How Do Astronomers Define Latitude & Longitude on Other Planets

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It took centuries for the people on Earth to decide on a common meridian to measure longitude from, but other planets also need everyone to agree about the origins of their mapping systems. In the case of the terrestrial planets a single bright spot was chosen in the early stages of exploration, and as maps improved the exact location is defined with increasing accuracy. For tidally locked moons the meridian is defined based on orientation relative to the parent body, but even then there’s a lot of room for improvement as data improves.
Finally some bodies are just not suited to spherical coordinated, because they’re not particularly spherical.

  1. minethree58

    you mispronounced mercury as venus

  2. Robert Regalado

    hi Scott
    do you think Starship has got a wide enough stance just in case the lunar surface or Mars surface is compacted enough to handle that much tonnage.
    so what doesn’t topple over

  3. ifell3

    Scott that video of the moon wobbling was stunning. My daughter is scared of the moon and i’m trying to get her to love it as it’s always changing. Got any good links of websites for planets and moons etc. Regards

  4. Reed Bowman

    Could you discuss the weird decisions about definitions of ‘above’ and ‘below’ the ecliptic and then galactic north and south? What I’ve been able to find on galactic coordinates make it seem not just arbitrary, but counter-intuitive.

  5. Live. Vibe. Lasers.

    (x, y, z) solved.

  6. Isaac Westawski

    Nice intro. Its like a quickley drafted spacex starship

  7. EauRouge

    Highly Edumacational, eh? Thanks!

  8. Chopstyx

    I think the Star Citizen developers need to watch this video. lol

  9. Woodworker Don

    How do astronomers define latitude & longitude on other planets?

  10. extreme blank

    Epic video, you earn subscriber!

  11. Tom Koller

    Very interesting. Thanks.

  12. Russell Vernon

    Is there someplace that has all these awesome visualizations?

  13. Chris Peart

    Scott these days when I see a new science/astronomy/space related video from you I press like as soon as it starts playing. You are that consistent! Thank you for all the hours of entertainment/knowledge/amusement and most of all, science. Fly safe 👏👏👏

  14. James Barclay

    So Venus has north facing in the opposite direction to Earth’s? I guess it causes less confusion than flipping east and west but keeping north and south in the same direction.

  15. Pintuxo

    You know, Scott, maybe one day we’ll have GPS on Mars. Great video of yours. Interesting to say the least.

  16. TheOneWhoMightBe

    I thought the Pluto flyover was the Quake 2 intro for a moment.

  17. videolabguy

    Fly safe? NEVER! Where’s the thrill in that? (Great video as usual!)

  18. Extraordinary Voyage

    I think IAU should leave these problems to the Royal Navy :)

  19. Mr MEMé

    I remember the landing of Viking 1 in 1976, and Seeing Patrick Moore talk about it on the “Sky at Night” ¡¡¡¡

  20. theShowman

    Ha ha, In just a few minutes in this (fascinating) video I was thinking; what is he going to say about the gas giants ?
    It’s got me thinking about this which is good. Great video. Thanks.

  21. Tomas Beblar

    “most intelligent people agree” shots fired

  22. B1 Laxson

    This spins me right round, right round like a planet baby…

  23. Paul Putter

    The space x starship in the beginning alone warrants a like!

  24. John Manderson

    Perfect video ! Thanks a ton. ✅👍🏻

  25. JAMES! Since the 70's

    Wow who’d thunk it! something so simple, turns out to be so complicated!!!.. I guess looking at a few pictures, trying to find motion (of a planet) can be difficult ..

  26. Dark Knighte Apologeticz

    That’s awesome. I can remember when I was working on a calendar for Mars (I’m gonna make a video on it), at one point I actually had to look-up the coordinate system for Mars. I did this, so I could attempt to propose a tentative timezone map for Mars. (This will be mentioned in the video, I’m working on [for my channel].) I really like Mars, it’s my favorite planet (after earth). Keep an eye out for my video, it’s a big upcoming project (for my channel). I liked this.
    Great video, keep up the good work.
    Have a nice day/night.

  27. Martin D A

    PS That was absolutely fascinating. Thanks.

  28. Savior NT

    I’d also like to know how we would set up a time/calendar for other planets so that we, here on Earth, can line up dates and times. Do we have some sort of “universal” calendar?

  29. Chris Holt

    Fascinating! Thanks Scott!

  30. Deadzio

    I don’t have a clue what Scott is talking about, but still interesting :D

  31. Helium Road

    As if the whole Pluto controversy couldn’t any dumber, the seemingly minor semantic change of classification prompts a huge shift in coordinate system, upsetting all mapping work to that point, because common sense isn’tcommn. SMH.

