Processing math: 100%

Earth Similarity Index

Question P2.6.3

The Earth Similarity Index (ESI) attempts to quantify the physical similarity between an astronomical body (usually a planet or moon) and Earth. It is defined by ESIj=ni=1(1|xi,jxi,xi,j+xi,|)wi/n

where the parameters xi,j are described, and their terrestrial values, xi, and weights, wi given in the table below. The radius, density and escape velocities are taken relative to the terrestrial values. The ESI lies between 0 and 1, with the values closer to 1 indicating closer similarity to Earth (which has an ESI of exactly 1: Earth is identical to itself!)

iParameterEarth Value, xi,Weight, wi
1Radius1.00.57
2Density1.01.07
3Escape velocity, vesc1.00.7
4Surface temperature288 K5.58

The file ex2-6-g-esi-data.txt contains the above parameters for a range of astronomical bodies. Use these data to calculate the ESI for each of the bodies. Which has properties "closest" to those of the Earth?


Solution P2.6.3