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Earth“Moon
3.84403 105 km
distance
MM 7.35 1025 g
Moon mass
RM 1.738 108 cm
Moon radius
1.738 103 km
R0 8.5 kpc
galactic center“
Sun distance
v0
orbital speed of the 220 km/s
Sun about the
galactic center
Appendix C Units and conversions

Pre¬xes and symbols for powers of 10 Length

1 in 2.54 cm (exact)
1 m 1.094 yd
Standard form Symbol Pre¬x
1 km 0.6214 mi
10 18 (See Appendix B for astronomical length units.)
a atto
10 15 f femto
10 12 p pico
Energy
10 9 n nano
10 6 micro
1 joule 107 erg
10 3 m milli
1 erg 6.242 1011 eV
10 2 c centi
mpc2 938.3 MeV
10 1 d deci
mec2 0.511 MeV
101 da deca
1 jansky (Jy) 10 26 W/m2 Hz
102 h hecto
103 k kilo
106 M mega
109 G giga
1012 T tera
Appendix D Planet and satellite properties

Tables D.1 and D.2 were compiled from material appearing in NASA™s ˜Planetary fact sheet™.




Table D.1. Planet properties.
Orbital Axis
a period i Rotation tilt Mass Radius
Planet (AU) (yr) (deg) e period (deg) (Earth) (Earth)

58.8d
Mercury 0.387 0.241 7.00 0.205 0 0.055 0.383
244d
Venus 0.723 0.615 3.40 0.007 2 0.815 0.949
23.9h
Earth 1.000 1.000 0.00 0.017 23.5 1.000 1.000
24.6h
Mars 1.52 1.88 1.90 0.094 28.2 0.107 0.533
9.9h
Jupiter 5.20 11.9 1.30 0.049 3.1 318 11.2
10.7h
Saturn 9.58 29.4 2.50 0.057 26.7 95.2 9.45
17.2h
Uranus 19.2 83.7 0.78 0.046 82.1 14.5 4.01
16.1h
Neptune 30.1 163.7 1.78 0.011 28.3 17.1 3.88
6.39d
Pluto 39.2 248 17.2 0.244 122 0.002 0.19
a Semi-major axis of orbit; i inclination of orbit; e eccentricity of orbit. Rotation period is sidereal.
1 AU 149 600 000 km. Mass and radius are given as a fraction of Earth™s. Mass of Earth 5.997 1027 g.
Radius of Earth (equatorial) 6378 km.
556 APPENDIX D




Table D.2. Satellite properties.
Orbital
a period i Mass Radius
3
(1020 kg)
(10 km) (days) e (deg) (km)

Earth
18.3“28.6 Va
Moon 385 27.3 0.055 730 000 1738
Mars
Phobos 9.38 0.319 0.018 1.0 0.09 13
Deimos 23.5 1.26 0.002 2.0 0.02 7.5
Jupiterb
Galilean satellites
Io 422 1.77 0.000 0.04 893 1822
Europa 671 3.55 0.000 0.47 480 1561
Ganymede 1070 7.16 0.001 V 0.21 1482 2631
Callisto 1880 16.7 0.007 0.51 1076 2410
Lesser satellites
Metis 128 0.298 0 0.02 0.01 20
Adrastea 129 0.295 0 0.03 0.002 10*
Amalthea 181 0.489 0.003 0.4 0.075 75*
Thebe 222 0.670 0 0 0.008 50*
Leda 11 200 239 0.16 V 26.7 0.000 06 5
Himalia 11 500 251 0.16 V 27.6 0.095 85
Lysithea 11 720 260 0.110 V 29.0 0.0008 12
Elara 11 790 260 0.22 V 24.8 0.008 40
610 Rc
Ananke 21 280 0.24 V 149 0.0004 10
Carme 23 400 702 R 0.25 V 165 0.001 15
Pasiphae 23 620 708 R 0.41 V 15 0.003 18
Sinope 23 940 724 R 0.25 V 158 0.008 14
Saturna
Greater satellites
Mimas 184 0.942 0.020 1.5 0.0005 200*
Enceladus 238 1.37 0.004 0.0 0.001 248*
Tethys 295 1.89 0.000 1.9 0.01 527*
Dione 377 2.74 0.002 0.0 0.02 560
Rhea 527 4.52 0.001 0.4 0.034 764
Titan 1222 15.9 0.029 0.3 1.8 2575
Hyperion 1481 21.2 0.104 0.4 142*
Iapetus 3561 79.3 0.028 14.7 V 0.026 718
Lesser satellites
Pan 133 0.575 0.0 0.000 03 10
Atlas 138 0.602 0.002 0.3 0.0001 17*
Prometheus 139 0.613 0.004 0.0 0.0033 50*
Pandora 142 0.629 0.004 0.0 0.0020 45*
Epimetheus 151 0.694 0.009 0.3 0.0054 60*
PLANET AND SATELLITE PROPERTIES 557



Janus 152 0.695 0.007 0.1 0.0192 90*
Calypso 295 1.89 0.0 0.0004 12*
Telesto 295 1.89 0.0 0.0007 10*
Helene 377 2.74 0.005 0.2 0.0003 16*
Phoebe 13 000 550 R 0.163 175 0.072 110*
Uranus
Major satellites
Miranda 130 1.41 0.003 4.2 0.66 235
Ariel 191 2.52 0.003 0.3 13.5 580
Umbriel 266 4.14 0.005 0.3 11.7 585
Titania 436 8.71 0.002 0.1 35.2 789
Oberon 583 13.5 0.001 0.1 30.1 762
Lesser satellites
Cordelia 49 0.33 20
Ophelia 53 0.37 21
Bianca 59 0.44 27
Cresida 61 0.46 40
Desdimona 63 0.47 32
Juliet 64 0.49 47
Portia 66 0.51 68
Rosalind 70 0.56 36
Belinda 75 0.62 40
Puck 86 0.77 81
Caliban 7320 580 R 141 48
Stephano 8002 677 R 144 10
Sycorax 12 179 1283 R 159 95
Prospero 16 418 1993 R 152 15
Setebos 17 459 2202 R 158 15
Neptune
Naiad 48 0.29 29
Thalassa 50 0.31 40
Despina 52 0.33 74
Galatea 62 0.43 79
Larissa 74 0.55 95
Proteus 118 1.12 210
Triton 355 5.88 0.000 20 214 1353
Nereid 5513 360 0.75 28 0.2 170
Pluto
Charon 17 6.39 0.0 14 600 400
a semi-major axis of orbit; i inclination of orbit; e eccentricity of orbit.
a
For Jupiter and Saturn there are additional smaller satellites, which are not listed here.
b
V variable.
c
R retrograde.
*Indicates an average size for a non-spherical object.
Appendix E Properties of main sequence stars


Spectral type Mv BV T (K) MBOL M/M R/R L/L

105
O5 6 0.45 35 000 10.6 39.8 17.8 3.2
104
B0 3.7 0.31 21 000 6.7 17.0 7.6 1.3
102
B5 0.9 0.17 13 500 2.5 7.1 4.0 6.3
101
A0 0.7 0.0 9 700 0.0 3.6 2.6 7.9
101
A5 2.0 0.16 8 100 1.7 2.2 1.8 2.0
F0 2.8 0.30 7 200 2.7 1.8 1.4 6.3
F5 3.8 0.45 6 500 3.8 1.4 1.2 2.5
G0 4.6 0.57 6 000 4.6 1.1 1.05 1.3
1
G5 5.2 0.70 5 400 5.1 0.9 0.93 7.9 10
1
K0 6.0 0.54 4 700 5.8 0.8 0.85 4.0 10
1
K5 7.4 1.11 4 000 6.8 0.7 0.74 1.6 10
2
M0 8.9 1.39 3 300 7.6 0.5 0.63 6.3 10
3
M5 12.0 1.61 2 600 9.8 0.2 0.32 7.9 10
Appendix F Astronomical coordinates and timekeeping

