We’ll have a new “North Star” in just 1000 years | Precession of the equinoxes

[@DrBecky]

"Si-DEER-ial" - space is hard, words are harder.

[@examinatorant4522]

Sadly I learned that word when I was studying Astrology and using ephemerides believe it it or not using a slide rule! Mind you back then you asked a girl her star sign and she asked the male what sort of car did he have mini's were hot.( 1960's) . being able to delineate a girls horoscope was hot stuff. No I don't believe in it now or probably then either. But it did give me a wonderment of the stars.... and this was before Computers and real telescope images .... your field of expertise were like hens teeth , Catherine Johnson, was unicorn Yep I'm THAT old . To day I have university Qualifications including computer programing and MBA 9 not a total dinosaur ...yet. I love your shows information and enthusiasm. PS I hate social media and mobile phones. To me they're a social retrogressive step.

[@stevenverhaegen8729]

😀👍

[@evolutionCEO]

water at rest is flat and level.... gravitational space is a story, shared among the soulless. side-real is what it says.

[@hankhill6569]

Prove it!

[@evolutionCEO]

@@hankhill6569 heretic, neigh sayer, how dare you question the wisdom of the chosen ones?...

[@donsample1002]

Part of the reason for the riots when they shifted from the Julian to the Gregorian calendars was that many landlords charged their tenants for a full month’s rent.

[@NandR]

And still didn't fix the plumbing!

[@richard--s]

Today they would charge even more because of all the fuzz around, just so, because they can.

[@ShishakliAus]

Isn't it weird how the greed of the rich translates to the Ignorance of the poor given enough time and propaganda

[@jsalsman]

That's another reason to make sure your lease allows proration per calendar days in cases of leap years, February generally, and equatorial procession.

[@jimholmes6423]

Yeah, think of what they would have done with Covid.

[@petemelbourne42]

The "lost" 11 days is the reason the UK has such weird tax years. Originally tax was due on the quarter days with the main one being 25 March. When they switched to the Gregory's calendar they had to to move the payment day back by 11 days so that the tax being charged was still for a whole 365 day year rather than a year's tax being charged for a shorter time.

[@ronjon7942]

Interesting, Thank you. I now want to do a little research on this. Reading history and especially Catholic history, I just accepted the switch without considering at all the various social and economic repercussions. Thanks for the insight and dragging me out of my ignorance…at least this one time. :)

[@majiebb3024]

Your enthusiasm is genuinely infectious. People like you are why I've seriously considered going back to school for something astronomy related. I'm a 35 year old aircraft mechanic. Another fun fact is that America's first president, George Washington, was born on Feb 11, 1731 according to the Julian but is now listed as being born on Feb 22, 1732 according to the Gregorian. Also, I'm going to be THAT guy that people try not to roll their eyes for at the party (or in the KZbin comment section). "Sidereal" is four syllables. Pronounced like sy-DEER-ee-uhl. Sorry! Really do love and appreciate your content.

[@ELCADAROSA]

Dr. Becky, I’ve seen a view videos that cover parts of what yours just did, specifically the calendar shift, but none explained the reasons as clearly and completely as you did. Thank you for the time and effort you put into each and every one of these videos, and the delightful enthusiasm you exude into each!

[@hamishbindrinkin]

can't understate how valuable it is to have this level of information made consumable for the general public. Class act Dr Becky! You are surely an inspiration to a tomorrows STEM stars.

[@godsbeautifulflatearth]

Most of what she teaches is wrong.

[@chrisgeggis5603]

This is a great episode. It's amazing to me how little information exists on the internet regarding the precession of the equinoxes. So little in fact, a while ago I was having a tough time convincing myself that it's a real thing. I appreciate the additional evidence.

[@DrBecky]

Thanks Chris! I enjoyed making this one too

[@chrisgeggis5603]

@@DrBecky Now I feel a little star struck. I think it came from the north.

[@Semper_Fish]

Just wait until you discover that The Precession of the Equinox is a perfect repeating celestial clock that is impossible in the current lie of heliocentrism. The proof can be found by learning how the tropics of Cancer and Capricorn got their names over 2,000 years ago in the age of Aries, and our last age was Pisces where the tropic labels sgould have been Sagitarius and Gemini, and our current age of Aquarius should have new tropics labels of Taurus and Scorpio. There is even more to discover about The Precession of the Equinox and the lie of the axial tilt "wobble" that has to do with the obliquity of the ecliptic. The numbers of many of the specs in heliocentrism literally show how sinister the lie of heliocentric indoctrination is. Ever wonder why the alleged axial tilt is 23.4⁰? Subtract that from 90⁰ and you get 66.6⁰, or the claim of the earth orbitting the sun in an impossible ellipse at mach 88 or 66,616mph! The irony is that most heliocentrists are just regurgitating things they see and hear during the indoctrination process as children and they don't even know the basic specs of heliocentrism, and then they claim to know about The Precession of the Equinox when they can't even see that the luminaries don't reconcile with the claimed motions of heliocentrism.

