The Heat-Ray is the primary offensive weapon used by the Martians in the H. G. Wells's classic science fiction novel The War of the Worlds and its offshoots.

In the novel

Within the context of the novel, the term "Heat-Ray" is more commonly applied to the destructive energy it projects and not the weapon itself. The weapon that fires the Heat-Ray is described as a type of object that resembles a box or camera in which the fire is generated. This case is carried by one of the metallic arms of the Martians' fighting-machines.

The Heat-Ray is essentially a directed-energy weapon that incinerates anything it comes into contact with. It instantly sets ablaze flesh, vegetation and anything else flammable. When the Heat-Ray hits water, it almost instantly turns it into steam. It is also capable of melting metal. The novel explains the origin of the Heat-Ray as an intense beam of heat generated in a chamber of absolute nonconductivity, which is then projected against a parabolic mirror towards whatever target the Martians wish to incinerate. While the Heat-Ray is photonic in nature, passages in the novel describe the beam as invisible, with the only visible element being a flash emitted from the chamber while the Heat-Ray is fired. The Heat-Ray also possesses considerable range, striking targets at distances of at least two miles.

A thing to note is that if an actual energy weapon were to be constructed, it would probably operate much in the style of the Heat-Ray, without any visible "energy bolts" that are present in many science-fiction books and movies involving combat, such as Star Wars. It's described effect is almost identical to that of a powerful CO2 Laser.

In other adaptations

The Heat-Ray is one of the most common features of virtually every adaptation of the story. Many adaptations adhere fairly well to the characteristics given in the novel, such as the radio adaptation, even reciting near verbatim descriptions of how the device operates.

One of the few inconsistencies with the novel in the Jeff Wayne musical, as depicted in the artwork, is that The Heat-Ray generator is illustrated to be located within the hood of the machine, protruding from the hood, resembling a proboscis.

The Great Illustrated Classics adaptation of The War of the Worlds portrays the Heat-Ray as a massive flamethrower.

In Sherlock Holmes's War of the Worlds, the Heat-Ray is described as being based on nuclear energy, with it being projected from a pink-hued, multifaceted focusing crystal.

1953 film

For the 1953 film version, the Martians use a combination of three rays, one Heat-Ray on top of their ships which fire red sparks, and two disintegrator rays at the side, which are shown as green energy blobs. These two can only be pointed in the direction the ship is facing, while the one at the top can be pointed in any direction. Both types of the Heat-Ray have a less violent effect on its target as most of what they would hit would begin to glow and then vanish, sometimes leaving a stain or pile of ash as a remainder; the Heat-Ray differs from the disintegrators (also called "skeleton beam") as the former sets the surrounding environment ablaze as well as vaporizing the target. Although, often, the Heat-Ray does have a simple destructive effect on certain objects; other times, the ray would set objects ablaze or cause them to explode (as shown when the machines reach Los Angeles). In one scene, General Mann states that it is likely the Martians generate radiation without using heavy screening to power their rays. Doctor Clayton Forrester explained how these Heat-Rays worked as such:

TV series

As a sequel to the 1953 film, the Heat-Ray's use in the War of the Worlds TV series is rather notable. Aside from their employment in the first episode (its destruction replayed in the opening credit sequence in subsequent episodes of the season), the main Heat-Ray is put to more attention in an episode in which the aliens are unable to unearth a buried warship from a recon mission and are forced to remove the gooseneck device from the ship and strap it atop a hearse. The aliens' mission in this episode is put to end when The Heat-Ray hits them after being reflected off a makeshift parabolic mirror, an ironic nod to how the Heat-Ray is explained to have worked in the novel and radio play.

The series also offered perhaps the most distinctive take on the established weapon, not employed by a war machine, but rather as a personal weapon. "The Second Seal" episode deals with the discovery of archives that contain remnants of the 1953 invasion. Among the material found is a boomerang-shaped weapon that fires Heat-Rays. These rays are the kind of green blobs fired from the tips of their warships, and are similarly shot from the ends of the object.

The Heat-Rays featured in the series mirror the same power of the film it is based on. This includes the variation between their ability to visibly destroy something as well as simply making a target disappear. Although the word "Heat-Ray" is never applied in the series as it is in the 1953 or updated 2005 film, the term used in one episode is "Death-Ray".

Steven Spielberg film

In Steven Spielberg's War of the Worlds adaptation of Wells' novel, the Heat-Ray is portrayed as a bluish-white arc instead of a ray that appear to have a desiccating effect on living objects, such as animals, and a 'disruptive' effect on other objects. For example, when humans are hit by the ray, they are vaporized into a cloud of gray powder (possibly ash), while their clothes remain unaffected. However, a bridge in one scene is thrown from its pylons when hit by the ray, as if physically struck, and in an earlier scene, brick-and-wood buildings are either destroyed or catch fire when hit by the Heat-Ray. In the middle of the movie, a video of an army of tripods destroying a city is shown, with Heat-Rays collapsing targeted buildings in a similar fashion to the destruction of the bridge. Curiously, human clothing does not seem to be affected by The Heat-Ray, which is used to effect in one of the film's more poignant scenes.

Pendragon Pictures film

In the lesser-known 2005 film adaptation from Pendragon Pictures, H.G. Wells' The War of the Worlds, the generator is held by a small arm that extends from atop the hood of the machine (not one of the many visible arms they use to take humans). Three metallic fingers hold a type of disc that spins rapidly, generating the Heat-Ray and when it touches flesh their body begins to have an orange flame until it turns green turning the victim to nothing other than bones.

See also

• Archimedes
• Martian Technology Analysis Report
• Active Denial System