Home » Archimedes archive » Zipped Apps » Orrery » !Solar/Describe/Earth
!Solar/Describe/Earth
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Archimedes archive » Zipped Apps » Orrery |
| Filename: | !Solar/Describe/Earth |
| Read OK: | ✔ |
| File size: | 09E2 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
Earth is the third planet from the Sun. It is the first planet from the Sun to have a moon, a common feature for all the other planets beyond our orbit. The Earths atmosphere reaches to approximately 80km above the surface, but this is only about one-hundredth of the planets radius, and so occupies a relatively thin band around the planet. It is composed mainly of Nitrogen (78%) and oxygen (21%) with the remainder built up from small traces of other gases. These relative proportions remain fairly constant up to around 80km, but the heavy gases become rare at greater heights and only hydrogen and helium are found in the outermost regions. At the height of the stratosphere there is a concentrated layer of ozone, at about 25km. This ozone layer is vital to life on the planet, as it stops nearly all of the Suns harmful ultraviolet radiation from reaching the surface. The Earths atmosphere also contains a large amount of water vapour, although its concentration varies in different places and is subject seasonal variations. Most of it is visible as clouds, and most of these extend only to the top of the troposphere, up to 13km. It is in this region that the dominant weather systems are found. Above this lies a layer of warm air which holds cooler air below containing most of the water vapour, and the clouds that we see. The surface of the planet is subject to much Geological activity, and is shaped by continental drifting (Plate tectonics). This makes the planets surface relatively young, and taken in account with other factors such as the existence of an atmosphere and weathering, explains why few visible impact craters are to be found, unlike for example on the surface of the moon, which is heavily cratered, and gives a more accurate guide as to the quantity of collisions with debris making its way through the solar system. Here the surface features date back to the formation of the solar system, and have remained undisturbed due to the moons geological inactivity. The structure of the planet itself is divided into three regions, the crust which extends for roughly 7km beneath the oceans and 40km beneath the continents, the mantle which is roughly 2870km thick, and the core which accounts for the remaining 3480km. This core is composed of two layers, the inner is solid, the outer flows. They are both composed mainly of iron, and it is convection in the molten outer layer that plays an important role in accounting for the planets magnetic field.
