefly introduced the viewers to the topic. How the planets were found, what methods were used and to what accuracy, which later gave a perfect context for the rest of the video to show how weird it is for us not to spot such object or predict it in any way shape or form. Personally I want to believe something is out there, it would be amazing to find a new planet! So I stay neutral in the discussion of Planet Nine but Im still interested in the process and I hope the scientists will find something. How exciting would THAT be?! Great video! :3

For those wondering why the telescope is named after a car brand, Subaru is what the Japanese call the Pleiades (and also why Subaru’s logo is 6 stars) Just a random chunk of trivia I know and figured I’d share because if I didn’t I’d be wondering why a car company had a telescope haha.

Pluto will always be a planet to me. I was so obsessed with the planets when I was a kid, that I had their order memorized before even hearing about the My Very Educated Mother mnemonic device, but I have definitely used mnemonic devices for other things.

Great content! I knew all of this but you still had me the entire time! You’re a better story teller than you are a science explainer, and you’re a great science explainer!

I went on Zooniverse to look for planet 9, but I got completely distracted by the Californian burrowing owls project. Those cheeky fluffy little blighters had me hooked!

the real prize for finding planet 9 is the friends we made along the way. thanks to all the asteroids and baby planets we found for continuing helping us even today.

Every time I watch something about the universe, my mind is just blown away. "This topic" is just so fascinating

It seems we are actually getting close to NOT finding a planet 9 honestly.

6:59 - "even after his death, he encouraged others to keep looking for it." - I wonder what his post-mortem methods of encoragement were... 💀

Please do the tutorial! I'm pretty sure thousands of people are similarly interested in this project. Astrophysics is so fascinating!

8:07 I've also seen presentation of a paper (I think it was on SETI Seminars) that showed that this crown shape can be caused _without_ another massive planet. Rather, the apogee end of these highly eccentric orbits will attract each other. So what we need to form the observed crown-shaped structure is a few more of those, which (due to observation bias -- astronomers spot the ones that are currently near perigee) most likely exist. The dwarf planet spends most of its time in the extended lobe near the apogee, since it moves slower there and it is larger. This means planets hanging out there will attract each other and torque the orbits as shown. It is 20 other dwarf planets hanging out at the far end of the orbit, not a single massive body, that causes the observed clustering. Now the math shows that this effect _does happen_ . So why don't the Planet 9 people include it in their calculations and conclude that 1 large body or _n_ small bodies or some mixture of medium-sized bodies in this kind of extended orbit would do the trick?

The discovery of Neptune and the competing calculations of the flamboyant prodigy Le Varrier and the humble farm kid John Couch Adams is a fascinating story as well. I've read the book "The Neptune Files" by Tom Standage and it gave me a great appreciation of the abilities of these astronomers! And oh small correction: I believe the guy who tracked the orbit of Uranus was Alexis Bouvard - not Boulevard.

A "tutorial" on the astronomic data hunt would be awesome! Im looking forward for it :) Always wanted to help and actively engage in discoveries/tasks about the night sky

I remember in the 5th grade, 2016, we’d get issues of scholastic news. I recall seeing the theory of Planet X on the cover and it always fascinated me. I’m definitely going to assist in the hunt for it. Thanks to Zooniverse

Thank you for your grace video and I hope you have a blessed week ahead 🌎

another amazing video - really think you do a wonderful job!

I remember learning about this about five or six years ago. I’m anxious to know what’s really causing the perturbance. Finding a planet that far out is proving to be difficult.

I just love the idea that Planet 9 might be a Primordial Black Hole. That would be incredible if true because then we have a black hole we can feasibly send a probe to.

I took part in the same zooniverse project! It was really neat, even though I didn't find anything of significance: I actually spotted something in one of my batches, but it was something already logged. Still a really cool experience!

this thumbnail was amazing!

Astrum is the best channel on youtube, it never stops to fascinate me.

My Very Educated Mother Just Served Us Nine Pizzas, was my old go to. When Pluto was demoted I complained to my wife it won’t work anymore. She looked at me for a second and then smiled and said “your very educated mother just served you nachos!” She’s a gem 💎

1:55 oh my how i love that scenerey with the night sky and a somewhat lit desert with a ancient building and some palm trees next to a oasis i belive

I love this comment section. So much good-hearted talk about a ninth planet and primordial black holes, Vulcan and ancient astronomy -- I love it ❤️

i have been watching your videos since you only had 20k subscribers. so proud of you Alex!! look at all those subs!!!

