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The Sun's Journey Through Space

Having gained some idea of the nature of the electrical hypothesis of

solar disturbances and of the possible effect of other bodies upon the

sun's atmosphere, let us now compare the astronomical data with those of

geology. Let us take up five chief points for which the geologist

demands an explanation, and which any hypothesis must meet if it is to

be permanently accepted. These are (1) the irregular intervals at which

glacial periods occur; (2) the division of glacial periods into epochs

separated sometimes by hundreds of thousands of years; (3) the length of

glacial periods and epochs; (4) the occurrence of glacial stages and

historic pulsations in the form of small climatic waves superposed upon

the larger waves of glacial epochs; (5) the occurrence of climatic

conditions much milder than those of today, not only in the middle

portion of the great geological eras, but even in some of the recent

inter-glacial epochs.

1. The irregular duration of the interval from one glacial epoch to

another corresponds with the irregular distribution of the stars. If

glaciation is indirectly due to stellar influences, the epochs might

fall close together, or might be far apart. If the average interval were

ten million years, one interval might be thirty million or more and the

next only one or two hundred thousand. According to Schuchert, the known

periods of glacial or semi-glacial climate have been approximately as



1. Archeozoic.

(1/4 of geological time or perhaps much more)

No known glacial periods.

2. Proterozoic.

(1/4 of geological time)

a. Oldest known glacial period near base of Proterozoic in

Canada. Evidence widely distributed.

b. Indian glacial period; time unknown.

c. African glacial period; time unknown.

d. Glaciation near end of Proterozoic in Australia, Norway,

and China.

3. Paleozoic.

(1/4 of geological time)

a. Late Ordovician(?). Local in Arctic Norway.

b. Silurian. Local in Alaska.

c. Early Devonian. Local in South Africa.

d. Early Permian. World-wide and very severe.

4. Mesozoic and Cenozoic.

(1/4 of geological time)

a-b. None definitely determined during Mesozoic, although

there appears to have been periods of cooling (a) in the

late Triassic, and (b) in the late Cretacic, with at least

local glaciation in early Eocene.

c. Severe glacial period during Pleistocene.

This table suggests an interesting inquiry. During the last few decades

there has been great interest in ancient glaciation and geologists have

carefully examined rocks of all ages for signs of glacial deposits. In

spite of the large parts of the earth which are covered with deposits

belonging to the Mesozoic and Cenozoic, which form the last quarter of

geological time, the only signs of actual glaciation are those of the

great Pleistocene period and a few local occurrences at the end of the

Mesozoic or beginning of the Cenozoic. Late in the Triassic and early in

the Jurassic, the climate appears to have been rigorous, although no

tillites have been found to demonstrate glaciation. In the preceding

quarter, that is, the Paleozoic, the Permian glaciation was more severe

than that of the Pleistocene, and the Devonian than that of the Eocene,

while the Ordovician evidences of low temperature are stronger than

those at the end of the Triassic. In view of the fact that rocks of

Paleozoic age cover much smaller areas than do those of later age, the

three Paleozoic glaciations seem to indicate a relative frequency of

glaciation. Going back to the Proterozoic, it is astonishing to find

that evidence of two highly developed glacial periods, and possibly

four, has been discovered. Since the Indian and the African glaciations

of Proterozoic times are as yet undated, we cannot be sure that they are

not of the same date as the others. Nevertheless, even two is a

surprising number, for not only are most Proterozoic rocks so

metamorphosed that possible evidences of glacial origin are destroyed,

but rocks of that age occupy far smaller areas than either those of

Paleozoic or, still more, Mesozoic and Cenozoic age. Thus the record of

the last three-quarters of geological time suggests that if rocks of all

ages were as abundant and as easily studied as those of the later

periods, the frequency of glacial periods would be found to increase as

one goes backward toward the beginnings of the earth's history. This is

interesting, for Jeans holds that the chances that the stars would

approach one another were probably greater in the past than at present.

