Posted on 12/13/2005 5:34:16 PM PST by saganite
Thanks for that update. I thought .1 was a little low!
Why is he so worried about Dark Ages ?
The precondition for a Dark Age is a wave of barbarian conquest triggered by the superiority of the barbarian horse archer over the peasant spearman. That ended with the invention of firearms.
I guess i have time to order Pizza delivered.
Whew - almost scared me to death! First time I read it, I thought it said 1.6 million years...
Good. Maybe I'll finally be able to take a nap after lunch.
"_ _ _ _ _ _ _ _ _ _ _." = "BoyBeenIced."?
"looks like I picked the wrong week to quit drinking."
That's a big problem for growing crops for food. 2 weeks of constant darkness, not to mention the utility bills for your house to compensate for cold nights and hot days!
Hey Lancey,
Tell me again your favorite line from the movie "The Cinncinati Kid". Please!
Lancey Howard: "Gets down to what it's all about, doesn't it? Making the wrong move at the right time."
Cincinnati Kid:"Is that what it's all about?"
Lancey Howard: "Like life, I guess. You're good, kid, but as long as I'm around you're second best. You might as well learn to live with it."
Same reason we gave it up - the kids discovered more interesting things to do than studying. ;)
Some dinosaurs were bipedal, had opposable claws, and were pretty intelligent—so why didn’t they, for example, invent space travel?
Well there was that one good Star Trek Enterprise episode where the sentient dinosaurs of old earth just decided to leave the planet before the asteroid hit. But then they forgot about earth altogether.
I am going to mark these dates in my dayplanner so they don't sneak up on me.
We're dead, Jim.
Right?
Antartica used to be a warm, tropical place. Fossils proved this. This fact was even mentioned in the latest film, "The March of the Penguins".
I would think that Antartica could have been victim of a "flip" eons ago.
That is why Antartica is one of many locations in where Atlantis used to be..
Looks like Uranus is "flipped" right now!
From the following link...
"Uranus is distinguished by the fact that it is tipped on its side. Its unusual position is thought to be the result of a collision with a planet-sized body early in the solar system's history. Voyager 2 found that one of the most striking influences of this sideways position is its effect on the tail of the magnetic field, which is itself tilted 60 degrees from the planet's axis of rotation.""
Collision? Perhaps not.
http://www.solarviews.com/eng/uranus.htm
Sounds like that intergalactic war a former Canadian politician was spewing about the other day.
In about 50 billion years. The Sun will have gone Nova long before this.
However, this is the cause of the leap second being accompished this month.
Ok, let us take a look at the Moon.
How was the Moon formed?
There were at least five major ideas that were proposed as to the formation of the Moon.
Fission – The Moon split off from the Earth.
Capture – The Moon was captured by the gravity of the Earth.
Condensation – The Moon coalesced out of the same “stuff” the Earth did.
Colliding Planetesimals – Formed from colliding Planetesimals during the early formation of the solar system.
Collision – A body collided with the Earth causing a piece of the Earth’s crust to form the Moon from a resultant ring produced by that collision
The evidence points to the collision theory. First, the Moon does not have an iron core. This pretty much rules out that it coalesced from the same cloud of debris that the Earth did. Second, throughout the solar system, the oxygen isotopes have been found to be different. If the Moon were captured, it too would not match the Earth’s oxygen isotope ratio (which it does). Fourth, by looking at the angular momentum and energy required, the theory that the Moon spun off the Earth after the Earth formed does not hold up.
This leaves us with the Collision theory as the best model we have for the formation of the Moon. The resultant collision caused a ring of debris from the Earths crust to form outside the Roche limit. If it had not, tidal forces would have not allowed for the Moon we see today.
A more in depth discussion of tidal locking since the Moon is tidal locked to the Earth. The reason the Moon keeps one face to the Earth (Its rotation on its axis matches the period of its orbit) is it is tidally locked to the Earth. Here is a more in depth explanation. The total angular momentum of the earth moon system, which is spin angular momentum plus the orbital angular momentum, is constant. (The Sun plays apart also) Friction of the oceans caused by the tides is causing the Earth to slow down a tiny bit each year. This is approximately two milliseconds per century causing the moon to recede by about 3.7 centimeters per year. As the Earth slows down, the Moon must recede to keep the total angular momentum a constant. In other words as the spin angular momentum of the earth decreases, the lunar orbital angular momentum must increase. Here is an interesting side note. The velocity of the moon will slow down as the orbit increases.
Another example of tidal locking is the orbit period and rotation of the planet Mercury. What is interesting about this one is that instead of a 1:1 synchronization where Mercury would keep one face to the Sun at all times, it is actually in a 2/3:1 synchronization. This is due to the High eccentricity of its orbit.
There also can be more than one body “locked” to each other. Lets take a look at the moon Io. Io is very nearly the same size as the Earth’s moon. It is approximately 1.04 times the size of the moon. There is a resonance between Io, Ganymede, and Europa. Io completes four revolutions for every one of Ganymede and two of Europa. This is due to a Laplace Resonance phenomenon. A Laplace Resonance is when more than two bodies are forced into a minimum energy configuration.
And finally a look at the asteroid belt since there are many that are tidally locked to Jupiter as well:
The asteroid belt has an estimated total combined mass of less than 1 tenth of the Earth’s moon. Jupiter has a profound effect on the asteroid belt. Jupiter has a semimajor axis of 5.2 AU (1 AU is the distance from the Sun to the Earth) and it has an orbital period of 11.86 years. Since the asteroids are not all at the same distance from the sun, some of them will have an orbital period of one half of Jupiter. This puts that asteroid in a 2:1 orbital resonance with Jupiter. The result of this resonance are gaps called Kirkwood’s gaps. So here is the rub; why did not these asteroids for a planet? The reason is the gravitational force of Jupiter. It perturbs the asteroids giving them random velocities relative to each other. Another effect of both Jupiter and the Sun on the asteroid belt is a group of asteroids that both precede and follow Jupiter in its orbit by 60 degrees. These asteroids are known as the Trojans.
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