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.
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.
That's another reason to make sure your lease allows proration per calendar days in cases of leap years, February generally, and equatorial procession.
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.
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. :)
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 RUclips comment section). "Sidereal" is four syllables. Pronounced like sy-DEER-ee-uhl. Sorry! Really do love and appreciate your content.
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!
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.
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.
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.
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 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.
@@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)?
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.
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. :)
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!
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.
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.
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.
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.'
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!
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.
@@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.
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!
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.
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!
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.
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.
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).
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.
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...
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.
@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.
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.
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?
@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.
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.
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
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.
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.
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.
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?
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.
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?
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!
Brian, I recommend checking out a search on RUclips - milankovic cycles. The precession talked about here is just one part of the geometric relationship to the sun, with big effects on climate
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".
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.
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*.
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).
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
@@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").
@@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.
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 :)
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) ruclips.net/video/IVQ3yH-Zusg/видео.html
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.
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.
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).
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.
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. :)
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.
@@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.
@@-_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.
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))
You might want to comment on other calendars, in particular J.R.R. Tolkien's Lord of the Rings calendar. It's unique in that it does not change from year to year. To achieve that, the extra days needed to keep the seasons in synch with dates are not part of the normal Sunday-to-Saturday cycle. I describe its special features in _Untangling Tolkien_ a day-by-day chronology of the events in LOTR. I also tracked down the the lunar calendar that Tolkien use to track how the moon behaves in his tale. When he has the moon rise. I give the time and relative brightness. The book is a very astronomical look at LOTR.
Well explained, thanks! I saw these 'future skies' shown at a planetarium where they showed what the stars would have looked like something like 2000 years ago and thousands of years in the future and when certain bright northern stars will be the 'north star'. Quite a spectacular way to see it. I'm glad you mentioned a bit about how precession affects the climate. I believe it's also the precession of the perihelion (OK you mentioned that - where it is relative to the equinoxes) and the change in size of the wobble (tilt or inclination changes with time) that affect it as well... oh yes the other thing was that the eccentricity of the orbit changes. I don't know how all these orbit/axis things might affect the Earth's magnetic field and how its poles move with time, but it's probably all connected somehow. If the moon's distance from Earth is increasing that might make the precession rates slow down maybe. I believe the tidal effect of the moon slows down the Earth's rotation but maybe it would be slowing down more slowly in future if the moon is further away. So maybe by the time the stars are visible in the opposite season (about 13000 years) the tropical year would be a bit less in terms of days if the day length has increased. I guess the year length could have changed a bit over time as well if the Earth's orbit is moving towards or away from the sun. Maybe it would move away from the sun gradually if Earth is being slowed down by any 'drag' or tidal effects of the planets or pushed by solar wind, or would move closer to the sun if the sun's mass is increasing if it's still growing and swallowing things like stray comets and asteroids? I was wondering if light years (and the year lengths of the other planets) are measured using the tropical year or the sidereal year and found it's usually the Julian year probably for simplicity of the numbers 365.25 mean solar days. Parsecs also need the astronomical unit to be a fixed amount but if the Earth's eccentricity or orbit mean distance change over time it would mean calibrating parsecs would change, slightly changing the way we measure distances to stars and galaxies.
"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.
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.
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?
Cosmos was a favorite show for me. But I learn five new facts from you, In the time it took for Carl to say; "Billions and Billions" Coolest Precession Video EVER ! 👍
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.
That question needs to go to the solid-earth geophysics department, not to an astrophysicist. The thing is, the behavior of geomagnetism is unpredictable and is unlikely to ever become predictable. But magnetic pole reversals happen all the time every million years of so with shorter reversals in- between and thousands-year periods of no magnetic field at all, and there is nothing in the fossil record to suggest that it is any big deal as far as threats to life or anything. With the ubiquity of GPS, we don't even need compasses anymore. Save your worrying for nuclear war and catastrophic global heating, and worst of all, the ways that one of them can cause the other - and vice-versa.
on the no south star: A few years back my FIL named two of our dogs Zubenelgenubi (Zubi short wise) and Vega because these are the stars in the southern hemisphere and northern hemisphere respectively that Ship pilots utilize with their sextants to circumnavigate.
"Si-DEER-ial" - space is hard, words are harder.
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.
😀👍
water at rest is flat and level.... gravitational space is a story, shared among the soulless. side-real is what it says.
Prove it!
@@hankhill6569 heretic, neigh sayer, how dare you question the wisdom of the chosen ones?...
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.
And still didn't fix the plumbing!
Today they would charge even more because of all the fuzz around, just so, because they can.
Isn't it weird how the greed of the rich translates to the Ignorance of the poor given enough time and propaganda
That's another reason to make sure your lease allows proration per calendar days in cases of leap years, February generally, and equatorial procession.