[@tscoffey1]

I hadn’t considered the fact that even though the seasons would flip by 6 months, the calendar would remain unchanged due to it being a solar calendar, not sidereal. Of course, what calendrical system might actually exist 10,000 years from now can only be imagined.

[@AceSpadeThePikachu]

By then we may be using something more like the "Star Dates" from Star Trek to account for colonies on other worlds like Mars or even Proxima Centari.

[@Mathewmatic]

Hopefully we adopt the metric calendar by then.

[@tscoffey1]

@@AceSpadeThePikachu Well, “Star dates” are a complete writer-invented plot device. They are used inconsistently across the various series, and even from plot to plot within a series. So I wouldn’t reference them as a future solution.

[@tscoffey1]

@@Mathewmatic What is a “metric calendar”? Not sure something like that can exist, since the ratio of Earth’s rotation period to solar revolution period isn’t an integer value. How you do break it up into tenths, and not have something resembling “leap days” to account for the ratio I just mentioned not being an integer (and thus, requiring periodic corrections)?

[@AceSpadeThePikachu]

@@tscoffey1 I know I just meant as a concept of interplanetary time-keeping, not the ACTUAL "Star dates" from Star Trek.

[@34lalaram]

My daughter loves you, Dr. Becky, and I too. Thanks for being there. God bless you, and God bless your family!

[@autohmae]

I'm always amazed by your enthusiasm for something which will happen in a 1000 years.

[@ArveEriksson]

And how that's really not a long time...

[@vigilantcosmicpenguin8721]

Well, it's space. It's doesn't do much, so you have to hold on to the little changes.

[@DeathlyTired]

The Julian calendar; as opposed to a year divided into very fine strips of time, which is, of course, the Julienne calendar.

[@condorboss3339]

You're going to get shredded for that.

[@phild8095]

Some people win the internet for a day with a youtube comment. Then there's the dad jokes section.

[@starknifez4846]

*sigh* take my damn thumbs up

[@TerpstraMark]

That busted-year 3000 insert triggered memories of my childhood , cant believe that song came out 20 years ago

[@LanceMcCarthy]

I loved the animated illustrations in this episode. Those visualizations really drove home the concepts, and I thank you for the extra effort

[@spiritsplice]

Too bad they are wrong. kzbin.info/www/bejne/Y6Czdmaiaqprq80

[@macscotsman51]

Another Dr. Becky masterclass. This is going to need a couple more watches. Fascinating. Thank you

[@briankgarland]

There's nothing I love more than the reaction of people when they learn that, the thing they just learned, was first learned by people thousands of years ago.

[@rrmemphis427]

When I was young I wanted to be an astrophysicist and I actually studied a little bit but unfortunately life didn't take me in that direction. I love your videos!

[@SocietyIsCollapsing]

I was accepted to do Astrophysics at Edinburgh Uni. Like a right muppet,I went to Glasgow for something far less interesting. Not my best decision ever.

[@antoniousai1989]

HOLY MOLY. This video removed every doubt and unclear explanation I had about ancient calendars and Earth's movements. THANKS

[@olegvidogon4338]

Thank you for the great video, but I spotted a slight inaccuracy. You stated that the Gregorian calendar fixed the date shift by introducing leap years. It's not the case. The Julian calendar (one used in Europe before Gregorian and still in use by orthodox church) has leap years as well, in fact there are more leap years in the Julian calendar then in Gregorian. Basically in the Julian calendar every fourth year is a leap year, it gives us an average year of 365,25 days. While in Gregorian uses next rule: Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. So the average year in the Gregorian calendar is 365.2425 days long(compared to 365.25 in Julian and 365.2422 in solar year).

[@nickfosterxx]

I think I'm going to have to watch this several times. It's late and now I remember how it feels when you mind just says 'Enough. But you DO need to understand this bit.'

