ARRHENIUS, WORLDS IN THE MAKING

thelivyjr
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Re: ARRHENIUS, WORLDS IN THE MAKING

Post by thelivyjr » Fri Feb 21, 2020 1:40 p

VIII

THE SPREADING OF LIFE THROUGH THE UNIVERSE
, continued ...

On the road from the earth the germs would for about a month be exposed to the powerful light of the sun, and it has been demonstrated that the most highly refrangible rays of the sun can kill bacteria and their spores in relatively short periods.

As a rule, however, these experiments have been conducted in such a manner that the spores could germinate on the moist surface on which they were deposited (for instance, in Marshall Ward's experiments).

That, however, does not at all conform to the conditions prevailing in planetary space.

For Roux has shown that anthrax spores, which are readily killed by light when the air has access, remain alive when the air is excluded.

Some spores do not suffer from insulation at all.

That applies, for instance, according to Duclaux, to Thyrothrix scaber, which occurs in milk and which may live for a full month under the intense light of the sun.

All the botanists that I have been able to consult are of the opinion that we can by no means assert with certainty that spores would be killed by the light rays in wandering through infinite space.

It may further be argued that the spores, in their journey through universal space, would be exposed during most of that period to an extreme cold which possibly they might not be able to endure.

When the spores have passed the orbit of Neptune, their temperature will have sunk to 220, and farther out it will sink still lower.

In recent years experiments have been made in the Jenner Institute, in London, with spores of bacteria which were kept for twenty hours at a temperature of 252 in liquid hydrogen.

Their germinating power was not destroyed thereby.

TO BE CONTINUED ...

thelivyjr
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Re: ARRHENIUS, WORLDS IN THE MAKING

Post by thelivyjr » Sat Feb 22, 2020 1:40 p

VIII

THE SPREADING OF LIFE THROUGH THE UNIVERSE
, continued ...

Professor Macfadyen has, indeed, gone still further.

He has demonstrated that micro-organisms may be kept in liquid air (at 200) for six months without being deprived of their germinating power.

According to what I was told on the occasion of my last visit to London, further experiments, continued for still longer periods, have only confirmed this observation.

There is nothing improbable in the idea that the germinating power should be preserved at lower temperatures for longer periods than at our ordinary temperatures.

The loss of germinating power is no doubt due to some chemical process, and all chemical processes proceed at slower rates at lower temperatures than they do at higher.

The vital functions are intensified in the ratio of 1 : 2.5 when the temperature is raised by 10 C. (18 F.).

By the time that the spores reached the orbit of Neptune and their temperature had been lowered to 220, their vital energy would, according to this ratio, react with one thousand millions less intensity than at 10.

The germinating power of the spores would hence, at - 220, during the period of three million years, not be diminished to any greater degree than during one day at 10.

It is, therefore, not at all unreasonable to assert that the intense cold of space will act like a most effective preservative upon the seeds, and that they will in consequence be able to endure much longer journeys than we could assume if we judged from their behavior at ordinary temperatures.

It is similar with the drying effect which may be so injurious to plant life.

In interplanetary space, which is devoid of atmosphere, absolute dryness prevails.

An investigation by B. Schrober demonstrates that the green alga Pleurococcus vulgaris, which is so common on the trunks of trees, can be kept in absolute dryness (over concentrated sulphuric acid in a desiccator) for twenty weeks without being killed.

Seeds and spores may last still longer in a dry atmosphere.

Now, the tension of water vapor decreases in nearly the same ratio as the speed of the reaction with lower temperatures.

The evaporation of water i. e., the drying effect may hence, at a temperature of 220, not proceed further in three million years than it will in one day at 10.

We have thus several plausible reasons for concluding that spores which oppose an effective resistance to drying may well be carried from one planet to another and from one planetary system to another without sacrificing their vital energy.

TO BE CONTINUED ...

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Re: ARRHENIUS, WORLDS IN THE MAKING

Post by thelivyjr » Sun Feb 23, 2020 1:40 p

VIII

THE SPREADING OF LIFE THROUGH THE UNIVERSE
, continued ...

The destructive effect of light is, according to the experiments of Roux, no doubt due to the fact that the rays of light call forth an oxidation by the intermediation of the surrounding air.

This possibility is excluded in interplanetary space.

Moreover, the radiation of the sun is nine hundred times fainter in the orbit of Neptune than in the orbit of the earth, and half-way to the nearest fixed star, Alpha Centauri, twenty million times feebler.