This conclusion is based on the assumption that our universe is like the

spiral nebulae in which the orbits of the various members are nearly

circular during the younger stages. Jeans considers it certain that in

such cases the orbits will gradually become larger and more elliptical

because of the attraction of one body for another. Thus as time goes on

the stars will be more widely distributed and the chances of approach

will diminish. If this is correct, the agreement between astronomical

theory and geological conclusions suggests that the two are at least not

in opposition.

The first quarter of geological time as well as the last three must be

considered in this connection. During the Archeozoic, no evidence of

glaciation has yet been discovered. This suggests that the geological

facts disprove the astronomical theory. But our knowledge of early

geological times is extremely limited, so limited that lack of evidence

of glaciation in the Archeozoic may have no significance. Archeozoic

rocks have been studied minutely over a very small percentage of the

earth's land surface. Moreover, they are highly metamorphosed so that,

even if glacial tills existed, it would be hard to recognize them.

Third, according to both the nebular and the planetesimal hypotheses, it

seems possible that during the earliest stages of geological history the

earth's interior was somewhat warmer than now, and the surface may have

been warmed more than at present by conduction, by lava flows, and by

the fall of meteorites. If the earth during the Archeozoic period

emitted enough heat to raise its surface temperature a few degrees, the

heat would not prevent the development of low forms of life but might

effectively prevent all glaciation. This does not mean that it would

prevent changes of climate, but merely changes so extreme that their

record would be preserved by means of ice. It will be most interesting

to see whether future investigations in geology and astronomy indicate

either a semi-uniform distribution of glacial periods throughout the

past, or a more or less regular decrease in frequency from early times

down to the present.

2. The Pleistocene glacial period was divided into at least four epochs,

while in the Permian at least one inter-glacial epoch seems certain, and

in some places the alternation between glacial and non-glacial beds

suggests no less than nine. In the other glaciations the evidence is not

yet clear. The question of periodicity is so important that it

overthrows most glacial hypotheses. Indeed, had their authors known the

facts as established in recent years, most of the hypotheses would never

have been advanced. The carbon dioxide hypothesis is the only one which

was framed with geologically rapid climatic alternations in mind. It

certainly explains the facts of periodicity better than does any of its

predecessors, but even so it does not account for the intimate way in

which variations of all degrees from those of the weather up to glacial

epochs seem to grade into one another.

According to our stellar hypothesis, occasional groups of glacial epochs

would be expected to occur close together and to form long glacial

periods. This is because many of the stars belong to groups or clusters

in which the stars move in parallel paths. A good example is the cluster

in the Hyades, where Boss has studied thirty-nine stars with special

care.[120] The stars are grouped about a center about 130 light years

from the sun. The stars themselves are scattered over an area about

thirty light years in diameter. They average about the same distance

apart as do those near the sun, but toward the center of the group they

are somewhat closer together. The whole thirty-nine sweep forward in

essentially parallel paths. Boss estimates that 800,000 years ago the

cluster was only half as far from the sun as at present, but probably

that was as near as it has been during recent geological times. All of

the thirty-nine stars of this cluster, as Moulton[121] puts it, "are

much greater in light-giving power than the sun. The luminosities of

even the five smallest are from five to ten times that of the sun, while

the largest are one hundred times greater in light-giving power than our

own luminary. Their masses are probably much greater than that of the

sun." If the sun were to pass through such a cluster, first one star and

then another might come so near as to cause a profound disturbance in

the sun's atmosphere.

3. Another important point upon which a glacial hypothesis may come to

grief is the length of the periods or rather of the epochs which compose

the periods. During the last or Pleistocene glacial period the evidence

in America and Europe indicates that the inter-glacial epochs varied in

length and that the later ones were shorter than the earlier. Chamberlin

and Salisbury, from a comparison of various authorities, estimate that

the intervals from one glacial epoch to another form a declining series,

which may be roughly expressed as follows: 16-8-4-2-1, where unity is

the interval from the climax of the late Wisconsin, or last glacial

epoch, to the present. Most authorities estimate the culmination of the

late Wisconsin glaciation as twenty or thirty thousand years ago. Penck

estimates the length of the last inter-glacial period as 60,000 years

and the preceding one as 240,000.[122] R. T. Chamberlin, as already

stated, finds that the consensus of opinion is that inter-glacial epochs

have averaged five times as long as glacial epochs. The actual duration

of the various glaciations probably did not vary in so great a ratio as

did the intervals from one glaciation to another. The main point,

however, is the irregularity of the various periods.