[@eckligt]

Dr Smethurst, I read an interview in the Guardian with one of your fellow Oxfordians, Dr Suzie Sheehy, because she is out with a new book. Maybe you could invite her for a chat on your channel?

[@john.ellmaker]

I’m always intrigued by this subject and it reminded me that the stars themselves will drift on large timescales. I’m pretty sure in my younger astronomy reading that I saw a representation of Ursa Major after a long time but I don’t recall how much time however I imagine in 13,000 years we’d see some moves especially the closer galactic neighbors.

[@jmanig76]

Most of the dipper (the seven brightest stars) are actually from the same cluster and move as a group, so that part won’t lose too much of it shape. But yeah, the hours I spent playing around in Celestia looking at what the sky will look like 20,000 years from now. In fact, you’ve given me something to do on a rainy holiday afternoon. :)

[@darrenskjoelsvold]

So glad I came upon this channel. This is very interesting. I had always assumed that the poles shifting would be more dramatic. You learn something new every day.

[@MCsCreations]

Actually, in the south we have a crux who points to the south. 😊 Stay safe there with your family, dr. Becky! 🖖😊

[@solsystem1342]

In the northern hemisphere Polaris sits (more or less) directly on the north pole meaning navigation can be much more precise by the stars (without lots of training/practice that is). Just a weird thing.

[@georget.8548]

Good job as always Dr. Becky

[@mickwilson99]

Australian here. There exists polaris australis, the southern pole star, and it is naked-eye visible. Just. In dark skis, with your eyeballs well dark adapted. It's called sigma Octans (or Octanis, depending which source you pick) and it is there, so there. And who the heck is this "us" that have "our" pole star? Is this boreocentricism, hmmmm?

[@barthennin6088]

I almost didn't watch this video because I read "We’ll have a new North Star” and thought Yes I know that...old news...but then I watched and WOW, the video went so much deeper but in Soooooooo INTERESTING a way!!! Great video Dr. Becky!

[@oda_margrethe]

This is such a fascinating topic! Thanks for yet another quality learning opportunity!

[@pierreabbat6157]

There have been four versions of the Roman calendar so far: the Romulan, with no January or February but a vague winter period instead; the Pompilian, with an extra month sometimes inserted into February; the Julian; and the Gregorian. Then there are Hebrew, Arabic, Indian, and Greek calendars, and various others (and there were several Greek calendars).

[@likebot.]

My takeaway from procession is that Astrology has a shelf-life.

[@likebot.]

@Just Looking I see what you're saying, but in a few thousand years what we see and when we see it will be completely randomized as compared to what we have now. We'll have new patterns and different patterns and numbers of constellations gracing the zodiacal path. It's beyond unconscionable that anyone can put the least amount of belief in astrology while at the same time eschewing the very notion of a God.

[@AusNetFan13]

Hello Dr. Becky. You have a great singing voice. Isn't Astronomy fun? I usually have arguments with some people about the length of the day. They can't believe that the day is shorter than 24 hours. I give them an experiment to do: First night for them to note a position of a star against a land object and start the stopwatch, the following night check the position of the reference star against the land object. When the star gets into the same position, stop the stopwatch and note the time. They usually get real quiet after that. Welcome to the Sidereal Day.

[@MrGonzonator]

Wow... Your pronunciation of side real make a lot more sense than the "sigh-DE-RE-yal" I was taught 20 years ago.

[@rensin2]

Which makes it a shame that the one you are taught 20 years ago is the correct pronunciation.

[@ronjon7942]

@@rensin2 Chill out, Oscar, there might be nationality differences, and if not, who cares. Nothing worse than a person who downplays a (very significant) person’s interpretation by harping on the minutest detail. Do you really think she’s in idiot?? I certainly don’t. However, you? You’re soooo clever. Foff. Just tired of insignificant critics. Go watch a different channel, you won’t be missed. Bye. Ass.

[@camrat3460]

As a non-native English speaker I was surprised to hear the word "siderial" pronounced in English for the first time. I was expecting *si-derial*, rather than *side-real*.

[@frankowot4]

Or side-ear-ee-al

[@k3dhj]

I can listen to Dr. Becky talk for hours, hanging on every word.

[@nekite1]

The earth's wobbling axis is a bit of a pain for those of us who need to align our telescopes in order to track celestial objects accurately.

[@thirstfast1025]

Really? 26,000yrs is not enough time to adjust?

[@thirstfast1025]

@Anna Wolffinger An guess an didn't. What gives an sarcasticness away?

