Yesterday at 11:58 PM JohnR7 said this in Post #54 (http://www.christianforums.com/showthread.php?postid=676328#post676328)
Yes I do see problems with it. It has nothing to do with what I am talking about.
The spindown rate of the earth is 1.5 to 2 mili-sec every 100 years. That means 1 million years ago, the day would be 15 seconds shorter. But what about 4.5 billion years ago?
.002 = 100 years
.02 = 1000 years
.2 = 10,000 years
2 seconds = 100,000 years
60 seconds = 3,000,000 years
1 hour = 180,000,000 years
24 hours = 4,320,000,000 years
4.32 billion years ago, a day would be 24 hours shorter than it is now. Based on the current spindown rate of the earth.
I couldn't help but think there's something fundementally wrong with this, especially since
the formula over at talk.origins uses a rate only slightly slower than the one John is using, and arrives at 14 hour days, 4.6 billion years ago.
So, I tried out the numbers myself:
First of all, the rate of spin down I used was 0.002 seconds per day per century from
this site (the same one John uses).
0.002 seconds per day per century = 2.0 seconds per day per 100 000 years = 0.00002 seconds per day per year
I translated it into seconds per year rather than per day (to make it compatible with the formula from the talk.origins article) by multiplying by 365.25 (since there are 365.25 days in a year). 730.05 seconds per year per 100 000 years (or 0.0073005 seconds per year per year).
Then I plugged it into their formula. I first tried it for 50 000 years ago, to confirm what it says on the site:
In other words, as the Earth slowly loses spin energy, the period of rotation (one day) gets one second longer every 50,000 years.
Here's the math:
50 000 years x .0073005 seconds per year per year = 365.025 seconds per year = 0.004 days per year (divide by 86400, number of seconds in a day)
(365.25 + 0.004) days per year = 365.254 days per year
8766 hours per year / 365.254 days per year = 23.9997 hours per day = 86399 seconds per day (50 000 years ago)
This is versus 86400 seconds per day today. Hence, 50 000 years ago, each day was 1 second shorter. This confirms that the formula works (i.e. it arrives at the answer expected from the site).
Next, I tried it for 4.6 billion years ago:
4 600 000 000 years x .0073005 seconds per year per year = 33582300 seconds per year = 388.7 days per year (extra)
(365.25 + 388.7) days per year = 753.95 days per year
8766 hours per year / 753.95 days per year = 11.6 hours per day
So, 4.6 billion years ago, the Earth had 11.6 hours in a day.
Now, obviously something is wrong with John's method, except I'm too tired right now to figure it out (and my head hurts from all this math). Does someone want to take a crack at explaining this?
edited to fix slight error in math (didn't really affect the results, though)