Pluto you are best

If Planet X is real I hope it is named Kronos or Zeno

I swear a few years ago, they found that in the mathematical calculation of another planet outside of Pluto's orbit was due to a mathematical error in a data sets that had always been used, and as soon as they took that out, all the planets followed Newtonian physics basically perfectly.

Fantastic video again! Even though I already knew the story of the discovery of Neptune, your telling of it is the most condensed yet informative version I've ever had. Also, I had no intention this morning of signing up for a year of Brilliant but yet just did. Lol.

I remember watching videos on UKposts when I was maybe 10 or 11, with titles like "Planet X is coming". Of course, I didn't fully understand what they meant, so I thought it was like a roaming planet that scientists found that was coming to swallow the Earth lol. It's nice that I know the full story of its legend so many years later.

Aside from your interesting videos, you have a wonderful speaking voice that's pleasant to hear.

Hello Alex, a joy to watch another of your videos.

A few days ago i had a dream about reading that they found planet nine,i couldnt believe it,so i started searching for it on my phone,just to find out it was real,it was all over the news. Funny you now made a video about planet x ;)

If the Kuiper Belt’s thickness measures 10 AU, and Planet #9(whatever we’re going to name it)takes 10K years to complete an orbit, would you think it orbits on the outside of the Kuiper Belt?

The reason Planet Nine has not been observed, yet, is a combination of factors: the background it is in front of from our perspective, and the possibility that it is at or near the farthest point of its orbit and is therefore moving so slowly across our sky that some background objects are moving faster than it is, thus keeping it mistaken for a background object.

I was just watching your videos now when i got this lovely notification of the new video ❤️

Awesome channel with awesome content and great quality as always say 🌍💯🔥

I'm always stunned by the sheer beauty of the planets.

Pluto will always be as ninth planet in our hearts.

I jus wanna also add that the planetX team make an awesome band on a side note. Love that bass ...ty 4 this comprehensive video and yes love Brilliant no matter how frustrated I get until I get it and feel awesome 😎

Thank you for covering this in such a thorough manner! I am constantly hungering for new information on a variety of topics, and news of Planet X has always made my brain itch in such a pleasant manner. Please keep up the great work! 🖤🐻🧙🏻‍♂️

Very interesting episode. Thanks!

YES please do a video tutorial on how to use zooniverse that would be amazing

Excellent content as always

I recall somebody doing some calculations to see how probable it'd be for only the objects Brown and Batygan considered to have ended up in those orbita solely by pure random chance, but I can't remember who they were or what their results were.

For me, Pluto is still planet 9.

I'd like the research to be bold for this is something that has an equation to look at and maybe something new to ad in a different way of planning cosmology.

I like the theory that planet nine could be a very small black hole in a stable orbit around the sun. It would explain the mass and why it's so hard to spot.

Yes Pluto is no longer a full planet but it is still a dwarf planet, so in actuality we have like 13 planets 5 of them being Dwarf planets and 4 being Jovian planets and the other 4 are the inner rocky planets. Though I'm starting to think Mercury should be given it's own classification as a Core Planet as that's all that's left of it.

It is possible that the observed long-period objects are traces of the gravitational influence of a stray planet that visited the Solar System millions of years ago. The induced orbital changes are preserved, and the wandering planet can already travel far.

Reading recent comments is a wild rollercoaster ride of emotion.

James Webb in a couple of months: "I gotchu fam, give me a sec"

Zooniverse would be interesting. You forgot to mention that many stars close to Sol are in high relative motion to it, including dozens of red dwarf stars plus binary and triplet stars (Alpha Centauri is a triplet star, which is obvious, but suppose two or more red dwarfs are orbiting each other and so on). Plus all the millions of Kuiper Belt icy asteriod sized objects beyond Neptune (which Pluto is one, Eris is another) This adds to the complications of finding planet X.

Yes please!! We need the tutorial!!

Good video, very interesting, thanks.

I'd love to see more information about all the brown dwarfs and the like which the search for Planet X has incidentally found throughout their search. How many have they found? How far away are these places? Are they a part of their own solar systems or are they far flung exclaves of a much larger star system sort of like how Proxima Centurai is to the Alpha Centurai star system? Would any of these celestial objects be both close enough and interesting enough to potentially send some form of probe to in the next century? There's a lot of different questions that the unintended finding of these objects bring up and it'd be great to get a run down of them.

I've wondered for a while if a passing massive object could have perturbed far out orbiting objects in the past, and their orbits have been elongated ever since. Also I'm pretty sure scientists have already pointed out a giant star that will pass close by to our Sun millions of years from now. There's just so many things it could be!

