Appendix-C
Some Astronomical Data
| To the moon* | To the sun* | To the nearest star (Proxima Centauri) | To the center of our galaxy | To the Andromeda Galaxy | To the edge of the observable universe |
|---|---|---|---|---|---|
| \(1.50 \times 10^{11}m\) | \(3.82 \times 10^8m\) | \(4.04 \times 10^{16}m\) | \(2.2 \times 10^{20} m\) | \(2.1 \times 10^{22} m\) | \(\approx 10^{26} m\) |
*Mean distance.
| Property | Unit | Sun | Earth | Moon |
|---|---|---|---|---|
| Mass | Kg | \(1.99 \times 10^{30}\) | \(5.98 \times 10^{24}\) | \(7.36 \times 10^{22}\) |
| Mass | Kg | \(1.99 \times 10^{30}\) | \(5.98 \times 10^{24}\) | \(7.36 \times 10^{22}\) |
| Mass | Kg | \(1.99 \times 10^{30}\) | \(5.98 \times 10^{24}\) | \(7.36 \times 10^{22}\) |
| Mean radius | m | \(6.96 \times 10^{8}\) | \(6.37 \times 10^{6}\) | \(1.74 \times 10^{6}\) |
| Mass | Kg | \(1.99 \times 10^{30}\) | \(5.98 \times 10^{24}\) | \(7.36 \times 10^{22}\) |
| Mean density | \(Kg/m^3\) | \(1410\) | \(5520\) | \(3340\) |
| Free-fall acceleration at the surface | \(m/s^2\) | \(274\) | \(9.81\) | \(1.67\) |
| Free-fall acceleration at the surface | km/s | \(618\) | \(11.2\) | \(2.38\) |
| Mass | Kg | \(1.99 \times 10^{30}\) | \(5.98 \times 10^{24}\) | \(7.36 \times 10^{22}\) |
| \(Period ~of ~rotation^a\) | — | \(37~ d~ at~ poles^b\) \(26~ d~ at~ equator^b\) | \(23~ h~ 56~ min\) | \(27.3~ d\) |
| \(Radiation~ power^c\) | Kg | \(3.90 \times 10^{26}\) |
\(^{a}Measured~ with ~respect~ to~ the ~distant~ stars.\) \(^{b}The~ Sun, ~a ~ball~ of~ gas,~ does~ not~ rotate~ as~ a ~rigid~ body.\) \(^{c}Just~ outside~ Earth’s~ atmosphere~ solar~ energy~ is~ received,~ assuming~ normal ~incidence,\)\(~at ~the~ rate~ of~ 1340~ W/m^2\).
Table 13-3 Some Properties of the Planets
| Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto\(^d\) | |
|---|---|---|---|---|---|---|---|---|---|
| \(Mean~distance\)\(~from~Sun,\)\(~10^6 km\) | 57.9 | 108 | 150 | 228 | 778 | 1430 | 2870 | 4500 | 5900 |
| Eccentricity of orbits | 0.206 | 0.0068 | 0.0167 | 0.0934 | 0.0485 | 0.0556 | 0.0472 | 0.0086 | 0.250 |
| Period of revolution, y | 0.241 | 0.615 | 1.00 | 1.88 | 11.9 | 29.5 | 84.0 | 165 | 248 |
| Period of rotation,\(^a\) d | 55.7 | -243\(^b\) | 0.997 | 1.03 | 0.409 | 0.436 | -0.451\(^b\) | 0.658 | 6.39 |
| Orbital speed, km/s | 47.9 | 35.0 | 29.8 | 24.1 | 13.1 | 9.64 | 6.81 | 5.43 | 4.74 |
| Inclination of axis to orbit, degree | \(< 28^\circ\) | \(\approx 3^\circ\) | \(23.4^\circ\) | \(25.0^\circ\) | \(3.08^\circ\) | \(26.7^\circ\) | \(97.9^\circ\) | \(29.6^\circ\) | \(57.5^\circ\) |
\(^a\) Measured with respect to distant stars.
\(^b\) Venus and Urenus rotate opposite their orbital motion.
\(^c\) Gravitational acceleration measured at the planet’s equator.
\(^d\) Pluto is a dwarf planet.