[@kamion53]

I think you are referring to the obliquity of the Earth axis, the angle it makes with the ecliptic, it changes from 22,1 degrees to 24,5 degrees over a period of 41.000 years, that is 46,8 seconds a century. Or is it Nutation, another slight wobble of the Earth axis?

[@thirstfast1025]

@Anna Wolffinger Now we're an the same page, An

[@Richardj410]

My alignment scope has it all laid out. Just through the scope and it shows where north star will be every few years. It's not perfect but it helps.

[@LeftCoastStephen]

Eastern Orthodox Church still has Christmas and Easter ~2 weeks after “western” churches. Growing up in Saskatchewan, I had many friends of Ukrainian descent and I was always jealous that they got 2 Christmases.

[@YegresAL]

Even more, at Ukraine we have two New Years to celebrate and one more "gifts for children" day - Saint Mykolay Day at start of December ) But now its not time for jealousing...

[@LeftCoastStephen]

@@YegresAL And 2 visits from the Easter Bunny! Twice as much chocolate! I hope that those days return to Ukraine 🇺🇦

[@karlakirkpatrick2214]

Well sometimes they actually meet up.

[@karlakirkpatrick2214]

This year the Passover was started with Good Friday and Ramadan

[@LeftCoastStephen]

@@karlakirkpatrick2214 orthodox Easter was April 24.

[@stusue9733]

7:59 That graph shows leap century's and non-leap century's really well.

[@billc3278]

Could you tackle the Milankovitch cycles which cause the Glacial/interglacial cycles we are currently in ? The equinox precession is just one part of them. My head explodes trying to comprehend all of them and their interactions.

[@theAmateurBhutanese]

New JWST images out, can't wait to hear about it from you..

[@robwood2868]

Love how you share your enthusiasm and knowledge in a consumable way. Also love when you sing. I think you should write, perform and publish the world’s first (according to my Googling) “Astrophysics Opera”. Keep up the good work.

[@paulr.3220]

Wow! Dr. Becky just answered a question that I have been pondering for some time. Her explanation of Sidereal Year and Tropical Year opened my eyes. Darn, she's good.

[@matthewmatics6928]

My favorite application of this was with the Great Pyramids at Giza. It was thought that they were not aligned with anything, but when they were built ~4600 years ago they were aligned celestially. Due to the procession of the earths axis over ~4600 years they are no longer in alignment.

[@jeromebirth2693]

Add one more zero

[@Rasip]

Yep it was aligned with Thuban.

[@Rasip]

@@jeromebirth2693 the cycle is 26000 years. The great pyramid was build around 2600BCE or 4600 years ago.

[@EBDavis111]

Turns out that's a myth. A person made that claim and it became a meme, but when astronomers actually checked there was no such alignment.

[@scbarberi]

Thanks, Dr. Becky. For your next lecture, can you explain precession vs nutation?

[@indianajon7980]

This reminds me of my undergrad dissertation in archaeology. Looking at Millankovich cycles in relation to stadials, interstadials and the late Pliestocene megafaunal extinction event! Over 20 years later and its still stuck in my mind!

[@bardmadsen6956]

Mid April correct?

[@bj8342]

@Dr. Becky That was very well done - thanks. I have sent this link to my young Nieces for their High School Science where they are doing some Astronomy studies/Environment studies. Great content plus they see a good role model for Ladies in STEM.

[@robertpietschmann8287]

You explain the future reasonable and enthusiastic! I like the way you do your videos.

[@matheuscastello6554]

i was just googling about the precession of the equinoxes a few weeks ago, i was curious why the zodiac signs for example didn't line up at all with where the sun actually is, say. i was able to get it all with my own research, but it's nice to see you make a video about this just a few weeks later, haha! i hope it can help more people learn about this (and other cool astronomy stuff in your channel) more easily and accessibly! also honorable mention to polaris australis! it's nowhere near as bright as polaris, but it does exist, hahaha!

[@-_James_-]

@Bobb Grimley Unless you know something the rest of us don't, Polaris is a triple star system.

[@originalhgc]

I took a couple semesters of Astronomy in college. I distinctly remember finding out why the "first point of Aries" points to Pisces. Procession!

[@RazvanMihaeanu]

Not for long, Aquarius is next.

[@frankowalker4662]

Great vid as always. in the 70's I was taught to pronounce Sidereal as Cy-deer-ree-al. (?)

[@AnthonyWilliams-ew3wp]

Me too

[@jadefinchscene5644]

precession is one of my favorite topics about the earth.

