The more massive a black hole, the larger its horizon, and its average density drops fast. Divide the mass of M87*, about 6.5 billion suns, by the volume inside its horizon and you get less than the density of air. It's a formal calculation, since the mass sits at the centre. But it shows a black hole isn't necessarily ultra-compact.
A large share of Earth's water molecules formed in the interstellar cloud that existed before the Sun was even born, more than 4.6 billion years ago. You are literally drinking a cosmic fossil.
By day, the Martian sky looks butterscotch because of fine dust hanging in the air. But at dusk, those same grains scatter blue light forward, creating a bluish glow around the Sun. Rovers have photographed these blue sunsets: the exact reverse of what we see on Earth.