It rose into prominence with wonderful quickness, and sank equally fast.
At its height it outshone our sun eight thousand times! This star was
so far from us that it was reckoned its light must take about three
hundred years to reach us, consequently the great conflagration, or
whatever caused the outburst, must have taken place in the reign of
James I., though, as it was only seen here in 1901, it was called the
new star of the new century.

When these new stars die down they sometimes continue to shine faintly
for a long time, so that they are visible with a telescope, but in other
cases they may die out altogether. We know very little about them, and
have but small opportunity for observing them, and so it is not safe to
hazard any theories to account for their peculiarities. At first men
supposed that the great flame was made by a violent collision between
two bodies coming together with great velocity so that both flared up,
but this speculation has been shown by the spectroscope to be
improbable, and now it is supposed by some people that two stars
journeying through space may pass through a nebulous region, and thus
may flare up, and such a theory is backed up by the fact that a very
great number of such stars do seem to be mixed up in some strange way
with a nebulous haze.

All these new stars that we have been discussing so far have only
blazed up once and then died down, but there is another class of stars
quite as peculiar, and even more difficult to explain, and these are
called variable stars. They get brighter and brighter up to a certain
point, and then die down, only to become bright once more, and these
changes occur with the utmost regularity, so that they are known and can
be predicted beforehand. This is even more unaccountable than a sudden
and unrepeated outburst, for one can understand a great flare-up, but
that a star should flare and die down with regularity is almost beyond
comprehension. Clearly we must look further than before for an
explanation. Let us first examine the facts we know. Variable stars
differ greatly from each other. Some are generally of a low magnitude,
and only become bright for a short time, while others are bright most of
the time and die down only for a short time. Others become very bright,
then sink a little bit, but not so low as at first; then they become
bright again, and, lastly, go right down to the lowest point, and they
keep on always through this regular cycle