  32. zanderboy

    Before I watched this I assumed they navigate using the time, Daneb and Phobos as per the Martian

  33. TheFLOW1978

    Thank you, great topic.

  34. Hans Isbrücker

    What if we use a more dynamic system for gas giants: the line perpendicular to a straight line from the Sun to that planet.
    For the Sun we could define the meridian as where the Earth is at the moment 🤔

  35. JB Alien

    Hi. Thank you. This is the first time that I ever heard of an astronomical object that was named after, something from the Meso-American culture. Hun KAL. Hopefully, ill forever remember it. Thank you.

  36. Dave B

    Believe it or not I was actually thinking about this recently when looking at some of the beautiful planetary Globes available now.

  37. Kyle Brown

    like the new intro :)

  38. vima78

    nice new intro !!

  39. Mark Warbington

    I’ve been following you for a while and this is probably your most informative video yet. Tons of stuff I didn’t know. Great job!

  40. BuLLeT_ZA

    Space cartography. Love it.

  41. Biliary Clinton

    Thanks Scott (for the imagery).

  42. James Dubben

    Thanks, been wondering an about this

  43. C Rodriguez

    Was literally going to ask this question so its amazing that you can read minds LoL

  44. ThirteenthAndy

    Already earned that “like” just based on the new intro animation!

  45. efrandsen72

    Scott’s new rocket for intro:

  46. John Długosz

    _All_ the moons? My first thought is *Hyperion* .

  47. p4p3rm4t3

    Low key one of your best videos.
    A scene in The Expanse where someone explains how The Belters map rocks would be cool.

  48. IN A FLASH

    I like that starship intro

  49. Nico D. Sun

    Future Astronomy exam: Define latitudes and longitudes for a thick pancake.

  50. Faustin Gashakamba

    The time-lapse animation of the moon is awe-inspiring. It seems dancing for us…come to daddy!

  51. Jack N. Larocque

    Love your videos, this was mindblowing, never really taught about this.!. 🤯 Keep up the great and Interesting work, Bet I’m not the only one wanting more! 🇨🇦😁👌

  52. Scout Combs

    Thanks, Scott, you’re the best


    Another good one. It is amazing there is this level of agreement on the details among the members of our species.

  54. NorthernChev

    Oh! The very subtle, Scott Manley-style slam of Jim Bridenstein! I saw what you did there, Scotty… Noice

  55. RufftaMan

    Just when I thought there will be an explanation how to get a consistent system for contact binaries and such, the video ends. =(

  56. Iron Man

    Love the into, Scott.

  57. Slikx666

    A very interesting question followed by an interesting answer.
    Thanks Scott.

  58. Christopher Schuster


  59. Philipp Maas

    Hey Scott, i´m visiting Los Angeles in November, can you recommend a good pub where i could by you a beer? :)

  60. cowthedestroyer

    “Google earth” hmmmmmmmmmm

  61. Anarchy Antz

    I knew the Moon wobbled but seeing it like this for the first time was really cool and rather hypnotic.

  62. Anthony Calleja

    I love how Scott Manley says “hwere” “hwy” “hwen” etc… a bit like Stewie’s cool “hwip” from Family Guy. Mr Manley if you are reading this say “Cool Hwip” in your next video! Greetings from Malta!

  63. Agent XX302

    Hey Scott, would you fly with Bombers Bar ?
    We would love to have you join us for an evening :)
    Fly safe o7

  64. Peter Hobelsberger

    Starship intro! Awesome :D

  65. Lulu 1266

    Such intelligent content! This was really interesting and so well explained. Thank you Scott – great vlog!

  66. dosmastrify

    Coords needed to fly safe!!

  67. Silvia Rodriguez

    For objects like Ultima Thule I propose that Americans use one system, while the rest of the world uses another system.

  68. Bitchute is better than Youtube

    Fun fact, if a planet doesnt have Greenwich it sucks :P
    Also surprised you didnt mention there was a vote on where 0 would start, Dutch captains etc i beleive voted and since London/UK was the centre of trade they decided it would be most useful to have time “start” from there.
    Unless im completely wrong but thats what i heard and have remembered.

  69. Why

    Love the intro! And the topic which I didn’t know I wanted to know about but now I’m happy I do.

  70. QuantumBraced

    Love the new intro with Starship

  71. tau124

    4:31 Radar was able to penetrate the clouds.
    Someone tell this to the Indian Prime Minister!