Yeah, think of what they would have done with Covid.
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.
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. :)
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 RUclips comment section). "Sidereal" is four syllables. Pronounced like sy-DEER-ee-uhl.
Sorry! Really do love and appreciate your content.
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!
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.
Most of what she teaches is wrong.
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.
Thanks Chris! I enjoyed making this one too
@@DrBecky Now I feel a little star struck. I think it came from the north.
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.
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.
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.
Hopefully we adopt the metric calendar by then.
@@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.
@@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)?
@@tscoffey1 I know I just meant as a concept of interplanetary time-keeping, not the ACTUAL "Star dates" from Star Trek.
The Julian calendar; as opposed to a year divided into very fine strips of time, which is, of course, the Julienne calendar.
You're going to get shredded for that.
Some people win the internet for a day with a youtube comment. Then there's the dad jokes section.
*sigh* take my damn thumbs up
I loved the animated illustrations in this episode. Those visualizations really drove home the concepts, and I thank you for the extra effort
Too bad they are wrong. ruclips.net/video/-oPE3l5E8uk/видео.html
I'm always amazed by your enthusiasm for something which will happen in a 1000 years.
And how that's really not a long time...
Well, it's space. It's doesn't do much, so you have to hold on to the little changes.
My daughter loves you, Dr. Becky, and I too. Thanks for being there. God bless you, and God bless your family!
That busted-year 3000 insert triggered memories of my childhood , cant believe that song came out 20 years ago
HOLY MOLY. This video removed every doubt and unclear explanation I had about ancient calendars and Earth's movements. THANKS
Another Dr. Becky masterclass. This is going to need a couple more watches. Fascinating. Thank you
The singing in the bloopers is always my favorite part!! lolz Love your channel!
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.
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. :)
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!
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.
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.
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.
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.'
Good job as always Dr. Becky
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!
Great vid as always.
in the 70's I was taught to pronounce Sidereal as Cy-deer-ree-al. (?)
Me too
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.
7:59 That graph shows leap century's and non-leap century's really well.
Wow... Your pronunciation of side real make a lot more sense than the "sigh-DE-RE-yal" I was taught 20 years ago.
Which makes it a shame that the one you are taught 20 years ago is the correct pronunciation.
@@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.
This is such a fascinating topic! Thanks for yet another quality learning opportunity!
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!
Mid April correct?
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.
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!
@Bobb Grimley Unless you know something the rest of us don't, Polaris is a triple star system.
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.
I can listen to Dr. Becky talk for hours, hanging on every word.
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!!!
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.
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).
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.
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...
@@YegresAL
And 2 visits from the Easter Bunny! Twice as much chocolate!
I hope that those days return to Ukraine 🇺🇦
Well sometimes they actually meet up.
This year the Passover was started with Good Friday and Ramadan
@@karlakirkpatrick2214 orthodox Easter was April 24.
Actually, in the south we have a crux who points to the south. 😊
Stay safe there with your family, dr. Becky! 🖖😊
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.
@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.
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.
You explain the future reasonable and enthusiastic! I like the way you do your videos.
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.
Really? 26,000yrs is not enough time to adjust?
@Anna Wolffinger An guess an didn't. What gives an sarcasticness away?
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?
@Anna Wolffinger Now we're an the same page, An
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.
My takeaway from procession is that Astrology has a shelf-life.
@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.
This was an awesome video! Thank you.
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.
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.
Add one more zero
Yep it was aligned with Thuban.
@@jeromebirth2693 the cycle is 26000 years. The great pyramid was build around 2600BCE or 4600 years ago.
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.
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
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.
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.
I didn't know about the shifting of the seasons, cool!
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.
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?
Beautiful and brilliant. Thank you, Dr. Becky.
I took a couple semesters of Astronomy in college. I distinctly remember finding out why the "first point of Aries" points to Pisces. Procession!
Not for long, Aquarius is next.
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.
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?
New JWST images out, can't wait to hear about it from you..
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!
Brian, I recommend checking out a search on RUclips - milankovic cycles.
The precession talked about here is just one part of the geometric relationship to the sun, with big effects on climate
Thanks, Dr. Becky. For your next lecture, can you explain precession vs nutation?
And those bloopers are still coming! lol
Love it all Becks..... keep doing what you do girl.
Thanks Dr.Becky. Keep looking up ✨. Martin from the Emerald Isle 👍🍀
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".
I think I've heard ap-e-helion a lot more than afelion, partly because that's the way I've been saying it...
It was pretty cute
I saw the same thing...
Must be a British thing, as we all know they only have a basic grasp of English there :P
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.
Dr Becky, you would be a fascinating dinner guest. I enjoy your astronomical enlightenment.
precession is one of my favorite topics about the earth.