The relation of the stellar electrical hypothesis to the length of

glacial epochs may be estimated from column C, in Table 5. There we see

that the distances at which a star might possibly disturb the sun enough

to cause glaciation range all the way from 120 billion miles in the case

of a small star like the sun, to 3200 billion in the case of Betelgeuse,

while for double stars the figure may rise a hundred times higher. From

this we can calculate how long it would take a star to pass from a point

where its influence would first amount to a quarter of the assumed

maximum to a similar point on the other side of the sun. In making these

calculations we will assume that the relative rate at which the star and

the sun approach each other is about twenty-two miles per second, or 700

million miles per year, which is the average rate of motion of all the

known stars. According to the distances in Table 5 this gives a range

from about 500 years up to about 10,000, which might rise to a million

in the case of double stars. Of course the time might be relatively

short if the sun and a rapidly moving star were approaching one another

almost directly, or extremely long if the sun and the star were moving

in almost the same direction and at somewhat similar rates,--a condition

more common than the other. Here, as in so many other cases, the

essential point is that the figures which we thus obtain seem to be of

the right order of magnitude.

4. Post-glacial climatic stages are so well known that in Europe they

have definite names. Their sequence has already been discussed in

Chapter XII. Fossils found in the peat bogs of Denmark and Scandinavia,

for example, prove that since the final disappearance of the continental

ice cap at the close of the Wisconsin there has been at least one period

when the climate of Europe was distinctly milder than now. Directly

overlying the sheets of glacial drift laid down by the ice there is a

flora corresponding to that of the present tundras. Next come remains of

a forest vegetation dominated by birches and poplars, showing that the

climate was growing a little warmer. Third, there follow evidences of a

still more favorable climate in the form of a forest dominated by pines;

fourth, one where oak predominates; and fifth, a flora similar to that

of the Black Forest of Germany, indicating that in Scandinavia the

temperature was then decidedly higher than today. This fifth flora has

retreated southward once more, having been driven back to its present

latitude by a slight recurrence of a cool stormy climate.[123] In

central Asia evidence of post-glacial stages is found not only in five

distinct moraines but in a corresponding series of elevated strands

surrounding salt lakes and of river terraces in non-glaciated arid


In historic as well as prehistoric times, as we have already seen, there

have been climatic fluctuations. For instance, the twelfth or thirteenth

century B. C. appears to have been almost as mild as now, as does the

seventh century B. C. On the other hand about 1000 B. C., at the time of

Christ, and in the fourteenth century there were times of relative

severity. Thus it appears that both on a large and on a small scale

pulsations of climate are the rule. Any hypothesis of climatic changes

must satisfy the periods of these pulsations. These conditions furnish a

problem which makes difficulty for almost all hypotheses of climatic

change. According to the present hypothesis, earth movements such as are

discussed in Chapter XII may cooeperate with two astronomical factors.

One is the constant change in the positions of the stars, a change which

we have already called kaleidoscopic, and the other is the fact that a

large proportion of the stars are double or multiple. When one star in a

group approaches the sun closely enough to cause a great solar

disturbance, numerous others may approach or recede and have a minor

effect. Thus, whenever the sun is near groups of stars we should expect

that the earth would show many minor climatic pulsations and stages

which might or might not be connected with glaciation. The historic

pulsations shown in the curve of tree growth in California, Fig. 4, are

the sort of changes that would be expected if movements of the stars

have an effect on the solar atmosphere.

