Gettin' high on the Moon

By Phil Plait | November 3, 2010 7:03 am

I live less than an hour from some spectacular Rocky Mountain peaks. The view from up there is always magnificent, and when we hike we’re always curious about just how high we are. 11,500 feet? 12,000? That knowledge isn’t necessarily useful, but it’s fun.

Hiking in the Moon is a different matter. How would you know how high up you are? Well, if you had the elevation data made by the the Lunar Reconnaissance Orbiter you’d be all set, because then you’d know that if you were at a latitude of 5.4125° and longitude of 201.3665°, you’d be on the highest spot on the Moon!

LRO_moon_highestpoint<br clear="all".

[Click to enelevate.]

See that red arrow? That's the spot. If you stood there, you'd be 10,786 meters (35,387 feet, about 6.7 miles) above the average lunar elevation*.

Funny, too: as soon as I saw that, my first thought — after wondering just how high up it was — was how steep the slope is there. Turns out the LRO folks wondered too, and found that a hike up to that point wouldn’t be very taxing, since the slope is about 3°. That’s a 5 meter rise for every 100 meters hiked. I do some hiking here in the Rocky Mountains, and that slope wouldn’t be too tough. On the Moon, with 1/6th gravity, it would be a snap.

Of course, the air is a bit thinner there.

According to the LRO page, this region of the Moon has such a high elevation probably due to the monster impact that formed the 2500-km-wide Aitken Basin at the Moon’s south pole. The debris piled up all over the place, and near this position would’ve been tremendous. Imagine! Several billion years ago, an asteroid perhaps 200 km (120 miles) across [200 kilometers across aiiieee!!!] plows into the Moon at a speed 30 times faster than a rifle bullet. A huge hole is excavated, and all that debris has to go somewhere. Even on the lunar equator, 2700 km (1600 miles) away, ejecta material falling piles up to depths of 10,000 meters! Incredible!

Still and all, I was trying to think of some sort of scientific use of knowing where this particular point on the Moon is. I’ll be honest: I’m not sure there is one. I mean, sure, having elevation maps is interesting and useful, and knowing where places have higher elevation can lead to insight into formation mechanisms and all that.

But knowing where the actual highest point is?

Well, maybe there isn’t scientific usefulness for it. But you know what? It’s cool. And sometimes that’s enough.

Image credit: NASA/GSFC/Arizona State University



* There’s no water flowing on the Moon, so sea level isn’t a useful standard. Instead, the lunar geoid is used; a sort-of average shape of the Moon using its gravity as a reference (go here and scroll down to #4). Getting this shape is really hard, and I imagine the laser altimeter on LRO will be used to refine the surface maps.

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures
MORE ABOUT: LRO, Moon

Comments (41)

Links to this Post

  1. Astronews Daily Ext. Edition (2455505) | November 4, 2010
  1. So, where’s the lowest point, and how long would it take to ski from “top” to “bottom”?

    And as soon as I saw your reference to “average lunar elevation”, I, too, thought of “sea level”.

    And, before someone asks why, with 1/6th the gravity, the highest point is “only” 74% higher than on Earth, I’ll just say two words… “plate tectonics”.

  2. Wow, I never thought the moon would have a point so high in comparison with the rest of the moon.

    I know you say there is no water and so no sea level but still: also no contenants running into each other or other crazy plate tectonics issues forming giant mountains right?

  3. UmTutSut

    Future lunar residents will undoubtedly print bumper stickers with the legend, “This Car Climbed 5.4125°/201.3665.” :-P

  4. The use of “average lunar elevation” versus “sea level” got me thinking…

    If one were able to flood the surface of the Moon with a liquid to the right depth, how close would the surface of the liquid match the “lunar geoid” being used to determine “average lunar elevation”?

    Or, for that matter, if the Moon were to be melted, how closely would it resemble the “lunar geoid”? (Don’t worry. We won’t actually melt the moon. We’ve set our laser to “stun”.)

  5. Isn’t feeding our hungry, nerdy brains scientifically useful? I think so.

  6. I suspect the elevation information would be useful if you were “flying” in a really low lunar orbit and didn’t want to smack into the ground at that particular spot.

  7. DrFlimmer

    Maybe one can use the spot as a future launch place for rockets, since the gravity of that particular spot should be the lowest on the moon. And, did I get that correctly?, it’s also not terribly far away from the equator, so the centrifugal force will give a slight kick, as well.

  8. Pete Jackson

    If they know the absolute height data at every place on the Moon, then it should be possible to generate how the landscape or ‘view’ would look if you were standing there. So, maybe someone can generate the view from latitude of 5.4125° and longitude of 201.3665°, and see whether you get a great view from this place. Horizons on the Moon are normally only about 1/4 as far as on the Earth because the Moon is only 1/4 the size of the Earth, but we should still get a decent view from the highest point.

