“Interstellar” was recently released on Blu-ray and DVD. “Gravity” recently received a Blu-ray special edition release.

Last year’s “Interstellar” and the previous year’s “Gravity” follow different paths in a long tradition of asking ultimate questions against the biggest canvas available to our senses: the universe itself.­

As we find attested as early as Plato’s famous anecdote about the pre-Socratic philosopher Thales becoming so lost in the night sky that he stumbled into a well, the starry heavens have long inspired philosophical and existential wonder.

“If the Stars should appear one night in a thousand years,” wrote Ralph Waldo Emerson, “how would men believe and adore; and preserve for many generations the remembrance of the city of God which had been shown!” Yet the first man to cast off the surly bonds of Earth and set foot among the stars, the cosmonaut Yuri Gagarin, is supposed to have remarked, “I don’t see any God up here.”

The latter quotation appears to be apocryphal — a bit of anti-religious Soviet propaganda placed on the lips of a man who was, it seems, a practicing Orthodox Christian. Even so, the endless sea in which our planet floats in the night speaks powerfully to the imaginations of both believers and nonbelievers.

Is anyone out there, or are we alone? Either possibility is fraught with a kind of fearfulness. Perhaps the most universal sentiment is that of the Catholic polymath Blaise Pascal, who wrote in his “Pensées,” “The eternal silence of these infinite spaces alarms me.”

Science fiction has explored man’s cosmic loneliness and the question of ultimate mystery in various ways. H.G. Wells’ oft-adapted “War of the Worlds” presented a Darwinian picture of cosmic conflict — a conflict in which religion, in the figure of a demented clergyman, collapses under pressure.

Conversely, C.S. Lewis’ “Space Trilogy” (as yet unfilmed, possibly unfilmable) offered a contrasting spiritual vision of the cosmos fused with the medieval vision of “the heavens” filled with angelic spirits. Lewis also borrowed from classical paganism, assigning monarchical spirits to the planets of the solar system corresponding to the gods Mercury, Venus, Mars, etc. (The angelic archon of our fallen planet, alas, is Lucifer.)

In cinema, this theme was given a defining exploration in Stanley Kubrick’s “2001: A Space Odyssey” (1968), with its secular ascent-of-man mythology taking humanity from ape-like hominids to cosmic Star Child with the aid of mysterious black monoliths of extraterrestrial origin. The monoliths are loci of mystery in some way casting mankind’s place in the cosmos as a matter of purpose rather than blind chance — though the question of chance or purpose is not definitively answered, only pushed back a step, from mankind of the unknown makers of the monoliths.

Christopher Nolan’s “Interstellar” and Alfonso Cuarón’s “Gravity,” despite similar cover imagery depicting figures in white space suits, are far more different than alike.

“Interstellar” is a conceptually ambitious, meticulously researched, hard sci-fi epic about mankind’s fate and future set in a universe of wormholes, black holes, and higher dimensions. “Gravity” is a far more modest, down-to-earth affair, a non-sci-fi space adventure set in low Earth orbit, concerned only with the lives of a few characters.

Still, there are points of contact. Both films depict space-faring characters helplessly adrift in an uncaring cosmos. Matthew McConaughey’s astronaut Coop in “Interstellar” is adrift in inconceivably remote locales, even passing beyond ordinary three-dimensional space, while Sandra Bullock’s mission specialist Ryan Stone in “Gravity” never leaves low Earth orbit. Yet Stone’s experience of lostness, depicted in a stunning sustained shot (only the second shot in the film) exploring the principle of relativity in a way unlike any shot in any other film I’ve ever seen, is paradoxically more disorienting and frightening.

Both films focus on parent-child relationships, and in particular on the experience of parents separated from their children. Both also suggest that the ties that bind us to our loved ones may be more resilient than we think, perhaps transcending space time or even death.

Coop, selected for a secret NASA project to travel through a wormhole in search of a new home for humanity, leaves behind two young children, but it’s his special bond with his brainy daughter Murphy that provides the film’s emotional center.

Stone’s defining relationship is also with a daughter, the key difference being that her daughter has died. Yet once Coop passes the event horizon of the black hole, Murphy might as well be dead; due to relativity, in fact, Murphy might well die of old age before Coop returns to Earth.

Both films involve experiences that characters could or do interpret as spectral or spiritual phenomena. In early scenes in “Interstellar,” Murphy believes she has encountered a ghost in her bedroom. While the eventual explanation is couched in sci-fi rather than spiritual terms, metaphorically the device suggests that our loved ones who have passed beyond this world may not be as absent as they seem.

By contrast, Stone’s enigmatic encounter in “Gravity” with a character who logically can’t really have been there is not ultimately explained, but could be construed as a trauma-induced hallucination, a telepathic phenomenon, or some sort of visionary experience.

Both parents address words to their absent children which they hope, but cannot know, will reach them. Coop records video messages which he transmits back to Earth, though they will take years to arrive. Stone, meanwhile, speaks to the character who seemed to appear to her as Catholics pray to saints, asking that a message be passed on to her departed daughter.

While neither film’s protagonist is religious, “Gravity” is interested in religion in a way that “Interstellar” isn’t. Convinced that she is doomed to die in space, Stone laments that not only will no one on Earth pray for her soul, she was never even taught to pray and doesn’t know how to pray for her own soul.

Improbably traveling to two different space stations, Stone encounters a Russian Orthodox icon of Saint Christopher carrying the child Jesus in a Russian spacecraft and a smiling Buddha statue in a Chinese spacecraft. (Strikingly, the only analogous object on the American space shuttle is a statue of Marvin the Martian — an ironic comment, perhaps, on religiously deracinated Western secularism?)

“Interstellar” shows no similar interest in religious themes or iconography — nor, as my friend Kenneth R. Morefield pointed out, in most other facets of human culture and history. It is biodiversity, not music, literature, or art (even popular art, such as Marvin the Martian), let alone religion, that “Interstellar” is concerned with taking into space.

The two film’s differing attitudes toward human religion may not be unrelated to their contrasting attitudes toward the Earth itself. “Mankind was born on Earth,” Coop says; “we were never meant to die here.” In a similarly deft couplet (the sort of line Nolan and his brother and writing partner Jonathan love to write), Coop complains, “We used to look up and wonder at our place in the stars. Now we look down and worry about our place in the dirt.”

As these lines suggest, “Interstellar” is decidedly ambivalent about mankind’s relationship to the world of our birth. “Earth’s atmosphere is 80 percent nitrogen. We don’t even breathe nitrogen,” a character frets. For Nolan, the search for mankind’s future seems to involve a turning away from our past. Notably, by the film’s end, Coop has made a sort of return journey — not to his actual home, but only to a facsimile.

For “Gravity,” conversely, the only good trip into space is a round trip. The Earth, which looms throughout the film as a kind of silent character, always present but inaccessible, is our home and our mother, the locus of life and human connection. Space is not our future; it is at best a beautiful but unfriendly sea into which we sometimes voyage, but from which we hope always to return.

While I can appreciate the spacefaring techno-optimism of “Interstellar” on a poetic level, realistically I have long been persuaded by the scientific case that mass colonization of space or of other planets, despite considerable ill-founded enthusiasm, is not a realistic possibility; that, for all our micro-voyages and space stations, mankind is unlikely to leave the Earth behind in any serious or sustained way.

In the end, then, I find the terrestrial attachments of “Gravity” to be more truly humanistic and satisfying. The way forward for humanity is not to sever ourselves from our roots — either to the world of our origins, or to our religious heritage.