Not only are fully a third of all the visible stars double, as we have

already seen, but at least a tenth of these are known to be triple or

multiple. In many of the double stars the two bodies are close together

and revolve so rapidly that whatever periodicity they might create in

the sun's atmosphere would be very short. In the triplets, however, the

third star is ordinarily at least ten times as far from the other two as

they are from each other, and its period of rotation sometimes runs into

hundreds or thousands of years. An actual multiple star in the

constellation Polaris will serve as an example. The main star is

believed by Jeans to consist of two parts which are almost in contact

and whirl around each other with extraordinary speed in four days. If

this is true they must keep each other's atmospheres in a state of

intense commotion. Much farther away a third star revolves around this

pair in twelve years. At a much greater distance a fourth star revolves

around the common center of gravity of itself and the other three in a

period which may be 20,000 years. Still more complicated cases probably

exist. Suppose such a system were to traverse a path where it would

exert a perceptible influence on the sun for thirty or forty thousand

years. The varying movements of its members would produce an intricate

series of cycles which might show all sorts of major and minor

variations in length and intensity. Thus the varied and irregular stages

of glaciation and the pulsations of historic times might be accounted

for on the hypothesis of the proximity of the sun to a multiple star, as

well as on that of the less pronounced approach and recession of a

number of stars. In addition to all this, an almost infinitely complex

series of climatic changes of long and short duration might arise if the

sun passed through a nebula.

5. We have seen in Chapter VIII that the contrast between the somewhat

severe climate of the present and the generally mild climate of the past

is one of the great geological problems. The glacial period is not a

thing of the distant past. Geologists generally recognize that it is

still with us. Greenland and Antarctica are both shrouded in ice sheets

in latitudes where fossil floras prove that at other periods the climate

was as mild as in England or even New Zealand. The present glaciated

regions, be it noted, are on the polar borders of the world's two most

stormy oceanic areas, just where ice would be expected to last longest

according to the solar cyclonic hypothesis. In contrast with the

semi-glacial conditions of the present, the last inter-glacial epoch was

so mild that not only men but elephants and hippopotamuses flourished in

central Europe, while at earlier times in the middle of long eras, such

as the Paleozoic and Mesozoic, corals, cycads, and tree ferns flourished

within the Arctic circle.

If the electro-stellar hypothesis of solar disturbances proves well

founded, it may explain these peculiarities. Periods of mild climate

would represent a return of the sun and the earth to their normal

conditions of quiet. At such times the atmosphere of the sun is assumed

to be little disturbed by sunspots, faculae, prominences, and other

allied evidences of movements; and the rice-grain structure is perhaps

the most prominent of the solar markings. The earth at such times is

supposed to be correspondingly free from cyclonic storms. Its winds are

then largely of the purely planetary type, such as trade winds and

westerlies. Its rainfall also is largely planetary rather than cyclonic.

It falls in places such as the heat equator where the air rises under

the influence of heat, or on the windward slopes of mountains, or in

regions where warm winds blow from the ocean over cold lands.

According to the electro-stellar hypothesis, the conditions which

prevailed during hundreds of millions of years of mild climate mean

merely that the solar system was then in parts of the heavens where

stars--especially double stars--were rare or small, and electrical

disturbances correspondingly weak. Today, on the other hand, the sun is

fairly near a number of stars, many of which are large doubles. Hence it

is supposed to be disturbed, although not so much as at the height of

the last glacial epoch.

After the preceding parts of this book had been written, the assistance

of Dr. Schlesinger made it possible to test the electro-stellar

hypothesis by comparing actual astronomical dates with the dates of

climatic or solar phenomena. In order to make this possible, Dr.

Schlesinger and his assistants have prepared Table 6, giving the

position, magnitude, and motions of the thirty-eight nearest stars, and

especially the date at which each was nearest the sun. In column 10

where the dates are given, a minus sign indicates the past and a plus

sign the future. Dr. Shapley has kindly added column 12, giving the

absolute magnitudes of the stars, that of the sun being 4.8, and column

13, showing their luminosity or absolute radiation, that of the sun

being unity. Finally, column 14 shows the effective radiation received

by the sun from each star when the star is at a minimum distance. Unity

in this case is the effect of a star like the sun at a distance of one

light year.

