A View from the Back of the Envelope top

Kilometers in your hands
103 meters per mm (Magnification of ×10-6)
Scaling the universe to your desktop
How Big Are Things?
Length Area Volume Speed
10 [ | -6 | -3 | 0 | 3 | 6 | 9 | 12 | 15 | 18 ]
At 15 miles to the inch... 106 meters per meter

1 km
10 km
100 km
1000 km
103 m
0.3 km
316 m
1/5 mile
1 kft		 3 km
3162 m
2 miles
10 kft
104 m
32 km

20 miles
104 kft
105 m
316 km
0.3 Mm
197 miles
106 m
3162 km
3 Mm
1965 miles
top of troposphere
~12 km

height of 1/2 sea-level pressure
~6 km

mean ocean depth
~4 km

1 km per mm
Actual size (though rough, as screen resolution varies).

Picturing altitude above maps

 ...
Map scale is about 1 : 1 000 000 000 (To generate your own map, click.)

(orig, less mangled)
1/2 lt·ms (ticks every 1/10 light-millisecond (lt·10-3s))
0 1/10 2/10 3/10 1/2 lt·ms

A View from the Back of the Envelope
Comments encouraged. - Mitchell N Charity <mcharity@lcs.mit.edu> 

Notes:
  Earth cross-section mangled from THE INTERIORS OF THE TERRESTRIAL PLANETS.
    Encountered using The Great Globe Gallery.
  Clouds image from Picturing altitude above maps and NASA JSC Imagery Services.
  Hmm... clouds image might be too small by a factor of two...?  15 km to tropo.
  Boston map and scale bar is from U.S. Census Bureau's TIGER Map Service
 and was generated Oct 97 using this URL.
  USGS has some ok 1:1,000,000 maps (Boston is NK-19),
    as does DMA/ONC (ids like F-19).
  USGS has 1:100 000 metric maps (10 m contour lines), but while they are
a nice reference, I prefer the 1:25 000 series, because you can see local
streets and landmarks.
  troposphere, depth, 1/2 pressure height - from [Cow p235]
Other meta info on zero magnification page. 
Doables:
  Check scale of cloud image.
  On a sheet of paper
  Max ocean depth.
  How much does atmosphere depth vary?

History:
 2003-Feb-03   Repaired links - 1 fixed, 1 left (tiger).
 2002-Apr-11   Changed link (evacuating www.tiac.net).
 2001.Apr.20   Added link to `How Big Are Things?'.
 1999.Jul.17   Added sketch of earth cross-section.
 1998.Jun.17   Corrected error with magnitude boundaries (3.333->3.162).
 1998.May.09   Added ocean/atmosphere numbers.
 1997.Oct.17   Added boston map and scale bar.
 1997.Aug.25   Created.