So that seems to have quietened them down. Matter evolves to space but it takes a long long time to complete the process. 
Is the earth expanding?
- Thread starter bgjyd834
- Start date
Motor Daddy
Valued Senior Member
So that seems to have quietened them down. Matter evolves to space but it takes a long long time to complete the process.
Kinda hard to argue with the second law.
...but if you ask James, if he can't observe his computer getting less dense it isn't so. :bugeye:
BTW, James seems to have slipped out the back door. He's done that to me before, when he started taking on water, and his ship started to sink. Maybe he tripped and fell into the life boat. Bwahahahaahaha
Last edited:
It is the time to complete the process that others don't appreciate. I would like you to acknowledge that for moments there will be events that temporarily appear to go against this principle.
Why is the oldest ocean plate only 200 million years old? That is a real difficult question.
Has there been a perfect explanation for no ocean plate being no older than 200 million years?
The oceanic plates (that we observe and date) are only 200 m.y. old because OLDER plate segments have already been SUBDUCTED (back into the asthenosphere) at active plate margins. The YOUNGEST oceanic plate lithosphere is near the mid-ocean spreading centers - where they originate - from upwelling of partially-melted asthenosphere . . . i.e., basaltic magma . . . that then solidifies (crustallizes to solid rock) to become relatively rigid oceanic plate lithosphere that then slowly 1-10 cm/yr (approx) migrate toward the plate margins. Oceanic plates are thus 'recycled' and we can only (at the surface, anyway) 'date' the oldest "exposed" rocks comprising the oceanic plates.
Last edited:
By what mechanism do things get less dense over time?
Which fundamental forces of nature are involved?
Show me an equation predicting the rate at which anything gets less dense over time.
Your "theory" is non-quantitative and contentless. It doesn't "explain" anything or allow anything to be predicted.
For example, what causes the moon to move away from the Earth? Isaac Newton explained that back in the 1600s. His explanation involves a detailed mathematical proof of the mechanism, checked against actual observations made by real scientists.
And you? You have no mechanism - just an assertion that something happens by magic (unexplained).
Then, let's look at some of your things. First: fire. When a hydrogen molecule combines with an oxygen molecule to form water (i.e. burns), is the end result more or less dense than the initial components?
Second: condensation. When it rains, water vapour turns into liquid water and falls to the ground. Is the resulting liquid more dense or less dense than the initial vapour? How does your "theory" account for this?
Show me some relevant data that supports this claim.
The second law of thermodynamics has nothing to do with density.
It's not our fault that you have no idea what entropy is.
If you think it is getting less dense, prove it. It's your claim.
OK I understand the mechanism behind what you say here, but you would think there would be some locations where the subduction failed (locked up or whatever so that material say 1 billion year old basaltic plate would be around.
There is, but it's been incorporated into continents through accretionary processes.
. . . CORRECT, RobittyBob! . . . there ARE "accreted wedges" of stuff that pack onto continents (that's one way that continents "grow") rather than being subducted. There are also slivers of oceanic crust (and partially-subducted material) caught-up in back arc areas. These however, commonly are metamorposed in the accretion process and thus their radiometric 'date' can be reset via recrystallization, to a seemingly younger radiometric 'age'. Sometimes, zircons that survive (i.e., are not recrystallized) these metamorphic processes reflect older radiometric dates. These accretionary occurrences are volumetrically minor relative to the more active subduction tectonics.
Last edited:
So what are the key words I'd have to use to find about these on a Google search?
Looking for stuff about Ophiolites, or ophiolite sequences would be a good start.
Here's a List of Ophiolites on Wiki.
http://en.wikipedia.org/wiki/Island_arc
The way bands of island arcs have linked to continents is really interesting too.
Except that the oldest lithosphere of the pacific, atlantic, indian oceans is about -170 and -180 My old and is still present.
The oldest oceanic lithosphere still undersea is found in the eastern basin of the mediterranean sea (paleotethys), while the western basin opened in the last 30 My. Ophiolites found at the Indus suture are actually a bit younger (neotethys).
That patch in the Western pacific is odd where an old patch of sea floor is surrounded by younger material. West of that is a very broken up region. You can look at the Atlantic an imagine Africa and Americas separating from each other (they are separating aren't they?). But in that other area it is much more difficult to see it. But having the old piece in the middle is opposite to the subduction concept. These lines of growth appear to shift. How did India go over the top of the hotspot?
in addition to ophiolites (Ref. Trippy) . . . greenstone belts . . . . verde antique . . . meta-basalts . . probably others as well . . .
Except that the oldest lithosphere of the pacific, atlantic, indian oceans is about -170 and -180 My old and is still present.
The oldest oceanic lithosphere still undersea is found in the eastern basin of the mediterranean sea (paleotethys), while the western basin opened in the last 30 My. Ophiolites found at the Indus suture are actually a bit younger (neotethys).
. . . . oceanic and continental plates 'travel' (move) at different rates . . . some faster . . . some slower . . . also subduction rates vary . . some faster . . . some slower . . . ergo, some oceanic plate material at margins is younger . . . or older . . . also some 'continental plates' are relatively fixed (> subduction at margin) . . .some are more mobile (i.e., move, < subduction at margin)
That region appears very broken up, because it is the location of multiple mantle extrusions that took place at different time and in different directions. These extrusions overprinted the west side of the old pacific lithosphere.
See a close up:
http://en.wikipedia.org/wiki/Island_arc
The way bands of island arcs have linked to continents is really interesting too.
Arcs (volcanic) are typically related to subduction of oceanic plates. As oceanic plates subduct they may be subject to 'partial' melting as they 'dive' (or recycle) into the asthenossphere. Partial melting typically generates magmas that are intermediate (i.e., not thyolitic and not basaltic) These intermediate magmas are generally andesitic in composition . . . have a look at a basic igneous rock chart for more info.