It is well known that radiation of all kinds, including light, heat, and

electrical emissions, varies in direct proportion to the exposed

surface, that is, as the square of the radius of a sphere, and inversely

as the square of the distance. From black bodies, as we have seen, the

total radiation varies as the fourth power of the absolute temperature.

It is not certain that either light or electrical emissions from

incandescent bodies vary in quite this same proportion, nor is it yet

certain whether luminous and electrical emissions vary exactly together.

Nevertheless they are closely related. Since the light coming from each

star is accurately measured, while no information is available as to

electrical emissions, we have followed Dr. Shapley's suggestion and used

the luminosity of the stars as the best available measure of total

radiation. This is presumably an approximate measure of electrical

activity, provided some allowance be made for disturbances by outside

bodies such as companion stars. Hence the inclusion of column 14.





1 Groombr. 34

2 ++[Greek: e] Cassiop.


4 ++[Greek: k] Tucanae

5 [Greek: t] Ceti

6 [Greek: d]2 Eridani

7 ++[Greek: e] Eridani

8 ++40(0)^2 Eridani

9 Cordoba Z. 243

10 Weisse 592

11 ++[Greek: a] Can. Maj. (Sirius)

12 ++[Greek: a] Can. Min. (Procyon)

13 ++Fedorenko 1457-8

14 Groombr. 1618

15 Weisse 234

16 Lalande 21185

17 Lalande 21258


19 Lalande 25372

20 ++[Greek: a] Centauri

21 ++[Greek: x] Bootes

22 ++Lalande 27173

23 Weisse 1259

24 Lacaille 7194

25 ++[Greek: b] 416

26 Argel -0.17415-6

27 Barnard's star

28 ++70p Ophiuchi

29 ++[Greek: S] 2398

30 [Greek: s] Draconis

31 ++[Greek: a] Aquilae (Altair)

32 ++61 Cygni

33 Lacaille 8760

34 [Greek: e] Indi

35 ++Krueger 60

36 Lacaille 9352

37 Lalande 46650

38 C. G. A. 32416

(++ Double star.)

(1) (2) (3) (4) (5) (6)

Right Declination Visual Spectrum Proper Radial

Star Ascension [Greek: d] Mag. m Motion Velocity

code [Greek: a] 1900 km. per

1900 sec.


1 0^h 12^m.7 +43 deg.27' 8.1 Ma 2".89 + 3

2 43 .0 +57 17 3.6 F8 1 .24 + 10

3 43 .9 +4 55 12.3 F0 3 .01 .....

4 1 12 .4 -69 24 5.0 F8 .39 + 12

5 39 .4 -16 28 3.6 K0 1 .92 - 16


6 3 15 .9 -43 27 4.3 G5 3 .16 + 87

7 28 .2 - 9 48 3.8 K0 .97 + 16

8 4 10 .7 - 7 49 4.5 G5 4 .08 - 42

9 5 7 .7 -44 59 9.2 K2 8 .75 +242

10 26 .4 - 3 42 8.8 K2 2 .22 .....


11 6 40 .7 -16 35 -1.6 A0 1 .32 - 8

12 7 34 .1 + 5 29 0.5 F5 1 .24 - 4

13 9 7 .6 +53 7 7.9 Ma 1 .68 + 10

14 10 5 .3 +49 58 6.8 K5p 1 .45 - 30

15 14 .2 +20 22 9.0 ... .49 .....


16 57 .9 +36 38 7.6 Mb 4 .78 - 87

17 11 0 .5 +44 2 8.5 K5 4 .52 + 65

18 12 .0 -57 2 12.0 ... 2 .69 .....

19 13 40 .7 +15 26 8.5 K5 2 .30 .....

20 14 32 .8 -60 25 0.2 G 3 .68 + 22


21 14 46 .8 +19 31 4.6 K5p .17 + 4

22 51 .6 -20 58 5.8 Kp 1 .96 + 20

23 16 41 .4 +33 41 8.4 ... .37 .....