    So this should be one of the ‘top ten’ spots for lunar tourism. Other spots I would suggest:

    Tranquility Base (Apollo 11)
    Hadley Rille
    Dark spots on Alphonsus
    Clavius Base (Clavius Crator)
    Sea of Moscow (Mare Moscoviense)

    anybody want to add some more?

  9. Messier Tidy Upper

    Wewll there are seas on the Moon actually – they’re called Mare (Maria the plural form – or is it vice versa? Too tired.) & they were seas of lava that have now cooled down. Don’t they count as Lunar “sea level” then? ;-)

    Several billion years ago, an asteroid perhaps 200 km (120 miles) across [200 kilometers across aiiieee!!!] plows into the Moon at a speed 30 times faster than a rifle bullet. A huge hole is excavated, and all that debris has to go somewhere.

    I wonder if much of it was ejected from the Moon and landed on Earth?

    “Several billion years ago” – could one of the earliest known mass extinctions be caused by this? Or is that too far back for life to have been beyond the bacterial stage?

    I think – but might be mistaken – that for the first half of Earth’s history life was just microscopic and oxygen levels were very low so maybe not?

    @8. Pete Jackson : anybody want to add some more?

    Sinus Irridium – the Bay of Rainbows

    Schroters Valley (spelling?)

    That Lunar natural rock bridge (forget exact name, sorry.)

    The last resting places of the Lunakhod rovers

    The Lunar poles with permanent shadow /sunlight craters eg. Cabeus

    The libration zone where Earth is permanently just rising / setting

    Copernicus and Tycho craters (where you can dig for TMA-1!)

    &

    The Whalers-on-the-Moon amusement park from Futurama ;-)

    ****

    PS. Count down clock now at T-minus 1 day 4 hours 53 minutes 55 secs for the penultimate Shuttle flight and discpvery‘s finale.

  10. @ Pete Jackson:

    Kuhnigget’s Lunar Spa and Resort. Bring your purple wigs and go-go boots.

  11. Messier Tidy Upper

    @ ^ kuhnigget : Boots in a spa? Umm .. okay. ;-)

    Guess we all weigh a lot less there so they won’t do too much damage ..

  12. @ MTU:

    Those who don’t like the dress code are free to spend their lunar holidays elsewhere. Might I suggest the Shepherd Links Golf Academy, just a couple of maria over?

  13. Messier Tidy Upper

    Dress codes fine with me – its your spa after all. Can we bring along some artificial wings? I gather you can fly under your own power in Lunar gravity! I’d love to try that. 8)

    Lunar cricket now *that* might be interesting too .. ;-)

  14. Messier Tidy Upper

    Add to the Lunar tourist sites list please this place :

    http://blogs.discovermagazine.com/badastronomy/2010/07/29/lunar-triple-sunset/

    The central peaks of the crater Bhabha where you see a triple sunrise & also this place :

    http://blogs.discovermagazine.com/badastronomy/2010/05/24/lunar-boulder-hits-a-hole-in-one/

    Which has to be the site of that Shepherd Links course surely! ;-)

    Plus this one :

    http://www.universetoday.com/73891/lro-finds-bridges-on-the-moon/

    Which I’m pretty sure the BA has blogged about as well but I couldn’t find via his site.

  15. Nigel Depledge

    MTU (13) said:

    Lunar cricket now *that* might be interesting too ..

    Yes, provided you don’t use a fast bowler – otherwise he might end up sending the ball into orbit. ;-)

  16. Nigel Depledge

    Pete Jackson (8) said:

    anybody want to add some more?

    Apollo 12 / Surveyor 3 rendezvous site

    Apollo 15 memorial lunar rover raceway

  17. nick flann

    When will the elevation data and the high resolution image data be combined so we can fly over the surface of the moon and visit some of our favorite places? I’d love to see what the view is like when climbing the mountains and traversing the valleys around the Apollo landing sites. Apollo 15 and 17 would be particularly spectacular.

  18. Spad31

    I just want to go. Good stuff Phil.

  19. Martin Hajovsky

    The Olde Course at Alan Shepherd Links?

  20. Matt

    Wouldn’t it be a “lunoid” rather than a “lunar geoid”?

  21. Tbird49er

    For reference, it would be interesting to know the “average earth elevation” (sea level is only an approximation we choose to use). Factoring in the very deep ocean trenches and Mount Everest would be more open for a “wow” factor, I presume. Does glacial and artic melting (that raises the sea level) raise “sea level” as used in our altimeters? Does a rise in sea level reduce the relative heights of our mountain peaks vis a vis sea level (or do they use atmospheric pressure to arrive at such distinctions)? lol A topographic map-makers nightmare! hehe

  22. Doug Little

    We always here about asteroids smacking into the earth but what would happen if a large one smacked into the moon instead? How large would it have to be to effect things here on Earth?

    Would be a hell of a show though.

  23. Keith (the first one)

    When I looked at the picture with the arrow, it played a trick on my eyes and I immediately thought, “that must be the lowest place on the moon”. It’s the whole hill or crater thing again.