Coordinate systems one hour for each hour that the Earth rotates. In
addition, at any instant, observers at different lon-
gitudes will measure different hour angles for the
When we want to locate a star, or any other astronomi-
same object. (The hour angles differ by the differ-
cal object, we only need to specify its direction. We
ence in longitudes.)
don™t need its distance. We therefore need only two
(2) To achieve a coordinate system that is the same for
coordinates, two angles, to locate an astronomical
all observers and doesn™t change with time, we
object. Sometimes, it is convenient to think (as the
must fix that coordinate system with respect to a
ancients did) of the stars as being painted on the inside
location on the celestial sphere. We choose as our
of a sphere, the celestial sphere. Just as we can locate
reference point one of the two intersections of the
any place on the surface of Earth with two coordinates,
celestial equator and the ecliptic (the Sun™s path
latitude and longitude, we need two coordinates to
around the sky). These two points are called equinox-
locate an object on the celestial sphere.
es. (When the Sun is at either equinox, all observers
We choose coordinate systems for convenience in a
on Earth have a 12 hr day and a 12 hr night. This
particular application. In general, to set up a coordinate
occurs on the first day of spring and the first day of
system we first identify an equator and then choose coor-
fall.) We choose the vernal equinox, the point where
dinates that correspond to latitude and longitude.
the Sun is on the first day of spring, as our starting
A convenient system for any particular observer is
point for the coordinate, right ascension, designated
the horizon system. The horizon becomes the equivalent
by the symbol . The right ascension is measured
of the equator in that system. The angle around the
from 0 to 24 hr, increasing from west to east. That
horizon, measured from north, through east, south
is, objects with higher right ascensions cross an
and west, is the azimuth. The angle above the horizon is
observer™s meridian later than objects with lower
called elevation. Instead of elevation, we can use the
right ascensions.
zenith distance, which is the angle from the zenith
(overhead) to the object. From their definitions, we can One effect of the Earth™s precession is to move the
see that the sum of the zenith distance and the eleva- equinoxes by about 50 arc sec per year. Thus, the origin
tion is always 90 . The azimuth ranges from 0 to 360 , of our coordinate system is drifting. Therefore, in com-
and the elevation from 90 to 90 (with negative ele- piling a catalog of objects, the time, or epoch, at which
vations being below the horizon). The problem with the coordinates apply must be specified. The epoch is
this system is that, as the Earth rotates, the azimuths usually put in parentheses after the and , for exam-
and elevations of the stars change in a complicated ple, (2000) and (2000). An observer can then calculate
way. It would not be very useful to prepare a catalog of where the objects will be on the date they are to be
stars, just giving their azimuths and elevations. observed (a relatively simple calculation). To keep
One solution is to use a coordinate system based on things simple, we generally agree on standard epochs,
the projection of the Earth™s equator onto the celestial and keep our catalogs on a common standard. Catalogs
sphere, the celestial equator. Such a system is called an that are just coming out use the standard epoch 2000.
equatorial coordinate system. The angle above or below the By changing the standard epoch every 50 years, we
celestial equator is called the declination, and it is desig- don™t have to change too often, and we are able to keep
nated by the symbol “ ”. It ranges from 90 to 90 . As the catalog coordinates reasonably close to the actual
the Earth rotates, the declinations of objects don™t coordinates. (In 50 years, the origin will have moved by
change. Also, the declination doesn™t change as less than one degree.)
observers move around the Earth. There are two ways to Other coordinate systems are useful for studying
measure the other coordinate. particular sets of objects. For example, in studying the
(1) We can measure the angle, going westward, from Solar System, ecliptic coordinates are useful. In this
the observer™s meridian. This is called the hour angle, system, the ecliptic latitude is measured above or
H. We can measure it from 0 to 360 , but it is con- below the ecliptic (from 90 to 90 ), and the ecliptic
venient to express it in units of time, from 0 to longitude is measured around the ecliptic, starting at
24 hr. As the Earth rotates, the hour angle of each the vernal equinox and increasing eastward (from 0
object changes, but in a simple way, increasing by to 360 ).
560 APPENDIX F



A coordinate system that is useful for studying go from one passage of your meridian to the next is this
galactic structure is the galactic coordinate system. (We much longer than the time for a star to go from one pas-
touched on this briefly in Chapter 16.) The galactic lati- sage to the next. Therefore, a day by the Sun, a solar day,
tude b is measured above and below the galactic plane. is longer, by this amount, than a day according to the
The galactic longitude / is measured from the galactic stars, a sidereal day.
center, increasing in the same direction as the right Another problem with solar time is that the right
ascension. ascension of the Sun does not change smoothly. This is
Once an object is located in one coordinate system, the result of two effects. (1) The Earth™s orbit is ellipti-
those coordinates can be transformed into any of the cal, so the Earth moves faster when it is closer to the
other systems. The equations for those transformations Sun, and slower when it is farther away. This variable
are beyond the scope of this brief summary, but the cal- speed is mirrored in the apparent motion of the Sun
culations can be done on a hand calculator, and cer- against the background of stars. (2) The Sun moves
tainly by a computer that would be involved in point- along the ecliptic, which makes a 23.5 angle with the
ing a large telescope. celestial equator. Therefore, the right ascension and dec-
lination of the Sun are both changing. Even if the Sun
were to move along the ecliptic at a constant rate, its
Timekeeping right ascension would change at a variable rate. Because
of these two effects, we define a fictitious object, called
the mean Sun, which moves along the celestial equator
It is natural to use the Earth™s rotation as a basis for
timekeeping. We can keep track of the Earth™s rotation at a uniform rate. Time kept by the mean Sun is called
the mean solar time, and it is the time that would be kept
by noting the motion of the stars. For each rotation of
the Earth the stars make a full circle in the sky. We can by a clock. The relationship between the mean Sun and
the real Sun is given by a quantity called the equation of
therefore measure time by choosing a star, or other
time. This quantity is depicted graphically by the dis-
point in the sky, and seeing the fraction of the daily cir-
cle that it has made. torted figure “8” that appears in the empty areas of
some globes. This is called an analemma.
We choose the reference point to be the vernal equi-
nox. We measure a time, called local sidereal time (LST), To the extent that the solar time is used in astro-
nomical timekeeping, it is usually universal time (UT),
by the progress of the vernal equinox. When the vernal
equinox is at an observer™s meridian, the LST is zero for which is the mean solar time at Greenwich, England. It
that observer. One hour later, the LST is 1 hr; in addi- is often useful to convert from UT to LST for any observ-
tion, the hour angle of the vernal equinox is 1 hr. This er. This is done with the aid of a publication, such as the
means that the LST is simply the hour angle of the vernal Astronomical Almanac, published by the US Naval
equinox. When the LST time is 1 hr, objects with a right Observatory. The Almanac gives, for each date, the LST at
Greenwich at 0h UT. To this, we add the UT of interest,
ascension of 1 hr will be on the meridian. This means
that the LST is also equal to the right ascension of the object multiplied by a factor to account for the difference
that happens to be on the meridian. Observers at two dif- between sidereal and solar times. This gives the LST at
ferent points on Earth will have different LSTs. The LSTs Greenwich at the UT of interest. We then subtract the
longitude of the observer L. We can write this as
will differ by the longitude difference between the two

LST1L, UT 2 10 3 2
observers.
L
LST10, 02 UT11 2.738
Most of our civil timekeeping is referenced to the
Where LST(0,0) is the LST at Greenwich at 0h UT.
Sun. We could define a local solar time, based on the
hour angle of the Sun. This is what a sundial measures, All of this is complicated by the effects of preces-
but this is not very useful for civil systems. For unifor- sion, and the wobble of the Earth, known as nutation.
mity, civil systems utilize time zones. This means that While true sidereal time is the actual hour angle of the
the Sun can be as much as a half an hour ahead or vernal equinox, our sidereal clocks really keep a mean
behind your local time, even more for some very wide sidereal time. There is also a problem in the definition of
time zones. a year. A sidereal year is the time for the Sun to return to
As the Earth moves around the Sun, the Sun appears the same place with respect to the fixed background of
projected against a changing background of stars (pro- stars. We could use this definition, but after a long
gressing through the constellations of the zodiac). This time the precession will cause the seasons to occur in
means that the right ascension of the Sun increases by different months. For this reason, we use a tropical year,
an average of 3m56.56s per day. The time for the Sun to defined as the time it takes for the Sun to travel from
ASTRONOMICAL COORDINATES AND TIMEKEEPING 561



vernal equinox to vernal equinox, remembering that stant rate. We base ephemeris time on the rate of the
mean Sun at the beginning of the year 1900. Ephemeris
the equinox moves while it is happening. A sidereal
time is a certain fraction of the tropical year 1900
year has 365.2564 mean solar days, while a tropical year
has 365.2422 mean solar days. (ephemeris year), which contains 365.242 199 mean
Our definition of the year also brings us back to a solar days, so the ephemeris second is defined as
definition for a universal time, which really has a con- 1/31 556 925 974 of an ephemeris year.
Appendix G Abundances of the elements