00000000 45 61 72 74 68 20 69 73 20 74 68 65 20 74 68 69 |Earth is the thi| 00000010 72 64 20 70 6c 61 6e 65 74 20 66 72 6f 6d 20 74 |rd planet from t| 00000020 68 65 20 53 75 6e 2e 20 49 74 20 69 73 20 74 68 |he Sun. It is th| 00000030 65 20 66 69 72 73 74 20 70 6c 61 6e 65 74 20 0a |e first planet .| 00000040 66 72 6f 6d 20 74 68 65 20 53 75 6e 20 74 6f 20 |from the Sun to | 00000050 68 61 76 65 20 61 20 6d 6f 6f 6e 2c 20 61 20 63 |have a moon, a c| 00000060 6f 6d 6d 6f 6e 20 66 65 61 74 75 72 65 20 66 6f |ommon feature fo| 00000070 72 20 61 6c 6c 20 74 68 65 20 0a 6f 74 68 65 72 |r all the .other| 00000080 20 70 6c 61 6e 65 74 73 20 62 65 79 6f 6e 64 20 | planets beyond | 00000090 6f 75 72 20 6f 72 62 69 74 2e 20 54 68 65 20 45 |our orbit. The E| 000000a0 61 72 74 68 73 20 61 74 6d 6f 73 70 68 65 72 65 |arths atmosphere| 000000b0 20 72 65 61 63 68 65 73 20 0a 74 6f 20 61 70 70 | reaches .to app| 000000c0 72 6f 78 69 6d 61 74 65 6c 79 20 38 30 6b 6d 20 |roximately 80km | 000000d0 61 62 6f 76 65 20 74 68 65 20 73 75 72 66 61 63 |above the surfac| 000000e0 65 2c 20 62 75 74 20 74 68 69 73 20 69 73 20 6f |e, but this is o| 000000f0 6e 6c 79 20 0a 61 62 6f 75 74 20 6f 6e 65 2d 68 |nly .about one-h| 00000100 75 6e 64 72 65 64 74 68 20 6f 66 20 74 68 65 20 |undredth of the | 00000110 70 6c 61 6e 65 74 73 20 72 61 64 69 75 73 2c 20 |planets radius, | 00000120 61 6e 64 20 73 6f 20 6f 63 63 75 70 69 65 73 20 |and so occupies | 00000130 61 0a 72 65 6c 61 74 69 76 65 6c 79 20 74 68 69 |a.relatively thi| 00000140 6e 20 62 61 6e 64 20 61 72 6f 75 6e 64 20 74 68 |n band around th| 00000150 65 20 70 6c 61 6e 65 74 2e 20 20 49 74 20 69 73 |e planet. It is| 00000160 20 63 6f 6d 70 6f 73 65 64 20 6d 61 69 6e 6c 79 | composed mainly| 00000170 20 0a 6f 66 20 4e 69 74 72 6f 67 65 6e 20 28 37 | .of Nitrogen (7| 00000180 38 25 29 20 61 6e 64 20 6f 78 79 67 65 6e 20 28 |8%) and oxygen (| 00000190 32 31 25 29 20 77 69 74 68 20 74 68 65 20 72 65 |21%) with the re| 000001a0 6d 61 69 6e 64 65 72 20 62 75 69 6c 74 20 75 70 |mainder built up| 000001b0 20 0a 66 72 6f 6d 20 73 6d 61 6c 6c 20 74 72 61 | .from small tra| 000001c0 63 65 73 20 6f 66 20 6f 74 68 65 72 20 67 61 73 |ces of other gas| 000001d0 65 73 2e 20 54 68 65 73 65 20 72 65 6c 61 74 69 |es. These relati| 000001e0 76 65 20 70 72 6f 70 6f 72 74 69 6f 6e 73 20 0a |ve proportions .| 000001f0 72 65 6d 61 69 6e 20 66 61 69 72 6c 79 20 63 6f |remain fairly co| 00000200 6e 73 74 61 6e 74 20 75 70 20 74 6f 20 61 72 6f |nstant up to aro| 00000210 75 6e 64 20 38 30 6b 6d 2c 20 62 75 74 20 74 68 |und 80km, but th| 00000220 65 20 68 65 61 76 79 20 67 61 73 65 73 20 0a 62 |e heavy gases .b| 00000230 65 63 6f 6d 65 20 72 61 72 65 20 61 74 20 67 72 |ecome rare at gr| 00000240 65 61 74 65 72 20 68 65 69 67 68 74 73 20 61 6e |eater heights an| 00000250 64 20 6f 6e 6c 79 20 68 79 64 72 6f 67 65 6e 20 |d only hydrogen | 00000260 61 6e 64 20 68 65 6c 69 75 6d 20 0a 61 72 65 20 |and helium .are | 00000270 66 6f 75 6e 64 20 69 6e 20 74 68 65 20 6f 75 74 |found in the out| 00000280 65 72 6d 6f 73 74 20 72 65 67 69 6f 6e 73 2e 20 |ermost regions. | 00000290 41 74 