Cry me a River

jpanhalt

Joined Jan 18, 2008
9,730
I wonder about the drop of only 1 cm /45 m when the movement is North, i.e., closer to the axis of rotation of the Earth.

Couldn't find a discussion of that exact subject easily (5-minute search), but I did find this discussion of what would happen to South flowing rivers like the Mississippi should the Earth stop rotating: http://physics.stackexchange.com/questions/209805/rivers-that-flow-uphill-due-to-earths-rotation In brief, they flow up hill relative to gravity, but the rotation keeps them flowing South.

Here are the approximate data I gathered from the video:
Terminus = Beijing (latitude 39°55'N)
Origin = 1200 km South approximate latitude = 29°N
Distance to Earth center at Bejing = 6,369,000 m (https://www.google.com/search?q=mean+seal+level+with+latitude?&newwindow=1&rlz=1C1AVNG_enUS626US626&espv=2&biw=1493&bih=944&tbm=isch&imgil=k2aHzvpJ6PwHHM%3A%3BvpnG_jCiNyx-6M%3Bhttp%253A%252F%252Fwww.summitpost.org%252Fmean-sea-level-distance-vs-latitude%252F850062&source=iu&pf=m&fir=k2aHzvpJ6PwHHM%3A%2CvpnG_jCiNyx-6M%2C_&usg=__Tjz96uWIwyrEQQ8u79cmZta6D28=&ved=0ahUKEwjHnu_U6qnMAhWHuIMKHYZxCAkQyjcIOw&ei=VxMeV4eXBofxjgSG46FI#imgrc=k2aHzvpJ6PwHHM:)
Distance to Earth center at origin = 6,372,500 m (loc. cit. from graph)
Difference in center distance = 3,500 m
Circumference relative to axis at Bejing approx. 30,642 km (assuming a sphere)
Circumference at origin approx. 34,985 km
"Fall" = 1 cm/45 m = 267 m/1200 km (26,667 sections) Relative to what? MSL?

Can anyone here calculate whether that small amount of "fall" and the increased gravity is enough to make this river flow North against the rotational effect? I am assuming the Chinese have done that calculation, but would be interested in seeing the calculation.

John
 

GopherT

Joined Nov 23, 2012
8,012
@jpanhalt

The report from BBC is not exactly correct. According to the Atlantic magazine and several others, there will be pumping stations.

from The Atlantic...
The project’s eventual goal is to move 44.8 billion cubic meters of water across the country every year, more than there is in the River Thames. The infrastructure includes some of the longest canals in the world; pipelines that weave underneath riverbeds; a giant aqueduct; and pumping stations powerful enough to fill Olympic-sized pools in minutes. It is the world’s largest water-transfer project, unprecedented both in the volume of water to be transferred and the distance to be traveled​
 

jpanhalt

Joined Jan 18, 2008
9,730
Maybe moving that much mass North will increase the rotation velocity of the Earth and for the first time ever, we will have a negative leap second. ;)

Thanks for the more complete information. It is truly a massive project.

John
 

Thread Starter

MaxHeadRoom

Joined Jul 18, 2013
20,898

jpanhalt

Joined Jan 18, 2008
9,730
Earth is already bulged at the equator. The bulge would disappear if Earth stopped rotating. The stackexchange discussion addresses that subject.

John
 
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