Atomic number Symbol Element Atomic weight Relative abundance
by numbera

1 H hydrogen 1.008 1.00
10 1
2 He helium 4.003 1.45
10 9
3 Li lithium 6.939 1.00
10 10
4 Be beryllium 9.013 2.51
10 10
5 B boron 10.812 6.31
10 4
6 C carbon 12.012 3.02
10 5
7 N nitrogen 14.007 9.12
10 4
8 O oxygen 16.000 6.76
10 7
9 F ¬‚uorine 18.999 2.51
10 4
10 Ne neon 20.184 2.75
10 6
11 Na sodium 22.991 1.66
10 5
12 Mg magnesium 24.313 2.88
10 6
13 Al aluminum 26.982 1.91
10 5
14 Si silicon 28.09 2.95
10 7
15 P phosphorus 30.975 3.39
10 5
16 S sulphur 32.066 1.66
10 7
17 Cl chlorine 35.454 2.51
10 6
18 Ar argon 39.949 4.17
10 8
19 K potassium 39.103 7.59
10 6
20 Ca calcium 40.08 1.66
10 10
21 Sc scandium 44.958 8.13
10 8
22 Ti titanium 47.90 6.61
10 9
23 V vanadium 50.944 6.03
10 7
24 Cr chromium 52.00 2.40
10 7
25 Mn manganese 54.940 1.26
10 6
26 Fe iron 55.849 7.94
10 8
27 Co cobalt 58.936 5.25
10 7
28 Ni nickel 58.71 8.51
10 8
29 Cu copper 63.55 4.47
10 8
30 Zn zinc 65.37 1.91
10 10
31 Ga gallium 69.72 2.82
10 9
32 Ge germanium 72.60 1.51
10 10
33 As arsenic 74.924 2.0
10 9
34 Se selenium 78.96 1.6
10 10
35 Br bromine 79.912 4.0
10 9
36 Kr krypton 83.80 1.6
10 10
37 Rb rubidium 85.48 2.24
10 10
38 Sr strontium 87.63 5.62
10 10
39 Y yttrium 88.908 2.51
10 10
40 Zr zirconium 91.22 2.5
10 11
41 Nb niobium 92.91 5.0
10 11
42 Mo molybdenum 95.95 8.32
43 Tc technetium 99.0
ABUNDANCES OF THE ELEMENTS 563



10 11
44 Ru ruthenium 101.07 3.31
10 12
45 Rh rhodium 102.91 6.03
10 11
46 Pd palladium 106.4 1.78
10 12
47 Ag silver 107.874 5.0
10 11
48 Cd cadmium 112.41 3.16
10 12
49 In indium 114.82 7.9
10 11
50 Sn tin 118.70 3.55
10 11
51 Sb antimony 121.78 4.0
10 10
52 Te tellurium 127.61 1.0
10 11
53 I iodine 126.909 2.5
10 10
54 Xe xenon 131.30 1.0
10 11
55 Cs caesium 132.91 1.3
10 10
56 Ba barium 137.35 1.29
10 11
57 La lanthanum 138.92 2.5
10 11
58 Ce cerium 140.13 4.0
10 12
59 Pr praseodymuim 140.913 6.3
10 11
60 Nd neodynium 144.25 3.2
61 Pm promethium 147.0
11
62 Sm samarium 150.36 1.0 10
12
63 Eu europium 151.96 5.0 10
11
64 Gd gadolinium 157.25 1.3 10
12
65 Tb terbium 158.930 2.5 10
11
66 Dy dysprosium 162.50 1.6 10
12
67 Ho holmium 164.937 3.2 10
12
68 Er erbium 167.27 7.9 10
12
69 Tm thulium 168.941 1.3 10
11
70 Yb ytterbium 173.04 1.3 10
12
71 Lu lutecium 174.98 2.0 10
12
72 Hf hafnium 178.50 4.0 10
12
73 Ta tantalum 180.955 2.0 10
11
74 W tungsten 183.86 1.3 10
12
75 Re rhenium 186.3 4.0 10
11
76 Os osmium 190.2 2.0 10
11
77 Ir iridium 192.2 1.6 10
11
78 Pt platinum 195.10 4.0 10
12
79 Au gold 196.977 5.0 10
12
80 Hg mercury 200.60 7.9 10
12
81 Tel thallium 204.38 3.2 10
11
82 Pb lead 207.20 4.0 10
12
83 Bi bismuth 208.988 5.0 10
84 Po polonium 210.0
85 At astatine 211.0
86 Rn radon 222.0
87 Fr francium 223.0
88 Ra radium 226.05
89 Ac actinium 227.0
12
90 Th thorium 232.047 2.0 10
91 Pa protactinium 231.0
12
92 U uranium 238.03 1.0 10

(Continued)
564 APPENDIX G




Atomic number Symbol Element Atomic weight Relative abundance
by numbera

93 Np neptunium 237.05
94 Pu plutonium 242.0
95 Am americium 242.0
96 Cm curium 245.0
97 Bk berkelium 248.0
98 Cf californium 252.0
99 Es einsteinium 253.0
100 Fm fermium 257.0
101 Md mendelevium 257.0
102 No nobelium 255.0
103 Lr lawrencium 256.0
104 Rf rutherfordium 261.0
105 Ha hahnium 262.0
a
Abundances are by number, relative to hydrogen.These represent the best determinations of solar or
Solar System abundances. No entry means that the abundance is not well determined.
Index

and orbit eccentricity, 440, 440
062000, 217 gravitational effects, 371“2
21 cm line, 247, 248 M84, 372 quantization of, 29
and clouds, 249 M87, 372 and star formation, 267
and HI shells, 249, 250 results, 372“3 angular resolution, 41, 42“3
and Hubble constant, 344 jets, 370 angular size, 390
primordial, 409 large energy output, 370 anisotropies, 402
light curves, 365
and redshift surveys, 345 annular eclipse, 438
line spectra, 363
and Zeeman effect, 249 Antarctica, 55
30 Dorado, 323“4, 323 quasars, 362“8 antiparticle, 162, 411
30 m telescope, 72 antiquark, 411“12, 414
radio galaxies, 355“9
300 m telescope, 70 rapid variability, 370 Aphrodite Terra, Venus, 485
APM Galaxy Survey, 336
3C48 (quasar), 364 Seyfert galaxies, 361“2
3C273 (quasar), 363“4, 364, 388 starburst galaxies, 353“5 Apollo mission photographs
spectrum, 364 Apollo 11, 472“3
supermassive black holes, 370
3C279, superluminal expansion, 360 Apollo 17, 472“3
unified picture of, 370“3
3C465 (radio galaxy), 356 Adams, John C., 499 Apollos asteroids, 533
4 m telescope, 47, 55 adiabatic process, 171, 460 apparent magnitudes, 20
40 Eriadni, 146 ages of rocks, 471 Arcturus, 27
5 m telescope, 47, 47 AGN, see active galactic nuclei Aricebo, Puerto Rico, 69, 70
1000 ft telescope, 70 albedo, 242 Aristotle, 430
Armstrong, Neil, 471, 472
of asteroids, 533
A spectral type, 35 of Earth, 453 asteroid belt, 532“3
AAVSO, see American Association of of Jupiter, 508 asteroids, 429, 532“4
Variable Star Observers of Uranus, 498 types, 533
Aldrin, Edwin E., 471, 472
Abell 2218, gravitational lensed astigmatism, 44
quasars, 369 astrometric binary, 83, 84
Algol, 83
aberration 44 Allende meteorite, 531 astronomical unit (AU), 18, 433
of starlight, 126, 126 ALMA, see Atacama Large Millimeter asymptotic giant branch, 179
aberrations, 44 Array Atacama Desert, 75
Alpha Bootes, 27
absolute magnitudes, 20“1 Atacama Large Millimeter Array
Alpha Canis Majoris, 27 (ALMA), 75, 76, 323
absolute simultaneity, 127
absorption, 237, 256, 256 alpha particle, 27, 161 atmosphere, 43, 454“65
absorption coefficient, 103 Alpher, Ralph, 395 Earth, 450
absorption lines, 25, 26, 245, 245 layers, 455
and Follin and Herman, 408
absorption of radiation, 102 from space, 455
and Herman, Robert, 398, 401
abundances alt-azimuth mount, 49 Io, 515
of elements, 101 aluminization, 47 Jupiter, 497
of light elements, primordial, 408 aluminization chamber, 47 Neptune, 504
acceleration in expansion, 391 ambipolar diffusion, 271 outer planets, 500“5
acceleration of gravity, neutron American Association of Variable Star Saturn, 497, 504
star, 198 Observers, 180 Solar System, life in, 543
Titan, 517, 517“18
accelerators, 410 amino acids, on early Earth, 541
Andromeda Galaxy, M31, 315, 317
accretion disks, active galaxies, 370 Uranus, 504
CO map, 326
achondrites, 531 atmosphere (unit), 455
FIR map, 326
achromat, 45 atmospheric transmission, 12
HI map, 325, 325
active galactic nuclei (AGN), 353 atomic number, 159
unified picture, 370“3; see also AU, see astronomical unit
Angstrom, A. J., 10
active galaxies angular magnification, 44 aurora
Earth, 466, 466“7
active galaxies, 322, 353“73 angular measure, 19
Jupiter, 503
accretion disks, 370 angular momentum, 254, 537
Saturn, 503
BL Lac objects, 362 of Earth, 469
in elliptical orbits, 91“2, 92
black hole searches, 371“3 auto-correlation function, 71
566 INDEX



