Various intuitive methods have been used to present cosmological distances, or cosmological and geological time. Carl Sagan's "cosmic year" was one way: We take the entire history of the universe to consist of one year, which leaves all of human history to some fraction of the last second.
The following table does this a different way. If a millimeter is taken to represent a light-year, and if the Hubble Constant is 50 km/s/MPC, making the Hubble Time 19.5 billion years (Gy), the entire universe would fit on the surface of the earth: the semi-circumference of a great circle, started at Los Angeles, is 20,002 km, or 20 billion millimeters. Similarly, if a millimeter is taken to represent a year, the history of the universe fits on the surface of the earth, the history of the earth reaches out to about Nome, Alaska or to Haiti, and recorded human history would not get outside the classroom that I use.
This device gives us a comprehensible scale to relate human history, even a single lifetime, to the age and size of the entire universe. A millimeter is a small but familiar unit of distance. As a year, it means that moving across the room gets out out of human history, down the street, outside the existence of homo sapiens, and not too far down the freeway to the Jurassic. We can go all the way back to the beginning of the Paleozoic without leaving California. As a light year, a millimeter gives us the entire Milky Way Galaxy on about the same scale as the Campus Center building at Valley College. The Local Group is easily contained in the area of Sherman Oaks, while the Virgo Cluster is little more than the distance to Palmdale. The closest bright quasar, 3C 273, is then about as far away as Nashville, Tennessee. The truly distant quasars are nearly as far as Mauritius.
A millimeter as a year enables us to relate the scale of our own lives (a few inches) to historical (the room), anthropological (across campus), geological (down the road), and cosmological (across the continent) time. A millimeter as a light year gives us a corresponding astronomical scale, but a light year as a unit of distance is really larger, in a sense, than a year as a unit of time. Light takes a year to go a light year, but even travelling at the speed of sound, it would take us a million years to go the same distance. Four millimeters as the distance to the closest star is good for a map of the galaxy, but it gives us no sense of how much further that is than the distance from the earth to the moon, the sun, or Jupiter. If a millimeter were an astronomical unit, the mean distance from the earth to the sun, then the closest star (Alpha Centauri, at 4.24 light years), would be 268 meters away (across campus). There are 63,240 astronomical units to a light year. Unfortunately this scale then puts even the Andromeda Galaxy (2.38 million light years) at 150,512 kilometers away, almost halfway to the moon. This is well outside of what we can intuitively relate to. A millimeter as a light year thus keeps the universe with reach, even if we lose the finest detail.
All distances are calculated starting with the classroom, in the Campus Center building of Los Angeles Valley College, in Van Nuys, California. To those unfamiliar with the Los Angeles area, distances starting at about 300 m will become mysterious with references to local streets and nearby communities and cities. At about 200 km we start getting to major cities in California and beyond. Entries that merely note distances and times on the geological or cosmological scale, are indented slightly.
Basic information on galaxies for this list is derived from the Nearby Galaxies Catalog, by R. Brent Tully, Cambridge University Press, 1988. This uses 75 km/s/MPC for the Hubble Constant. The distances of the most distant galaxies and quasars that follow have been calculated on the basis of a Hubble Constant of 50 km/s/MPC. However, the distances for many nearer galaxies have not yet been recalculated from Tully's Constant of 75. Such distances are therefore liable to be too small by up to several million light-years. Some duplicate entries occur, so the differences can be compared. Although it is not important for the purpose of this demonstration, this inconsistency should be kept in mind; and the following figures should not be used as an independent source for galactic distances.
I must say that I prefer 50 km/s/MPC for this exercise, since it makes the universe fill the surface of the earth so neatly. However, estimates of Hubble Constant have been growing steadily larger since the 70's. I am informed by astronomers at UCLA that their best estimate for the Constant now is 71 km/s/MPC. If it is as large as 75 km/s/MPC, then the Hubble Radius is only as far as 13040 km, which on this chart gets us as far as the open universes -- the distance to Chad or St. Helena.