[@littleleaven9682]

This was an awesome video! Thank you.

[@annayosh]

In the video you say that the difference between the Gregorian and Julian calendar is based on the difference between the tropical and sidereal year. It is not. The Julian calendar is also based on the tropical year, it just uses a less precise estimation of it - although the lack of precision is such that it actually ends up about halfway between the tropical year and the sidereal year: tropical year: 356.2422 days Gregorian year: 356.2425 days Julian year: 356.2500 sidereal year: 356.2564 days Another interesting factoid is that our Gregorian calendar is not the most precise one that exists. The Mayans had a year of 365.2420 days, slightly closer to the tropical year. To get an even better calendar we could make an exception to the exception to the exception of the leap year exception, and make 4000 (and all other years divisible by 4000) not a leap year even though it is divisible by 400, giving us a 356.24225 day year.

[@helderalmeida3417]

I can see you really work hard to make a interesting video for us to watch. I thank you for all you do and your hard work is much appreciated.

[@robinleicester]

Great explanation and fascinating subject, as always. You may want to review pronunciation of sidereal though. I believe it should be 'sider-eal' rather than 'side-real', and means 'of or purtaining to the sideus', ie the distant/fixed stars.

[@chuckasualty]

I caught that too and Merriam-Webster agrees with you...thought maybe it's the British way to pronounce the word though

[@transient_]

I didn't know about the shifting of the seasons, cool!

[@iowafarmboy]

Would the drift of stars as we travel through the galaxy effect the location of the north star within that timeframe? Or is it still too short to be really noticeable?

[@kevinmould6979]

That'd be 'affect'.

[@sonderoffizierguck]

One thing that you didn't really mention correctly or at least correctly enough: The Julian calender also had leap years. So the thing that makes the Gregorian calender "more accurate" than the Julian calender are NOT leap years, but the fact that the Gregorian calendar ignores some years that should be leap years. Otherwise the dates would have drifted much more in 1600 years (1600/4=400, so the calendar would be off by more than a year without any leap years). Roughly speaking, the Gregorian calendar skips the leap year every 100 years and skips the skip every 400. This brings you much closer to the roughly two weeks off that you have mentioned.

[@bryannida1412]

I am suprised to hear your great singing, and I just thought you were just a pretty geek,who could smile. You are the full package!!!

[@arcaneminded]

"not that long left" Most people: Only a few weeks away. Astronomers : Everyone you know and 40 generations of their offsping have all died of old age.

[@DrBecky]

“Fairly recently” - within the last million years

[@bryan5549]

Beautiful and brilliant. Thank you, Dr. Becky.

[@Crusty_Camper]

The Calendar Rioters had good cause for being unhappy. They were paid by the day but rents were charged by the month. So in the month that it was changed, they were 11 days short on wages but had a full month's rent to pay. Not so foolish, our ancestors.

[@eckligt]

Dr Becky, I was giddy with excitement that you pronounced "aphelion" correctly (it's often mispronounced as "afelion"!), but moments later you went ahead and said "side-real" for "sidereal". It's actually supposed to be "sigh-DEE-reh-al".

[@EnglishMike]

I think I've heard ap-e-helion a lot more than afelion, partly because that's the way I've been saying it...

[@objective_psychology]

It was pretty cute

[@gregalbert4033]

I saw the same thing...

[@milkdrinker7]

Must be a British thing, as we all know they only have a basic grasp of English there :P

[@Rob2]

Indeed I was surprised when she said side-real while I would expect it to be pronounced as si-de-re-al knowing our word for it derived from the same origin.

[@bierrollerful]

That calendar bit was really interesting. Never thought leap days had anything to do with precession.

[@klah2u]

Dr Becky, you would be a fascinating dinner guest. I enjoy your astronomical enlightenment.

[@michaelcogley3150]

Very interesting as always. I have to admit that I kind of got excited at the beginning of the video with the opening background music. It felt like the start of a documentary-like presentation and I immediately wondered if you the entire video would structured as such. I think it would be fun to see you create the occasional mini documentary because I think that is a format you would excel at.

[@AceSpadeThePikachu]

Assuming humanity survives the next hundred years, I'd assume in a thousand years we'll be an interplanetary species, so Martian and Lunar colonies, maybe even Jovian moon colonies, will need to have their own calenders and clocks. It's fun to speculate what a Martian calendar would look like, or if they even continue to use hours and minutes on their clocks.