20 74 68 65 20 68 65 69 67 68 74 20 6f 66 |At the height of| 000002a0 20 74 68 65 20 0a 73 74 72 61 74 6f 73 70 68 65 | the .stratosphe| 000002b0 72 65 20 74 68 65 72 65 20 69 73 20 61 20 63 6f |re there is a co| 000002c0 6e 63 65 6e 74 72 61 74 65 64 20 6c 61 79 65 72 |ncentrated layer| 000002d0 20 6f 66 20 6f 7a 6f 6e 65 2c 20 61 74 20 61 62 | of ozone, at ab| 000002e0 6f 75 74 20 0a 32 35 6b 6d 2e 20 54 68 69 73 20 |out .25km. This | 000002f0 6f 7a 6f 6e 65 20 6c 61 79 65 72 20 69 73 20 76 |ozone layer is v| 00000300 69 74 61 6c 20 74 6f 20 6c 69 66 65 20 6f 6e 20 |ital to life on | 00000310 74 68 65 20 70 6c 61 6e 65 74 2c 20 61 73 20 69 |the planet, as i| 00000320 74 20 0a 73 74 6f 70 73 20 6e 65 61 72 6c 79 20 |t .stops nearly | 00000330 61 6c 6c 20 6f 66 20 74 68 65 20 53 75 6e 73 20 |all of the Suns | 00000340 68 61 72 6d 66 75 6c 20 75 6c 74 72 61 76 69 6f |harmful ultravio| 00000350 6c 65 74 20 72 61 64 69 61 74 69 6f 6e 20 0a 66 |let radiation .f| 00000360 72 6f 6d 20 72 65 61 63 68 69 6e 67 20 74 68 65 |rom reaching the| 00000370 20 73 75 72 66 61 63 65 2e 0a 0a 54 68 65 20 45 | surface...The E| 00000380 61 72 74 68 73 20 61 74 6d 6f 73 70 68 65 72 65 |arths atmosphere| 00000390 20 61 6c 73 6f 20 63 6f 6e 74 61 69 6e 73 20 61 | also contains a| 000003a0 20 6c 61 72 67 65 20 61 6d 6f 75 6e 74 20 6f 66 | large amount of| 000003b0 20 77 61 74 65 72 20 0a 76 61 70 6f 75 72 2c 20 | water .vapour, | 000003c0 61 6c 74 68 6f 75 67 68 20 69 74 73 20 63 6f 6e |although its con| 000003d0 63 65 6e 74 72 61 74 69 6f 6e 20 76 61 72 69 65 |centration varie| 000003e0 73 20 69 6e 20 64 69 66 66 65 72 65 6e 74 20 70 |s in different p| 000003f0 6c 61 63 65 73 20 0a 61 6e 64 20 69 73 20 73 75 |laces .and is su| 00000400 62 6a 65 63 74 20 73 65 61 73 6f 6e 61 6c 20 76 |bject seasonal v| 00000410 61 72 69 61 74 69 6f 6e 73 2e 20 4d 6f 73 74 20 |ariations. Most | 00000420 6f 66 20 69 74 20 69 73 20 76 69 73 69 62 6c 65 |of it is visible| 00000430 20 61 73 20 0a 63 6c 6f 75 64 73 2c 20 61 6e 64 | as .clouds, and| 00000440 20 6d 6f 73 74 20 6f 66 20 74 68 65 73 65 20 65 | most of these e| 00000450 78 74 65 6e 64 20 6f 6e 6c 79 20 74 6f 20 74 68 |xtend only to th| 00000460 65 20 74 6f 70 20 6f 66 20 74 68 65 20 0a 74 72 |e top of the .tr| 00000470 6f 70 6f 73 70 68 65 72 65 2c 20 75 70 20 74 6f |oposphere, up to| 00000480 20 31 33 6b 6d 2e 20 49 74 20 69 73 20 69 6e 20 | 13km. It is in | 00000490 74 68 69 73 20 72 65 67 69 6f 6e 20 74 68 61 74 |this region that| 000004a0 20 74 68 65 20 0a 64 6f 6d 69 6e 61 6e 74 20 77 | the .dominant w| 000004b0 65 61 74 68 65 72 20 73 79 73 74 65 6d 73 20 61 |eather systems a| 000004c0 72 65 20 66 6f 75 6e 64 2e 20 41 62 6f 76 65 20 |re found. Above | 000004d0 74 68 69 73 20 6c 69 65 73 20 61 20 6c 61 79 65 |this lies a laye| 000004e0 72 20 6f 66 20 0a 77 61 72 6d 20 61 69 72 20 77 |r of .warm air w| 000004f0 68 69 63 68 20 68 6f 6c 64 73 20 63 6f 6f 6c 65 |hich holds coole| 00000500 72 20 61 69 