General Remarks

Abstract

The study of equilibrium and stability of different gravitating systems must evidently play an important role in the construction of the picture of their evolution. The instants when the system loses its stability are defined by the critical points of the line of evolutionary development, when the smooth evolution of the system should be replaced by a rapid reconstruction. Some authors [195] indeed observe some traces of jumplike transformations which have occurred in our Galaxy. On the other hand, the smooth evolution must evidently follow the sequence of quasistationary states. On the line of evolutionary development, the quasistationary states present such points, to which all the stellar systems observed in sufficient abundance must correspond. This is similar to the situation in the world of stars [150], where the spectrum-luminosity diagram shows the presence, in appreciable quantities, of only stars in the regions of the diagram familiar in its stationarity (above all, on the Main Sequence): the regions corresponding to strongly nonstationary states are very rapidly “rushed” by the evolving system.

A gentleman went out

for a walk along a street,

he was struck on the skull:

a flower-pot had dropped on him,

thrown down by some hooligans!

But, to tell the truth there were no

hooligans anywhere around,

as today all hooligans

were sitting in Prevel’s Hall

listening to Mozart.

Therefore it was the wind.

But that again is not true,

as the wind is abominably inert

and calm today and could not

topple the flower-pot.

But nevertheless

the gentleman going for a walk

has been struck on the skull.

How! Apropos of nothing?

How! Without the slightest cause?

It was incomprehensible, and the

profundity of this problem no one

could measure.

The gentleman applies

an antiseptic plaster

to his bruised skull

and does not believe

in anything since...

Remon Ceno