[@-_James_-]

We'll more than likely have permanent colonies on both the Moon and Mars within 20 years. No need to guess what their calendars will be like. We can just wait and see. :)

[@dbmail545]

John Dalmas wrote about an interstellar civilization that adopted the convention of every planet having a 24 hour day and a 12 month year despite the actual length of day or year.

[@AceSpadeThePikachu]

@@dbmail545 Since measuring time is fundamental to science, I don't see having the length of the same unit of time being different on every world practical. In fact it was because of trains that cities on Earth needed a global system of time-keeping to begin with for commerce reasons. One of the reasons the metric system was invented is because of the disparities of units of measurement in the old systems between European countries. A civilization needs to have certain common units of measurement; be it for space, time, mass, energy, speed, ect.; in order to properly function. If space travel becomes fast enough for relativistic time dilation to be noticeable that will have to be factored in too.

[@AceSpadeThePikachu]

@@-_James_- Scientific outposts and mining stations sure, but I think full-on cities with populations in the millions that Elon Musk dreams of will take a bit longer than that.

[@johngiromini5745]

Dr. B, that was about the most interesting astronomy video I have viewed in quite some time. Precession was something learned a long time ago, but the equinox changes were apparently skipped over. Keep'em coming.

[@ROCdave5861]

The Revised Julian calendar of the Orthodox Churches keeps the new spring equinox if March 21 for about 25,000 years (it has a 900 year leap year cycle; the Gregorian has a 400 year cycle)(the original Roman spring equinox was March 25-corrected at Nicea 1 (ad 325))

[@chillneophite8863]

Singing? You have a nice voice. Thanks for not cutting that out.

[@micheal49]

No wonder I had problems standing up this morning!

[@NandR]

I did a 33 minute long star trail photo in West Texas. It is one of my favorites and the North Star has a clear wobble to it already, as you showed here. I'm just jealous of the people 13,000 years from now that will be able to see the Galactic Core in winter, when the nights are early and long. But they'll be amongst the stars themselves I suppose.

[@Guido_XL]

Polaris is roughly 0.6 degrees remote from the Northern Celestial Pole (NCP), so, it is to be expected that your photo reveals this fact. Whenever we amateur-astronomers use our equatorial mounts, we align the mount's right ascension (RA) axis to the Earth's axis by applying an optical tool that supports this. It is called a polar scope and basically is just a small lens telescope, fitted into the mount. Peeking through it, Polaris is supposed to be visible as a small dot, located on a reticle pattern. The reticle supports the proper alignment by showing both Polaris and the NCP (not actually visible, of course, but represented as a small cross). It's up to the user to adapt the mount's azimuth and elevation screws in such a way as to get Polaris' dot positioned onto a certain location on a circle around the NCP. The method that I like best is to have a reticle with a clock-pattern that shows "hours" and "minutes" at a decent degree of accuracy. Once I have retrieved Polaris' current transit time (one easy source would be Stellarium), I know at which clock-position Polaris is supposed to be on the moment that I'll do the polar alignment. Then, all I have to do is apply the azimuth and elevation manipulation screws in order to have Polaris' dot on the designated location on the clock-circle. A necessary condition for the success of this method is that the reticle is well calibrated inside the mount (its center should coincide with the mount's RA-axis) and that the reticle is aligned with the mount's elevation direction, which can be simply verified and corrected by applying the elevation screw and aligning the RA-axis, so that Polaris' dot only seems to move vertically across the reticle's pattern.

[@kamilkardel2792]

In Slavic languages (except Russian) and Lithuanian, names of months are based on seasonal activities or phenomena. E.g. in Polish, August is the month of the sickle (i.e. grain harvest). I wonder how our future generations deal with the shift of season.

[@rickarizpe8661]

@drbecky I don't know if this is just because you're British, but ... sy-DEER-ee-al, from the Latin sidus (SY-dus or SEE-dus), meaning star. Sider-eal, 'pertaining to sidus.' It surprised me to hear 'side real' from an astronomy professional. When nitpicking your pronunciation is the only criticism I can find, you know you're doing excellent work!

[@davidvik1451]

Great presentation as usual. I noticed that you pronounce sidereal as side-real I have always heard it as si.di.rial (or close, can't do the diacritical markings). Is this just a Yank vs. UK thing? Keep looking up!

[@roberttolbert7002]

Hey two questions for anybody that knows. 1 Is the change in tilt connected to the changing of the magnetic poles? 2 How far away will the moon be?