average gas distribution, Milky Way, binary stars, 83“4 bulge, Milky Way, 293
302“4 and circular orbits, 87“91 buoyant force, 169
Doppler shifts, 90 Burnell, Jocelyn Bell, 199
burster, 214
B spectral type, 35 extrasolar planets, 545
Baade, Walter, 202 binary system Butler, R. Paul, 545“7
Butterfly cluster, 222
Baade™s star, 202 binding energy, 90
with circular orbit, 87 butterfly diagram, 114
balloon collection, meteoroids, 530
binding energy, 30, 160“1, 160 Byrd telescope (GBT), 67, 70, 70
Balloon Observations of Millimetric
Extragalactic Radiation and of binary system, 90
Geophysics (BOOMERANG), biological clocks, 129 C , 244
bipolar flows, 283, 283“4
403“4 CII regions, 278
measurements, 404 Callisto, 512, 513
extrasolar planets, 547
Balmer, Johann Jakob, 28 BL Lac objects, 362“3 camera, image formation in, 43
Markarian 421 spectrum, 363 optics of, 44
Balmer formula, 28, 31
Balmer series, 31 black hole, 148“52 Cannon, Annie Jump, 26
approaching, 149, 149
quasars, 363“4 capture, 474
bar (unit), 455 in close binaries, 216“18 carbon dioxide (CO2), on Earth, 448
Barnard™s star, 222 evaporation of, 152 carriers of forces, 411“12
Cas A, supernova remnant in, 195
barred spirals, 317 radio galaxies, 358
Cassegrain focus, 47, 48, 48
barrier penetration, 164 searches for in active galaxies,
Barringer crater, 532 371“3 Cassini™s division, 507
causality problem, 405, 405, 420
baryon, 410 blackbodies, 13“6
CCD, see charge-coupled-device
baryon number, 418 cosmic background radiation of,
density, primordial, 408 395 C2H, 252
cD galaxies, see central dominant
basalts, 470 spectra of, 14
see also cosmic background
on Earth, 448 galaxies
CDM, see cold dark matter
basic features of planets, radiation
Mars, 480“1 blockage in prime focus, 48 cell walls, 543
Mercury, 479 blueshift, 86 cellular level, 541
Cen A (radio galaxy), 357
outer planets, 497“500 Bode™s law, 435, 539
Centaurus cluster, 335, 337
Venus, 479“80 Boeing 747 SP, 64
X-ray image, 338
Bell Telephone Laboratories, 68, Bohr, Neils, 28
Bohr atom, 28, 28“31
251, 398 center of mass, 88
belts, Jupiter, 502 Bohr model, 31 center of universe, 385
asteroid 532“3 Bok, Bart, 68, 268 central dominant (cD) galaxies, 338
bending of electromagnetic radia- Bok globules, 268 central minimum, 42
tion, 144“5 bolometer, 64 central pressure of Sun, 169
bending of starlight, 144 bolometric correction, 21 central temperature of Sun, 170
Besselian year, 180 bolometric magnitude, 20 centrifugal force, asteroids, 533
beta decay, 162, 166 Boltzmann constant, 15 Cepheid distance scale, 182
beta particle, 162 Boltzmann distribution, 33 Cepheid mechanism, 180“1
Betelgeuse, 97 Boltzmann equation, 400 Cepheid variables, 179“83, 221, 315,
BOOMERANG, see Balloon
Bethe, Hans, 395 341, 343, 391
big bang, 384, 395“422 Observations of Millimetric use in measuring Hubble constant,
see also cosmic background Extragalactic Radiation and 342
radiation Geophysics in Milky Way, 293
period luminosity relation for, 182
big bang cosmologies, 395 bottom-up evolution of universe,
347, 348 Cerro Paranal, 50, 51, 52, 55
big bang nucleosynthesis, 407“10
big bang theories, 378 bound system, 29 Cerro Tololo Interamerican
Observatory, 47, 54, 55
big crunch, 384 bound“free process, 105
binary pulsar, 147, 215 Bragg crystal, 75 CH, 245
CH+, 245
energy loss, theory and Brahe, Tycho, 432
observation, 216 brightness of image, 44 CH3CH2OH (ethyl alcohol), 251
orbit of, 215 Brookhaven National Laboratory, 172 CH3OH (methyl alcohol), 251
INDEX 567



CH4 (methane), closed universe, 382 color force, 415, 417
on early Earth, 541 clouds Venus, 479 color“magnitude diagram
for cluster of stars, 231
on Earth, 448 Jupiter, 500“1
for globular cluster, 232
on Titan, 517 Uranus, 498
Chandra, 76, 77 colorless combinations, 414, 414
clumps, interstellar clouds, 266
Chandrasekhar, S., 189 cluster dynamics, 335“8 colors of stars, 12“15
Chandrasekhar limit, 189, 193, 213 cluster variables, 183 column density, 103
channels, Mars, 487 clusters of galaxies, 335“51, 390 coma, 526
dark matter, 337, 338
charge conjugation, 413 spectra, 526
Coma cluster, 335, 336
charge-coupled-device (CCD), 59 Doppler shifts, 336
readout, 60 dynamics, 335“8 comet tails, 526, 530“2
Charon, 523, 524 effect on background radiation, comets, 429, 524“30
relation to meteoroids, 532
chemistry on Jupiter, 500“1 406
internal motions, 337
Chile, 75 co-moving coordinate system,
Chilean Andes, 55 virial mass, 336“7 385, 388
chondrites, meteoroids, 531 X-ray emission, 337 composite spectrum binary, 83
chondrules, 539 clusters of stars, 221“32 composition of planets and moons
color“magnitude diagram, 231
meteoroids, 531 Jupiter, 500
chromatic aberration, 44, 45 for globular cluster, 232 Neptune, 504
chromosphere, 101, 109“10 evaporation time, 229 Titan, 517
circular orbits, 86“91 HR diagram, 231“2 Uranus, 504
circulation pattern, Earth, 464, 464 Venus, Earth and Mars, 492
main sequence fitting, 231
classical Cepheids, 182 internal dynamics, 225 Compton, A. H., 17
Compton scattering, 406, 407
classification of elementary particles, population I, 232
computer models, 421
411 population II, 232
classification potential energy for globular clus- Earth, 464
of galaxies, elliptical galaxies, 315 ter, 227 atmosphere, 454
relaxation time, 228, 228“9
spiral galaxies, 317 interiors, 491, 506
close binaries, 209“11 rms velocity, 227 magnetic effects, 270
accretion disk, 211, 211 virial mass, 229 protostars, 273
binary pulsar, 215 virial theorem, 225“31 universe, 348
energy loss, theory and observa- CN, 245 computer simulations, 539
tion, 216 interstellar, cosmic background condensation, 474
orbit, 215 radiation, 399“401, 400 configuration of planets, 432
burster, 214 CNO cycle, 166, 166 conjunction, 432
with black holes, 216“18 CO (carbon monoxide), 251, 255 conservation laws, 412
classification, 211 in Andromeda Galaxy, M31, 326 conservation of angular
contact, 210, 211 in early Earth, 541 momentum, 265
detached, 210, 211 in Milky way, 303 continental drift on Earth, 451
effective potential, 209, 210 CO maps, 269 ˜continents™ on Venus, 485
Her X-1, 214 Large Magellanic Cloud (LMC), 324 continuous creation, 378
HZ Her, 214 CO observations continuum, 13
Lagrangian points, 209, 210 galaxies, 323 continuum opacity, 395
mass accretion luminosity, 212 starburst galaxies, 353 convection, 171, 273
mass transfer in, 211 CO2, in early Earth, 540“1 on Earth, 460“1
COBE, see Cosmic Background on Jupiter, 500“1, 502
millisecond pulsars, 215
and weather on Earth, 461
neutron stars in, 213“15 Explorer Satellite
novae, 212, 212 cold dark matter (CDM), 348, 420, 421 convection zones, 106
Roche Lobes, 209, 210 collapsing clouds, 272 convergent point, in moving cluster,
224, 224
runaway stars, 214 luminosity, 272
semidetached, 210, 211 Collins, Michael, 471 cooling by evaporation, on Earth, 463
collisional excitation, 32, 256
systems with white dwarfs, 211 Copernican system, 431
type I supernova, 213 color, 413“16 Copernicus, Nicholas, 431, 433
light curve, 213 color changes, Mars, 480 Copernicus (satellite), 63
568 INDEX



