No, those were Mars’ moons, Phobos and Deimos. …Which in the real world aren’t spherical, but are basically large asteroids…

John Carter takes place in the universe where Earth is hollow and has an inverse pattern of the continents on the inside, with the core floating in the center as an undying sun, and Africa is filled with cities which are remnants from intact ancient Mediterranean cultures which can only be accessed by a British earl who was adopted by apes and taught their spoken language. But you can totally access the hollow center through the 500-mile-deep hole in the North Pole.

Plus the guns they’re firing on Mars are shooting genuine radium bullets. Go Radium Age!!

Way too scientifically illiterate.

Even though I’ve read a ton of science fiction, please indulge my use of only cinematic examples with my reply.

My oldest brother defines science fiction as “begin with an outlandish premise, then develop logically from there”.  I guess that’s true, but it’s an incomplete, unsatisfying definition.

The way I see it and at the risk of laying an oxymoronic egg here, at its’ best, sci-fi becomes a bona fide scientific mythology for the twentieth century and beyond, free of the trappings of farmboys, samurais and cowboys in space.  My go-to example of this is also my favorite film, “Space Odyssey”, curious and ironic that the word “odyssey” is in there, I think.  Another true beauty is “The Man From Earth”.  Or the final, mesmerizing scene from Tarkovsky’s “Stalker”, yowza!

If I want or need a rousing, operatic fantasy, and I often do, I’ll put on “Empire Strikes Back” or “Excalibur”.

For the record, I’m in the process of reading Iain Banks’ “The Player Of Games”, I’m starting to plow my way through The Culture in chronological order.

Granted that invading martians and ancient demons may be quaint artifacts of the pre-atom bomb era.
If I want to have the living daylights scared outta me, I’ll take Harlan Ellison over Lovecraft anytime, as an example “I Have No Mouth And I Must Scream” holds up extraordinarily well almost fifty years later.
Asimov’s short story “Nightfall” and the subsequent collaborative novel with Silverberg exemplify why science fiction became a true literature of ideas.  Off the top of my head, I could many more by name.

However, in any genre and era, including Golden Age or even contemporary science fiction, there’s mostly competent material and a few true jewels scattered here and there, and it seems odd and out of character for Asimov to make a dismissive blanket statement like that.

To my mind radio-activity is a real disease of matter. Moreover, it is a contagious disease. It spreads. You bring those debased and crumbling atoms near others and those too presently catch the trick of swinging themselves out of coherent existence. It is in matter exactly what the decay of our old culture is in society, a loss of traditions and distinctions and assured reactions. When I think of these inexplicable dissolvent centres that have come into being in our globe—these quap heaps are surely by far the largest that have yet been found in the world; the rest as yet mere specks in grains and crystals—I am haunted by a grotesque fancy of the ultimate eating away and dry-rotting and dispersal of all our world. So that while man still struggles and dreams his very substance will change and crumble from beneath him. I mention this here as a queer persistent fancy. Suppose, indeed, that is to be the end of our planet; no splendid climax and finale, no towering accumulation of achievements, but just—atomic decay! I add that to the ideas of the suffocating comet, the dark body out of space, the burning out of the sun, the distorted orbit, as a new and far more possible end—as Science can see ends—to this strange by-play of matter that we call human life. I do not believe this can be the end; no human soul can believe in such an end and go on living, but to it science points as a possible thing, science and reason alike. If single human beings—if one single ricketty infant—can be born as it were by accident and die futile, why not the whole race? These are questions I have never answered, that now I never attempt to answer, but the thought of quap and its mysteries brings them back to me.

Sort of the tone of the latter parts of The Time Machine, despairing, apocalyptic, posthuman. Fun guy, that Wells.

The period isn’t wholly forgotten, what with John Carter of Mars suddenly shewing up for his first movie at long last.

The problem is, one stumbles over all that overt racism every other paragraph. Not really sure you can do utopias without destroying a selection of human beings. But, there you go. A challenge!