Light, therefore, will not do much harm to the spores during their transference.

If, therefore, spores of the most minute organisms could escape from the earth, they might travel in all directions, and the whole universe might, so to say, be sown with them.

But now comes the question: how can they escape from the earth against the effect of gravitation?

Corpuscles of such small weight would naturally be carried away by any aerial current.

A small raindrop falls, at ordinary air pressure, about 4 cm. per second.

We can calculate from this observation that a bacteria spore 0.00016 mm. in diameter would only fall 83 m. in the course of a year.

It is obvious that particles of this minuteness would be swept away by every air current they met until they reached the most diluted air of the highest strata.

An air current of a velocity of 2 m. per second would take them to a height where the air pressure is only 0.001 mm. i.e., to a height of about 100 km. (60 miles).

But the air currents can never push the particle outside of our atmosphere.

In order to raise the spores to still higher levels we must have recourse to other forces, and we know that electrical forces can help us out of almost any difficulty.

At heights of 100 km. the phenomena of the radiating aurora take place.

We believe that the aurorse are produced by the discharge of large quantities of negatively charged dust coming from the sun.

If, therefore, the spore in question should take up negative electricity from the solar dust during an electric discharge, it may be driven out into the sea of ether by the repulsive charges of the other particles.

TO BE CONTINUED ...

thelivyjr
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Re: ARRHENIUS, WORLDS IN THE MAKING

Post by thelivyjr » Tue Feb 25, 2020 1:40 p

VIII

THE SPREADING OF LIFE THROUGH THE UNIVERSE
, continued ...

We suppose, now, that the electrical charges like matter cannot be subdivided without limit.

We must finally come to a minimum charge, and this charge has been calculated at about 3.5.10"" 10 electrostatic unit.

We can, without difficulty, calculate the intensity of an electric field capable of urging the charged spore of 0.00016 mm. upward against the force of gravity.

The required field-strength is only 200 volts per metre.

Such fields are often observed on the surface of the earth with a clear sky, and they are, indeed, almost normal.

The electric field of a region in which an auroral display takes place is probably much more intense, and would, without doubt, be of sufficient intensity to urge the small electrically charged spores which convection currents had carried up to these strata, farther out into space against the force of gravity.

It is thus probable that germs of the lowest organisms known to us are continually being carried away from the earth and the other planets upon which they exist.

As seeds in general, so most of these spores, thus carried away, will no doubt meet death in the cold infinite space of the universe.

Yet a small number of spores will fall on some other world, and may there be able to spread life if the conditions be suitable.

In many cases conditions will not be suitable.

Occasionally, however, the spores will fall on favorable soil.

It may take one million or several millions of years from the age at which a planet could possibly begin to sustain life to the time when the first seed falls upon it and germinates, and when organic life is thus originated.

This period is of little significance in comparison with the time during which life will afterwards flourish on the planet.

The germs which in this way escape from the planets on which their ancestors had found abode, may either wander unobstructed through space, or they may, as we have indicated, reach outer planets, or planets moving about other suns, or they may meet with larger particles of dust rushing towards the sun.

We have spoken of the Zodiacal Light and that part of it which has been designated the counter-glow.

This latter glow is regularly seen in the tropics and occasionally in that portion of our heavens which is just opposite the sun.

Astronomers ascribe the counter-glow to streams of fine dust which are drawn towards the sun (compare page 147).

Let us assume that a seed of the diameter of 0.00016 mm. strikes against a grain of dust which is a thousand times as large (0.0016 mm. diameter), and attaches itself to its surface.

This spore will be carried by the grain of dust towards the sun; it will cross the orbits of the inner planets, and it may descend in their atmospheres.

Those grains of dust do not, by any means, require very long spaces of time to pass from one planetary orbit to another.

If we assume that the spore starts with zero velocity near Neptune (in which case the seed might originate from the moon of Neptune; for Neptune itself, like Uranus, Saturn, and Jupiter, is not yet sufficiently cooled to sustain life), the spore would reach the orbit of Uranus in twenty-one years, and of Mercury in twenty-nine years.

With the same initial velocity such particles would be twelve years in passing between the orbits of Uranus and Saturn, four years between Saturn and Jupiter, two years between Jupiter and Mars, eighty-four days between Mars and the earth, forty days between the earth and Venus, and twenty-eight days between Venus and Mercury.