spectrum of, 197
core density values
Crab Pulsar, 203
of Earth, 447 of Callisto, 513
of high mass star, 179 variations in, 205 of Europa, 513
core evolution of high mass stars, cratering, on Mercury, 483 of Ganymede, 513
193“4 craters, caused by meteoroids, 530“2, of Io, 513
532
coriolis force of matter, 397
on Earth, 463“4 Crick, James, 542 of neutron stars, 197
on Jupiter, 497 critical density, 383, 390 of Jupiter, 497
coriolis pseudo-force, 463 CRL 2688, 184 of radiation and matter, 398
corona, 101, 110“13 cross section, 102 of Saturn, 497
and effect of scattered light, 111 CS (carbon sulfide), 255 of universe, 409
CTIO, see Cerro Tololo Interamerican
coronagraph, 111 of Uranus, 498
cosmic abundances, 167 Observatory density bounded HII region, 278
Cosmic Background Explorer Satellite Curtis, Heber D., 315 density distribution of dark matter in
(COBE), 401“3 curved space-time, 139, 391“2 galaxies, 331
diagram of satellite, 401 and orbit of Mercury, 144 density parameter, 383, 392, 420“1
Cyg X-1, 216, 216
measuring dipole anisotropy, 402, density wave,
403 Cygnus A, radio galaxy, 356 spiral structure, explanations of,
327, 327“8
measuring small-scale anisotropy,
δ Cephei, 180
403 trigger, 266
spectrum, 402 light curves for, 181 deoxyribose nucleic acid (DNA) 542
cosmic background radiation, 378, D/H, primordial, 409 Descartes, Rene, 537
395“407, 419, 421 dark clouds, 268 detection, 58“60
blackbody spectrum of, 395 dark current, 59 deuterium, primordial, 407“8
CN, interstellar, 399“401, 400 dark matter, 348, 390, 420 deuteron binding energy, 161
COBE study of, 401“3 dark matter in galaxies, 330-3 differential rotation
in Sun, 116
cosmological redshift, 397 density distribution of, 331
Milky Way, 294“302; see also Milky
decoupling, 396 gravitational effects, 330
in clusters of galaxies, 337, 338
density of radiation and matter, Way
398 in individual galaxies, 330“3 differentiation, Earth, 447
diffraction, 42, 42
era of recombination, 395 in the Milky Way, 301
diffraction grating, 60, 61
isotropy, 398 massive compact halo objects
diffraction pattern, 49
matter-dominated universe, 398 (MACHOs), 331
observed spectrum, 399 mass-to-light ratios, 331 dilute blackbody, 245
plasma, 395 neutrino mass, 331 dipole anisotropy, 402
radiation and matter in expanding rotation curves, 330“1 dirty snowball, 525
universe, 396 331 discovery of planets
radiation-dominated universe, 398 data handling, 58“63 Neptune, 498“9
redshifted blackbody spectrum, Davis, Raymond, 172 Pluto, 523
397 DCN, primordial, 409 Uranus, 497“8
spectrum of radiation, 397 disk; see also interstellar clouds, 266
de Broglie, Louis, 31
cosmic rays, 410 de Broglie wavelength, 31 circumstellar, 286, 287
cosmological constant, 384, 389, de Buffon, Georges Leclerc, 537 formation of, 537
391“2, 420, 421 de Laplace, Pierre Simon, 537 in formation of extrasolar
cosmological parameters, values of, de Sitter models, 384 planets, 547
420“2 de Vaucouleur™s law, 317 Milky Way, 293, 301
cosmological principle, 377, 385 deceleration parameter, 383, 388, disk formation, 537
cosmological redshift, 386“8, 387, 397 disks, 286
390, 391
cosmology, 377“92 decoupling, 396, 405, 420 287
expansion of universe, 378“81 degeneracy pressure, 186 extrasolar planets, 547
dispersion, 205, 205
and general relativity, 384“90 degenerate gas, 178, 186
coud© focus, 49, 49 energy levels in, 186 displaying images, 66“8
Crab Nebula, 196, 202 Deimos, 494 distance ambiguity, Milky Way, 302
at different wavelengths, 196 dense cloud cores, 269 distance from Sun, effect of, 538“40
INDEX 569