Within the galaxy, the best source found was The Guide to the Galaxy, by Nigel Henbest and Heather Couper, Cambridge University Press, 1994. It is hard to keep track of where all the stellar and deep space distances came from, but the Sky Catalogue 2000.0, Vols. 1 & 2, edited by Alan Hirshfeld and Roger W. Sinnott, Sky Publishing Corporation and Cambridge University Press, 1982, was used extensively. Some Quasar distances were just plucked out of Sky & Telescope at different times, often as they were discovered.
Most of the terrestrial distances listed were calculated with a program called "BEARINGS," 1982, 1986, Zephyr Services, 1900 Murray Ave., Pittsburgh, PA 15217. Many other distances in the United States, especially the local ones, were determined by using the CD-ROM "MapExpert," Version 2.0 for Windows, 1993, DeLorme Mapping, Lower Main Street, P.O. Box 298, Freeport, Maine 04032. Sometimes different results for the distances were obtained, since measuring the distance to a city or a country depends on where you pick to measure to. So occasionally alternate distances are given.
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HOLOCENE EPOCH, present-10,000 y .....4.24 LY [1], Alpha Centauri [2] .....8.80 LY, Sirius [3] 1 cm = 10 y .....26.4 LY, Vega .....35.8 LY, Arcturus .....[Far Edge of Local Fluff] [4] .....42.4 LY, Capella .....68.5 LY, Aldebaran 7 cm = 2.75 inches = 70 y, approximate length of a human lifetime .....94.5 LY, Algol 10 cm = 100 y .....121 LY, Almach 12.8 cm = 128 y, time since the Civil War (1861-1865) .....150 LY, Hyades Open Cluster [5] .....[Local Bubble] .....179 LY, Rasalas 8.5 inches, width of this page [in hard copy] = 21.6 cm = 216 y 21.7 cm = 217 y, time since the Declaration of Independence (1776) .....258 LY, Spica 11 inches, length of this page [in hard copy] = 27.9 cm = 279 y |
PLEISTOCENE EPOCH, 10 ky-2 My
.....17.9 kLY, M 12 Globular Cluster [13]
18 m = 18 ky, time since height of the Wisconsin Glacial
.....25.0 kLY, NGC 3603 Nebula [Sagittarius Arm]
.....27.7 kLY, Center of the Milky Way Galaxy
35 m = 35 ky, time since the origin of Homo sapiens sapiens
.....36.9 kLY, M 2 Globular Cluster
.....56.1 kLY, M 53 Globular Cluster
.....75 kLY, far edge of the Milky Way Galaxy
85 m = 85 ky, Campus Center to the Physics Building = time since beginning of Wisconsin Glacial [14]
.....113 kLY, NGC 7006 Globular Cluster
100 m = 100 ky, approximate length of Campus Center building
.....100 kLY, approximate diameter of the Milky Way Galaxy
125 m = 125 ky, Campus Center to the Engineering Building = time since the origin of Homo sapiens neanderthalensis
.....163 kLY, Large Magellanic Cloud (0524-69, Local Group) [15]
.....196 kLY, Small Magellanic Cloud (0051-73, Local Group)
200 m = 200 ky, Campus Center to the Planetarium = time since "Eve" (origin of all present human mitochondrial DNA) [16]
