When we look at Jupiter we see only the uppermost cloud layers in its atmosphere. The composition of the atmosphere at this level can be determined spectroscopically . The first re¬ported observations of dark absorption bands in Jupiter’s spectrum were made by Angelo Secchi in 1863. It was not until the early 1930s that the […]
Jupiter, the nearest, of the giant, planets, in also the largest and most massive. It appears brighter than any other planet apart from Venus; at times it may even cast, a shadow. Some of its surface features, and the four brightest satellites, can easily be seen in a small telescope, or even in binoculars. .Jupiter’s […]
The inner planets and their satellites, described in the previous chapter, comprise less than half of one per cent of the planetary mass in the Solar System: more than 99.5 per cent of the planetary matter is found beyond the orbit of Mars. This region includes most of the asteroids and comets, the giant planets […]
Mars has two small satellites, PHOBOS and DEIMOs, . They are irregularly shaped, very dark objects liberally covered with craters . This gives them the appearance of modestly-sized asteriods but their almost circular orbits make it unlikely that they are simply captured asteroids. Several astronomers have suggested that they are the shattered remains of an […]
Compared TO the Earth. Mars has a thin atmosphere and Venus & thick one whereas Mercury and the Moon do not have one at all. Table 10.3 lists some of the gases which we might expect to find in planetary atmospheres because they are volatile compounds of the cosmically common elements. If a planet ever […]
From measurements of radioactive decay products, it is possible to measure the age pattern of the Earth’s continents. They are found to have an ancient nucleus, at least 2.5 billion years old, onto which successively younger extensions have been welded, a process still continuing today. The growth has not been regular and in particular there […]
Owing to the thick clouds we know little of the surface of Venus. Reference has already been made to the craters observed by radar. There is a scarcity of small craters; this is to be expected because the dense atmosphere would burn up the smaller meteoroids which would otherwise produce these craters. Venus is a […]
Because Mercury is so much nearer to the Sun, it receives ten times as much solar energy per unit surface area when it is at perihelion than does the Moon. Because of the coupling between Mercury’s orbital motion and rotation the meridians at 0° and 180° longitude receive two and a half times more radiation […]
Perhaps the most remarkable aspect of the Martian surface is the distribution of craters larger than 10km in diameter, which are much commoner in the southern hemisphere than hi the northern. Much of the northern hemisphere has been flooded with lava and this has evidently obliterated the craters that must have existed at one time. […]
The surface of the Moon can, roughly speaking, be divided into two contrasting types – dark, comparatively smooth areas called MARIA (singular: mare) and brighter, more rugged regions called TERRAE. The maria cover about one-third of the Moon’s near side but are almost completely absent from the far side. Maria is the Latin word for […]