24 17 11 .5 -46 32 5.7 K .97 .....

25 12 .1 -34 53 5.9 K5 1 .19 - 4


26 37 .0 +68 26 9.1 K 1 .33 .....

27 52 .9 + 4 25 9.7 Mb 10 .30 - 80

28 18 0 .4 + 2 31 4.3 K 1 .13 .....

29 41 .7 +59 29 8.8 K 2 .31 .....

30 19 32 .5 +69 29 4.8 G5 1 .84 + 26


31 45 .9 + 8 36 1.2 A5 .66 - 33

32 21 2 .4 +38 15 5.6 K5 5 .20 - 64

33 11 .4 -39 15 6.6 G 3 .53 + 13

34 55 .7 -57 12 4.8 K5 4 .70 - 39

35 22 24 .4 +57 12 9.2 ... .87 .....


36 59 .4 -36 26 7.1 K 6 .90 + 12

37 23 44 .0 + 1 52 8.7 Ma 1 .39 .....

38 59 .5 -37 51 8.2 G 6 .05 + 26

(7) (9) (11) (13) (14)

Present Minimum Magnitude Luminosity Effective

Parallax Distance at Min. Dist. radiation

[Greek: p] Light Yrs. at


(8) (10) (12) distance

Star Maximum Time of Absolute from sun

Code Parallax Minimum Magnitude



1 ".28 ".28 11.6 -4000 8.1 10.3 0.0063 0.000051

2 .18 .19 17.1 -47000 3.5 4.9 0.91 0.003110

3 .24 .... .... ...... .... 14.2 0.00017 ........

4 .16 .23 14.2 -264000 4.2 6.0 0.33 0.001610

5 .32 .37 8.8 +46000 3.3 6.1 0.30 0.003840


6 .16 .22 14.8 -33000 3.6 5.3 0.63 0.002960

7 .31 .46 7.1 -106000 3.0 6.3 0.25 0.004970

8 .21 .23 14.2 +19000 4.3 6.1 0.30 0.001470

9 .32 .68 4.8 -10000 7.6 11.7 0.0017 0.000074

10 .17 .... .... ...... .... 9.9 0.009 ........


11 .37 .41 8.0 +65000 -1.8 1.2 27.50 0.429000

12 .31 .32 10.2 +34000 0.5 3.0 5.25 0.051300

13 .16 .16 20.4 -24000 7.9 8.9 0.023 0.000055

14 .18 .23 14.2 +69000 6.3 8.1 0.048 0.000238

15 .19 .... .... ...... .... 10.4 0.0057 ........


16 .41 .76 4.3 +20000 6.2 10.7 0.0044 0.000238

17 .19 .22 14.8 -20000 8.2 9.9 0.009 0.000041

18 .34 .... .... ...... .... 14.7 0.00011 ........

19 .19 .... .... ...... .... 9.9 0.009 ........

20 .76 1.03 3.2 -28000 -0.5 4.6 1.20 0.117500


21 .17 .22 14.8 -598000 4.0 5.8 0.40 0.001815

22 .18 .19 17.1 -36000 5.6 7.1 0.12 0.000412

23 .18 .... .... ...... .... 9.7 0.011 ........

24 .19 .... .... ...... .... 7.1 0.12 ........

25 .17 .17 19.2 +21000 5.7 7.1 0.12 0.000329


26 .22 .... .... ...... .... 10.8 0.004 ........

27 .53 .70 4.7 +10000 9.1 13.3 0.0025 0.000114

28 .19 .... .... ...... .... 5.7 0.44 ........

29 .29 .... .... ...... .... 11.1 0.0030 ........

30 .20 .23 14.2 -49000 4.5 6.3 0.25 0.001238


31 .21 .51 6.4 +117000 -0.7 2.8 6.30 0.153600

32 .30 .38 8.6 +19000 5.1 8.0 0.053 0.000715

33 .25 .26 12.6 -11000 6.6 8.6 0.030 0.000189

34 .28 .31 10.5 +17000 4.6 7.0 0.13 0.001230

35 .26 .... .... ....... .... 11.3 0.0025 ........