.....219 kLY, Draco Dwarf Galaxy (U 10822, Local Group)
.....274 kLY, Sculptor Dwarf Galaxy (0057-33, Local Group)
300 m = 300 ky, Campus Center to Burbank Blvd = time since the origin of archaic Homo sapiens
.....304 kLY, NGC 2419 Globular Cluster
445 m = 445 ky, Campus Center Room 205 to the corner of Burbank & Fulton
.....450 ky, age of Kohala volcano, Island of Hawaii
.....500 ky, age of Mauna Loa volcano, Island of Hawaii
.....613 kLY, Fornax Dwarf Galaxy (0237-34, Local Group)
.....860 ky, age of East Maui volcano (Haleakala), Island of Maui
1 kilometer = 1000 m = 1,000,000 y = 1 My, distance to the corner of Fulton & Weddington
.....1.03 My, age of volcano, Island of Kahoolawe
.....1.46 My, age of volcano, Island of Lanai
.....1.6 My, time since origin of Homo erectus
.....1.63 My, age of West Maui volcano, Island of Maui
1.7 km = 1.7 My, Campus Center to the corner of Fulton & Addison
.....1.50 MLY, NGC 6822 Barnard's Galaxy (Local Group)
.....1.70 MLY, 2044-13 Aquarius Dwarf Galaxy (Local Group)
.....1.75 My, age of East Molokai volcano, Island of Molokai
.....1.84 My, age of West Molokai volcano, Island of Molokai
.....2 My, time since the origin of Homo habilis and the beginning of the Pleistocene Epoch and the Quaternary Period
TERTIARY PERIOD, 2 My-65 My
2.1 km = 2.1 My, Campus Center to the corner of Riverside Drive and Fulton
.....2.25 MLY, M 32 Galaxy (NGC 221, Local Group)
.....2.38 MLY, M 31 Great Andromeda Galaxy (NGC 224, Local Group) [17]
.....2.6 My, age of East Oahu (Koolau) volcano, Island of Oahu
.....2.94 MLY, M 33 Galaxy (NGC 598, Local Group)
3.0 km = 3.0 My, distance on Fulton to the Los Angeles River = time since beginning of Nevadan Orogeny--uplift of Sierra Nevada
.....<3.26 MLY, edge of the Local Group of Galaxies
.....3.8 My, age of West Oahu (Waianae) volcano, Island of Oahu
.....4.0 My, time since the origin of Australopithecus
4.1 km = 4.1 My, corner of Cedros & Ventura Blvd in downtown Sherman Oaks
4.3 km = 4.3 My, Harvard School on Coldwater Canyon
5 km (3.11 mi) = 5 My, the I-405 bridge across Ventura Blvd = time since beginning of the Pliocene Epoch
.....5.22 MLY, NGC 1569 Galaxy (M 81 Group)
.....5.72 My, age of volcano, Island of Kauai
.....7.5 My, age of volcano, Island of Nihoa
.....7.83 MLY, NGC 404 Galaxy (Local Outlier)
.....9.78 MLY, NGC 253 Galaxy (Sculptor Group)
10.5 km = 10.5 My, Hollywood Bowl
.....11.3 My, age of volcano, Necker Island
11.7 km = 11.7 My, Royce Hall, UCLA
13.9 km = 13.9 My, La Brea Tar Pits
.....14.0 MLY (.001c) [18], M 94 (Canes Venatici I Group)
MESOZOIC ERA, 65 My-248 My
.....68.2 MLY (.006c), NGC 157 Galaxy (Telescopium-Grus Cloud)
69.3 km = 69.3 My, Huntington Beach
70.0 km = 70.0 My, Oxnard
72.0 km = 72.0 My, Ontario
75.4 km = 75.4 My, Costa Mesa
.....89.3 MLY (.007c), NGC 2577 Galaxy (Cancer-Leo Cloud)
.....100 My, time since the beginning of the Gulfian Age (Late Cretaceous)