Himalayas, 452
distance indicators, Hubble constant, escape speed, 439
Kilauea, 449
342“3 history, 447“52
IR image, 454 mid-Atlantic ridge, 451
distance modulus, 20, 389“90
San Andreas fault, 452
distances to objects magnetic field, 447“8
magnetosphere, 465, 465“7 eclipse geometry, 437
to distant objects 341
aurora, 466
to galactic center 299 eclipse of Moon, 437
to an inner planet 433, 434 magnetic mirror, 466 eclipse of Sun, 436“7
van Allen radiation belts, 465
to moving clusters 221“5 eclipse seasons, 437
main tectonic plates, 451 eclipsing binary, 83, 84
to radio galaxies, 356
meteoroids, 531
DNA (deoxyribose nucleic acid), 542 ecliptic, 429
Doppler broadening, 112, 257 and Moon, 447“69 eddies on Jupiter, 502
of spectral lines, 108“9, 108 motion around Sun, 429 Eddington, Sir Arthur, 145
Doppler shift, 84“7, 108, 185, 270, 388 orbital speed, 439 calculation of radiative transfer
for circular orbit, 86 organic compounds, 450 459
clusters of galaxies, 336 origin of life on, 541“3 Eddy, John A., 113
effect of satellites, 512
extrasolar planets, 545“6 plate tectonics, 450“2
Mercury, 479 radioactive dating, 448“50 effective potential, 209
Milky Way, 297 radioactive decay, 450 Effelsburg, Germany, 70
radar, 481“2, 482 rocks found on, 448, 448, 450 efficiency of star formation, starburst
from space, 447; see also Earth,
rotation curves, 331 galaxies, 354
Egg Nebula (CRL 2688), 184
special relativity, 131 features from space
for waves, 85 steps in development of, 448 Einstein, Albert, 16, 125, 377, 384, 416
Drake, Frank, 547 temperature, 452“4 Einstein Observatory, 76, 216
tides, 467“9, 468 Einstein ring, 139
Drake equation, 547“8
see also searches for extraterrestrial precession, 468“9, 468 Einstein™s equation, 388
intelligence volcanoes on, 448 electric dipole moment, 254
Draper, Henry, 26 water vapor, 448 electric force, 415
Dumbbell Nebula (M27), 183 Earth, atmosphere, 464 electricity and magnetism, 416
dust lanes, explanations of spiral computer models, 454 electromagnetic radiation, 548
structure, 328 convection, 460“1 electromagnetic spectrum, 10“12
and weather, 461
dust storms on Mars, 485 electromagnetic waves, 11
dust tail from comets, 526 coriolis force, 463“4 electron, 186, 411
coriolis pseudo-force, 463
dwarf ellipticals, 315 electron degeneracy, 186
dwarfs, 36 general circulation, 463“5 electron degeneracy pressure, 197
greenhouse effect, 458
dynamic range, 60 electron“positron annihilations, 419
hurricanes, 464
dynamical state, superclusters, 345 electronic filters, 71
hurricane Andrew, 464
dynamically relaxed, 225 electroweak force, 416“17
hurricane Floyd, 464
dynamics elementary particles, 410
layers, 455
clusters of galaxies, 335 classification of, 411
elements, abundances of, 167
ring system, 509“12 Maxwell“Boltzmann distribution,
463 elliptical galaxies, 315“17
ozone hole, 462
E-corona, 111 classification of, 315
Eagle Nebula (M16), 275 pressure distribution, 455“7, 456 interstellar medium, 315
early spectral types, 27 pseudo-force, 463“4 luminosity profile, 317
early universe, time line, 418 radiative transport, troposphere, properties, 321
459
Earth, 447“69 rotation, 316“17
atmosphere, 450; see also Earth, retention, 462“3 elliptical orbits, 91“4
angular momentum, 91“2, 92
atmosphere rotation axis of, 429
from space, 455
core, 447 energy, 92“3
crust, 448 temperature distribution, 457“62, observing, 93“4
457 radial velocity vs. time, 93
differentiation, 447
temperature vs. time, 458 Elysium Planitia, Mars, 486
early chemistry, 540“1
emission, 256, 256
early history, 447“8 thickness, 454“5
emission lines, 25, 26
equilibrium temperature, 452“4 Earth, features from space
570 INDEX



FIR, see far infrared emissions
and absorption lines, quasars, 365 evaporation of black holes, 152
starburst galaxies, 353 evaporation time, in cluster of stars, fission, 162, 474
emissivity, Earth, 453 229 five minute oscillation, 106
event horizon, 150, 150
Encke, comet, 528 flaring, Milky Way, 293
energetic flow, Orion region, 282“7, evidence for extrasolar planets, 545“7 in H2, 304
289 evolution of early universe, 395 in HI, 303
bipolar flows, 283“4, 283, 284 evolution of spectrum, radio galaxies, flash spectrum, 110
CO line wings, 282“4, 282 355 flat fielding, 59
Herbig“Haro (HH) objects, 283“4, evolution off the main sequence, flatness problem, 419
283, 284 177“9 flocculent, spiral galaxies, 317
T Tauri stars, 285“6 evolutionary tracks, 178“9 flux, frozen, in neutron stars, 199
flux freezing, 270“2, 271
energy and momentum, in special evolving theories, 378
focal arrangements, 49
relativity, 135 excess of matter over antimatter, 418
energy density of radiation, 397 excitation, 32“3 focal plane, 44
energy flux, 9 excitation temperature, 33, 248 focal ratio, 44
exit cone, 149, 150
energy generation, 171 forces
expanding balloon analogy, 340
energy in elliptical orbits, 92“3 carriers of, 411“12
between neutrons and protons, 160
energy level diagram, 30 expansion of the universe, 339“45,
energy levels in a degenerate gas, 186 378“81; see also big bang; and particles, 412
energy-momentum four vector, 135 universe formation of light elements, primor-
with random motions, 342 dial, 407
energy“redshift problem, 366“8
black hole, 368 extinction, 237“8 formation of spectral lines, 32“6
gravitational redshift, 366 extragalactic distance scale, 391 four-vectors, 132
Hubble™s law, 366 extrasolar planets, 544“7 Fourier transform, 71, 73
kinematic redshift, 366 disks, 547 fractional charges, 411
Doppler shift, 546
quasars, 366“8 fragmentation of collapsing cloud,
266, 266
energy transport, 170 evidence for, 545“7
mass distribution, 547, 547
on Earth, 459 Fraunhofer spectrum, 25
Eotvos experiments, 143 Solar System, appearance of, 544“5 free quark, 411, 414“15
epicycles, 431, 431 eyepiece, 45 free-fall phase, 272
equation of state, Earth, 455 free-fall time, 264“5
free“free radiation, in HII regions, 279
equatorial mount, 49 F spectral type, 35
equilibrium F-corona, 112 Freidmann models, 384, 388“90
Earth, 463 Fabry“Perot interferometer, 61 frequency, 10
interstellar chemistry, 254 false color image, 66 fundamental forces, 411“12
ionization, 33 false gray-scale image, 66 color, 413“16
thermodynamic, 13 far infared emissions symmetries, 412“13
in Andromeda Galaxy (M31), 326
equilibrium temperature unification, 416“17
Earth, 452“4 observations in starburst galaxies, fundamental particles, 410“11
vs. distance from Sun, 454 363 and forces, 410“17
far side of Moon, 474
era of recombination, 395 fusion, 162
ergosphere, 150 fusion barrier, 163
Far Ultraviolet Spectroscopic Explorer
ESA, see European Space Agency (FUSE), 63 overcoming, 162“4
escape speed, Earth, 439, 462“3 Faraday™s law, 270“2
ESO, see European Southern Faraday™s law of induction, 11 G spectral type, 35
Observatory fault line, Earth, 452 gabbros, 448
Eta Carina Nebula (NGC 3372), 276, Fe, present on early Earth, 540 galactic cannibalism, 338
56
277 Fe, 193 galactic center, 68, 306“10
ether, 125 Fermilab, 410 3 kpc arm, 310
ferromagnet, 413, 414
Euclidean geometry, 392 activity, 306
Europa, 512, 513 Feynmann, Richard, 412 black hole, 308“10
cluster, 307, 308
European Southern Observatory filaments, 117
(ESO), 50, 51, 52, 54, 55, 75 filter, 13, 17 distribution of matter, 306“7
European Space Agency (ESA), 56, 66 filter systems, 18 Doppler shifts, 309
INDEX 571



