When silence is achieved, time has no duration. It is only because thoughts come and go that we are aware of time. When there are no thoughts, neither is there time. Time is limitless, beyond measure. One night, when Great Master T'ai-Hsu was meditating he heard the evening bells. Immediately afterwards, he heard the morning bells. Because he was in samadhi, a whole night had passed during which he had no sense of time.
The next line refers to space, a clear and vivid sense of the environment. When your mind is moving, your awareness is narrowly focussed by your thoughts. If you could see and hear without using your mind, and be very attentive at the same time, you would sense limitless space. But this is not an especially high state. Higher yet is the state of "not one thought." In this state distinctions of vast or small just don't exist.
There is a saying that all the Buddhas of the past, present, and future are turning the Dharma Wheel on the point of a fine hair. When you can empty your mind of all thoughts, the mind becomes all-inclusive and sees no difference between the infinitesimally small and the infinitely large.
Singularly illuminating is this bright awareness,
Full of wonder is the pure illumination.
The bright awareness that illuminates is that of a Buddha who sees sentient beings in their perfection, unlike ordinary awareness which is confused, and sees the world as dark. This brightness throws its light on all things, which take on the aspect of wonder. This is like the songs of Milarepa, which reveal the harmony between all things great and small. It is the wonder of the Avatamsaka Sutra, where everything is seen in such detail, from every point of view. A mind so illuminated could see the cosmos in a grain of sand. This is the realm perceived by wisdom arising from samadhi.
The moon's appearance, a river of stars,
Snow-clad pines, clouds hovering on mountain peaks.