Create a hyper-realistic 3D render of a human brain floating in a serene sky with soft, light clouds in the background. The brain should have intricate neural connections, with neurons and glial cells softly glowing in shades of pink, reddish-orange, and warm yellow. The background should feature a soft blue sky with wispy, realistic clouds to create a peaceful, ethereal atmosphere. Ensure the brain appears slightly illuminated by the natural light, blending with the clouds while standing out against the sky. The overall aesthetic should be realistic, calming, and visually appealing, highlighting the brain in a tranquil, natural environment."