36 .29 .29 11.2 -3000 7.1 9.4 0.014 0.000111

37 .17 .... .... ....... .... 9.9 0.009 ........

38 .22 .22 14.8 -7000 8.2 9.9 0.009 0.000041


On the basis of column 14 and of the movements and distances of the

stars as given in the other columns Fig. 10 has been prepared. This

gives an estimate of the approximate electrical energy received by the

sun from the nearest stars for 70,000 years before and after the

present. It is based on the twenty-six stars for which complete data are

available in Table 6. The inclusion of the other twelve would not alter

the form of the curve, for even the largest of them would not change any

part by more than about half of 1 per cent, if as much. Nor would the

curve be visibly altered by the omission of all except four of the

twenty-six stars actually used. The four that are important, and their

relative luminosity when nearest the sun, are Sirius 429,000, Altair

153,000, Alpha Centauri 117,500, and Procyon 51,300. The figure for the

next star is only 4970, while for this star combined with the other

twenty-one that are unimportant it is only 24,850.

Figure 10 is not carried more than 70,000 years into the past or into

the future because the stars near the sun at more remote times are not

included among the thirty-eight having the largest known parallaxes.

That is, they have either moved away or are not yet near enough to be

included. Indeed, as Dr. Schlesinger strongly emphasizes, there may be

swiftly moving, bright or gigantic stars which are now quite far away,

but whose inclusion would alter Fig. 10 even within the limits of the

140,000 years there shown. It is almost certain, however, that the most

that these would do would be to raise, but not obliterate, the minima on

either side of the main maximum.

from the stars.]

In preparing Fig. 10 it has been necessary to make allowance for double

stars. Passing by the twenty-two unimportant stars, it appears that the

companion of Sirius is eight or ten magnitudes smaller than that star,

while the companions of Procyon and Altair are five or more magnitudes

smaller than their bright comrades. This means that the luminosity of

the faint components is at most only 1 per cent of that of their bright

companions and in the case of Sirius not a hundredth of 1 per cent.

Hence their inclusion would have no visible effect on Fig. 10. In Alpha

Centauri, on the other hand, the two components are of almost the same

magnitude. For this reason the effective radiation of that star as given

in column 14 is doubled in Fig. 10, while for another reason it is

raised still more. The other reason is that if our inferences as to the

electrical effect of the sun on the earth and of the planets on the sun

are correct, double stars, as we have seen, must be much more effective

electrically than single stars. By the same reasoning two bright stars

close together must excite one another much more than a bright star and

a very faint one, even if the distances in both cases are the same. So,

too, other things being equal, a triple star must be more excited

electrically than a double star. Hence in preparing Fig. 10 all double

stars receive double weight and each part of Alpha Centauri receives an

additional 50 per cent because both parts are bright and because they

have a third companion to help in exciting them.

According to the electro-stellar hypothesis, Alpha Centauri is more

important climatically than any other star in the heavens not only

because it is triple and bright, but because it is the nearest of all

stars, and moves fairly rapidly. Sirius and Procyon move slowly in

respect to the sun, only about eleven and eight kilometers per second

respectively, and their distances at minimum are fairly large, that is,

8 and 10.2 light years. Hence their effect on the sun changes slowly.

Altair moves faster, about twenty-six kilometers per second, and its

minimum distance is 6.4 light years, so that its effect changes fairly

rapidly. Alpha Centauri moves about twenty-four kilometers per second,

and its minimum distance is only 3.2 light years. Hence its effect

changes very rapidly, the change in its apparent luminosity as seen from

the sun amounting at maximum to about 30 per cent in 10,000 years

against 14 per cent for Altair, 4 for Sirius, and 2 for Procyon. The

vast majority of the stars change so much more slowly than even Procyon

that their effect is almost uniform. All the stars at a distance of more

than perhaps twenty or thirty light years may be regarded as sending to

the sun a practically unchanging amount of radiation. It is the bright

stars within this limit which are important, and their importance

increases with their proximity, their speed of motion, and the

brightness and number of their companions. Hence Alpha Centauri causes

the main maximum in Fig. 10, while Sirius, Altair, and Procyon combine

to cause a general rise of the curve from the past to the future.