[@jamescollier3]

No, but it's the reason for ice ages, along with our orbit and sun spots

[@thirstfast1025]

1) No, the change in magnetic polarity occurs on a much less consistent periodicity. 2) The moon is slowly moving away from the Earth at about the same rate as human fingernails grow. In 1000yrs, it will be slightly less than 40m farther away than it is now.

[@roberttolbert7002]

@@thirstfast1025 Thanks

[@emilyfdee]

I remember learning the term “oblate spheroid“ in ninth grade earth science, and never forgot it. Right before you said those words, I knew they were coming, and I was oh so delighted to hear them

[@chrismccabe6934]

I can't be the only one who wants a Dr. Becky album, am I? Her blooper songs are enough to get me to buy a CD's worth of material.

[@FullMetalAsh]

Hey Dr. Becky - love your videos! They're a great distraction to watch when I should be working... Just wanted to ask whether you would consider doing a video detailing your PhD Application/Study experience? I've been applying this year and would love to hear your thoughts on how the whole process works, and what advice you would give aspiring physicists :)

[@erik-jan4434]

She did a video a few years back about that, I looked it up for you. Video title: How to become an Astrophysicist | My path from school to research (2004-2020) kzbin.info/www/bejne/f4e0ZKx-Yr-oqck

[@flatearthjackal9201]

The entire heliocentric model is built on lies.

[@denmaroca2584]

Gamma Cephei is a binary star. The primary - Gamma Cephei A, named Errai - is the one with the exoplanet, which is named Tadmor, not Tadmoor.

[@johnmurrell3175]

It is also the reason the tax year ends in April - it used to be on the Quarter day in March. It moved by 11 days due to the change in calendar

[@osmosisjones4912]

weebils wabble but they don't fall down

[@LanceB86]

We need more bloopers and singing!

[@alistairmcpherson2228]

Love your obvious passion for science. Your infectious presentation style is a revelation.

[@juzoli]

I can’t wait for the Orion to be a summer constellation. I don’t like night stargazing in the cold.

[@peterleane6807]

Dr Becky, just a couple of points you may wish to consider,... 1. Gravity is not a force and there is no torx on the Earth from the sun, you are referencing newtons Gravitational force formula. If the Earth was subjected to a force then there would be frictional forces as well that would slow the Earth down both on its journey around the sun and on its rotational spin. The tectonic plates on the Earth would be opening and closing with every revolution, creating massive Earth quakes, the friction of the moving plates would heat the Earth by many degrees per year. 2. The Earth goes around the sun and returns to the exact location within .0000000001mm and has done so for the last 3000 years, as recorded by many of the ancient sun recording datums. The frame of reference that we use for the Earth axis can not be defined due to the fact that the north star is also moving through the galaxy, alone with the sun and Earth, hence there is three moving frames of reference,..."the three body problem". Along with a moving frame of reference all Earth based telescopes have an inbuilt error that cannot even fix an Earth datum point reference, ( please refer to my Datum Telescope) To remove the frictional forces from your explanation you will have to use Einstein's relativity equations. In addition it is now accepted that the Earths orbit around the sun is a perfect circle and hence there is no wobble with the Earth axis, your explanation is some what out of date not to mention that you have the Earth accelerating and going in front of the sun with the 1960,s school text book elliptical diagram. Apologies for sounding crass but this video discredits your other great videos.

[@ShadyNetworker]

This is such an amazing video and told in such a fun way, thanks Dr. B! Sidenote: be wary or trolls aka flerfs to the north!

[@examinatorant4522]

Dr Becky and fans you should also take a look at "Smarter Every Day" youtube " why does the James web sun shade has holes in it" He is an engineer and his dad worked on the shield for six years ... they filmed a show in "THE clean room" where the JWS was designed and measured in order that a model could be designed for space manipulations Absolutely fascinating, nice and informative show .

[@rogeriopenna9014]

In 8000 AD, a bright star will finally be close to the southern hemisphere... oh what a bummer. Dr Becky, do those simulations consider the motions of the stars relative to one another while they orbit the Milky Way? Although I suppose even 10 thousand years is too short a time when considering even stars 10 ly away. ps: as I suspected Proxima Centauri has a relatively large proper motion-moving 3.85 arcseconds per year across the sky.[67] It has a radial velocity toward the Sun of 22.2 km/s.[7] Distances of the nearest stars from 20,000 years ago through 80,000 years in the future. Proxima Centauri is in yellow. Among the known stars, Proxima Centauri has been the closest star to the Sun for about 32,000 years and will be so for about another 25,000 years, after which Alpha Centauri A and Alpha Centauri B will alternate approximately every 79.91 years as the closest star to the Sun.