72 20 62 65 6c 6f 77 20 63 6f 6e 74 |r air below cont| 00000510 61 69 6e 69 6e 67 20 6d 6f 73 74 20 6f 66 20 74 |aining most of t| 00000520 68 65 20 0a 77 61 74 65 72 20 76 61 70 6f 75 72 |he .water vapour| 00000530 2c 20 61 6e 64 20 74 68 65 20 63 6c 6f 75 64 73 |, and the clouds| 00000540 20 74 68 61 74 20 77 65 20 73 65 65 2e 0a 0a 54 | that we see...T| 00000550 68 65 20 73 75 72 66 61 63 65 20 6f 66 20 74 68 |he surface of th| 00000560 65 20 70 6c 61 6e 65 74 20 69 73 20 73 75 62 6a |e planet is subj| 00000570 65 63 74 20 74 6f 20 6d 75 63 68 20 47 65 6f 6c |ect to much Geol| 00000580 6f 67 69 63 61 6c 20 0a 61 63 74 69 76 69 74 79 |ogical .activity| 00000590 2c 20 61 6e 64 20 69 73 20 73 68 61 70 65 64 20 |, and is shaped | 000005a0 62 79 20 63 6f 6e 74 69 6e 65 6e 74 61 6c 20 64 |by continental d| 000005b0 72 69 66 74 69 6e 67 20 28 50 6c 61 74 65 20 0a |rifting (Plate .| 000005c0 74 65 63 74 6f 6e 69 63 73 29 2e 20 54 68 69 73 |tectonics). This| 000005d0 20 6d 61 6b 65 73 20 74 68 65 20 70 6c 61 6e 65 | makes the plane| 000005e0 74 73 20 73 75 72 66 61 63 65 20 72 65 6c 61 74 |ts surface relat| 000005f0 69 76 65 6c 79 20 79 6f 75 6e 67 2c 20 0a 61 6e |ively young, .an| 00000600 64 20 74 61 6b 65 6e 20 69 6e 20 61 63 63 6f 75 |d taken in accou| 00000610 6e 74 20 77 69 74 68 20 6f 74 68 65 72 20 66 61 |nt with other fa| 00000620 63 74 6f 72 73 20 73 75 63 68 20 61 73 20 74 68 |ctors such as th| 00000630 65 20 65 78 69 73 74 65 6e 63 65 20 0a 6f 66 20 |e existence .of | 00000640 61 6e 20 61 74 6d 6f 73 70 68 65 72 65 20 61 6e |an atmosphere an| 00000650 64 20 20 77 65 61 74 68 65 72 69 6e 67 2c 20 65 |d weathering, e| 00000660 78 70 6c 61 69 6e 73 20 77 68 79 20 66 65 77 20 |xplains why few | 00000670 76 69 73 69 62 6c 65 20 0a 69 6d 70 61 63 74 20 |visible .impact | 00000680 63 72 61 74 65 72 73 20 61 72 65 20 74 6f 20 62 |craters are to b| 00000690 65 20 66 6f 75 6e 64 2c 20 75 6e 6c 69 6b 65 20 |e found, unlike | 000006a0 66 6f 72 20 65 78 61 6d 70 6c 65 20 6f 6e 20 74 |for example on t| 000006b0 68 65 20 0a 73 75 72 66 61 63 65 20 6f 66 20 74 |he .surface of t| 000006c0 68 65 20 6d 6f 6f 6e 2c 20 77 68 69 63 68 20 69 |he moon, which i| 000006d0 73 20 68 65 61 76 69 6c 79 20 63 72 61 74 65 72 |s heavily crater| 000006e0 65 64 2c 20 61 6e 64 20 67 69 76 65 73 20 61 20 |ed, and gives a | 000006f0 0a 6d 6f 72 65 20 61 63 63 75 72 61 74 65 20 67 |.more accurate g| 00000700 75 69 64 65 20 61 73 20 74 6f 20 74 68 65 20 71 |uide as to the q| 00000710 75 61 6e 74 69 74 79 20 6f 66 20 63 6f 6c 6c 69 |uantity of colli| 00000720 73 69 6f 6e 73 20 77 69 74 68 20 0a 64 65 62 72 |sions with .debr| 00000730 69 73 20 6d 61 6b 69 6e 67 20 69 74 73 20 77 61 |is making its wa| 00000740 79 20 74 68 72 6f 75 67 68 20 74 68 65 20 73 6f |y through the so| 00000750 6c 61 72 20 73 79 73 74 65 6d 2e 20 48 65 72 65 |lar system. Here| 00000760 20 74 68 65 20 0a 73 75 72 66 61 63 65 20 66 65 | the .surface fe| 00000770 61 74 75 72 65 73 20 64 61 74 65 20 62 61 63 6b |atures date back| 00000780 20 74 6f 20 74 68 65 20 66 6f 72 6d 61 74 69 6f | to the formatio| 00000790 6e 20 6f 66 20 74 68 65 20 73 6f 6c 61 72 20 0a |n of the solar .