Isomorphismes

> data(quakes)
> head(quakes)

     lat   long depth mag stations

1 -20.42 181.62   562 4.8       41

2 -20.62 181.03   650 4.2       15

3 -26.00 184.10    42 5.4       43

4 -17.97 181.66   626 4.1       19

5 -20.42 181.96   649 4.0       11

6 -19.68 184.31   195 4.0       12

> summary(quakes)

      lat              long           depth            mag      

 Min.   :-38.59   Min.   :165.7   Min.   : 40.0   Min.   :4.00  

 1st Qu.:-23.47   1st Qu.:179.6   1st Qu.: 99.0   1st Qu.:4.30  

 Median :-20.30   Median :181.4   Median :247.0   Median :4.60  

 Mean   :-20.64   Mean   :179.5   Mean   :311.4   Mean   :4.62  

 3rd Qu.:-17.64   3rd Qu.:183.2   3rd Qu.:543.0   3rd Qu.:4.90  

 Max.   :-10.72   Max.   :188.1   Max.   :680.0   Max.   :6.40  

    stations     

 Min.   : 10.00  

 1st Qu.: 18.00  

 Median : 27.00  

 Mean   : 33.42  

 3rd Qu.: 42.00  

 Max.   :132.00  

> plot(quakes,     pch=20, col=rgb(0,0,0,.1) , lwd=.6) 

> require(ggplot2)
> qplot(data = quakes, x = lat, y = long, size = exp(mag), color = mag, alpha = I(.8))

UPDATE: In the comments, Sean Mulcahy shared his much better post on earthquakes: http://seanmulcahy.blogspot.com/2011/11/global-earthquakes-desktop.html. He shows how to grab up-to-date earthquake data from the U.S. Geological Survey and display it with R’s maps package. Hooray!

Not talking about camping outside. I mean the elements as in the periodic table of the elements.

How did they come to be? Why are there more of some and less of others? Why does 29 protons conduct electricity 10 times better than 31 protons? Etc.

There are six salient facts that a theory of the origin of the elements must explain:

1. H and He are by far the most abundant.
2. Elemental abundances generally drop with increasing atomic number.
3. Even atomic numbers are more common than odd atomic numbers.
4. Li, Be, and B are anomalously rare.
5. Fe is anomalously abundant.
6. Tc, Pm, and elements above Bi are extremely scarce or nonexistent — except for U and Th.

(Source: ocw.mit.edu)

How come the planets aren’t arranged spherically around the sun?

Instead of being spherical, as seems to be the default shape of things in the universe, the planets are arranged in a more-or-less flat disk — a series of concentric ellipses.

What’s up with that?

Answer: angular momentum + gravity.

The nascent planets (or planetesimals) may have started out spherically arranged around the sun.

But then the spinning sun (or proto-sun) flung its satellites—including Earth—further out into space, like how a merry-go-round flings you off when it spins fast.  So the shape would have become an oblate spheroid, with the major axis being the direction of the sun’s spin.

At the same time as centrifugal force pushed out in just one circle, gravity pulled in on the entire sphere.

So the minor axis of the oblate spheroid had nothing pushing it out, only something pulling in, while the major axis was being pushed and pulled.  Eventually the minor axis mostly collapsed and now we humans observe the “flat disk” shape.

SOURCE: Essentials of Geophysics, Part One