Astronomy — Solar System & EM Spectrum

Planetary data, orbital properties, emission spectra, and the electromagnetic spectrum.

Solar System Objects Data Table

Key physical and orbital properties of planets, the Moon, dwarf planets, and asteroids. Note trends in revolution period, eccentricity, and density.

Reference Table p. 2

1
Highest orbital eccentricity (planet)Mercury (0.206)
2
Lowest orbital eccentricity (planet)Venus (0.007) / Neptune (0.009)
3
Largest planet (diameter & mass)Jupiter (142,984 km)
4
Least dense planetSaturn (~0.69 g/cm³, would float in water)
5
Dwarf planets listedCeres, Pluto, Eris
6
Revolution vs. Distance trendPeriod of revolution increases with distance from Sun

Celestial Object	Mean distance (million km)	Revolution	Rotation	Eccentricity	Diameter (km)	Axial Tilt
Sun	---	---	27 d	---	1,392,000	7.25°
Mercury	57.9	88 d	59 d	0.206	4,879	0.03°
Venus	108.2	224.7 d	243 d	0.007	12,104	177.4°
Earth	149.6	365.26 d	23 h 56 min 4 s	0.017	12,756	23.49°
Earth’s Moon	149.6	27.3 d	27.3 d	0.055	3,476	6.68°
Mars	228.0	1.9 y	24 h 37 min 23 s	0.094	6,792	25.19°
Jupiter	778.5	11.9 y	9 h 50 min 30 s	0.048	142,984	3.13°
Saturn	1432.0	29.5 y	10 h 14 min	0.054	120,536	26.73°
Uranus	2867.0	83.7 y	17 h 14 min	0.047	51,118	97.77°
Neptune	4515.0	163.7 y	16 h	0.009	49,528	28.32°

Portion of Electromagnetic Spectrum & Emission Spectra

Electromagnetic spectrum ordered by wavelength and frequency. As wavelength decreases, photon energy and frequency increase. Star emission spectra identify composition.

Reference Table p. 3

1
Longest wavelength / lowest frequencyRadio waves
2
Shortest wavelength / highest energyGamma rays
3
Visible spectrum range400 nm (violet) to 700 nm (red)
4
Wavelength vs. Frequency relationshipInversely related (shorter wavelength = higher frequency)
5
Redshift observationSpectral lines shifted toward longer wavelengths indicate object moving away