We cannot see inside the Sun. Although the interior is unquestionably ablaze with radiation, we can view it only indirectly; theory alone can light the way.
On the outside, however, fairly direct observations can be relied upon for clues to the workings of our local star. If, as is almost universally accepted, the Sun is a thermonuclear engine whose primary concern on the outside is the radiation of excess energy liberated from matter deep in its core, observations of the visible regions, particularly the brilliantly luminous shell that masks the interior, ought to suggest as much. We have no reason to suspect that nature in the physical universe goes out of its way to camouflage its activities.
Suppose, then, that we put aside our preconceptions of whatever may be happening within the Sun and look to the visible evidence. As we emerge from the unseeable depths into the light of the solar atmosphere, the first region we come to is the photosphere - a white-hot envelope of hot plasma that gives off practically all the radiant energy we think of as sunshine.
Here is where the Sun could well be expected to "end," if indeed the dissipation of internally generated energy were basic to the maintenance of its mechanical equilibrium, as the accepted theory claims. Yet the photosphere in no way ends the Sun; rather, it is more truly just the beginning, or base, of an atmosphere of enormous reach and baffling complexity that seems perversely contrived to hinder more than help radiant energy to escape.