one degree on the sky

The typical scale of the hotspots is also telling. The most common size is
about one degree on the sky, twice the full Moon’s diameter. This is exactly
what theorists have predicted by looking at the pattern of matter in the
universe today and projecting it backwards, taking into account the
universe’s expansion.
这句话讲到了热区的规模，天空一度如何理解？求高人指点。

应该指的是天球上（赤经赤纬）的一度，或是两倍满月视面积大小。