Re: What would happen if all the mass of the earth stopped rotating

Dear Mr. Baty,
    I assume your phrase "all the mass of the earth" refers to the crust, 
mantle and core but not to the oceans, plants, animals, humans and our 
structures and the atmosphere. If the earth stopped rotating, you and me, 
our oceans, the soil and all that grows in and on it would still be moving 
west to east at hundreds of miles per hour! Here in Michigan, the 
rotational velocity of the earth is about 650 mph. At the equator, it is 
slightly more that 1000 miles per hour. Since buildings, people, the air, 
and everything else on the earth is moving so fast, when the earth stopped 
we'd simply keep going. The oceans would wash over the continents until 
they hit mountain ranges, your house and school and the ground they stand 
on would tumble to the east at 650 mph, bashing to pieces as they did. 
   There are two reasons not to worry. Number one, bacteria and many 
insects would survive such a cataclysm. Bacteria living in the smashed and 
tumbled soil would probably survive ages in the narrow zone between the 
broiling day side of a stationary earth and the frozen night side. Reason 
number two, with a mass of ~6,000,000,000,000,000,000,000,000 kg, our earth 
 can't be stopped by any conceivable force. Even a hypernova explosion 
right next door to us would leave sizable chuncks of our planet spinning 
because angular momentum is always conserved. On the negative side, over 
the next 5 or 6 billion years, tidal friction caused by the moon is 
gradually slowing our rotational rate. We estimate the day gets one second 
longer every 40,000 years due to this effect. Eventually our day length 
will be 40x24, the same as the moon's at that distant time.

     Thank you very much for your question and don't worry!

Jim Foerch in the Woods
James C. Veen Observatory
Lowell, Michigan

[Moderator's note: several other answers on our site also deal with this
question -- try searching on 'Earth rotation' to find out more.]