Craft an immersive digital illustration of a silver holographic universe depicted in the form of a round spiral. Use a combination of digital painting techniques and special effects to create the spiral shape, with holographic stars and galaxies arranged in a mesmerizing pattern. The holographic effect should give the impression of depth and movement, with colors shimmering and shifting along the curvature of the spiral. Incorporate subtle hints of otherworldly hues such as iridescent purples, blues, and greens to enhance the surreal atmosphere. Pay attention to the lighting, using soft, diffused light to accentuate the holographic elements and create a sense of ambiance. Experiment with composition to draw the viewer's gaze into the captivating beauty of the silver holographic spiral universe, evoking a sense of fascination and wonder.