100.2 km = 100.1 My, Mojave
103.1 km = 103.1 My, San Bernardino
104.0 km = 104.0 My, Carpinteria
.....106 MLY (.009c), NGC 474 Galaxy (Cetus-Aries Cloud)
135.2 km = 135.1 My, Isla Vista, California
PALEOZOIC ERA, 590 My-248 My (= 367 mi-154 mi)
252.6 km = 252.6 My, Visalia, California
258.7 km = 258.7 My, Morro Bay
.....286 My, time since the beginning of the Permian Period
.....303 MLY (.023c .023) [22], Ab. 1656 (Coma Berenices) Cluster
311.5 km = 311.5 My, Fresno, California [318 km]
.....312 MLY (.016c), Abell 3627 (The Great Attractor?) [23]
357.1 km = 357.1 My, Needles, California
358.9 km = 358.9 My, Blythe, California
.....360 My, time since the beginning of the Carboniferous Period
371 km = 371 My, Las Vegas, Nevada
404.6 km = 404.6 My, Salinas, California
407.3 km = 407.3 My, Panorma Point, Yosemite Valley, California
.....408 My, time since the beginning of the Devonian Period
415.0 km = 415.0 My, Monterey, California
415.4 km = 415.4 My, Kingman, Arizona
PRECAMBRIAN TIME, PROTEROZOIC EON, 590 My-2.6 Gy
592.4 km = 592.4 My, Phoenix, Arizona [598]
.....600 My, time since formation of Pannotia Supercontinent
605 km = 605 My, Reno, Nevada
.....645 MLY (.033c .034), Abell 2506 Cluster
.....670 MLY (.051c .053), Abell 1377 (Ursa Major I) Cluster
724 km = 724 My, Tucson, Arizona
.....724 MLY (.037c .038), Abell 2151 Hercules Cluster
.....750 My, time since breakup of Rodinia Supercontinent
.....800 My, time since end of Grenville & Beltian Orogenies
.....821 MLY (.042c 0.043), Abell 76 Cluster
.....823 MLY (.063c .065), Abell 1452 Cluster
870.8 km = 870.8 My, Mt. Shasta Pk., California
896.4 km = 896.4 My, Gallup, New Mexico
.....900 My, time since beginning of Neoproterozoic Era
920 km = 920 My, Salt Lake City, Utah
.....940 MLY (.072c .075), Ab. 2065 (Corona Borealis) Cluster
991 km = 991 My, Guaymas, Mexico
.....997 MLY (.051c 0.053), Abell 1377 Ursa Major I Cluster
ARCHAEAN EON [25], 2.6 Gy-3.9 Gy
2623 km = 2.623 Gy, Jackson, Mississippi
2661 km = 2.661 Gy, Acapulco, Mexico
2705 km = 2.705 Gy, Veracruz, Mexico
2707 km = 2.707 Gy, New Orleans, Lousiana
2796 km = 2.796 Gy, Chicago, Illinois
2808 km = 2.808 Gy, Milwaukee, Wisconsin
2813 km = 2.813 Gy, Clipperton Is. (Fr.)
.....2.855 GLY (.146c 0.158), 3C 273 Quasar [26]
2869 km = 2.869 Gy, Mobile, Alabama
2869 km = 2.869 Gy, Nashville, Tennessee
2886 km = 2.886 Gy, Thunder Bay, Canada
2908 km = 2.908 Gy, Birmingham, Albama
2911 km = 2.911 Gy, Indianapolis, Indiana
2935 km = 2.935 Gy, Juneau, Alaska
2945 km = 2.945 Gy, Louisville, Kentucky
.....3.0 Gy, time since end of Saganagan Orogeny
3018 km = 3.018 Gy, Chattanooga, Tennessee
3056 km = 3.056 Gy, Cincinatti, Ohio
3082 km = 3.082 Gy, Dayton, Ohio
3095 km = 3.095 Gy, Columbus, Georgia
3121 km = 3.121 Gy, Knoxville, Tennessee
3123 km = 3.123 Gy, Atlanta, Georgia
3152 km = 3.152 Gy, Lansing, Michigan
