The iconic film 'Alien' came out 40 years ago. A scientist explains why Hollywood depictions of extraterrestrials have changed since then.

In the decades since "Alien" came out, depictions of aliens in movies have changed dramatically.
Instead of showing extraterrestrial life as humanoid, directors have instead depicted aliens as bacteria, as in the movie "Life," or as amorphous lifeforms like in the movie "Arrival."
According to one scientist, these depictions are more scientifically realistic and align more with what researchers think potential aliens may look like.
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The 1979 blockbuster "Alien" opens with tension-filled scene: A spider-like creature attacks astronaut Thomas Kane on an unknown planet.

The crew of Kane's ship bring him back on board with the mysterious critter still attached to his spacesuit. Under the fluorescent lights, the creature seems to die, detaching from Kane's face. When the astronaut eventually wakes up, he seems unharmed by the encounter.

But a miniature alien later bursts out of his chest in a shower of blood, as his shocked crewmates scream.

The xenomorph, as it's called, grows to be larger than any human, with glossy black skin, razor sharp teeth, claws, and a tail.

Alien Facehugger 1979 20th Century Fox via YouTube

In the four decades since "Alien" came out the film's 40th anniversary was in May that creature's image has influenced movie-goers' mental pictures of alien life.

But as NASA has embraced the objective of searching for extraterrestrial life in our galaxy, the scientific understanding of what extraterrestrials might look like has converged around a type of lifeform far different than director Ridley Scott's brainchild.

Today, astrobiologists suspect that extraterrestrial lifeforms are likely to be microscopic in nature, akin to the bacteria scientists find in extreme environments on Earth .

Hollywood filmmakers have started to embrace this idea and depict aliens as less humanoid, according to physicist and author Sidney Perkowitz. In other words, the days of little green men and giant scaly monsters in alien movies are gone.

"In the old science-fiction flicks of the 1950s and 60s, if you did an alien, monster, or robot, it was a guy dressed up and stomping around a sound stage," Perkowitz, who cofounded the National Academy of Sciences' Science and Entertainment Exchange group , which connects directors with science advisers, told Business Insider. "In the last few decades, CGI has changed that, allowing for the potential of really life-like, imaginative creatures."

No more little green men

The chance that alien life looks humanoid is infinitesimal.

"We don't have any reason to believe that they would look anything like us," Andrew Siemion, director of the Berkeley SETI (Search for Extraterrestrial Intelligence) Institute, told Vox . "The form of a human being is the result of several billion years of evolution."

Perkowitz said that Scott and other directors' decisions to make extraterrestrials appear human-like could simply boil down to cost.

"Humanoid aliens are cheap to portray," he said.

He added that the problem with "Alien" wasn't just that the movie portrayed the alien as humanoid it was that the extraterrestrial was depicted as unintelligent and beast-like. The xenomorph doesn't try to communicate with the astronaut crew; instead, it eats them one by one until Sigourney Weaver's character blasts it into space.

"It's hard to imagine a different lifeform would have such a negative reaction to another lifeform nothing lives for pure evil." Perkowitz said, adding, "if we always decide that 'the other' is hostile or contemptible how does that encourage our efforts to relate to them?"

But the examples of non-hostile aliens in Hollywood are few and far between (Steven Spielberg's E.T. not withstanding). That's because, according to Perkowitz, society uses film to explore what it's afraid of.

Sci-fi films are reflections of what society is worried about

Hollywood blockbusters' references to science don't arise in a vacuum they mirror current trends in scientific discovery and their effects on our culture. In the 1950s and 1960s, for example, movies like Doctor Strangelove featured nuclear scientists because people had memories of the atomic bomb and a fear of nuclear war, Perkowitz said.

"Even if the sci-fi film doesn't know it's doing it, a closer watch shows that the movies reflect society's current anxieties," he said.

Alien movies are no different. These days, Perkowitz said, humanity isn't afraid of carnivorous xenomorphs. Instead, we worry about "something viral a biological entity that spreads quickly and causes harm."

In an era in which mosquitoes carrying viruses like Zika and dengue fever are spreading farther due to climate change, "nuclear radiation isn't the concern anymore," Perkowitz said. So some alien movies now depict a contagion that comes from outer space.

In the 2017 movie "Life," for example, Jake Gyllenhaal's character and his crewmates aboard the International Space Station discover alife form that supposedly caused extinction on Mars and threatens life on Earth.

life science fiction alien horror movie sony pictures jake gyllenhaal Sony Pictures Entertainment, Inc.

Film studios primarily choose to present aliens as malevolent microbes in this way to get people to the box office, Perkowitz said "on the whole, Hollywood isn't concerned with the social responsibility of getting the science right."

But in this case, he added, the depiction could help establish more appropriate expectations for any potential discovery of life that NASA might make. The agency plans to look for extraterrestrial life on Jupiter's moon Europa with its planned Clipper mission in 2025. Scientists expect any potential life there "may look like microbes, or maybe something more complex," a NASA report said .

The best portrayal of aliens in film?

Perkowitz pointed to the creatures called heptapods in the 2016 movie "Arrival" as an exemplary depiction of non-humanoid aliens that attempt intelligent contact. That's because they don't remotely resemble humans, are not hostile, and try to communicate rather than attack.

In the movie, Amy Adams plays a linguistics professor who works to communicate with the heptapods, which sport long muscular torsos and seven legs. Eventually, she discovers that the aliens speak using logograms inkblot-like symbols that can stand for a word, an entire sentence, or even a feeling.

The humans and aliens, through extensive trial and error, establish a mutual language without destroying each other.

arrival alien language Paramount Pictures

"That movie is a great example of, perhaps, how would we really go about meeting aliens if we do ever meet intelligent life out there," Perkowitz said.

NOW WATCH: How humans can communicate with aliens

The iconic film 'Alien' came out 40 years ago. A scientist explains why Hollywood depictions of extraterrestrials have changed since then.

No more little green men

Sci-fi films are reflections of what society is worried about

The best portrayal of aliens in film?

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