When you open your eyes and face towards the Sun, it may appear as though you see the Sun instantaneously, but in reality, there is a slight delay between the actual moment when you see the Sun and when the light reaches your eyes.
The delay you perceive is due to the processing time of your visual system. When light from the Sun enters your eyes, it interacts with the light-sensitive cells in your retina, initiating a series of biological and neurological processes. These processes involve the conversion of light into electrical signals, their transmission through the optic nerve, and the interpretation of those signals by your brain to form the visual perception of the Sun.
Although these processes occur rapidly, they still take a finite amount of time. The perceived delay is typically very short and can be considered instantaneous for most everyday purposes. The human visual system operates at a remarkable speed, allowing us to perceive the world in near real-time.
In the case of the Sun, it takes approximately 8 minutes for light to travel from the Sun to Earth, covering a distance of about 93 million miles (150 million kilometers). However, the time it takes for the light to be processed by your eyes and for your brain to generate the visual perception of the Sun is significantly shorter, typically on the order of milliseconds.
So, while you may have the sensation of seeing the Sun instantaneously upon opening your eyes, there is still a slight delay involved in the processing of light by your visual system.