Retrograde Motion

This video surveys observations, historical theories, use of a mechanical demonstration, and compares the apparent motion for all superior planets of the motion.

[@CrisHaasbro]

I finally understand, that demonstration was phenomenal

[@suketupb]

I teach Astronomy, and this is one of the best demonstrations I have seen explaining retrograde motion! Congratulations!!

[@productivitysharma3455]

where do you teach

[@familyshare3724]

Please don't tell kids that one model is right or wrong. They are only more or less complicated and more or less predictive.

[@familyshare3724]

Geocentrism is what we actually see, standing on Earth. Heliocentrism is easier to draw on paper. But try to do the math.

[@familyshare3724]

Galileo, Copernicus, Kepler could not predict eclipses nor planetary positions far into the future. Whereas Babylon since before 747 BC and C Ptolemy since AD 150 could. Not until Haily and Newton AD 1700 could we painfully produce more accurate results and only because we had 3000 years of geocentric data. Even NASA relies upon and cites Babylonian and ancient Chinese records.

[@Tamara-dv7vo]

Thank you for finally helping me understand. I think maybe it 85% make sense to me now which is SO much more progress than I've made with other videos / explanations!

[@noneyabeezwax8865]

Finally, a prefect explanation and beautiful visual model!

[@pchebbi]

Simply love the speaker's voice. Crystal clear. What an awesome and novel effort of mechanical demo! Hats off!!!

[@wojohugo]

This is the BEST video I have come across explaining "apparent" retrograde motion of superior planets... a job very well done!

[@hoorainbaig2024]

I am an audit and accounting student. I've recently grew an interest in astronomy so i've been watching videos related to it. Your video explained it really well. And if anyone sees my comment do recommend good beginners guide to astronomy.

[@Almuric.Tychos]

kzbin.info/www/bejne/g6Sth4GIr9Fjh7M

[@hoorainbaig2024]

@@Almuric.Tychos Thankyou

[@yaltschuler]

In case anyone is curious, the song is "I Don't See the Branches, I See the Leaves" by Chris Zabriskie.

[@mikesnyder1788]

As a newcomer to star watching I observed retrograde motion of Mars in either 1978 or 1979 but had no idea what was happening. Took me a few years to run across a scientific explanation and - Bingo - my riddle was solved. Very good presentation! Regards.

[@saadasad6481]

Thanks for this video, I understand this phenomenon now due to your phenomenal demonstration and explanation.

[@ShivangiKrishna]

That demonstration tool was sooo good and well explanatory

[@DifferentSaturner]

You explained it very well, Tina. Thank you. It's about how we see those from distance. The sun & the moon are too far & very close, so we don't see those go retrograde. It's including galaxies, distant planets, objects. (Fri 12 Aug 2022 15h32)

[@brigettebradley9914]

Mind blown. Thank you. This visual was Much needed! And I love the hand crank for teaching

[@eiliam7274]

Simply, brilliant! Thank you for this.

[@alexanderestk]

I'm in love with the speakers voice.

[@kamranahmad9094]

Why are you not in love with creator 😊

[@ilsedemolder3973]

Too feminine.

[@nanivins]

Excellent presentation.

[@VishalMotwani9]

So clear and simple .. finally understood the thing .. thanks for your efforts

[@simonshack1]

Unfortunately, this explanation for the observed retrogrades of our planets does not stand up to close scrutiny. Mars, for instance, is actually observed to retrograde for less time (61 days) and width during its CLOSEST passages to Earth (approx. 0.37AU) - and for more time (83 days) and width during its FURTHEST passages to Earth (approx. 0.67AU). This is contrary to the most basic laws of perspective - as thoroughly expounded and illustrated in my book "The TYCHOS - Our Geoaxial Binary System" (2022).