3178 km = 3.178 Gy, Merida, Mexico
3185 km = 3.185 Gy, Columbus, Ohio
3196 km = 3.196 Gy, Detroit, Michigan
3196 km = 3.196 Gy, Windsor, Ontario, Canada
.....3.3 Gy, time since beginning of Saganagan Orogeny
3306 km = 3.306 Gy, Cleveland, Ohio
3313 km = 3.313 Gy, Akron, Ohio
3380 km = 3.380 Gy, Wheeling, West Virginia
3414 km = 3.414 Gy, Sudbury, Canada
3423 km = 3.423 Gy, Charlotte, North Carolina
3425 km = 3.425 Gy, Columbia, South Carolina
3428 km = 3.428 Gy, Niagara Falls, New York
3439 km = 3.439 Gy, Pittsburgh, Pennsylvania
3460 km = 3.460 Gy, Jacksonville, Florida
3461 km = 3.461 Gy, Guatemala
3461 km = 3.461 Gy, Savannah, Georgia
3482 km = 3.482 Gy, Belize
3499 km = 3.499 Gy, Toronto, Canada
.....3.5 Gy, time since oldest Stromatolites
3535 km = 3.535 Gy, Buffalo, New York
3556 km = 3.556 Gy, Charleston, South Carolina
3560 km = 3.560 Gy, Orlando, Florida
3641 km = 3.641 Gy, Rochester, New York
3684 km = 3.684 Gy, Richmond, Virginia
3700 km = 3.700 Gy, Havana, Cuba
3702 km = 3.702 Gy, Harrisburg, Pennsylvania
3704 km = 3.704 Gy, Washington, DC
HADEAN EON [27], 3.9 Gy-5.0/4.6 Gy
3969 km = 3.969 Gy, Montreal, Quebec
.....3.970 GLY (.203c 0.229), Hydra II Cluster
3989 km = 3.989 Gy, Burlington, Vermont
4007 km = 4.007 Gy, Bridgeport, Connecticut
4009 km = 4.009 Gy, Bahamas
4031 km = 4.031 Gy, New Haven, Connecticut
4044 km = 4.044 Gy, Hartford, Connecticut
4051 km = 4.051 Gy, Springfield, Massachusetts
4065 km = 4.065 Gy, Nicaragua
4068 km = 4.068 Gy, Cayman Is.
4111 km = 4.111 Gy, Honolulu, Hawaii
4115 km = 4.115 Gy, Worcester, Massachusetts
4136 km = 4.136 Gy, Manchester, New Hampshire
4152 km = 4.152 Gy, Providence, Rhode Island
4160 km = 4.160 Gy, Quebec, Quebec
4181 km = 4.181 Gy, Boston, Massachusetts
4230 km = 4.230 Gy, Portland, Maine
.....4.28 Gy, time since oldest contintental rocks on Earth (Porpoise Cove, Canada)
.....4.3-4.1 Gy, time since the emergence of continents
.....4.381 GLY (.224c 0.256), 3C 79 Radio Galaxy
4390 km = 4.390 Gy, San Andres (Colum.)
.....4.44-4.41 Gy, time since formation of atmosphere
4409 km = 4.409 Gy, Costa Rica
4414 km = 4.414 Gy, Bajo Nuevo (Colum.)
4451 km = 4.451 Gy, Jamaica
.....4.498 GLY (.230c 0.264), 3C 323.1 Quasar
4512 km = 4.512 Gy, Guantanamo Bay (U.S.)
4537 km = 4.537 Gy, Cocos Is.
4563 km = 4.563 Gy, St. John, New Brunswick, Canada
.....4.6 Gy, lower limit for the time since the origin of the Earth and the Moon
PRE-HADEAN TIME, COSMOLOGICAL TIME, 5.0 Gy-19.556 Gy
5088 km = 5.088 Gy, Cartegena, Columbia
5177 km = 5.177 Gy, Barranquila, Columbia
5299 km = 5.299 Gy, St. Pierre (Fr.)
5364 km = 5.364 Gy, East Kiribati
5371 km = 5.371 Gy, Medellin, Columbia
5377 km = 5.377 Gy, Thule, Greenland
5400 km = 5.400 Gy, Maracaibo, Venezuela
5430 km = 5.430 Gy, Desecheo Is. (U.S.)
5430 km = 5.430 Gy, Puerto Rico
5436 km = 5.436 Gy, Johnston Is. (U.S.)
5451 km = 5.451 Gy, Kingman Reef (U.S.)
