Is Alien's tagline 'In space no one can hear you scream' actually scientifically accurate?

The answer

The tagline for Ridley Scott's 1979 film Alien is completely accurate. Sound requires a medium - such as air, water, or solid matter - to travel through. In the vacuum of space, there are no molecules to vibrate and transmit sound waves, so no sound can propagate. This means explosions, screams, and engine roars would all be completely silent in the void. The tagline was created by advertising executive Barbara Gips at the agency Alien Poster Company, and 20th Century Fox initially resisted it. The film, made for just $11 million, grossed $203 million worldwide and spawned a franchise worth over $1.6 billion. NASA itself has confirmed the physics: their official stance is that space is a near-perfect vacuum where conventional sound cannot travel.