The comet of Biela is approaching the earth's orbit with increasing
velocity, and towards the end of the following month it will partially
intersect the course which the earth traverses in its journey round the
sun. Happily, the comet will be in advance of the earth, so that unless
our globe augments its pace, or the anticipated visitant retards its
journey, there will be no risk of any dangerous proximity, much less of
a hostile collision. During this return, at least, it will always be
more than two hundred times the moon's distance from us; and were it,
at any future time, to approach very much nearer than the orbit of our
satellite, its influence would be too inconsiderable to affect any of
the elements of the earth's path.
This comet is about 40,000 miles in diameter, and of that class termed
nebulous, having no tail, and probably no solid nucleus. The point where
the comet's centre crosses the plane of the ecliptic is within and very
near the curve which the earth describes,--so very near, that the
outskirts of the nebulous matter of the comet might possibly, at some
future visit, envelope our planet, and would thus enclose the earth, it
is not unlikely, at its ensuing return, if it were about a month later
than the time calculated, of its intersecting the plane of the earth's
motion.
The presence of the moon during the past week has interfered with
telescopic observations, or probably the comet might have been detected
as a small round nebulosity, moving midway between the northern horn of
Taurus and the bright star Capelle, towards Gemini. There are nebulae
near its course for which it must not be mistaken.