5471 km = 5.471 Gy, Palmyra Is. (U.S.)
5514 km = 5.514 Gy, Cali, Columbia
5545 km = 5.545 Gy, St. John's, Newfoundland, Canada
5546 km = 5.546 Gy, Curacao, Netherlands Antilles
5561 km = 5.561 Gy, Virgin Is. (U.S.)
5577 km = 5.577 Gy, British Virgin Islands
5578 km = 5.578 Gy, Midway Is. (U.S.)
5628 km = 5.628 Gy, Bogata, Columbia
5641 km = 5.641 Gy, Quito, Ecuador
5655 km = 5.655 Gy, Barquisimto, Venezuela
5656 km = 5.656 Gy, Kure Is. (U.S.)
5687 km = 5.687 Gy, Aves Is.
5731 km = 5.731 Gy, Anguilla
5742 km = 5.742 Gy, St. Martin Is.
5742 km = 5.742 Gy, Saint Martin (Fr.)
5797 km = 5.797 Gy, Nevis, St. Kitts
5827 km = 5.827 Gy, Caracas, Venezuela
5862 km = 5.862 Gy, Barbuda, Antigua
5888 km = 5.888 Gy, Montserrat
.....5.925 GLY (.303c 0.367), 3C 48 Quasar
5964 km = 5.964 Gy, Guadeloupe (Fr.)
6066 km = 6.066 Gy, Dominica
6125 km = 6.125 Gy, Martinique (Fr.)
6172 km = 6.172 Gy, St. Lucia
6202 km = 6.202 Gy, St. Vincent
6210 km = 6.210 Gy, Grenada
6335 km = 6.335 Gy, Tinidad & Tobago
6430 km = 6.430 Gy, Barbados
6594 km = 6.594 Gy, French Polynesia
OPEN UNIVERSES [28]
.....13.044 GLY (.667c 1.238), 3C 68.1 Quasar
13054 km = 13.054 Gy, Chad
13059 km = 13.059 Gy, St. Helena
13086 km = 13.086 Gy, Calcutta, India
13098 km = 13.098 Gy, Bangladesh
13111 km = 13.111 Gy, Saigon, Vietnam
13128 km = 13.128 Gy, Sao Tome
13147 km = 13.147 Gy, Adelaide, Australia
13151 km = 13.151 Gy, Cameroon
13170 km = 13.170 Gy, Annobon
13189 km = 13.189 Gy, Bahrain
13205 km = 13.205 Gy, Jabal at Tair, Abu Ail
13258 km = 13.258 Gy, South Sandwich Is. (Brit.)
13263 km = 13.263 Gy, Rangoon, Burma
13278 km = 13.278 Gy, Bangkok, Thailand
13282 km = 13.282 Gy, Qatar
13320 km = 13.320 Gy, Eastern Malaysia
13330 km = 13.330 Gy, Equatorial Guinea
13384 km = 13.384 Gy, Antarctica
13401 km = 13.401 Gy, Saudi Arabia
13424 km = 13.424 Gy, Karachi, Pakistan
13428 km = 13.428 Gy, Mecca, Saudi Arabia
13494 km = 13.494 Gy, Tristan & Gough Is. (Br.)
13518 km = 13.518 Gy, United Arab Emirates
13590 km = 13.590 Gy, Gabon
13674 km = 13.674 Gy, Khartoum, Sudan
13781 km = 13.781 Gy, Central African Republic
13852 km = 13.852 Gy, Andaman & Nicobar Is. (Ind.)
13929 km = 13.929 Gy, Kuala Lampur, Malaysia
13954 km = 13.954 Gy, Oman
13972 km = 13.972 Gy, Congo
13975 km = 13.975 Gy, Bombay, India
.....14002 MLY (.716c 1.459), 3C 43 Quasar
14009 km = 14.009 Gy, Hyderabad, India
14096 km = 14.096 Gy, Singapore
14286 km = 14.286 Gy, Yemen
14399 km = 14.399 Gy, Madras, India
14417 km = 14.417 Gy, Jakarta, Indonesia
14417 km = 14.417 Gy, Bali, Indonesia
14558 km = 14.558 Gy, Djibouti (Fr.)