Love your obvious passion for science. Your infectious presentation style is a revelation.
That calendar bit was really interesting. Never thought leap days had anything to do with precession.
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!
This video was BRILLIANT! helped me through this SIDREAL VS. TROPICAL Business... Well done!
Great Dr. Becky, I like the way you explain the matters.
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*.
Or side-ear-ee-al
Looking forward for this. Had the 4 planet alignment occurred.
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).
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
@@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").
@@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.
Wonderful video as always!
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 :)
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) ruclips.net/video/IVQ3yH-Zusg/видео.html
The entire heliocentric model is built on lies.
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.
This is amazing. Love it.
Becky,
Please record and release an album of you singing. You've got a good voice for it.
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.
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.
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.
I caught that too and Merriam-Webster agrees with you...thought maybe it's the British way to pronounce the word though
Thank you Becky 👍
No wonder I had problems standing up this morning!
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).
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.
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. :)
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.
@@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.
@@-_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.
Thanks for that super interesting explanation!
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))
I can hardly wait!!
You might want to comment on other calendars, in particular J.R.R. Tolkien's Lord of the Rings calendar. It's unique in that it does not change from year to year. To achieve that, the extra days needed to keep the seasons in synch with dates are not part of the normal Sunday-to-Saturday cycle. I describe its special features in _Untangling Tolkien_ a day-by-day chronology of the events in LOTR. I also tracked down the the lunar calendar that Tolkien use to track how the moon behaves in his tale. When he has the moon rise. I give the time and relative brightness. The book is a very astronomical look at LOTR.
But Arda was a flat-earth, was it not? Until the time when Eru/Valar made it round?
Loved it, like usual!
Well explained, thanks! I saw these 'future skies' shown at a planetarium where they showed what the stars would have looked like something like 2000 years ago and thousands of years in the future and when certain bright northern stars will be the 'north star'. Quite a spectacular way to see it.
I'm glad you mentioned a bit about how precession affects the climate. I believe it's also the precession of the perihelion (OK you mentioned that - where it is relative to the equinoxes) and the change in size of the wobble (tilt or inclination changes with time) that affect it as well... oh yes the other thing was that the eccentricity of the orbit changes.
I don't know how all these orbit/axis things might affect the Earth's magnetic field and how its poles move with time, but it's probably all connected somehow. If the moon's distance from Earth is increasing that might make the precession rates slow down maybe. I believe the tidal effect of the moon slows down the Earth's rotation but maybe it would be slowing down more slowly in future if the moon is further away. So maybe by the time the stars are visible in the opposite season (about 13000 years) the tropical year would be a bit less in terms of days if the day length has increased. I guess the year length could have changed a bit over time as well if the Earth's orbit is moving towards or away from the sun. Maybe it would move away from the sun gradually if Earth is being slowed down by any 'drag' or tidal effects of the planets or pushed by solar wind, or would move closer to the sun if the sun's mass is increasing if it's still growing and swallowing things like stray comets and asteroids?
I was wondering if light years (and the year lengths of the other planets) are measured using the tropical year or the sidereal year and found it's usually the Julian year probably for simplicity of the numbers 365.25 mean solar days. Parsecs also need the astronomical unit to be a fixed amount but if the Earth's eccentricity or orbit mean distance change over time it would mean calibrating parsecs would change, slightly changing the way we measure distances to stars and galaxies.
"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.
“Fairly recently” - within the last million years
I can’t wait for the Orion to be a summer constellation. I don’t like night stargazing in the cold.
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.
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?
That'd be 'affect'.
Cosmos was a favorite show for me.
But I learn five new facts from you,
In the time it took for Carl to say;
"Billions and Billions"
Coolest Precession Video EVER ! 👍
Never thought calendars can be this cool!
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.
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
Can you please do a follow up on this but just regarding the magnetic pole migration? This is going the have a huge impact. Thanks :)
That question needs to go to the solid-earth geophysics department, not to an astrophysicist.
The thing is, the behavior of geomagnetism is unpredictable and is unlikely to ever become predictable. But magnetic pole reversals happen all the time every million years of so with shorter reversals in- between and thousands-year periods of no magnetic field at all, and there is nothing in the fossil record to suggest that it is any big deal as far as threats to life or anything. With the ubiquity of GPS, we don't even need compasses anymore.
Save your worrying for nuclear war and catastrophic global heating, and worst of all, the ways that one of them can cause the other - and vice-versa.
I have your book and i started watching your channel a few days ago and ive only just realised its you!!
on the no south star: A few years back my FIL named two of our dogs Zubenelgenubi (Zubi short wise) and Vega because these are the stars in the southern hemisphere and northern hemisphere respectively that Ship pilots utilize with their sextants to circumnavigate.