[@mikeuu3104]

The Tychos model has to be the correct model of the solar system!!!!!!!!!!! amazing

[@Shiva1945]

Best I have seen yet

[@jolaola1987]

Very helpful for astrology students. Thank you for this easy to understand excellent presentation. 🌌🌠🌜

[@pramodm3540]

It is sometimes observed in transparent lift confusing whether we are going up or down after it stops midway, watching outside. It happens coincidentally and not consciously.

[@mjdarcy2002]

The video is amazing. Great job and thank you. The only improvement I can think of would be a tiny camera on the earth ball that would show Mars against the changing background. But that would be tricky.

[@abhaychandajkar]

Good Model for explanation....especially the motion of houses and fixed signs is good to visualize how personal charts are developed...Thanks for good video...and keep it up.

[@marutinandan67532]

Thanks for the wonderful explanation. 🙏

[@bl-ll550]

great illustration.

[@selvamthiagarajan8152]

Thank you for this educational video. I learned something new.

[@sumitdagar9806]

Excellent explanation, thanks for such a great video.

[@gargigupta472]

Couldn't have been any better

[@trumpsmarkethack5676]

2:40 So how is it at this point we are able to see Mars move across the background which are fixed stars when the Earth in your model is now facing another portion of the Stars which is not possible for us to see being as Mars is now well behind us in the Nights sky?

[@chrisbahnsen7551]

Excellent explanation. These times and angles are averages. Thanks to stellarium's ephemeris tool, I noted vast discrepancies with Mars. During favorable oppositions when its closest to the sun in its orbit, retrograde time can be as short as 59 days and as great as 81 during "far" oppositions. I'm guessing its span is affected by its orbital speed. Favorable oppositions (July-Oct) when Mars is moving faster and closer to the orbital speed of Earth have 10 degree loops while unfavorable ones (Jan-April) where Mars is slow and far, we whiz by and it has loops as big as 19.5 degrees. Only elliptical Mercury has a similar effect of spans vastly varying. Her method is very accurate for more circular orbits such as Jupiter, where I found a period at 116-125 days with no span changes.

[@lucydyer6309]

this is great explanatory regarding retrograde motion. thanks

[@davidosmond5965]

I really enjoy the model that you made to demonstrate this system. Starting at 2:50. Do you happen to know the gear ratios? I'm interested in making one.

[@pressaltf4forfreevbucks179]

Tha ratio is probably the same as the ratio of the periods of the 2 orbits.

[@mamatheshkumar5711]

planets have 360 degree wobbling along the plane of revolution.

[@billgarrity6720]

Excellent demonstration.

[@fredastrology]

Thank you for this amazing explanation! I'd like to have your permission to embed this video on our website. :)

[@AgungTendaChannel]

good video thanks for sharing..

[@angelcastro1707]

Nice Model and explanation. Thanks!

[@bhajan2011]

That was well explained. Cheers major. Gen Harry

[@YelenaIzKislovodska]

great demonstration. helpful on the journey of learning about history of astronomy^^

[@erykczajkowski8226]

Didn't Einstein establish that all movement is relative and depends on frame of reference? Then how can you say that the ptolemeic system is wrong? It is an accurate description of retrograde phenomenon, just using a different frame of reference. Not the simplest one, but still working.

[@savoryseaweed495]

Because the planets don’t move in an epicycle

[@kmorendha]

Just great! I hope now someone could connect this phenomena with astrological explanation. Thanks indeed!

[@Sama-zd4nb]

very great explanation of retrograde motion!

[@PerimeterPermaculture]

please demonstrate why Mar's retrograde period is variable. It is not always 72 days. It's angular loops size also changes.

[@rickkwitkoski1976]

Because all planets orbits are NOT circular. The are elliptical. So there are times when the two ellipses, earth and Mars, are closer together and then farther apart as earth passes Mars. Watch this again and think of Mars being closer to earth at some points, and then father away, like the unnamed planet that was shown, so the apparent retrograde loop is smaller.

[@lesdell]

@@rickkwitkoski1976 That is not a demonstration sir.