| 000007a0 73 79 73 74 65 6d 2c 20 61 6e 64 20 68 61 76 65 |system, and have| 000007b0 20 72 65 6d 61 69 6e 65 64 20 75 6e 64 69 73 74 | remained undist| 000007c0 75 72 62 65 64 20 64 75 65 20 74 6f 20 74 68 65 |urbed due to the| 000007d0 20 6d 6f 6f 6e 73 20 0a 67 65 6f 6c 6f 67 69 63 | moons .geologic| 000007e0 61 6c 20 69 6e 61 63 74 69 76 69 74 79 2e 0a 0a |al inactivity...| 000007f0 54 68 65 20 73 74 72 75 63 74 75 72 65 20 6f 66 |The structure of| 00000800 20 74 68 65 20 70 6c 61 6e 65 74 20 69 74 73 65 | the planet itse| 00000810 6c 66 20 69 73 20 64 69 76 69 64 65 64 20 69 6e |lf is divided in| 00000820 74 6f 20 74 68 72 65 65 20 0a 72 65 67 69 6f 6e |to three .region| 00000830 73 2c 20 74 68 65 20 63 72 75 73 74 20 77 68 69 |s, the crust whi| 00000840 63 68 20 65 78 74 65 6e 64 73 20 66 6f 72 20 72 |ch extends for r| 00000850 6f 75 67 68 6c 79 20 37 6b 6d 20 62 65 6e 65 61 |oughly 7km benea| 00000860 74 68 20 74 68 65 20 0a 6f 63 65 61 6e 73 20 61 |th the .oceans a| 00000870 6e 64 20 34 30 6b 6d 20 62 65 6e 65 61 74 68 20 |nd 40km beneath | 00000880 74 68 65 20 63 6f 6e 74 69 6e 65 6e 74 73 2c 20 |the continents, | 00000890 74 68 65 20 6d 61 6e 74 6c 65 20 77 68 69 63 68 |the mantle which| 000008a0 20 69 73 20 0a 72 6f 75 67 68 6c 79 20 32 38 37 | is .roughly 287| 000008b0 30 6b 6d 20 74 68 69 63 6b 2c 20 61 6e 64 20 74 |0km thick, and t| 000008c0 68 65 20 63 6f 72 65 20 77 68 69 63 68 20 61 63 |he core which ac| 000008d0 63 6f 75 6e 74 73 20 66 6f 72 20 74 68 65 20 0a |counts for the .| 000008e0 72 65 6d 61 69 6e 69 6e 67 20 33 34 38 30 6b 6d |remaining 3480km| 000008f0 2e 20 54 68 69 73 20 63 6f 72 65 20 69 73 20 63 |. This core is c| 00000900 6f 6d 70 6f 73 65 64 20 6f 66 20 74 77 6f 20 6c |omposed of two l| 00000910 61 79 65 72 73 2c 20 74 68 65 20 0a 69 6e 6e 65 |ayers, the .inne| 00000920 72 20 69 73 20 73 6f 6c 69 64 2c 20 74 68 65 20 |r is solid, the | 00000930 6f 75 74 65 72 20 66 6c 6f 77 73 2e 20 54 68 65 |outer flows. The| 00000940 79 20 61 72 65 20 62 6f 74 68 20 63 6f 6d 70 6f |y are both compo| 00000950 73 65 64 20 6d 61 69 6e 6c 79 20 0a 6f 66 20 69 |sed mainly .of i| 00000960 72 6f 6e 2c 20 61 6e 64 20 69 74 20 69 73 20 63 |ron, and it is c| 00000970 6f 6e 76 65 63 74 69 6f 6e 20 69 6e 20 74 68 65 |onvection in the| 00000980 20 6d 6f 6c 74 65 6e 20 6f 75 74 65 72 20 6c 61 | molten outer la| 00000990 79 65 72 20 74 68 61 74 20 0a 70 6c 61 79 73 20 |yer that .plays | 000009a0 61 6e 20 69 6d 70 6f 72 74 61 6e 74 20 72 6f 6c |an important rol| 000009b0 65 20 69 6e 20 61 63 63 6f 75 6e 74 69 6e 67 20 |e in accounting | 000009c0 66 6f 72 20 74 68 65 20 70 6c 61 6e 65 74 73 20 |for the planets | 000009d0 6d 61 67 6e 65 74 69 63 20 0a 66 69 65 6c 64 2e |magnetic .field.| 000009e0 0a 0a |..| 000009e2
.