Astronomy Picture of the Day
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.
2016 September 11 
Posted on 09/12/2016 5:54:40 AM PDT by ThomasMore
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.
2016 September 11
Explanation: How much of planet Earth is made of water? Very little, actually. Although oceans of water cover about 70 percent of Earth's surface, these oceans are shallow compared to the Earth's radius. The featured illustration shows what would happen if all of the water on or near the surface of the Earth were bunched up into a ball. The radius of this ball would be only about 700 kilometers, less than half the radius of the Earth's Moon, but slightly larger than Saturn's moon Rhea which, like many moons in our outer Solar System, is mostly water ice. How even this much water came to be on the Earth and whether any significant amount is trapped far beneath Earth's surface remain topics of research.
(Excerpt) Read more at apod.nasa.gov ...
Re: Mauna Loa Hawaii.
The big island of Hawaii is the tallest mountain on Earth from base to peak. Obviously, most of it lies under water.
The highest point on Earth, if measured from the center of earth, is not the top of Mt Everest, but rather the peak of that other mountain I mentioned above, located somewhere along the equator. Again, it’s the highest point due to the mountain’s location at the equator, where the earth has a larger radius from center to surface due to the equatorial bulge described above.
Re: The peak of Mount Chimborazo in Ecuador
Thanks.
With all the time I spent replying, I should have just looked it up myself. :)
I think I had a Chimborazo at my local Mexican Restaurant last week.
Now I know why it’s named after a volcano...................
Round enough then. Thanks.
While ready about the earth being smother than a billiard ball, I remembered this question.
If the could rap a rope around the earth and cut it where the ends meet. How far, in feet, would the ends be apart if you could raise it 6 inches on supports around the circumference at any point?
BVB
1?...............
No. Think about PI in relation to circles.
BVB
3.14159 feet?.............
Since the interior of the Earth is above 212 degrees Fahrenheit, any water therein would be in a gaseous state.
Yes, but it seems they were re-thinking the theory that all water on the earth was brought here via comets or some other extra-terrestrial source.
Or just for balance, add a little ball showing what they consider to be ‘surface material.’ We’re always told the surface of the earth is 3/4 liquid, which makes that graphic a bit hard to stomach.
Yes. We add 1 foot to the diameter so it is one more times PI. If we raise it 1/2 mile, the ends would be 3.14 miles apart.
BVB
According to Al Gore the temperature at the center of earth is "millions of degrees". He was 'only' off by a factor between 4 and 5 hundred!! (several million vs ~7230 deg F!)
By Noel Sheppard | November 18, 2009
[snip]
CONAN O'BRIEN, HOST: ...to create energy, and it sounds to me like an evil plan by Lex Luthor to defeat Superman. Can you, can you tell me, is this a viable solution, geothermal energy?
AL GORE: It definitely is, and it's a relatively new one. People think about geothermal energy - when they think about it at all - in terms of the hot water bubbling up in some places, but two kilometers or so down in most places there are these incredibly hot rocks, 'cause the interior of the earth is extremely hot, several million degrees, and the crust of the earth is hot ...
[snip]
The physics and astronomy website Physlink contests Gore's absurd claim:
It is approximately 4000 degC [7230 degF] at the centre of the Earth.
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