[@chrisbahnsen7551]

It has to do with its eccentric orbit. Looked through ephemeris on stellarium. Ranges from 59 days during perihelic (close) oppositions to 81 days in bad aphelic ones. My theory for the change in retrograde span is due to changes in orbital speed of Mars. During its perihelion and favorable oppositions, it moves faster like a skater almost going your speed so it doesn't retrograde as far, as low as 10 degrees, inversely during aphelic oppositions, even though parallax should make it smaller, Mars is traveling MUCH slower, allowing it to appear to retrograde vastly, as much as 19.5 degrees.

[@hemendrgupta1681]

very beautifully explained!

[@lionellee4216]

For retrograde motion to take place, Mercury has to orbit slower than Earth. But isn't Mercury's orbit the fastest in 88 days? In all the visuals in the video, Mercury's orbit is shown as further out from the Sun but that isn't true right?

[@ageofagesworldteacher7939]

Outstanding presentation 👏👌👍

[@RaghavBabbar]

Very interesting, so I am guessing it's kind of similar to how we think that other vehicles are going backwards when we overtake them, except the effect is caused because apparent position of the planet is different from what it actually is, all a matter of perspective

[@lakhanshahi3637]

Great information vedio. Thanks

[@cakewaltzing]

Very good 10/10 but how does this work for inferior planets like Venus or mercury. Would it actually be considered Earth in retrograde in relation to them? Because earth has a longer orbit? Additionally could we even see mercury or Venus in this retrograde period? Or would it be during the day. I’m going to look all of this up in a couple minutes lol I’m just stating my questions here

[@rickkwitkoski1976]

No. Mercury and Venus both are seen in retrograde but neither of them go past the earth. Each only gets so far from the sun and then goes back the other direction. From either of them, earth would appear in retrograde as Mars and further plants appear to be from earth.

[@pawanagrawal652]

Thank You so very much God Bless You

[@liber8r]

Great demonstration!

[@eileensmyth5250]

This is great but it's too bad you didn't do a second demonstration with the model, showing smooth motion that doesn't stop. Studens usually need to see things more than once. (You could edit it in, even now.)

[@bohol_netherlands]

Absolutely great video. However I looked many times at the last graph and still don’t get it. Why are the t=121 days positions of Earth, Mars and Jupiter projected as the position on the celestial sphere at t=0 days? It just doesn’t make sense to me. What’s the explanation or is this a mistake?

[@althecowbow6405]

man why wasn i taught that in school. this super interesting! the model is really cool!

[@reggaetyro9659]

Try turning that flat disk motion explanation into a 3D explanation.

[@sindhujaalagarsamykalidoss7488]

Thankyou for very thoughtful explanation. Although this makes me wonder what if the movement of the other planets like Saturn or Jupiter which seems to be normal may actually have retrograde motion.

[@saidyacine]

a very useful movie I am grateful thanks

[@SnehaChavan]

What about interior planets? Does the same logic apply like mercury went in retrograde yesterday 9th September 2020.

[@rickkwitkoski1976]

Not quite

[@Infinite_curiousity]

thank you for this explanation! It was very helpful.

[@trapOrdoom]

Wow, you killed that shit, perfect explanation.

[@directortele-iirdso166]

Nice and understandable expiation.

[@martinb174]

SO SICK!!!

[@daem3n]

Great explanation!

[@theedspage]

Thanks. I shared this video on my social media accounts.

[@ElevenDollarCheese]

Thank you. Well done.

[@chucknorris5680]

This shows half of Earth's orbit around the Sun, but what about when Earth is on the other side of the Sun? Shouldn't Mars or other planets disappear between us and the Sun at some point?

[@JoseBarbosa-gv2mr]

They change facts to fit the theory.

