NEO Distances
When a report is made of a close approach of an asteroid to the Earth, distances are often specified in Astronomical Units (AU) or possibly in Lunar Distances (LD). The table below relates these two units to the more familiar unit of the kilometre, and also to the Earth's radius (Re).
Note that 1 AU is just under 150 million km, and 1 LD = 0.00256 AU ~ 60 Re.
| AU | LD | KM | Earth Radii |
|---|---|---|---|
| 0.0001 | 0.04 | 14,960 | 2 |
| 0.0002 | 0.08 | 29,920 | 5 |
| 0.0003 | 0.12 | 44,879 | 7 |
| 0.0004 | 0.16 | 59,839 | 9 |
| 0.0005 | 0.19 | 74,799 | 12 |
| 0.0006 | 0.23 | 89,759 | 14 |
| 0.0007 | 0.27 | 104,719 | 16 |
| 0.0008 | 0.31 | 119,678 | 19 |
| 0.0009 | 0.35 | 134,638 | 21 |
| 0.001 | 0.39 | 149,598 | 23 |
| 0.002 | 0.78 | 299,196 | 47 |
| 0.003 | 1.17 | 448,794 | 70 |
| 0.004 | 1.56 | 598,392 | 94 |
| 0.005 | 1.95 | 747,989 | 117 |
| 0.006 | 2.34 | 897,587 | 141 |
| 0.007 | 2.72 | 1,047,185 | 164 |
| 0.008 | 3.11 | 1,196,783 | 188 |
| 0.009 | 3.5 | 1,346,381 | 211 |
| 0.01 | 3.89 | 1,495,979 | 234 |
| 0.02 | 7.78 | 2,991,957 | 469 |
| 0.03 | 11.68 | 4,487,936 | 703 |
| 0.04 | 15.57 | 5,983,915 | 938 |
| 0.05 | 19.46 | 7,479,894 | 1172 |
| 0.06 | 23.35 | 8,975,872 | 1407 |
| 0.07 | 27.24 | 10,471,851 | 1641 |
| 0.08 | 31.13 | 11,967,829 | 1876 |
| 0.09 | 35.03 | 13,463,809 | 2110 |
| 0.1 | 38.92 | 14,959,787 | 2345 |
| 0.2 | 77.83 | 29,919,574 | 4690 |
| 0.3 | 116.75 | 44,879,364 | 7034 |
| 0.4 | 155.67 | 59,839,148 | 9379 |
| 0.5 | 194.59 | 74,798,936 | 11724 |
| 0.6 | 233.5 | 89,758,728 | 14069 |
| 0.7 | 272.42 | 104,718,512 | 16414 |
| 0.8 | 311.34 | 119,678,296 | 18758 |
| 0.9 | 350.26 | 134,638,080 | 21103 |
Material prepared by John Kennewell
