Mercury retrograde, explained WITHOUT astrology

By | August 15, 2019

You may have heard that Mercury is retrograde
again. But if you try to find out what that means,
search results are dominated by astrologers who believe Mercury can make you spill coffee
on your favorite shirt or cause your car to break down. But if you set aside all those creative interpretations,
there’s actually a real astronomical phenomenon underneath. So let’s start with the basic layout of
our solar system. The planets closest to the sun move faster
and the outer planets move slower, but they all go in the same direction. “Apparent retrograde motion” is when planets
appear to temporarily change the direction of their orbit. They don’t change direction, it just looks
that way from Earth. It’s an illusion that unfolds over a matter
of weeks or months. In this image, Mars was photographed every
5-7 days between October 2011 and July 2012. Once all the photos were combined by aligning
the stars in the background, it appears as though Mars looped back on itself before continuing
on its orbit. A retrograde illusion happens when we lap
an outer planet, like we do with Mars every 2 years, or when an inner planet laps Earth,
like Mercury does every 4 months or so. But for both Mercury and Venus, the illusion
is hard to actually capture since they’re located on Earth’s day side, not our night
side. When those planets are visible, it’s only right
around sunset and sunrise. But assuming you could see it, here’s a
diagram of how the Mercury retrograde illusion would work. This line shows our view of Mercury against
the background stars. As Mercury passes us by, our line of sight
shifts so that for about 3 weeks Mercury will appear to loop back on itself when viewed
from Earth. It’s simply a function of two objects orbiting
in the same direction at different speeds. If you stood on Mercury, you would see Earth
make an apparent loop too. I wanted to recreate this illusion on a tabletop
so I stuck a post-it note to the wall in the background to represent the fixed stars. I grabbed a ball of play-doh to be Mercury and my phone
camera is Earth. I took 10 photos of them orbiting in the same direction with Mercury
passing by Earth. If you simply view the images in sequence,
you don’t really see the loop, but remember, the illusion is relative to the background
of fixed stars. So once you line up the images so that that
post-it note star is fixed, the retrograde loop appears. Here’s another visualization of the retrograde
loop of Mars as Earth passes it. The bottom part shows the positions of the
planets and the top is the corresponding view of Mars from Earth. The key is to always remember that Earth is
moving too. So retrograde motion was baffling to early
astronomers who thought that Earth was stationary and at the center of the solar system. In the 2nd century, Ptolemy devised a complicated
system of loops and orbits within orbits to account for the apparent retrograde motion
of planets. That model was accepted for 1500 years because
it seemed to fit the observations, even though it was completely wrong. Once Copernicus showed that all the planets,
including Earth, move around the sun, then then retrograde motion was easily explained as
an illusion. So if there’s any life lessons to learn
from Mercury retrograde, it’s that we may be vulnerable to illusions
when we think everything revolves around us. It’s really frustrating how misleading the scale is on every illustration of the solar system So I feel compelled to point out that the real distance between Earth and Mercury, when those planets are closest together, is more than 6,000 times the diameter of Earth.

100 thoughts on “Mercury retrograde, explained WITHOUT astrology

  1. Capt Danvers Post author

    When Copernicus said the Earth wasn't the center of the universe he was actually murdered by the church.

  2. Ismael Soum Post author

    Or maybe the illusion is that everything does revolve around us, we just aren't seeing the full picture

  3. Mike JH Post author

    It has to be said, though, the man who really showed that the planets orbited the sun was Johannes Kepler. For some reason he's not as well known, but neither Copernicus or Galileo could get their Heliocentric systems to work properly because they both insisted that the orbits were circular. As a result, their predictions of planetary motion showed errors of a similar magnitude to those that had made them doubt the Ptolemaic system in the first place. Kepler was able to show that if you modelled the planetary orbits as ellipses rather than perfect circles, the errors disappeared.

  4. Dawn Tavish Flynn Post author

    This is the first straight answer I've been able to find that explains what "retrograde" actually means, so thanks

  5. Camila Ruiz Post author

    The ending phrase !!!!! Wow. I am now subscribed.