[@noodoo19]

+Chuck Norris At 2:31 she talks about Mars being at "opposition," which is when the sun, Earth and Mars are aligned with Earth in the middle and Mars on the opposite side of us from the sun. When the Earth is aligned with Mars having the sun directly in between them, i.e. with Mars on the other side of the sun, that is called a "superior/solar conjunction" at which point Mars is blocked from the Earth's view for a couple of weeks roughly every 2 years.

[@Even-Rays]

Thats fantastic Richard Fitt. But a greater problem appears unexplained that at if we take a point on the earth orbit to be the start point for that time it takes to go round the sun at a point quarter-way on the sun should be hidden towards the southern pole ifthe planet retains its north direction else the polar star should rise above to the equator

[@ZeroThree31]

Yes. They do disappear.... not sure what you're asking

[@TheDestineyAngel]

You guys are unbelievable. When Earth is behind the Sun but Mars is in "front" of the Sun, you should be able to observe Mars during the day and not at night. If you don't don't believe me then do what astronomer in the video did, make a model, and see for yourself. If your last objection is, the real sun is too bright for Mars to be fully visible during the day, then you will realize why we don't see many stars during day or maybe God wasn't want to you to see the stars because you're unworthy for heaven.

[@ketanvagadia]

Great Illustration... Jai Ho!

[@familyshare3724]

Retrograde is what we observe when we ride the "spinning tea cups" at an amusement park. It's a "real" phenomena, when both the observer and observed are both in motion.

[@mr.washingtonsbuddy.8454]

IMPORTANT! All of this is in relation to the STARS, not the Sun. If you take a picture, say at midnight, each (solar) day facing the same direction (in relation to the horizon) you won't see the retrograde motion of the outer planets (also in relation to the horizon) because they are mostly far away; you may notice them slow down or speed up a tiny tiny bit, but they will still go westwards (in the sky) each day except for Mars, which speeds up and slows down quite a bit (but never moves eastwards) since it is closer. You can, although, see the inner planets move East in the sky each day when the Sun is more or less between them and Earth.

[@briciolaa]

ah, then i didnt get it at all ^^" how do i see the outer planets going "retrograde"? like, irl, where should i look? do i choose a star or constellation and take pics based on that one? :D

[@mr.washingtonsbuddy.8454]

@@briciolaa Exactly. Choose a star/constallation that is relatively close (in the sky) to the planet you want to track and stick to it. Take a picture of that one sidereal day (23h 58 min) from one another and you should see the farther outer planets' retrograde motions against the static starry background. Planets usually move East in relation to the stars. Retrograde motion is when they start going West in relation to the stars (any star other then the Sun, that is). In the original comment I said not to use the Sun as reference, since it moves around 0,98° to the East each day in relation to the other stars. Since you'd be using the Sun as reference, in each day's picture (one solar day from one another, since the Sun is the time reference here) you'd see the Sun in the same spot, but the stars and everything else moving at 0,98° degrees to the West per day. This makes it hard to see the retrograde motion of the outer planets, since (in relation to the Sun!!!) everything already goes West in the sky (except the Moon -- the Moon goes to the East both in relation to the Sun and the other Stars -- and the inner planets, Mercury and Venus, when the Sun is in between Earth and them. Also, keep in mind we're talking about a day-by-day observation. If you were to take a picture of the sky, say, every hour you'd see everything -- no exception -- going West, since the rotation of the Earth is so fast relative to everything else in the sky). What I'd recommend for a better understanding: download SkySafari, choose a location close to the Equator line in the settings. Then find Saturn (just as an example, could be Jupiter too, if you want), find a star very close to it and select said star. Then go to the "selection" option and choose "center object" (this will make the star you chose as your anchor point, your reference. Now go to the "time" option and highlight the day of the month. Now tap the "fast-forward" button. This will show you the sky every sidereal day. Notice that the Sun goes to the East with each step. Saturn will also go East, however, it will start slowing down and then go West for a little while. I can make a video on it if you want me to.