[@benjaminkaufman5484]

I really appreciate this video, the visualizations and the explanations right now. It's so fascinating how I would never even begin to think to study something like this but you seem so lit up about it. Fascinating how all of us each just hyperfocus on a million different things that are in our ballpark and then all that knowledge and experience accumulates together. Wow.

[@imark_b]

The singing in the bloopers is always my favorite part!! lolz Love your channel!

[@Chew1964]

The Brits freaked out with the calendar change because landlords wanted to charge them a full month’s rent; instead of charging them 18 days rent.

[@dukemetzger3784]

LOL I agree with being upset about Pluto!!! It is and always has been my absolute favorite planet and I am not alone! Now that we know what it looks like, even more the love I have for it.

[@condorboss3339]

I was hoping you would add a reference to the Milankovitch Cycles which are related to the precession of the equinox and are a determining factor in ice ages.

[@onnietalone3181]

I live in the aroura and it is the rays that are stronger here in the winter time, yes , as my southern shingles wear way quicker, that means the UV rays are stronger here in winter and should use caution? and not byuild to shade your neighbours? it counts!>3 your habatat, and yes your lawns are made to take in water can be one inch below your walkout you all use to gutter the water!

[@arctic_haze]

Precession of equinoxes takes ∼25.8 ky. However precession of the perihelion (one of the Milankovitch cycles) takes about ∼21 ky. This means that we were in the perihelion in July not ∼13,000 but ∼10,500 years ago. As a source, I can give for example the "Climatic precession" article by H. Pälike in Encyclopedia of Geology (2005). PS. It is caused by the joint effect of the axial precession (26 ky) and apsidal precession (112 ky) because 1/112 + 1/26 = 1/21 (almost exactly).

[@Anamadh]

True, but but I think this was a valid simplification on Dr. Becky’s part to showcase axial precession only. The precession in Milankovitch theory indeed refers to the combined effect of apsidal and axial precession (the latter being shown in Dr. Becky video here). This combined ‘double wobble’ then dictates the total solar radiation received at a given latitude (for instance 65° N) at a give time, which then results in the c. 21 kyr climatic precession with its 3 distinct frequency components. And once we go that route and consider precession in the context of climatic variability we also need to start considering the modulation of precession by eccentricity changes (with a periodicity of c. 100 and c. 405 kyr). And also of course Obliquity which results in a variation of the inclination of the earths rotaional axis every c. 41 kyr. Gotta love the Milankovitch Theory of Climate. Source: Laskar et al. (2011) DOI: 10.1051/0004-6361/201116836

[@arctic_haze]

@@Anamadh Yes, I know this author as I actually teach about the Milankovitch cycles. But thanks for the link as I have not read that paper (there was an older one from 2004 by Laskar et al. with his previous "new solution").

[@Anamadh]

@@arctic_haze Same and I work with it in research (at least on the application of Milankovitch theory to paleoclimate data correlation and age dating through "orbital tuning"). Awesome to see another 'cyclo-person' here on youtube.

[@williammaddock9179]

Becky, Please record and release an album of you singing. You've got a good voice for it.

[@brianmyers13]

I have to admit that I almost didn't watch this. I mean the Earth has a wobble...yeah? Glad I did watch it! I didn't realize that the season location relative to the orbit would change with the wobble. Cool. Thanks!

[@neilaspinall5005]

Brian, I recommend checking out a search on KZbin - milankovic cycles. The precession talked about here is just one part of the geometric relationship to the sun, with big effects on climate

[@duderoony]

And those bloopers are still coming! lol Love it all Becks..... keep doing what you do girl.

[@miridium121]

This should mean that ancient navigation would have been based on another star than Polaris? Or how long ago would that have been?

[@ragnkja]

In most of classical antiquity they didn’t have a pole star that was anywhere near as close to the pole as Alpha Ursae Minoris is today. Wikipedia has a list of the pole stars in the cycle and when they were the pole star most recently and will be again.

[@ronjon7942]

I vote for an analogy episode of Dr. Becky’s Bloopers. I’ve found myself looking forward to them almost as much as her amazing content.

[@lpappas474]

If I would have watched the entire video I would have noticed you were referring to the gyroscopic procession causing a change in the cycle of the seasons. Sorry about that.