  6. kimberly miller Post author

    Bad things happen in retrograde because people think that bad things happen in retrograde. Your thoughts come back to you positive or negative.

  7. Diggity Daws Post author

    More videos like this please! (And less about identity politics…)

  8. My Life As A Human Post author

    It’s sad that people are closing themselves to the idea of spirituality and astrology. All that is real

  9. German Roads Post author

    Dont mind me, i am only here to see if any flatearther has a explaination why this couldn´t be ´cause earth isn´t a sphere.

  10. Forugh Esmaili Post author

    My husband spilled coffee on his shirt today, lost his backpack, found it again to spill beer on it, later I spilled a drink on his hand and shoes! Mercury in retrograde or not, we are one messy couple.

  11. Stealthy Sloth Post author

    Who's the beautiful woman? Oh.. Joss Fong. 😀

  12. Krystina Saragos Post author

    This video is for art, English, and History majors. I don’t fit in on any of those and I still don’t get it. ??

  13. Video Graham Post author

    "Astrology" otherwise known as "con artistry"

  14. Alien Gamer127 Post author

    Seriously do a video on the history of hot cross buns

  15. Duane Hanselman Post author

    Is there anything that can be explained by astrology? I am certainly not aware of anything in science that can be explained by it. Astrology has only proven to be a way to make people part with their money.

  16. aryan bhaskar Post author

    When astrology was dissed right in the last line…

  17. Cesar Carbajal Post author

    As a Tarot Card Reader, I love seeing stuff like this. Educational and insightful. I appreciate!

  18. Petitio Principii Post author

    484 Gemini people have disliked the video.

  19. Ahtziri Sanchez Post author

    Thank you so much for this! I’m tired of all this astrology bs

  20. The Quantum Nerd Post author

    It’s not astrology, it’s complicated science.

  21. MasJoko Post author

    mbak joss ini udah cantik, pinter bangatt… hhhh makin sukak deh

  22. beau danner Post author

    Omg… Thank you SO much for explaining that 🙂

  23. CrisMelo DotCom Post author

    Sciancetists don't remind people that they can only access a smallish part of knowledge. They can't touch anything metaphysical so they try to find humor in that by discounting other sources of knowledge as invalid. "Creative" is also what the first person ever that indicated the moon and sun may have an influence on tides on Earth was called. Creative. lol

  24. artur ferreira Post author

    well only yesterday i broke my new television, ruined my wall’s and celling’s paint, broke a glass container and then cut my finger… well after all this i decide to relax sunbathing… the chair broke itself…

  25. Emika Ervin Post author

    me getting my purse and car key stolen: "mercury is in gatorade :("

  26. Joseph Malan Post author

    I love your work! Keep up the excellence, Vox!

  27. lol Post author

    finally, an explanation of this that isn't something like "rEtRogRaDe MeAnS iF Ur A LeO yOu WiLl Be DePrEsSeD fOr 3 wEeKs" or some other bs

  28. lazy Guitarist Post author

    For 15000 years humans thought earth was the center of the universe…


    were not ready for time travel

  29. ᏚᎻᎪᎻᏆᎪ ᏴᎬᏞᏙᎪ Post author

    "explained WITHOUT astrology"
    THANK you may i buy you a gift

  30. Carbonoid1 Post author

    Thank you for the explanation I love learning and clarification!

  31. Gage GoSkate Post author

    You had me at “without astrology” and also that passive aggressive ending was so good and subtle. 10/10

  32. Astrid Pinel Post author

    She imported each file individually to after effects and then manually cropped its time duration…. when she could've simply imported the footage as an image sequence and then adjust the playback speed. ??why couldn't the editor of this video help her out on that?! it could've avoided her so much painstaking cropping ??

  33. LAB-Lil' Angry B!tch Post author

    I hate Mercury Retrograde, what an awful time to be alive.