TO BE CONTINUED ...

thelivyjr
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Re: ARRHENIUS, WORLDS IN THE MAKING

Post by thelivyjr » Tue Feb 25, 2020 1:40 p

VIII

THE SPREADING OF LIFE THROUGH THE UNIVERSE
, continued ...

We see from these time estimates that the germs, together with the grains of dust to which they have attached themselves, might move towards the sun with much smaller velocity (from ten to twenty times smaller) without our having to fear any loss of their germinating powers during the transit.

In other words, if these seeds adhere to the particles, ninety or ninety-five per cent, of whose weight is balanced by the radiation pressure, they may soon fall into the atmosphere of some inner planet with the moderate velocity of a few kilometres per second.


It is easy to calculate that if such a particle should, in falling, be arrested in its motion after the first second, it would yet, thanks to the strong heat radiation from it, not be heated by more than 100 Cent. (212 F.) above the temperature of its surroundings.

Such a temperature can be borne by the spores of bacteria without fatal effects for much more than one second.

After the particles, together with the seed adhering to them, have once been stopped, they will slowly descend, or will be carried down to the surface of the nearest planet by descending convection currents.

In this way life would be transferred from one point of a planetary system, on which it had taken root, to other locations in the same planetary system which favor the development of life.

The seeds not caught by such particles of dust may be taken over to other solar systems, and finally be stopped by the radiation pressure of their suns.

They cannot penetrate any farther than to spots at which the radiation pressure is as strong as at their starting-points.

Consequently, germs from the earth, which is five times as near the sun as Jupiter, could approach another sun within a fifth of the distance at which germs from Jupiter would be stopped.

Somewhere near the suns, where the seeds are arrested by the radiation pressure to be turned back into space, there will evidently be accumulations of these seeds.

The planets which circulate around their suns have therefore more chance of meeting them than if they were not in the vicinity of a sun.

The germs will have lost the great velocity with which they wandered from one solar system to another, and they will not be heated so greatly in falling through the atmospheres of the planets which they meet.

TO BE CONTINUED ...

thelivyjr
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Re: ARRHENIUS, WORLDS IN THE MAKING

Post by thelivyjr » Wed Feb 26, 2020 1:40 p

VIII

THE SPREADING OF LIFE THROUGH THE UNIVERSE
, concluded ...

The seeds which are turned back into space when coming near a sun will there perhaps meet with particles whose weight is somewhat greater than the repelling power of the radiation pressure.

They would, therefore, turn back to the suns.

Like the germs, and for similar reasons, these particles would consequently be concentrated about the sun.

The small seeds have, therefore, a comparatively better chance of being arrested before their return to space by contact with such particles, and of being carried to the planets near that sun.

In this manner life may have been transplanted for eternal ages from solar system to solar system and from planet to planet of the same system.

But as among the billions of grains of pollen which the wind carries away from a large tree, a fir-tree, for instance, only one may on an average give birth to a new tree, thus of the billions, or perhaps trillions, of germs which the radiation pressure drives out into space, only one may really bring life to a foreign planet on which life had not yet arisen, and become the originator of living beings on that planet.

Finally, we perceive that, according to this version of the theory of panspermia, all organic beings in the whole universe should be related to one another, and should consist of cells which are built up of carbon, hydrogen, oxygen, and nitrogen.

The imagined existence of living beings in other worlds in whose constitution carbon is supposed to be replaced by silicon or titanium must be relegated to the realm of improbability.


Life on other inhabited planets has probably developed along lines which are closely related to those of our earth, and this implies the conclusion that life must always recommence from its very lowest type, just as every individual, however highly developed it may be, has by itself passed through all the stages of evolution from the single cell upward.

All these conclusions are in beautiful harmony with the general properties characteristic of life on our earth.

It cannot be denied that this interpretation of the theory of panspermia is distinguished by perfect consistency, which is the most important criterion of the probability of a cosmogonical theory.

There is little probability, though, of our ever being able to demonstrate the correctness of this view by an examination of seeds falling down upon our earth.

For the number of germs which reach us from other worlds will be extremely limited not more, perhaps, than a few within a year all over the earth's surface; and those, moreover, will presumably strongly resemble the single-cell spores with which the winds play in our atmosphere.

It would be difficult, if not impossible, to prove the celestial origin of any such germs if they should be found contrary to our assumption.

https://archive.org/stream/worldsinmaki ... h_djvu.txt

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