with the Lares (q.v.) proves that he is not regarded as a war-god who could avert the raid of an enemy. Still more striking is the invocation of Mars (with the cult-title Silvanus) in the yearly lustration of his land by the Roman farmer (Cato, De re rustica, 141), where it is not a human enemy, but disease, and all unwholesome influences, which the god is besought to avert from the farm and land, plantations and flocks. Three times the procession went round the land, reciting prayers and driving the victims to be sacrificed, viz. ox, sheep and pig (suovetaurilia), representing the farmer’s most valuable stock. We can hardly doubt that in the state ceremony of the Ambarvalia, i.e. the lustratio of the ager romanus in its earliest form, the same god was invoked and the same ritual used (Fowler, op. cit. p. 124 seq.). Again in the curious ritual of the sacrifice to Mars of the October horse (Oct. 15: Fowler op. cit. 241), though the animal was undoubtedly a war-horse, the head was cut off and decked with cakes, as we are told (Paul. Diac. 220) ob frugum eventum. Even Quirinus, the form of Mars worshipped in the Quirinal community, is not without an association with agricultural perils, for it was his flamen who sacrificed the victims at the Robigalia on the 25th of April, when the spirit of the mildew (robigus) was invoked to spare the corn (Ovid, Fasti, 4. 901 seq.).
War and agriculture are thus the two factors of human life and experience which are unquestionably prominent in the cult of Mars, and explain his importance in a community like that of Rome: and there is no need, in a short account of this religious conception, to determine whether he was by origin a solar deity, a storm-god, or a vegetation-spirit. His name gives us no help, its etymology is uncertain (Roscher in Mythological Lexicon, s.v. “Mars,” p. 2436). But we are safe in conjecturing that Mars first came into prominence among the Latins and kindred peoples in the course of their long struggle for settlements among the mountains and forests of Italy. The clearing of primeval woodland, the perils of agriculture from the raids of enemies and of wild beasts, and from the ravages of disease, are all indicated in the later Mars cult. The wolf and the woodpecker, denizens of the forest, always remained his sacred animals, and were believed in Italian legend to have led the Piceni and Hirpini to their places of settlement. Mars is specially associated with the early foundation legends of Italy, as was the case at Rome: and it was to him that the ver sacrum was dedicated, i.e. the entire produce of a spring, including the children born then, who were eventually driven forth from their homes to form new settlements elsewhere (Roscher in Lex. Myth. 2411). The fierce character of the god, gained no doubt in this period of struggle and danger, never entirely left him. Even in the hymn of the Fratres Arvales he is the “fierce Mars” (fere Mars), and in the prayer of Cato’s farmer, though he has become “Father Mars,” he is Silvanus (q.v.), the dweller in the woodland which surrounded the agricultural clearing.
See Roscher in Myth. Lex. s.v. 2385 seq.; Wissowa, Religion und Kultus der Römer, p. 129 seq.; Preller, Römische Mythologie, ed. Jordan, i. 332 seq.; Fowler, Roman Festivals, p. 33 seq. (W. W. F.*)
MARS, in astronomy, the fourth planet in the order of distance
from the sun, and the next outside the earth. To the naked
eye it appears as a bright star of a decidedly reddish or lurid
tint, which contrasts strongly with the whiteness of Venus
and Jupiter. At opposition it is brighter than a first magnitude
star, sometimes outshining even Sirius. It is by virtue of
its position the most favourably situated of all the planets
for observation from the earth. The eccentricity of its orbit,
0.0933, is greater than that of any other major planet except
Mercury. The result is that at an opposition near perihelion
Mars is markedly nearer to the earth than at an opposition
near aphelion, the one distance being about 35 million miles;
the other 63 million. These numbers express only the minimum
distances at or near opposition, and not the distance at other
times. The time of revolution of Mars is 686.98 days. The
mean interval between oppositions is 2 years 4912 days, but,
owing to the eccentricity of the orbit, the actual excess over
two years ranges from 36 days to more than 212 months. Its
period of rotation is 24 h. 37 m. 22.66 s. (H. G. Bakhuyzen).
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| Fig. 1.—Orbits of Mars and the Earth, showing aspects of the planet relative to the earth and sun. |
Motions.—The accompanying diagram will convey a notion of the varied aspects presented by the planet, of the cycles of change through which they go, and of the order in which the oppositions follow each other. The outer circle represents the orbit of Mars, the inner one that of the earth. AE is the line of the equinoxes from which longitudes are counted. The perihelion of Mars is in longitude 335° at the point π. The ascending node Ω is in longitude 47°. The line of nodes makes an angle of 74° with the major axis, so that Mars is south of the ecliptic near perihelion, but north of it near aphelion. Around the inner circle, representing the earth’s orbit, are marked the months during which the earth passes through the different parts of the orbit. It will be seen that the distance of Mars at the time of any opposition depends upon the month in which opposition occurs. The least possible distance would occur in an opposition about the end of August, a little before Mars reached the perihelion, because the eccentricity of the earth’s orbit throws our planet a little farther from the sun and nearer the orbit of Mars in July than it does in August. The opposition of 1909 occurred on the 24th of September, at a point marked by the year near the equinox, and the month and years of the oppositions following, up to 1941, are also shown in the same way. Tracing them around, it will be seen that the points of opposition travel around the orbit in about 16 years, so that oppositions near perihelion, when Mars is therefore nearest the earth, occur at intervals of 15 or 17 years.
The axis of rotation of the planet is inclined between 23° and 24° to the orbit, and the equator of the planet has the same inclination to the plane of the orbit. The north pole is directed toward a point in longitude 355°, in consequence of which the projection of the planet’s axis upon the plane of the ecliptic is nearly parallel to the line of our equinoxes. This projection is shown by the dotted line SP–NP, which corresponds closely to the line of the Martian solstices. It will be seen that at a September opposition the north pole of the planet is turned away from the sun, so that only the southern hemisphere is presented to us, and only the south pole can be seen from the earth. The Martian vernal equinox is near Q and the northern solstice near A. Here at the point S.P. the northern hemisphere is turned toward the sun. It will be seen that the aspect of the planet at opposition, especially the hemisphere which is visible, varies with the month of opposition, the general rule being that the northern hemisphere of the planet is entirely seen only near aphelion oppositions, and therefore when farthest