  34. Alex Cope Post author

    This video was awesome and super informative but I would have cut the tabletop demonstration. IMO more confusing than helpful

  35. Mike Smith Post author

    OMG Mercury is in Gatorade and I’m an asparagus which means this week is gonna be super challenging for me

  36. bennemann Post author

    How can there be people who actually believe that the planets are in on some evil plot to make them… spill their coffee? I would have imagined it took a rare combination of extreme egotism AND paranoia to even consider something like that, but apparently I'm giving humanity way too much credit…

  37. Vegan Buddhist Post author

    Is this right? Im pretty sure retrograde means it changes the direction that it rotates on it’s axis. Most planets turn counterclockwise and when retrograde it goes clockwise

  38. Mace Windu Post author

    Who doesn’t believe there is at least something behind astrology is pretty ignorant. we humans, during all ages, watched the stars and reoccurring patterns to draw conclusions to our own cycles. We simply don’t remember the archetypal origins

  39. 102030405060 Post author

    when you click on the video thinking it’s a ghostmane video

  40. daya morales Post author

    I hate astrology. And especially after taking astronomy classes in college and debunking/destroying all astrological claims, I hate astrology even more haha.

  41. Keep it Short Post author

    Key : it's not just motion, it's relative motion. Time Bends but only on relative scale. Einstein was right.

  42. Diego Maugeri Post author

    Oh, com'on! Mercury is retrograde because he is the messenger of the gods and has to go to and fro among the other planets. Duh!
    You are welcome.

  43. ssplintergirl Post author

    Dear religion and cults, please stop making people blatantly ignorant

  44. The Foxfires Post author

    Joss is my absolute favorite host. She always breaks things down logically but in a fun way!

  45. III Post author

    more and more i see signs that this is a simulator..we've gotta decode this, maybe we werent designed to know the game, but have fun in the mystery surrounding it, the journey, connecting the dots..which has been interesting, but id rather just know now so i play the game & win, or some cheat codes.

  46. III Post author

    ..since its just an illusion of reverse movement, not gravity or some other force, then why i run into people from my distant past every retrograde, or mail delayed, computer suddenly slow, but some positives too, anything re- tends to go well

  47. III Post author

    …i get how the moon affects gravity pull and behavior here, but the mercury illusion wreak so much havoc, consistently, by just the appearance of reverse..and we aren't even observing it, so what is?

  48. meesalikeu Post author

    great job you only vocal fried at the very end, which is unfortunate and will date this clip to its era, but otherwise well done explanation here.

  49. Kain. Post author

    We are vulnerable to illusions when we think that the world revolves around us

  50. IsuckharderthanLife Post author

    What's truly twisted is the extraspecial unique individuals who live the illusion of the universe revolving around their ego convinced themselves that their ego revolves around their illusion they call "truth".

  51. jeaniebird Post author

    0:32 I thought Venus went the other direction? Isn't it the only planet that does? Or is it it's rotation on it's axis that's backwards?

  52. jeaniebird Post author

    Oh! No wonder it seems as if Mercury is constantly in retrograde!

  53. SpenceRina Post author

    “We may be vulnerable to illusions when we think that everything revolves around us”

  54. EARTH IS seriously FLAT Post author


  55. Sandra Keddy Post author

    thank the lord for this. mercury retrogade had me thinking it was some kind of 80s party.

  56. lizzi Post author

    It is always a bad idea to enter the comment section.
    Lack of logic.

  57. Aras 9volt Post author

    This is like swimming in a pool without water

  58. onorebakasama Post author

    The animation of the orbits at 1:26 was just the visualization needed to spell out how the apparent retrograde motion works for me. Excellent video.

  59. Anaya Chanel Post author

    Same phenomena with car tires and spinners lol

  60. Figo Fig Post author

    just everyone knows, astrology preceeds astronomy , ouch

  61. Esperanza Macias Post author

    So does the ending statement mean astrology isn’t real?

  62. 7656869940 Jessebaldwin Post author

    let's spin the ball this new year

  63. Alcocer Christian Post author

    Copernicus did not "show" the Earth orbits the Sun; he had a very strong theory that Galileo proved much later. (Galileo provided very strong evidence, based on his observations with recently-developed telescopes and his analysis.)


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