h bar, 29
free“free radiation, 306 Orion region, 287
H and Chi Persei, 13
magnetic effects, 307 starburst galaxies, 353“4
color“magnitude diagram, 231
Milky Way, 293 giants, 36
molecular clouds, 306 Glashow, Sheldon, 416 H burning shell, 178“9
proper motions, 309, 309, 310 glitches, 203, 204 H ions, 105
radio emission, 306, 307 global maps, Mars, 489 HI clouds, 252
Schwarzschild radius, 308 global warming on Earth, 459 HI in Andromeda Galaxy, M31, 325,
globular clusters, 221, 223 325
Sgr A*, 308“10
color“magnitude diagram, 232, 341
star formation, 307 HII regions, 252, 274“80
free“free radiation, 279
supernovae, 306 and determination of Hubble
synchrotron radiation, 306 constant, 342 galaxies, 323
Milky Way, 293, 294, 295
wave of star formation, 306 Large Magellanic Cloud, 323
X-ray emission, 306, 307 potential energy, 227 Milky Way, 304
globule, 237, 238, 415 in molecular clouds, 280
galactic clusters, 221
galactic coordinates, 297, 297 GMCs, see giant molecular clouds, Orion region, 287
galactic quadrants, 298 grain surface chemistry, 252 properties, 278“9
galaxies grand design, spiral galaxies, 317 recombination lines, 279
clusters of, 335“51 grand unified theories (GUTs), 416“17 spiral galaxies, 324
CO observations, 323 super GUTs, 417 trigger, 266, 279
H2, formation, 252, 252
HII regions, 323 granite, 448
granulation, 106, 106
H emission, 323 on early Earth, 541
interstellar medium, 322 gravitation, inverse square law, 434 H2CO (formaldehyde), 251
millimeter interferometer studies, gravitational binding, 263“6 H2O (water), 251
323 gravitational collapse, 264 on early Earth, 541
molecular clouds, 322“3 gravitational effects, active galaxies, on Earth, 448
star formation, 322“6 black hole searches, 371“2 H , 28, 34, 108, 109
galaxy collisions, 338, 339 gravitational energy, 271, 272 H absorption line, 32
galaxy formation, 348, 420 gravitational force, Milky Way, 296 H emission, 279
galaxy mergers, 338 gravitational interaction, 412 galaxies, 323
Galilean satellites of Jupiter, 512, 513 Large Magellanic Cloud, 323
gravitational lens, 145
gravitational lensed quasars, 368,
Galileo Galilei, 431“2, 512 redshift surveys, 345
T Tauri, 286
Galles, Johannes, 499 368“9
Abell 2218, 369
GALLEX, 174 H filter, 116
PG115 080, 369 H image of Sun, 110
gamma-ray, 161
Gamow, George, 395 gravitational lifetime of a star, 158 H line, quasars, 363“4
Gamow peak, 164 gravitational mass, 142 hadrons, 410“11, 417, 419
Ganymede, 512, 513 gravitational potential energy of a Hale, George Ellery, 115
Hale“Bopp, comet, 525
gas tail from comets, 526 sphere, 157“8
GBT, see Byrd telescope Hale telescope, 47, 47
gravitational radiation, 147
gravitational redshift, 145“7, 145
Gell-Mann, Murray, 411 Haleakala Crater, Maui, 111
general circulation, on Earth, 463“5 gravitational time dilation, 147 half-life, 449
Halley™s comet, 430, 525, 528
general relativity, 139“52, 377 graviton, 412
gravity assist, 441, 442“3, 442
tests of, 143“8 halo, Milky Way, 293, 301
gravity waves, 147
geometry Haro, Guillermo, 283
of ellipses, 91, 91 grazing incidence, 75 Harvard College Observatory, 26
of space-time, 385, 385 great attractor, 347, 402 Hawking, Stephen, 151
on the surface of a sphere, 139 Great Red Spot, Jupiter, 497, Hayashi, Chushiro, 273
502“3, 503
of universe, 384“6 Hayashi track, 274
Ghez, Andrea, 308, 308 greatest elongation, 432 HC11N, 252
Giacobini“Zinner, comet, 525 Green Bank telescopes, 68, 70, 70 HCN (hydrogen cyanide), 255
greenhouse effect, 458, 458
giant ellipticals, 315 HCO , 251
giant molecular clouds (GMCs), 268 ground-based observing, 53 HDE226868, 217
3
complexes, Large Magellanic Cloud, guardian satellites, 511“12 He, primordial, 410
GUTs see grand unified theories
324 He , 181
572 INDEX



heat capacity, 171 Hubble, Edwin, 315 inferior conjunction, 432
infinite redshift surface, 150
heat flow, 473 Hubble classification, 315
316 inflation, 419“21, 420
on Io, 514
heat and formation of Earth, 447 Hubble constant, 339“45, 391, 420 infrared, observing, 63“6
heat source, Jupiter™s internal 500“1 determination of, 341“5 infrared absorption features, 243
heavy elements, primordial, 409 Cepheids, 342 infrared arrays, 64
height of plane, HI, Milky Way, 303 distance indicators, 342“3 Infrared Astronomy Satellite (IRAS),
heliocentric model, 431, 431 early value, 341 64
infrared image of Earth, 454
heliocentric velocities, 297 globular clusters, 342
helium, primordial, 407“8 HR diagrams, 342 infrared observations of Mercury, 483
helium flash, 178 HST and, 343 Infrared Processing and Analysis
Helix Nebula, 184 recent values, 344, 345 Center (IPAC), 66
Her A, radio galaxy, 356 RR Lyrae stars, 342 Infrared Space Observatory (ISO),
Her X-1, 214 sources of error, 343 65, 66
infrared windows, 64, 64
Herbig, George, 283 spectroscopic parallax, 342
Herbig“Haro (HH) objects, 283“4, 283 initial mass function (IMF), 95, 95, 267
supernovae, 343
Hercules cluster, 335, 337 trigonometric parallax, 342 inner planets, 429, 479“94
Tully“Fisher relation, 344, 344
Herman, Robert, 395 atmospheres, 491“4
type I supernovae, 343, 344
Herschel, William, 498 basic features, 479“82
Hubble Deep Field, 349“50, 349, 350 distance to, 433
Hertzprung, Enjar, 36
interiors, 490“1, 490
Hertzprung“Russell (HR) diagram, Hubble flow, 341“2, 402
36“8, 37 Hubble parameter, 381 moons, 494
Hubble Space Telescope (HST), 56, 57,
horizontal branch, 178 surfaces, 483“90
58
Hubble constant, 342 intensities of spectral lines, 34“6
protostars on, 273 Hubble time, 341, 390 intensity function, 13
schematic for cluster of stars, 231 interacting galaxies, 339
current estimate, 345
Hubble™s law, 339“45, 340, 378, 380“1, interference filters, 61
for star cluster, 231
variable stars on, 180 386“8, 391 interferometers, 72“3
Hewish, Antony, 199 and Hubble flow, 341“2 interferometry, speckle, 96
interiors, 474
high energy astronomy, 75“7 quasars, 364
High Energy Astronomy Observatory superluminal expansion, 359 computer models, 506
core and mantle, 490“1, 490
(HEAO), 76 hurricanes, 464
hurricane Andrew, 464
high energy electrons, radio galaxies, Jupiter, 506
hurricane Floyd, 464
355 Neptune, 506
outer planets, 506, 506
high energy particles, 410 hydrogen, on early Earth, 540“1
high mass stars, 179 hydrogen burning shell, 177“9 Saturn, 506
hydrogen energy levels, 30
core evolution in, 193 Uranus, 506
hydrostatic equilibrium, 168, 168
highlands of the Moon, 471 internal dynamics of star clusters,
Himalayas, 451, 451 on Earth, 455“7 225
HZ Her, 214
Hipparchus, 9 internal motions, clusters of galaxies,
HL Tau, 285 337
Hobby-Eberly Telescope, 52, 53 igneous rocks, 448 internal structure
homogeneity, in universe, 377, 380 image formation Callisto, 513
horizon due to finite age of universe, in a camera, 43 Europa, 513
in refracting telescope, 45 Galilean satellites, 513
385
horizontal branch, 178 images, displaying, 66“8 Ganymede, 513
Horsehead Nebula, 239, 288 imaging, 58 Io, 513
IMF, see initial mass function Titan, 518
horseshoe orbit, 512
hot dark matter (HDM), 348 impact trigger, 474 International Ultraviolet Explorer
Hourglass Nebula, 184 impacts on Mercury, 483 (IUE), 63
inclination of orbit, 87
Hoyle, Fred, 395 interstellar chemistry, 252“3
HR diagram, see Hertzsprung“Russell induction, 11 H2 formation, 252
diagram inertial mass, 142 ion“molecule reactions, 253“4
HST, see Hubble Space Telescope inertial reference frame, 127 models, 254
INDEX 573



