Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: neilep on 19/04/2007 14:57:05

Title: Is the Earth's rotation slowing down?
Post by: neilep on 19/04/2007 14:57:05

How fast was the earth spinning in the early days compared to how fast it's spinning now ?

Is it slowing down at all ?..or is it now at a happy medium ?

Could the rate of spin have an effect on how life manifested and also the very nature of that life ?


whajafink ?

Title: Re: Is the Earth's rotation slowing down?
Post by: ukmicky on 19/04/2007 15:19:20

Its slowing dooooooooooooooooooooooooooooooowwwwwwwwwwwwwwwnnnnnnnnn.

Also when you were a kid about 4 billion years ago  [;D]when it was spinning a lot faster i suppose it would have reduced the length of exposure from the harmful suns rays when the earths atmosphere was different and shielded the earth less

Title: Re: Is the Earth's rotation slowing down?
Post by: Batroost on 19/04/2007 17:40:03

Yes - it's slowing down.

4.5 billion years ago a day and night together probably only lasted about 6.5 hours!

But, you still spend half your time in daylight and half in darkness so it made no difference to the rate of exposure to solar radiation. The differences in atmopshere would have been far more significant e.g. no free oxygen so, presumably no ozone layer?

Title: Re: Is the Earth's rotation slowing down?
Post by: ukmicky on 19/04/2007 22:39:53

Quote from: Batroost on 19/04/2007 17:40:03

But, you still spend half your time in daylight and half in darkness so it made no difference to the rate of exposure to solar radiation.

A shorter day could make a masive difference in regards to whether something lives or dies.
At the hotest part of the day the level of solar radiation would be the same but the fact that the earth was spinning faster means the period of high intensity would be over quicker and the recovery period would come sooner.

What would you prefer and what would give you your best chance of survival in the middle of the desert, 12 hours of sun and then a break or 4 an a half of sun and then a break.

Title: Re: Is the Earth's rotation slowing down?
Post by: Batroost on 19/04/2007 23:13:04

Ah. Understood. I thought you were referring to the exposure to solar radiation which is really just hours-in-the-sun dependent.

I agree, biologically, the time to cool down and rest is going to be significant. When you see film of Kangeroos in the outback it's hard to credit how long they have to survive in baking heat between the cooler evenings/mornings.

Not sure what Solar output was like 4.5 billion years ago - who's good on stars?

Title: Re: Is the Earth's rotation slowing down?
Post by: neilep on 20/04/2007 15:03:34

THANK YOU BOTH UKMICKY & BATROOST !


Do you think then that along with the time it took to cool and stuff that the earth had to slow down to make life (as we know it) viable ?.......if not !..I wonder what WE would look and act like if our days were 12 hours long instead of 24 ?