Let us now interpret Fig. 10 geologically. The low position of the curve

fifty to seventy thousand years ago suggests a mild inter-glacial

climate distinctly less severe than that of the present. Geologists say

that such was the case. The curve suggests a glacial epoch culminating

about 28,000 years ago. The best authorities put the climax of the last

glacial epoch between twenty-five and thirty thousand years ago. The

curve shows an amelioration of climate since that time, although it

suggests that there is still considerable severity. The retreat of the

ice from North America and Europe, and its persistence in Greenland and

Antarctica agree with this. And the curve indicates that the change of

climate is still persisting, a conclusion in harmony with the evidence

as to historic changes.

If Alpha Centauri is really so important, the effect of its variations,

provided it has any, ought perhaps to be evident in the sun. The

activity of the star's atmosphere presumably varies, for the orbits of

the two components have an eccentricity of 0.51. Hence during their

period of revolution, 81.2 years, the distance between them ranges from

1,100,000,000 to 3,300,000,000 miles. They were at a minimum distance in

1388, 1459, 1550, 1631, 1713, 1794, 1875, and will be again in 1956. In

Fig. 11, showing sunspot variations, it is noticeable that the years

1794 and 1875 come just at the ends of periods of unusual solar

activity, as indicated by the heavy horizontal line. A similar period of

great activity seems to have begun about 1914. If its duration equals

the average of its two predecessors, it will end about 1950. Back in the

fourteenth century a period of excessive solar activity, which has

already been described, culminated from 1370 to 1385, or just before the

two parts of Alpha Centauri were at a minimum distance. Thus in three

and perhaps four cases the sun has been unusually active during a time

when the two parts of the star were most rapidly approaching each other

and when their atmospheres were presumably most disturbed and their

electrical emanations strongest.

Note. The asterisks indicate two absolute minima of sunspots in 1810

and 1913, and the middle years (1780 and 1854) of two periods when the

sunspot maxima never fell below 95. If Alpha Centauri has an effect on

the sun's atmosphere, the end of another such period would be expected

not far from 1957.]

The fact that Alpha Centauri, the star which would be expected most

strongly to influence the sun, and hence the earth, was nearest the sun

at the climax of the last glacial epoch, and that today the solar

atmosphere is most active when the star is presumably most disturbed may

be of no significance. It is given for what it is worth. Its importance

lies not in the fact that it proves anything but that no contradiction

is found when we test the electro-stellar hypothesis by facts which were

not thought of when the hypothesis was framed. A vast amount of

astronomical work is still needed before the matter can be brought to

any definite conclusion. In case the hypothesis stands firm, it may be

possible to use the stars as a help in determining the exact chronology

of the later part of geological times. If the hypothesis is disproved,

it will merely leave the question of solar variations where it is today.

It will not influence the main conclusions of this book as to the causes

and nature of climatic changes. Its value lies in the fact that it calls

attention to new lines of research.


[Footnote 120: Lewis Boss: Convergent of a Moving Cluster in Taurus;

Astronom. Jour., Vol. 26, No. 4, 1908, pp. 31-36.]

[Footnote 121: F. R. Moulton: in Introduction to Astronomy, 1916.]

[Footnote 122: A. Penck: Die Alpen im Eiszeitalter, Leipzig, 1909.]

[Footnote 123: R. D. Salisbury: Physical Geography of the Pleistocene,

in Outlines of Geologic History, by Willis and Salisbury, 1910, pp.


[Footnote 124: Davis, Pumpelly, and Huntington: Explorations in

Turkestan, Carnegie Inst. of Wash., No. 26, 1905.

In North America the stages have been the subject of intensive studies

on the part of Taylor, Leverett, Goldthwait, and many others.]