interstellar clouds, 237, 248, 256; see Io, 512, 513
ion tail from comets, 526
also giant molecular clouds; ion“molecule reactions, 252
molecular clouds ionization, 33“4 K-corona, 112
clumps, 266 ionization bounded HII region, 278 K spectral type, 35
ionization energies, 34
collapse, 257 Kamiokande, 174
disks, 266 ionization equilibrium, 33“4 Kant, Immanuel, 537
ionization fraction, 34 KAO, see Kuiper Airborne Observatory
expansion, 257
Keck telescope, 52, 53
internal motions, 257 ionization temperature, 34
masses, 257 ionized carbon, 278 Kepler, Johannes, 432
rotation, 257 ionosphere Keplerian orbits, 296
Kepler™s laws, 89, 434, 434
and collapse, 265 Earth, 466
virial theorem, 257 Io, 515 Kepler™s third law, 89
interstellar dust grains, see IPAC, see Infrared Processing and extrasolar planets, 546
interstellar grains Analysis Center Milky Way, 296
IRAS, see Infrared Astronomy Satellite
interstellar electron density, 206 Saturn, 508
IRAS“Araki“Alcock, comet, 528, 528 Kilauea, 449
interstellar extinction, 237“42
interstellar extinction curves, 241“3, irons in meteoroids, 531 kinematic distances, Milky Way,
242 irregular galaxies, 322 302, 304
ISO, see Infrared Space Observatory
interstellar gas, 246“51 Kirchhoff, Gustav Robert, 25
absorption lines, 245 isotopes, 159 Kirkwood gaps, 511
Kitt Peak National Observatory, 54, 55,
interstellar grains isotropy, 381
72, 105
composition, 243“4 cosmic background radiation,
electric charge, 244“45 398, 401“7 Kohoutek, comet, 528
evolution, 246 universe, 377 Kuiper Airborne Observatory (KAO),
infrared spectra, 244 isotropy problem, 405 64
life cycle, 246 IUE, see International Ultraviolet Uranus, 508
shape, 243 Explorer Kuiper belt
size, 243 early Earth, 541
structure, 244 J quantum number, 29 objects, comets, 529“30
temperature, 245 Jansky, Karl, 68
interstellar masers, see masers La Silla, 54
Jeans length, 263“4, 267“8
Lagoon Nebula (M8), 275
interstellar matter, spiral structure, Jeans mass, 263“4
jet collimation, radio galaxies, 358
explanations of, 328 Lagrangian point, asteroids, 209, 533
landing sites, 471
interstellar medium, 237“59 jets, active galaxies, 370
elliptical galaxies, 315 Julian days, 180 Large Binocular Telescope, 52
Jupiter; see also Jupiter, almosphere;
galaxies, 322 large energy output, active galaxies,
interstellar molecules, 251“8 Jupiter, moons, 370
aurora, 503 Large Magellanic Cloud (LMC), 322
angular momentum, 254
30 Dorado, 323“4, 323
chemical reactions, 252 basic features, 497
CO maps, 324
destruction, 251 impacts with comet
Shoemaker“Levy, 529“30, 529, 530
discovery, 251“3 GMC complexes, 324
HII regions, 323
formation, 251 interiors, 506
H emission, 323
ion“molecule reactions, 258 magnetic field, 503“4
isotopic substitutions, 258 Pioneer spacecraft, 497 N11, 323“4
ring system, 508, 508
observing, 254 star formation, 323“4
supernova remnant in, 195
rotational energy, 254 and Saturn, temperature
distribution, 501
rotational levels, 254 Tarantula Nebula, 323
Jupiter, atmosphere, 500“1, 502
vibrational levels, 254 Las Campanas, 55
convection, 502
interstellar polarization, 242 Laser Interferometer Gravity
Great Red Spot, 503 Observatory (LIGO), 147
interstellar pressure, 250
interstellar radio lines, 247 Jupiter, moons laser measurement of Earth“Moon
interstellar reddening, 240“1, 240 Callisto, 516, 516 distance, 143
Europa, 515
inverse square law, gravitation, 434 lasers, 280
Io, 512, 513 Ganymede, 515, 516, 516 late spectral types, 27
574 INDEX



launch window, 441“2 luminosity class, 36 star formation, 270“2
Leavitt, Henrietta, 181 spiral galaxies, 317“19 magnetic energy, 270“1
Lee, T. D., 413 luminosity distance, 390 magnetic field
Lemaitre models, 384, 389 luminosity function, 96 Earth, 447“8
length contraction, 129, 130 luminosity profile, elliptical galaxies, interiors, 490
lenticular galaxies, 322 317 Jupiter, 503“4
Leonid meteor shower, 531 luminosity radius, 96 neutron stars, 199
lepton, 410, 411, 417 lunar eclipse, 437 pulsars, 204
level populations, 33 solar, 114, 115
lunar interior, 473“4
magnetic mirror, 466, 466
Leverier, Urbain, 499 lunar occultations, 96
librations, 435, 436 lunar phases, 435, 435 magnetic monopoles, 417
magnetosphere, 465“7, 465
Lick Observatory, search for lunar seismology, 473
extrasolar planets, 546 lunar soil, life in, 543 magnitudes, 9
life lunar surface, 470“2 main sequence, 36, 157“75
origin of, 537“49 Lyman alpha, primordial, 409 main sequence fitting, 231“2
search for on Mars, 481 Lyman-alpha forest, quasars, 365 Marcy, Geoffrey, 545“7
lifetime Lyman series, 31 maria on the Moon, 471
of black hole, 152 Mariner 10, Mercury, 479“80
of Sun, 165 M spectral type, 35 Mariner spacecraft, Mars, 480“1
light clock, 128 M3, 223 Markarian 421 spectrum, BL Lac
light cone, 134, 134 M5, 223 objects, 363
M6, 222 Mars, 480“1, 482
light curve, 180
δ Cephei, 181 M7, 222 density, 491
type I supernova, 213 M15, 223 dust storms, 493“4
M31, Andromeda Galaxy, 317
light element abundances, energy flow, 494
primordial, 408 M32, 316 liquid water on, 543
M37, 222
light gathering power, 41“2 Mariner flyby, 480“1
M45, 222
lightlike intervals, 134 rocks from, 544
M49, 316
lightning, on early Earth, 541 search for life on, 494, 543
LIGO, see Laser Interoferometer M51, Whirlpool Galaxy, 329 storm on, 493
tracers of spiral pattern, 330
Gravity Observatory strong winds, 493“4
limb darkening, 107, 107 M80, 223 surface, 485“90
M81, 320, 330
Lin, C. C., 328 surface pressure, 493
M82, 322
line of nodes, 437 Viking landers on, 543
spectrum, 354
line of sight, 85 Mars Global Surveyor, 486
through planetary nebulae, 185 starburst galaxy, 353 masers, 280“2
M83, 319 amplification, 281
line profile, 108
line spectra, active galaxies, 363 M84, active galaxies, black hole as distance indicators, 299
searches, 372
lithosphere, 451 Doppler shifts, 282
LMC, see Large Magellanic Cloud M87, 316 motions of clusters, 282, 282
LMCX-3, 216, 217 active galaxies, black hole searches, population inversion, 280“1
372
Local Group, 335, 345 proper motions, 282
radio galaxy, 356
motion, 346 pump, 280“1
M94, 320 source size, 281, 281
local standard of rest (LSR), 297
McDonald Observatory, 52, 53
local supercluster, 345 stimulated emission, 280“1
location, asteroids, 533 M100, 58 mass
M101, 318
Lomonosov, 492 of planets
M102, 321
long period variables, 180 of Jupiter, 497
M104, Sombrero, 319
long range forces, 411 of Pluto, 523
MACHOs, see massive compact halo
Lorentz, H., 129 of Saturn, 497
Lorentz contraction, 130 objects mass and spectral type, 94
Lorentz transformation, 132“3, 133 magnetic dipole, 114, 114 mass continuity, 168
Lowell, Percival, 523 magnetic effects mass function, 217
luminiferous ether, 125 computer simulations, 270
INDEX 575



mass interior to radius, Milky CO observations, 303 millimeter spectrum, 255
millimeter telescopes, 72
Way, 296 dark matter, 301
different wavelength images, 294
mass number, 159 millisecond pulsars in close binaries,
mass of the Sun, 88 differential rotation, 294“302 215
mass“luminosity relation, 94 disk, 293, 295, 301 minimum energy orbit to Venus, 441
mass-to-light ratios, 390 distance to galactic center, 299 Mira, 180
Doppler shifts, 297
dark matter in galaxies, 331 Mira variables, 180
massive compact halo objects flaring in HI, 303 mirrors, 47
MMT, see Multiple Mirror Telescope
(MACHOs), 331 flaring in H2 , 304
Mather, John, 401 galactic center, 293, 306“10 models for radio galaxies, 357“9
galactic coordinates, 297, 297
matter dominated universe, 398 of the universe, 388“90
galactic quadrants, 298
matter speed, spiral structure, 327“8 molecular clouds, 252
matter“antimatter imbalance, 418 globular clusters, 293 collapse, 257
Maudner, E. Walter, 113 HII regions, 304 expansion, 257
Mauna Kea, 52, 54, 55 halo, 293, 295, 301 galaxies, 322“3
height of plane, HI, 303

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