  24. Chris Winter

    There’s no scientific usefulness for it yet. I imagine such will be found, when we are there.

    One obvious practical use is as the site for a radio communications base/relay. I calculate the repeater there could cover a circle of 193.9 km in radius.

  25. Grand Lunar

    I had no idea the highest spot on the moon was THAT tall!

    This isn’t the same as a mountain on the moon at that height, is it?
    Just asking, because I recall reading the moon’s tallest mountains were 3 miles high.

  26. Michel

    I love it how you have no sense at all of the hight. The red arrow only accentuates that.

  27. OK. Someone has to step up and be the pedant here, so it might as well be me.
    I could have told you without doing any research that the slope at the highest point on the Moon is zero.
    Knowing the slope up to it is interesting, though. Thanks, Phil.

  28. Keith Bowden

    Okay, ever since I read Phil’s line about the impact at the Aitken Basin I’ve been wondering… did Luna or Earth have a ring for a while? And just how much larger did the moon appear at that point, since it was much closer? What a view…

  29. Doug Little

    OK. Someone has to step up and be the pedant here, so it might as well be me.
    I could have told you without doing any research that the slope at the highest point on the Moon is zero.
    Knowing the slope up to it is interesting, though. Thanks, Phil.

    I’ll see your pedant and raise you one

    Not necessarily depends if it is a smooth continuous function or not.

  30. speedlimit186k

    To be honest, I never thought about why the moon has differing elevations. Sure, I thought about craters meteor impacts and all, but I never thought about it in terms of highest and lowest points or even why they’re there at all. Maybe it’s just that nothing has provoked me to think about the moon in those terms, but god damn, the fact that I’m just now having that thought is making me feel like a lunar noob.

  31. Jeffersonian

    @Ken B
    At only a 3% grade at the steepest, it’d be a crappy run.

    Go for the Olympus Mons instead.

  32. Ick of the East

    I made a 3D Anaglyph of the spot. Much cooler:

    http://yfrog.com/0imoonhighpointj

    Go 3D Phil. As often as you can.

  33. Messier Tidy Upper

    @ ^ Jeffersonian :

    Olympus Mons is a pretty shallow incline mostly too – except for the central crater and some cliffs at the base. Same goes for most of the Martian volcanoes.

    If you really want steep mounatinous slopes then the Ouranian moon Miranda might be your best bet. Or the equator circling ridge on, I think , Iapetus that Cassini imaged or some of the central peaks of lunar and other craters. :-)

  34. Messier Tidy Upper

    Yep, Iapetus :

    http://blogs.discovermagazine.com/badastronomy/2007/07/17/cracking-a-scientific-nut/

    has the “moon spanning walnut ridge!” :-)

    & Miranda is seen here via Wikipedia :

    http://en.wikipedia.org/wiki/Miranda_(moon)

    & there’s more about Olympus Mons here :

    http://en.wikipedia.org/wiki/Olympus_Mons

    via its Wikipage. :-)

  35. Etienne

    Came expecting cool facts about how awesome it would be to smoke marijuana on the moon. Left dissapointed :)

  36. Nigel Depledge

    Tbird49er (21) said:

    Does glacial and artic melting (that raises the sea level) raise “sea level” as used in our altimeters? Does a rise in sea level reduce the relative heights of our mountain peaks vis a vis sea level (or do they use atmospheric pressure to arrive at such distinctions)?

    In short, yes.

    Mean sea level is rising by a few mm a year at present. Since all “spot heights” are specified against MSL, in principle our mountains are all getting smaller. However, since we generally only cite heights to the nearest m or nearest 10 ft, I think it’ll be a couple more decades before the maps need to be changed.

  37. @ Ken B

    “So, where’s the lowest point…”

    According to altimetry data recorded by the Japanese Kaguya spacecraft (which impacted the Moon last year), the lowest point is on the floor of Antoniadi crater (-9,138 metres – Lat 70.375S, Long 172.5W). The point is within a small crater (~ 15 km doameter) that was created by impact onto the floor of the much larger crater Antoniadi (~ 140 km diameter). As for skiiing down it, I think, the slope would be fairly low (again, around the 3 deg as Phil mentions above), so taking into account the 1/6 grav etc., the time from top to bottom would be longer than for the same crater/slope stats given to a similar crater on Earth.

    @ Ick of the east
    Cool anaglyph…the mountain really pops out (pity about the coordinates on it — though essential to see what the highest point is — they kinda ruin the effect).

    John (Moon Atlas guy)

  38. George

    A ha! The Moon did come from the Earth! *wink*

    This eleveation is essentially the same as Earth’s tallest – Mauna Kea (~ 35,000 ft.).

  39. JMW

    Wouldn’t the highest point on the moon be a logical place to have the ejection end of a lunar catapult? Especially since it’s only 5.4 degrees off the moon’s equator?

  40. ET

    Gooood. Now we know where ther first cell phone tower is so we can phone home.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »