2. Mercury
orbit: 57,910,000 km (0.38
AU) from Sun
diameter: 4,880 km
mass: 3.30e23 kg
• closest planet to the Sun and the eighth largest
• slightly smaller in diameter than the moons
Ganymede and Titan but more than twice as
massive
3. Mercury
• has been known since at least the time of
the Sumerians
• given separate names for its apparitions as
a morning star and as an evening star
• Heraclitus even believed that Mercury and
Venus orbit the Sun, not the Earth.
4. Mercury
• Has the most extreme temperature
variations in the solar system raging from
90K to 700K
• is in many ways similar to the Moon: its
surface is heavily cratered and very old; it
has no plate tectonics.
• Mercury is the second densest major body in
the solar system, after Earth (much denser
than the moon)
5. Mercury
Mercury Craters
This indicates that Mercury's dense iron core is
relatively larger than Earth's, probably
comprising the majority of the planet. Mercury
therefore has only a relatively thin silicate
mantle and crust.
6. Mercury
• Mercury's orbit is highly eccentric ; at
perihelion it is only 46 million km from the
Sun but at aphelion it is 70 million. The
position of the perihelion precesses around
the Sun at a very slow rate
7. Mercury
19th century astronomers made very careful observations of
Mercury's orbital parameters but could not adequately explain
them using Newtonian mechanics. The tiny differences
between the observed and predicted values were a minor but
nagging problem for many decades. It was thought that
another planet (sometimes called Vulcan) slightly closer to the
Sun than Mercury might account for the discrepancy. But
despite much effort, no such planet was found. The real
answer turned out to be much more dramatic: Einstein's
General Theory of Relativity! Its correct prediction of the
motions of Mercury was an important factor in the early
acceptance of the theory.
8. Venus
Venus (Greek: Aphrodite;
Babylonian: Ishtar) is the
goddess of love and beauty
• The planet is so named probably because it is the
brightest of the planets known to the ancients.
(With a few exceptions, the surface features on
Venus are named for female figures.)
9. Venus
• known since prehistoric times. It is the
brightest object in the sky except for the Sun
and the Moon
• Like Mercury, it was popularly thought to be
two separate bodies: Eosphorus as the
morning star and Hesperus as the
evening star , but the Greek astronomers
knew better. (Venus's apparition as the
morning star is also sometimes called
Lucifer.)
10. Venus
• There are strong (350 kph) winds at the
cloud tops but winds at the surface are very
slow, no more than a few kilometers per
hour.
• once had large amounts of water like Earth
but it all boiled away. Venus is now quite
dry. Earth would have suffered the same
fate had it been just a little closer to the Sun
11. Venus
• Most of Venus' surface consists of gently
rolling plains with little relief. There are also
several broad depressions: Atalanta
Planitia, Guinevere Planitia, Lavinia
Planitia.
12. Venus
• two large highland areas: Ishtar Terra in the
northern hemisphere (about the size of
Australia) and Aphrodite Terra along the
equator (about the size of South America)
13. Venus
• The interior of Ishtar consists mainly of a high
plateau, Lakshmi Planum, which is
surrounded by the highest mountains on
Venus including the enormous Maxwell
Montes.
14. Earth
orbit: 149,600,000 km (1.00 AU)
from Sun
diameter: 12,756.3 km
mass: 5.972e24 kg
• Earth is the third planet from the Sun and the
fifth largest
• Earth is the only planet whose English name does
not derive from Greek/Roman mythology. The
name derives from Old English and Germanic.
15. Earth
• There are strong (350 kph) winds at the
cloud tops but winds at the surface are very
slow, no more than a few kilometers per
hour.
• once had large amounts of water like Earth
but it all boiled away. Venus is now quite
dry. Earth would have suffered the same
fate had it been just a little closer to the Sun
16. Earth
The Earth is divided into several layers which have
distinct chemical and seismic properties (depths in
km):
0 – 40 Crust
40 – 400 Upper Mantle
400 – 650 Transition
Region
650 – 2700 Lower Mantle
2700 – 2890 D” Layer
2700 – 5150 Outer Core
5150 – 6378 Inner Core
17. Earth
Most of the mass of the Earth is in the mantle, most
of the rest in the core; the part we inhabit is a tiny
fraction of the whole (values below x10^24
kilograms):
Atmosphere 0.0000051
Ocean 0,0014
Crust 0,026
Mantle 4.043
Outer core 1.835
Inner core 0.09675
18. Mars
Mars (Greek: Ares) is the god
of War. The planet probably
got this name due to its red
color
• sometimes referred to as the Red Planet. (An
interesting side note: the Roman god Mars was a
god of agriculture before becoming associated
with the Greek Ares; those in favor of colonizing
and terraforming Mars may prefer this
symbolism.)
• The name of the month March derives from Mars.
20. Mars
• Mars' orbit is significantly elliptical. One result
of this is a temperature variation of about 30 C
at the subsolar point between aphelion and
perihelion (major influence on its climate)
• While the average temperature on Mars is
about 218 K (-55 C, -67 F), Martian surface
temperatures range widely from as little as 140
K (-133 C, -207 F) at the winter pole to almost
300 K (27 C, 80 F) on the day side during
summer.
21. Mars
The interior of Mars is known only by inference from data
about the surface and the bulk statistics of the planet. The
most likely scenario is a dense core about 1700 km in
radius, a molten rocky mantle somewhat denser than the
Earth's and a thin crust. Data from Mars Global Surveyor
indicates that Mars' crust is about 80 km thick in the
southern hemisphere but only about 35 km thick in the
north. Mars' relatively low density compared to the other
terrestrial planets indicates that its core probably contains
a relatively large fraction of sulfur in addition to iron (iron
and iron sulfide).
22. Mars
Mars has two tiny satellites which orbit very close
to the martian surface:
Satellite (000 km) (km) (kg) Discover Year
er
Phobos 9 11 1.08e16 Hall 1877
Deimos 23 6 1.80315 Hall 1877
23. Jupiter
Jupiter (a.k.a. Jove; Greek Zeus)
was the King of the Gods, the
ruler of Olympus and the patron
of the Roman state.
• Jupiter is the fourth brightest object in the sky
(after the Sun, the Moon and Venus)The name
of the month March derives from Mars
• known since prehistoric times as a bright
"wandering star".
24. Jupiter
• 1610 when Galileo first pointed a telescope
at the sky he discovered Jupiter's four large
moons Io, Europa, Ganymede and Callisto
(now known as the Galilean moons)
• This was the first discovery of a center of
motion not apparently centered on the
Earth.
25. Jupiter
It was a major point in favor of Copernicus's
heliocentric theory of the motions of the planets
(along with other new evidence from his telescope:
the phases of Venus and the mountains on the
Moon). Galileo's outspoken support of the
Copernican theory got him in trouble with the
Inquisition.
26. Saturn
Saturn is the god of agriculture.
The associated Greek god
• Saturn has been known since prehistoric times.
Galileo was the first to observe it with a telescope
in 1610
• Early observations of Saturn were complicated by
the fact that the Earth passes through the plane
of Saturn's rings every few years as Saturn moves
in its orbit
27. Saturn
• Saturn's rings remained unique in the known
solar system until 1977 when very faint rings
were discovered around Uranus (and shortly
thereafter around Jupiter and Neptune
• Saturn is visibly flattened (oblate) when viewed
through a small telescope; its equatorial and
polar diameters vary by almost 10% (120,536
km vs. 108,728 km). This is the result of its
rapid rotation and fluid state. The other gas
planets are also oblate, but not so much so.
28. Saturn
• Saturn is the least dense of the planets; its
specific gravity (0.7) is less than that of
water.
• Saturn is the least dense of the planets; its
specific gravity (0.7) is less than that of
water.
• Saturn's interior is similar to Jupiter's
consisting of a rocky core, a
liquid metallic hydrogen layer and a
molecular hydrogen layer. Traces of various
ices are also present.
29. Saturn
• Saturn's rings are extraordinarily thin:
though they're 250,000 km or more in
diameter they're
less than one kilometer thick. Despite
their impressive appearance, there's
really very little material in the rings -- if
the rings were compressed into a single
body it would be no more than 100 km
across.
30. Uranus
ancient Greek deity of the
Heavens, the earliest supreme
god
• the first planet discovered in modern times,
was discovered by William Herschel while
systematically searching the sky with his
telescope on March 13, 1781
• (the earliest recorded sighting was in 1690
when John Flamsteed cataloged it as 34
Tauri)
31. Uranus
• The name "Uranus" was first proposed by
Bode in conformity with the other planetary
names from classical mythology but didn't
come into common use until 1850.
• Uranus' axis is almost parallel to the ecliptic.
• Uranus' south pole was pointed almost
directly at the Sun. This results in the odd
fact that Uranus' polar regions receive more
energy input from the Sun than do its
equatorial regions.
32. Uranus
• Uranus is composed primarily of rock and
various ices, with only about 15%
hydrogen and a little helium (in contrast to
Jupiter and Saturn which are mostly
hydrogen).
• Uranus has bands of clouds that blow
around rapidly. But they are extremely
faint, visible only with radical image
enhancement
34. Uranus
• Uranus' blue color is the result of
absorption of red light by methane in the
upper atmosphere.
• Uranian rings were the first after Saturn's
to be discovered. This was of
considerable importance since we now
know that rings are a common feature of
planets, not a peculiarity of Saturn alone.
35. Neptune
the god of the Sea.
• . Neptune was first observed by Galle and
d'Arrest on 1846 Sept 23 very near to the
locations independently predicted by Adams
and Le Verrier from calculations based on
the observed positions of Jupiter, Saturn
and Uranus
36. Neptune
• Neptune's composition is probably similar
to Uranus': various "ices" and rock with
about 15% hydrogen and a little helium.
Like Uranus
• Neptune's blue color is largely the result
of absorption of red light by methane in
the atmosphere but there is some
additional as-yet-unidentified
chromophore which gives the clouds their
rich blue tint.
37. Neptune
• Neptune has rapid winds confined to
bands of latitude and large storms or
vortices. Neptune's winds are the fastest
in the solar system, reaching 2000
km/hour.
• Neptune has an internal heat source -- it
radiates more than twice as much energy
as it receives from the Sun.
38. Neptune
• Neptune's rings have been given names: the
outermost is Adams (which contains three
prominent arcs now named Liberty, Equality
and Fraternity), next is an unnamed ring co-
orbital with Galatea, then Leverrier (whose
outer extensions are called Lassell and
Arago), and finally the faint but broad Galle.
• Neptune's magnetic field is, like Uranus',
oddly oriented and probably generated by
motions of conductive material (probably
water) in its middle layers.
39. Neptune
Neptune can be seen with binoculars (if you
know exactly where to look) but a large
telescope is needed to see anything other
than a tiny disk. There are several
Web sites that show the current position of
Neptune (and the other planets) in the sky,
but much more detailed charts will be
required to actually find it. Such charts can
be created with a planetarium program.
40. Pluto
orbit: 5,913,520,000 km (39.5 AU)
from the Sun (average)
diameter: 2274 km
mass: 1.27e22 kg
• In Roman mythology, Pluto (Greek: Hades)
is the god of the underworld. The planet
received this name (after many
other suggestions) perhaps because it's so
far from the Sun that it is in perpetual
darkness and perhaps because "PL" are the
initials of Percival Lowell
41. Pluto
• Pluto was discovered in 1930 by a
fortunate accident
• After the discovery of Pluto, it was quickly
determined that Pluto was too small to
account for the discrepancies in the orbits
of the other planets
• Fortunately, Pluto has a satellite, Charon
42. Pluto
• Charon was discovered (in 1978) just before
its orbital plane moved edge-on toward the
inner solar system. It was therefore possible
• The surface temperature on Pluto
to observevaries between about -235 and -210 C over
many transits of Pluto
Charon and viceK). The "warmer"regions that
(38 to 63 versa
roughly correspond to the
regions
• Pluto's orbit is highly optical wavelengths times it is
appear darker in
eccentric. At
closer to the Sun than Neptune (as it was
from January 1979 thru February 11 1999).
Pluto rotates in the opposite direction from
most of the other planets.
43. Pluto
• The surface temperature on Pluto varies between
about -235 and -210 C (38 to 63 K). The "warmer"
regions roughly correspond to the regions that
appear darker in optical wavelengths
• Pluto's composition is unknown, but its density
(about 2 gm/cm3) indicates that it is probably
a mixture of 70% rock and 30% water ice much
like Triton. The bright areas of the surface
seem to be covered with ices of nitrogen with
smaller amounts of (solid) methane, ethane
and carbon monoxide
44. Pluto
Little is known about Pluto's atmosphere, but it probably
consists primarily of nitrogen with some carbon monoxide
and methane. It is extremely tenuous, the surface
pressure being only a few microbars. Pluto's atmosphere
may exist as a gas only when Pluto is near its perihelion;
for the majority of Pluto's long year, the atmospheric
gases are frozen into ice. Near perihelion, it is likely that
some of the atmosphere escapes to space perhaps even
interacting with Charon. NASA mission planners want to
arrive at Pluto while the atmosphere is still unfrozen
46. Moon
orbit : 384,400 km from Earth
diameter : 3476 km
mass : 7.35e22 kg
• It is the second brightest object in the sky
after the Sun
47. Moon
• Moon orbits around the Earth once per month, the
angle between the Earth, the Moon and the Sun
changes; we see this as the cycle of the Moon's
phases. The time between successive new moons
is 29.5 days (709 hours), slightly different from the
Moon's orbital period (measured against the stars)
since the Earth moves a significant distance in its
orbit around the Sun in that time.
• Due to its size and composition, the Moon is
sometimes classified as a terrestrial "planet" along
with Mercury, Venus, Earth and Mars.
48. Moon
• gravitational forces
between the Earth and the
Moon cause some
interesting effects. The
most obvious is the tides.
The Moon's gravitational
attraction is stronger on the
side of the Earth nearest to
the Moon and weaker on
the opposite side. Since the
Earth, and particularly the
oceans, is not perfectly
rigid it is stretched out
along the line toward the
Moon.
49. Moon The Moon has no atmosphere.
But evidence from
Clementine suggested that
there may be water ice in
some deep craters near the
Moon's south pole which are
permanently shaded. This
has now been reinforced by
data from Lunar Prospector.
There is apparently ice at the
north pole as well. A final
determination will probably
come from NASA's Lunar
Reconnaissance Orbiter,
scheduled for 2008.
50. Moon
• The Moon's crust averages 68 km thick and
varies from essentially 0 under Mare Crisium to
107 km north of the crater Korolev on the lunar
far side. Below the crust is a mantle and
probably a small core (roughly 340 km radius
and 2% of the Moon's mass).
51. Moon
There are two primary types of terrain on the
Moon: the heavily cratered and very old
highlands and the relatively smooth and
younger maria. The maria (which comprise
about 16% of the Moon's surface) are huge
impact craters that were later flooded by molten
lava. Most of the surface is covered with
regolith, a mixture of fine dust and rocky debris
produced by meteor impacts. For some
unknown reason, the maria are concentrated on
the near side.