14564 km = 14.564 Gy, Zaire
14633 km = 14.633 Gy, Addis Ababa, Ethiopia
.....14706 MLY (.752c 1.659), 3C 280.1 Quasar
14750 km = 14.750 Gy, Southern Sudan
14825 km = 14.825 Gy, Christmas Is. (Aus.)
14852 km = 14.852 Gy, Laccadive Is. (Ind.)
14933 km = 14.933 Gy, Sri Lanka
14969 km = 14.969 Gy, Angola
15008 km = 15.008 Gy, Perth, Australia
15120 km = 15.120 Gy, Uganda
15130 km = 15.130 Gy, Rwanda
15259 km = 15.259 Gy, Burundi
15506 km = 15.506 Gy, Namibia
15535 km = 15.535 Gy, Nairobi, Kenya
.....15547 MLY (.795c 1.956), 3C 191 Quasar
15568 km = 15.568 Gy, Somalia
15609 km = 15.609 Gy, Maldive Is.
.....15664 MLY (.801c 2.012), 3C 9 Quasar
15682 km = 15.682 Gy, Tanzania
15682 km = 15.682 Gy, Cocos Is. (Aus.)
.....15782 MLY (.807c 2.064), PHL 1305 Quasar
15892 km = 15.892 Gy, Zambia
16068 km = 16.068 Gy, Cape Town, South Africa
.....16114 MLY (.824c 2.223), PHL 8462 Quasar
16127 km = 16.127 Gy, Zanzibar, Tanzania
16377 km = 16.377 Gy, Malawi
16422 km = 16.422 Gy, Gaborone, Bostwana
16485 km = 16.485 Gy, Kimberley, South Africa
16625 km = 16.625 Gy, Zimbabwe
16646 km = 16.646 Gy, Seychelles
16651 km = 16.651 Gy, Chagos
16669 km = 16.669 Gy, Johannesburg, South Africa
16823 km = 16.823 Gy, Lesotho
.....16877 MLY (.863c 2.69), PHL 957 Quasar
16994 km = 16.994 Gy, Comoros
17006 km = 17.006 Gy, Swaziland
17008 km = 17.008 Gy, Mozambique
17075 km = 17.075 Gy, Mayotte (Fr.)
17094 km = 17.094 Gy, Durban, South Africa
17097 km = 17.097 Gy, Glorioso Is. (Fr.)
17313 km = 17.313 Gy, Agalega & St. Brandon
17325 km = 17.325 Gy, Juan de Nova Is. (Fr.)
17583 km = 17.583 Gy, Marion Is.
17713 km = 17.713 Gy, Heard Island (Aus.)
.....17737 MLY (.907c 3.53), OQ 172 Quasar
17817 km = 17.817 Gy, Malagasy Republic
17838 km = 17.838 Gy, Tromelin Is. (Fr.)
.....17.933 GLY (.917c 3.80), 4C 41.17 Galaxy [29]
.....18.070 GLY (.924c 4.03), PC 0910+5625 Quasar
.....18.109 GLY (.926c 4.11), Q0000-26 Quasar
18345 km = 18.345 Gy, Kerguelen Is. (Fr.)
18384 km = 18.384 Gy, Rodriguez Is.
18412 km = 18.412 Gy, Mauritius
18436 km = 18.436 Gy, Reunion Is. (Fr.)
18479 km = 18.479 Gy, Crozet (Fr.)
18494 km = 18.494 Gy, Amsterdam-St. Paul Is. (Fr.)
.....19.556 My, Hubble Time, 19556 MLY (1.00c [infinite]), Hubble Radius [30]
20002 km = 20.002 Gy, Antipode (61.6 degrees East by 34.2 degrees South)