# 3rd 'rock' from the Sun **URL:** \ **Category:** Factual Questions\ **Created:** [September 10, 2004, 2:01pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909 "2004-09-10T14:01:27Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![johne1892](https://avatars.discourse-cdn.com/v4/letter/j/b487fb/32.png) [@johne1892](https://boards.straightdope.com/u/johne1892)\ **Post date:** [September 10, 2004, 2:01pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909/1 "2004-09-10T14:01:27Z")
Ok, starting at a basic level the earth is round right ? well, sort of. Has anyone seen or have a picture of what the earth looks like without water ? We often see Atlas and globes of the earth showing a generally ‘round’ appearance but surely we are just living on an odd-shaped lump of rock? ---
**Author:** ![fezpp](https://avatars.discourse-cdn.com/v4/letter/f/da6949/32.png) [@fezpp](https://boards.straightdope.com/u/fezpp)\ **Post date:** [September 10, 2004, 2:10pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909/2 "2004-09-10T14:10:30Z")
The [deepest](http://www.whoi.edu/info/deepest-ocean.html) part of the ocean is only about 11,000 metres. Everest is [about](http://www.infoplease.com/ipa/A0777280.html) 9000 meters tall. The diameter of the earth is approximately [12,000 km](http://hypertextbook.com/facts/1999/RicardoMartinez.shtml) (12,000,000 metres). This means that the total distance from the bottom of the deepest ocean to the top of the largest mountain only accounts for 1.5 percent of the diameter of the earth. This means that the earth in reality is probably like a very round rock. The mountains and oceans are just ‘roughness’ on the surface! ---
**Author:** ![Futile\_Gesture](https://avatars.discourse-cdn.com/v4/letter/f/f05b48/32.png) [@Futile\_Gesture](https://boards.straightdope.com/u/Futile_Gesture)\ **Post date:** [September 10, 2004, 2:12pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909/3 "2004-09-10T14:12:56Z")
The geographical relief involved in seas, mountains etc is miniscule compared to the actual spherical curviture of the earth. If you were to shrink the earth down to the size of a billiard ball it would appear practically as smooth as one too (although it wouldn’t be a perfect sphere). So taking away the water on the surface isn’t going to make a noticable difference to its shape. ---
**Author:** ![Complex\_Conjugate](https://avatars.discourse-cdn.com/v4/letter/c/3bc359/32.png) [@Complex\_Conjugate](https://boards.straightdope.com/u/Complex_Conjugate)\ **Post date:** [September 10, 2004, 2:15pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909/4 "2004-09-10T14:15:10Z")
It’s 0.15% of the Earth’s diameter fezpp ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [September 10, 2004, 2:18pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909/5 "2004-09-10T14:18:15Z")
[Earth Without Water](http://www.howiesfunware.com/MotherEarthTextures.html). ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [September 10, 2004, 2:18pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909/6 "2004-09-10T14:18:28Z")
And those deepest parts of the ocean are essentially fissures, not big wide plains, so that just means that the orb is pretty much a ball with a few tiny cracks. Another analogy is that the oceans are pretty much like the skin of an apple. Insignificant in the overall shape. xo C. ---
**Author:** ![vd](https://avatars.discourse-cdn.com/v4/letter/v/b19c9b/32.png) [@vd](https://boards.straightdope.com/u/vd)\ **Post date:** [September 10, 2004, 2:55pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909/7 "2004-09-10T14:55:16Z")
Another reference point… About 0.3 mm of relief on a NBA regulation size basketball. About the same size as the bumps on a rubber basketball but mostly smoothed out. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [September 10, 2004, 3:10pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909/8 "2004-09-10T15:10:14Z")
Putting them on the scale of a large orange, about 4 inches (10 cm) in diameter, the irregularities on the Earth’s surface would amount to less than 0.2 millimeters, or less than one hundredth of an inch. ---
**Author:** ![johne1892](https://avatars.discourse-cdn.com/v4/letter/j/b487fb/32.png) [@johne1892](https://boards.straightdope.com/u/johne1892)\ **Post date:** [September 10, 2004, 4:10pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909/9 "2004-09-10T16:10:35Z")
Thanks very much for all your replies and your comparisons to fruit, basketballs and pool balls. Maybes I was hoping for something more exciting ☹ ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [September 10, 2004, 11:59pm UTC](https://boards.straightdope.com/t/3rd-rock-from-the-sun/263909/10 "2004-09-10T23:59:32Z")
> [@johne1892](#): > > Thanks very much for all your replies and your comparisons to fruit, basketballs and pool balls. > > Maybes I was hoping for something more exciting ☹ Well, the equatorial bulge is about 13 miles high. Is that exciting enough? On a marble 1/2 in. in diameter that would be an out-of-round of about 1.6 thousandths. To the eye the earth is a sphere.