DescentBB

"...•The major part of the Moon's libration in latitude is due to the inclination of the Moon's spin axis relative to the plane of of its orbit. This amounts to a variation of about ±6½° in the latitude of the observed center point (Roncoli, 2005, puts the maximum at 6.87°).
•The major part of the Moon's libration in longitude is due to its spinning like a top at constant velocity (relative to the stars), yet travelling in an elliptical orbit (which causes our angle of viewing it to change at a varying speed). The result is that the apparent center point varies by around ±8° in longitude (Roncoli, 2005, puts the maximum at 8.16°).
•In addition to these basic rocking motions, an observer's exact location on Earth will can change his perspective. An observer in the Earth's far north sees more of the Moon's northern parts; while one observing the Moon at moonrise sees more of the leading limb. This affect alters the coordinates of the apparent center by up to about ±1°. These true librations, as actually seen by the observer, are called the topocentric librations (as opposed to the geocentric librations -- which are computed for an imaginary observer at the Earth's center, and, although frequently tabulated in Almanacs, seldom apply to any real observer).
•Any variation beyond that which can be attributed to an idealized spinning top (such as would be observed if the Moon's spin rate about its axis were not perfectly constant) is categorized as a physical libration.
•The Moon's librations tend to make the observed center point wander around the "official" center in a quasi-circular or elliptical pattern. It would be rare, indeed, for the point of zero longitude and latitude (the "mean center") to actually be observed in the center, and even then, it would be seen so only for a single observer.
•The librations in longitude and latitude are frequently abbreviated by the letters "l" and "b" although this convention is by no means universal. "L" and "B" were probably originally abbreviations for the German words "länge" (longitude) and "breite" (latitude). On diagrams, and in mathematical discussions they are sometimes replaced by the Greek letters lambda and beta, although again, this is not a universal convention.
•The magnitudes of the librations are traditionally stated as +/- numbers (rather than N-S/E-W). As indicated in the definition, these are the selenographic coordinates of the Moon's apparent center. In longitude ("l"), positive values are in the Mare Crisium direction. In latitude ("b"), they are in the Mare Frigoris direction. Hence a "+" value for "l" means the Mare Crisium limb is tipped into view. A "+" value for "b" means the Mare Frigoris limb is tipped into view. The convention that longitudes towards Mare Crisium are positive is a very old one, so no change in the way librations are stated or understood was required when the IAU reversed the meaning of "east" and "west" on the Moon...."

For ESWI to occur, certain conditions must be met on these planets.

The substellar point, closest to the star, cannot be underwater. Land is required for the strongly temperature-dependant weathering.

Similarly, the gas that is absorbed by weathering must be the prevalent gas in the atmosphere.

Kite notes that, even if Earth were moved to another star and became tidally locked, it would not be in danger. Though weathering on Earth consumes carbon dioxide, nitrogen makes up most of the atmosphere.

Such results are not just limited to planets that can only reveal a single face to their star.

According to Kite, "All that's really important to get this process going is a large day/night temperature contrast."

Volcanoes, such as the Eyjafjallajökull volcano in southern Iceland, can spew out huge amounts of ash and gases, altering the composition of the atmosphere. Image Copyright: Marco Fulle (Stromboli Online)

As an example, the team worked with Itay Halevy, of the Weizmann Institute of Science, to consider a Martian mystery. Mars is not tidally locked but has wide temperature variations across a Martian day. The red planet lost its atmosphere long ago, and scientists are still trying to determine exactly how that happened.

Human impact on the nitrogen cycle is diverse. Agricultural and industrial nitrogen (N) inputs to the environment currently exceed inputs from natural N fixation.[1] As a consequence of anthropogenic inputs, the global nitrogen cycle (Fig. 1) has been significantly altered over the past century

A 2011 study found that nitrogen from rocks may also be a significant source of nitrogen, that had not previously been included

Kilarin wrote:I think what is safe to say about climate change is that BOTH sides have a political agenda and are unwilling to consider any possibility that the other side may have some points.

Spidey wrote:Damn, vision…it looks to me like your brain simply sloshed from one side of the issue to the other.
...
Prove to me, or at least make a convincing argument that…global climate change will be all bad. I have no problem with the science of this issue, but what is really pissing me off are the politics.

vision wrote:will we displace the current residents and turn that land into agricultural centers?

flip wrote:No, the point is there is no "conclusive" proof.

EDIT: Yeah, I want to see the e-mail.

woodchip wrote:If global warming is truly global then you would expect both poles to be melting. Since we only have the arctic experiencing warming then I'd say regional warming is occurring.

Krom wrote:

woodchip wrote:If global warming is truly global then you would expect both poles to be melting. Since we only have the arctic experiencing warming then I'd say regional warming is occurring.

You're confusing coverage with depth or density. Satellites can only tell you how much surface area the ice covers, not how thick the ice is. Even the arctic in recent years has set some records for the coverage of ice, but it is super thin ice that melts at the end of the season. So even though it covers more area, there is still significantly less of it.

woodchip wrote:True but in the case of Antarctica it's been gaining ice for the last 33 years at least and there was nothing about ice melting like in the Arctic. I wonder if this has anything to do with the 40k year wobble cycle?

woodchip wrote:True but in the case of Antarctica it's been gaining ice for the last 33 years at least and there was nothing about ice melting like in the Arctic.

Spidey wrote:Prove to me, or at least make a convincing argument that…global climate change will be all bad. I have no problem with the science of this issue, but what is really pissing me off are the politics.

Less rain here…more rain there.
Encroachment of shoreline…millions of arable acreage opening up in the north.
More CO2 may mean larger crop yields, and better forest re-growth?
Lower heating bills…perhaps offset by higher cooling bills, but for not me because I don’t use air con.

Jeff250 wrote: Your argument I'm assuming is that if the net win is positive, we shouldn't care.

Krom wrote:

woodchip wrote:True but in the case of Antarctica it's been gaining ice for the last 33 years at least and there was nothing about ice melting like in the Arctic.

I don't know where you heard this, but it is incorrect. The Antarctic has been shrinking/loosing mass consistently for some time and at an continually accelerating rate no less. (Read the article vision linked for example.)

Spidey wrote:

Jeff250 wrote:Your argument I'm assuming is that if the net win is positive, we shouldn't care.

How the hell did you come to that conclusion?

No, the point is more like fraud by omission, same as how the negative affects of certain programs are always ignored.