ndred milliards of cubic kilometers of
water at freezing-point.

Our little planet, gravitating at 149,000,000 kilometers (93,000,000
miles) from the Sun, arrests on the way, and utilizes, only the half of
a milliard part of this total radiation.

How is this heat maintained? One of the principal causes of the heat of
the Sun is its condensation. According to all probabilities, the solar
globe represents for us the nucleus of a vast nebula, that extended in
primitive times beyond the orbit of Neptune, and which in its
contraction has finally produced this central focus. In virtue of the
law of transformation of motion into heat, this condensation, which has
not yet reached its limit, suffices to raise this colossal globe to its
level of temperature, and to maintain it there for millions of years. In
addition, a substantial number of meteors is forever falling into it.
This furnace is a true pandemonium.

The Sun weighs three hundred and twenty-four thousand times more than
the Earth--that is to say, eighteen hundred and seventy octillions of
kilograms:

1,870,000,000,000,000,000,000,000,000,000
(1,842,364,532,019,704,433,497,536,945 tons).

In Chapter XI we shall explain the methods by which it has been found
possible to weigh the Sun and determine its exact distance.

* * * * *

I trust these figures will convey some notion of the importance and
nature of the Sun, the stupendous orb on whose rays our very existence
depends. Its apparent dimension (which is only half a degree, 32', and
would be hidden from sight, like that of the full moon, which is about
the same, by the tip of the little finger held out at arm's length),
represents, as we have seen, a real dimension that is colossal, _i.e._,
1,383,000 kilometers (more than 857,000 miles), and this is owing to the
enormous distance that separates us from it. This distance of
149,000,000 kilometers (93,000,000 miles) is sufficiently hard to
appreciate. Let us say that 11,640 terrestrial globes would be required
to throw a bridge from here to the Sun, while 30 would suffice from the
Earth to the Moon. The Moon is 388 times nearer to us than the Sun. We
may perhaps conceive of this distance by calculating that a train,
moving at constant speed of 1 kilometer (0.6214 mile) a minute, would
take 149,000,000 minutes, that is to say 103,472 days, or 283 years, to
cross the distance that separates us from this orb. Giv