  72. John V

    7:56 The most “intelligent” people :))

  73. NayZabeth1

    The story of 4 Vesta’s prime meridian is an interesting one, since the Dawn mission team and IAU did not really agree on it.

  74. FandersonUfo

    Thanks again for answering so many questions so clearly and efficiently.

  75. TheRecreator

    7:50 love that Pluto visualisation, never seen it before. Is the bumpiness 1:1 or is it exaggerated?

  76. Islacrusez

    1:35 other left!

  77. MottyGlix

    5:34 * ” … entire planet of Mercury.”

  78. Butter Johnson

    I wondered this a few weeks ago. I’m glad you helped us out with an answer!

  79. Kevin Moore

    Did you just mispronounce “Mercury” as “Venus”?

  80. survivaltest 370

    2:05 “these craters are kinda large and they move a little”
    What??? I’m incredibly confused rn. I thought mars doesn’t have plate tectonic (sry Google translate)! Why do they move? I’ve never heard of moving craters.
    Or do u just mean that bcs of sand storms etc they shape changes? Please explain!

  81. humanhiveanomaly

    @5:34 correction, you mispronounced “Mercury”.

  82. feha92

    The early martian observers? I knew it! Area 51 has martians that told them where the meridian is! Too bad he forgot his phone in there on the raid.

  83. Sean McDonough

    9:51 – It’s pretty easy to get them to agree on where an object is. The hard part is getting them to agree on what to call the location where that object is.

  84. ashwin shukla

    You sir are a true gem of YouTube. I have watched so so many of your videos, have learned so much and more important have dared to wonder. Thank you for everything, live long and prosper and as always fly safe

  85. justin h

    2:00 the large craters move a little?.. Can you explain?

  86. Ryben Flynn

    They threw darts at a wall size picture of the planet’s surface. “There! That’s Zero Longitude!”

  87. Sean McDonough

    7:41 – Of course, the truest measure of a gas or ice giant’s rotational period would be the rotation of its solid core. Bit tricky to measure, though.

  88. ADR

    A question I never knew I wanted an answer to.

  89. Sean McDonough

    5:33 – Although _Mariner 10_ *did* fly by Venus as well, I’m assuming you meant to say “Mercury” there.

  90. Tom Chan

    7:57 “Most intelligent people agree that it is a dwarf planet”
    Shots fired at Jim 🅱️ridenstine

  91. CMDR Terrorfirma

    I wondered this ever since we had planetary landing in Elite: Dangerous. How do they pick the zero Meridian on all these never before visited bodies.

  92. Kasual Steel

    The deepest dive into the tallest weeds, ever.
    LOVE IT!

  93. ot0m0t0

    I stack my pancakes differently.

  94. Martin D A

    Navigation at sea was a perilous occupation before Harrison developed the marine chronometer. It was not captains of ships, but owners of shipping and the cargo they held along with the lives of many sailors lost too. It was a big problem and the British government offered a prize of £20,000 in 1714 to anyone who could solve the longitude problem and allow safe passage for shipping. Dead reckoning was the only way sailors could position themselves for longitude. The latitude was easy. Pertinent to all navigation that followed the keeping of precise time was the answer and the true miracles of the age came in John Harrison’s timepieces. Long before that Delorean..
    There are many great stories surrounding the longitude prize and the chronographs including the fact that K1 the first copy of the priceless original H4 went with captain Bligh on the Bounty. The watch was stolen by the mutineers who discovered Pitcairn Island had been wrongly charted. They could only know this because of the watch… The line of longitude runs through the Royal Greenwich Observatory, which may be even more pertinent to space travel.

  95. ImBarryScottCSS

    Obviously they look for a landmark that looks like jolly old England and start there…

  96. TheoQuazar

    You forgot the most important body of them all, the sun! If a sun spot appears on a particular quadrant, how do they precisely say where it is for the ever roiling surface of the sun?

  97. Space 2123

    1:55 Everybody gansta till the meridian crater starts moving

  98. The Virtual Scotsman

    When the object is small enough to be made out of two lobes, its small enough to realistically model in 3D programs. On an object like that id suggest you use the two furthest points away from each other. Make that the x axis, the next largest the y and then perpendicular the z. As maps are used to make a 2d representation of a 3d body. When the object is this small, we can afford to make it 3d instead

  99. Tea_Wrecks

    There’s something fantastically ominous about watching the moon wobble about like that at 2:49

  100. randomnickify

    aaaand I’ve never saw moon’s wobble before, good addition Scott.

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