[@mr.washingtonsbuddy.8454]

@@briciolaa I can make a video on it if you want me to. I always wanted to make a video about that anyway.

[@mr.washingtonsbuddy.8454]

@@briciolaa please say yes

[@briciolaa]

@@mr.washingtonsbuddy.8454 thank u so so much for explaining!!!!! also yes of course, id love to see a video on it explained by you!!!

[@margaretsharp1430]

This makes it easy to understand the superior planets retrograde but what about, Venus?

[@TheDestineyAngel]

Margaret Sharp Earth has retrograde motion relative to Venus. And relative to Earth, Venus has phases almost like the moon except venus doesn't have either a full moon or new moon phase because the sun is between, so probably full moon Venus doesn't a thing and new moon Venus is the alignment of the sun, Venus, and Earth. Again I'm not to sure because inferior planets are less looked at.

[@White-Devil666]

Very well explained! Thanks

[@andtherefore8076]

Thank you so much, such a great explanation ❤️ Very helpful for my astronomy olympiad

[@josephpeter6796]

BRILLIANT !!!

[@manzell]

I racked my brains forever thinking about why this happened, until I realized that the movement is only retrograde to the background stars - not local midnight.

[@sharroon7574]

Great video

[@mayankshuklaiitdh8207]

very brilliant explanation

[@sabarishp9945]

Is there any software available to see the movement of other planets seen from the earth. (the top view)

[@chrisbahnsen7551]

Desktop stellarium has an ephemeris feature that allows you to see the apparent spot any planet and/or asteroid is in through a time period you pick, so you can trace its path.

[@OAlchemAzyl]

Great video thanks, I love science it’s far out👌

[@15_year_old26]

thankyou sensei

[@RoyaltyFam-nu7ol]

I got the answer right. Even tho it wasn’t because the same reason but I’m so happy and glad I got it and understand it 🎉🎉😊💜

[@mathewj11]

Thank You

[@murtiaji]

good explanation

[@magadhtaxashil8326]

completely Excellent video

[@chanduchilukuri4902]

Nice explianation

[@Vishnu_Vishnu555]

Good explanation

[@premabaul7570]

I'm with Ptolemy on this one.

[@GeorgChristophLichtenber-jg1zr]

Planets are wandering stars and consist of plasma, they are driven by the earth's electromagnetic field on their electromagnetic orbits (Van Allen belt). The so-called planetary loops occur because the stars are trapped in a magnetic bottle and collide with their own magnetic mirror during their orbit and only then pick up speed again. The earth is the center of the universe and stands still. It is extremely instructive to look at a fusion reactor in plasma physics, then you will understand it better. He didnt know electromagnetism back then, but I think he was right.

[@throwawayavclubber7269]

lol @@GeorgChristophLichtenber-jg1zr

[@AminAmin-wn4fr]

This is crazy

[@aivelu2737]

Why Does mars takes longer time to retrograde than the other outer planets?

[@ojas3464]

👍

[@acprtyler9564]

Bravo!

[@RiyadhAlDuwaisan]

Thnx 4 sharing

[@davidpearlman6631]

Got it. Thanks!

[@pablosdog2808]

Three body problem?

[@Science_sachet_9710]

Beauty

[@satyaallidona]

Indian rishis (saints) said about retrograde motion of planets before thousands of years.

1:34 I'm amazed at how he got that model, it is incorrect, but genius

[@VicDiCaraAstrology]

"completely wrong"? the "ptolomy" system explains retrogression as an artifact of the planets simultaneous apparent orbit of the earth and actual orbit of the sun. how is this "completely wrong"?

[@trumpsmarkethack5676]

2:40 your model is flawed as the Earth and the Night sky changes as it moves from right to left, but if we can look up in the sky and see Mars making its pattern is because The background of the sky Hasnt changed but in your model it shows otherwise.

[@anjoramma]

So helpful!!

[@knsb67]

210 degree, retro takes place for outmost planets.