وَمَا تَحْتَ الثَّرَ‌ىٰ (And whatever is beneath the soil - 20:6). (ثرٰی) (soil) means wet earth which comes out after digging upto a certain depth. Human knowledge does not go beyond) and what is beneath it is known only to Allah. Some years back scientists and researchers, using the latest and the most sophisticated instruments, spent considerable time and effort to pierce across the centre of the earth. According to newspaper reports they were able to penetrate upto a depth of six miles only after which they came across a rock casing and all their efforts to bore further down failed. Scientists were able to collect data only upto six miles, while the diameter of the earth covers thousands of miles. One has to admit, therefore, that the knowledge of what is below the soil is a special attribute of Allah.