Just to get a grasp on how far this planet X might be. 300 to 520 AU equals to roughly 1.5 to 3 light days.

Extra fun fact: Since Neptune was discovered with math, some scientists tried to discover a planet closer to the sun than Mercury, called Vulcan. There were even lots of misattributed sightings of Vulcan. The Newtonian math supposedly called for the new planet, but it wasn't accurate. When we got Einstein's Relativity, we were able to solve the math without the need for Vulcan.

I remember the German version of the mnemonic from my childhood :) "Mein Vater erklärt mir jeden Samstag unsere neun Planeten" I never thought about what it might be in other languages

I vote for the tutorial! I really love your work! Please keep it up!

I have found the counter arguments (if you can even call them some of them "arguments") quite unconvincing. Firstly, it is not "easy" to spot and track even largish objects at distances of 500+ AUs, especially when you don't know *where* on their orbital path they happen to be. It's a monumentally large amount of sky to sift through. Planet X could be as far as 1000 AUs (I'm not sure where your lower figures come from; perhaps more recent data) Secondly, the argument "then why haven't you found it yet" is not an argument, for reasons laid out in my first point. This would be like arguing back in the day that "Uranus and Neptune don't exist because why haven't you found them yet?" It would be more sensible to say "I will reserve judgement until an affective search method has either discovered or ruled out (to a convincing degree) planet 9". *Certainty based on a lack of evidence is utterly unscientific* I believe the modelling and tracking data of perturbed KBOs quite convincing; whether it's 99% convincing? In any case, the counter arguments *are* weak.

Awesome, new sub

Alex produces better content than big network corporations with enourmous budgets.

My young children and I cannot wait till when James Webb starts putting out unimaginable photos. It’s going to change the way we look into the sky.

Discovering planets can be a tricky business. Neptune: Let me introduce math to you. 😂 Ngl the story of Neptune's discovery is still the best science story in my opinion. It told us how amazing and powerful math and science are.

Not in our next zillions of years. Fascinating, but, curiosity in this subject is mind-blowing.

New Horizons found so many fascinating things on Pluto. At my age, I'm very certain I won't live to see any return mission to learn more.

The story of Vulcan is an essential part of this saga, it shows that another planet isn't always the right answer and there could be an alternate explanation for the observed phenomena (in Vulcan's case, Einstein's discoveries in physics)

With the new extraordinary James Webb telescope breaking theories concerning our universe left and right, wouldn't it be relatively simple to discover whether or not there is another planet existing in our solar system?

Just wanted to point out at 7:30 you said that we still haven't discovered Planet X to account for these oddities in the ice giant's orbits; these irregularities were solved when voyager 1 & 2 came along and gave us more accurate data on the planet's mass which showed that the orbits were completely normal, our data was what was wrong. Love the video though

I want to see an Ed Wood style movie on Planet X... Planet 9 from Outer Space! It orbits in the dark... but soon it will come to the light!

Planet 9 will always be Pluto for me 💖 LOVE YA, PLUTO, HAVE MY HEART!

Your videos are the best

By all means you should do the tutorial. Just because I will probably struggle to keep up doesn't mean that most of your other subscribers will, or that I won't still be able to appreciate and enjoy it.

Pluto will always be Planet Nine for me.

2:37 that looks so weird with a small sun and the other planets in more realistic sizes :D

I think for Planet 9 to exist it would be insanely lucky to be even found especially with say its orbit being a very long one. Whoever finds it will definitely remembered and go down in history but good luck if its ever found. Everyone putting in effort for over 100 years we could find it if its there

I love your channel!

About 25 years ago my year 2 teacher told us there might be an unknown planet X floating about the solar system. I'm looking forward to the day when I can say 'yes, you're right about that Mr Robertson'.

Tutorial please. Although it's fun to learn it yourself by trial and error but it will be helpful to know what to do and not to do. Otherwise, we might get overexcited about finding something more mundane than Planet X.

YES, YES YES ... please do the tutorial!

Alex i love your content.

I read somewhere that the Planet 9 could actually be a really small black hole which would explain why it is so difficult to spot

Quick fact check for 3:35 Oranos was the father of Cronus ( titan ) not Kronos ( Saturn )

3:27 Interestingly, Herschel named it “Georgium Sidus” meaning “George’s Star” or “Star of George” after his patron King George III. It was Johann Bode that later chose the name Uranus.

My stepdad told me a really easy way to spot planets in the sky. Stars twinkle, planets don't!