Astronomy Picture of the Day [1]Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2022 September 26 [2]The featured illustration shows Earth as it might look without water, while small blue beads depicting all of Earth's ocean and fresh water hover on the upper left. Please see the explanation for more detailed information. All the Water on Planet Earth Illustration Credit: Jack Cook, Adam Nieman, [3]Woods Hole Oceanographic Institution; Data source: Igor Shiklomanov Explanation: How much of planet Earth is made of water? Very little, actually. Although [4]oceans of water cover about 70 percent of Earth's surface, these oceans are [5]shallow compared to the Earth's radius. The [6]featured illustration shows what would happen if all of [7]the water on or near the surface of the Earth were bunched up into a [8]ball. The radius of this ball would be only about 700 kilometers, less than half the radius of the [9]Earth's Moon, but slightly larger than Saturn's moon [10]Rhea which, like many moons in our outer [11]Solar System, is mostly water ice. The next smallest ball depicts all of [12]Earth's liquid fresh water, while the tiniest ball shows the volume of all of Earth's [13]fresh-water lakes and [14]rivers. How any of this [15]water came to be on [16]the Earth and whether any significant amount is trapped far [17]beneath Earth's surface remain topics of research. Tomorrow's picture: furious sky __________________________________________________________________ [18]< | [19]Archive | [20]Submissions | [21]Index | [22]Search | [23]Calendar | [24]RSS | [25]Education | [26]About APOD | [27]Discuss | [28]> __________________________________________________________________ Authors & editors: [29]Robert Nemiroff ([30]MTU) & [31]Jerry Bonnell ([32]UMCP) NASA Official: Phillip Newman [33]Specific rights apply. [34]NASA Web Privacy Policy and Important Notices A service of: [35]ASD at [36]NASA / [37]GSFC, [38]NASA Science Activation & [39]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2209/WaterlessEarth2_woodshole_2520.jpg 3. https://www.whoi.edu/ 4. https://www.youtube.com/watch?v=moSBExlLu2M 5. http://www.cliffshade.com/colorado/images/earth_anatomy.gif 6. https://www.usgs.gov/media/images/how-much-water-there-earth-0 7. https://www.usgs.gov/media/images/all-earths-water-a-single-sphere 8. https://i.redd.it/n6ujzlqv19p51.jpg 9. https://apod.nasa.gov/apod/ap091118.html 10. https://apod.nasa.gov/apod/ap080513.html 11. https://solarsystem.nasa.gov/solar-system/our-solar-system/overview/ 12. https://solarsystem.nasa.gov/planets/earth/in-depth/ 13. https://apod.nasa.gov/apod/ap181218.html 14. https://apod.nasa.gov/apod/ap180826.html 15. https://en.wikipedia.org/wiki/Origin_of_water_on_Earth 16. https://apod.nasa.gov/apod/ap970316.html 17. https://ssec.si.edu/stemvisions-blog/there-ocean-below-your-feet 18. https://apod.nasa.gov/apod/ap220925.html 19. https://apod.nasa.gov/apod/archivepix.html 20. https://apod.nasa.gov/apod/lib/apsubmit2015.html 21. https://apod.nasa.gov/apod/lib/aptree.html 22. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 23. https://apod.nasa.gov/apod/calendar/allyears.html 24. https://apod.nasa.gov/apod.rss 25. https://apod.nasa.gov/apod/lib/edlinks.html 26. https://apod.nasa.gov/apod/lib/about_apod.html 27. http://asterisk.apod.com/discuss_apod.php?date=220926 28. https://apod.nasa.gov/apod/ap220927.html 29. http://www.phy.mtu.edu/faculty/Nemiroff.html 30. http://www.phy.mtu.edu/ 31. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 32. http://www.astro.umd.edu/ 33. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 34. https://www.nasa.gov/about/highlights/HP_Privacy.html 35. https://astrophysics.gsfc.nasa.gov/ 36. https://www.nasa.gov/ 37. https://www.nasa.gov/centers/goddard/ 38. https://science.nasa.gov/learners 39. http://www.mtu.edu/