KnowraPhotosphereLinked fromLinked fromThe 7 pages that link to Photosphere, each with the reason it gives.All 7Broader topic 5Compared with 2Stellar atmosphereBroader topic: It is the deepest atmospheric layer directly observed in most stars.Stellar radiusBroader topic: This boundary defines the radius used for ordinary stellar measurements.Solar spectrumBroader topic: Its hot, dense gas produces the near-continuous background of the solar spectrum.Solar physicsBroader topic: Its brightness and dark features provide the most familiar view of solar activity.Solar phenomenaBroader topic: Sunspots are dark features observed against this layer.