"Of all the planets in our solar system, Mercury may be the most
mysterious. It's so close to the Sun that terrestrial telescopes can have trouble looking at it, and what we've been able to gather about it has left scientists scratching their heads.A huge metallic core represents about half the planet's volume (Earth's is just 10 percent, by comparison). Some theorize it used to be a planet similar in characteristics to Earth and Venus but either had its crust stripped off by a collision or boiled by the sun. Either way, when it comes to this planet, there are a lot of questions without answers." BF
Well, here's an answer to the questions of Mercury---and why it's unique--as most planets are: Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds; Hebrews 1:2