avocado> db.geo.within(0,0,5 * 1000 * 1000).distance();
{ "name" : "Name0-0", "loc" : [ 0, 0 ], "_id" : "162972:24607900", "_distance" : 0 }
{ "name" : "Name10-0", "loc" : [ 10, 0 ], "_id" : "162972:27032732", "_distance" : 1111949.2664455874 }
.
.
{ "name" : "Name-20-10", "loc" : [ -20, 10 ], "_id" : "162972:19823772", "_distance" : 2476171.4106209576 }
{ "name" : "Name20--10", "loc" : [ 20, -10 ], "_id" : "162972:29392028", "_distance" : 2476171.4106209576 }
...more results...