MIAMI — For decades, South Florida schoolchildren and adults fascinated by far-off galaxies, earthly ecosystems, the proper ties of light and sound and other wonders of science had only a quaint, antiquated museum here in which to explore their interests. Now, with the long-delayed opening of a vast new science museum downtown set for Monday, visitors will be able to stand underneath a suspended, 500,000-gallon aquarium tank and gaze at hammerhead and tiger sharks, mahi mahi, devil rays and other creatures through a 60,000-pound oculus. Lens that will give the impression of seeing the fish from the bottom of a huge cocktail glass. And that’s just one of many attractions and exhibits. Officials at the $305 million Phillip and Patricia Frost Museum of Science promise that it will be a vivid expression of modern scientific inquiry and exposition. Its opening follows a series of setbacks and lawsuits and a scramble to finish the 250,000-square-foot structure. At one point, the project ran precariously short of money. The museum high-profile opening is especially significant in a state s