Captain Atom is a superhero in the DC Universe, formerly of the Charlton Universe.
The Charlton Comics version of Captain Atom was Allen Adam. The character's origin had Adam working as a technician in a special experimental rocket when it accidentally launched with him trapped inside. Adam was atomized when the rocket exploded while entering the upper atmosphere. However, he somehow gained superpowers that included the ability to reform his body safely on the ground. He was outfitted in a red and yellow costume that was designed to shield people from the radiation of his nuclear powers. When he powered up, his hair changed to a silverish-white. A new, post-Crisis version of the character was introduced in March 1987 with the launch of a monthly comic written by Cary Bates (long-time writer of The Flash and Superman), co-written by Greg Weisman and drawn by Pat Broderick. This modern captain's name is established as Nathaniel Christopher Adam, a United States Air Force officer and Vietnam War veteran. Adam had been framed for a crime and was, under military justice, condemned to death; this taking place under the purview of Col. Wade Eiling in the year 1968. As an alternative to execution, Adam was "asked" to participate in 'Project: Captain Atom', a military experiment with a slim chance of survival. He agreed to this in exchange for an unconditional presidential pardon. The experiment involved testing the hull of a crashed alien ship's durability by placing a human being (Adam) within the metal craft and then exploding an atomic weapon under it. The weapon went off and Adam was seemingly disintegrated. Eighteen years later, Adam suddenly reappeared. The alien metal, now bonded around his body, afforded him incredible abilities far beyond that of a mere mortal. Bonded with the metal, Nathaniel Adam now had powers that resulted from the metal's ability to tap into the "Quantum Field." It was revealed that the alien metal could absorb energy but past a certain threshold, any excess absorption would force it to jump forward in time, based on the amount of energy obtained. Flung into the year 1986, Adam becomes literally a "man out of time". Wade Eiling is now a military general and the second husband of Adam's now-deceased wife Angela. Everyone had assumed that Nathaniel Adam died the day of the experiment, so his presidential pardon was never issued and the current government refused to acknowledge the previous pardon. Seizing the opportunity at hand, Eiling uses the outstanding murder/treason charges against Adam to blackmail him into acting as a military-controlled, government-sanctioned superhero codenamed Captain Atom. The events of the Charlton stories are used cleverly by Bates as a readymade, fabricated past to convince the world that Adam had secretly been a superhero for years enabling him to quickly gain the trust and reputation as an unsung patriot and hero. For his non-superhero activities, Nathaniel uses the alias Cameron Scott, an Air Force intelligence operative. During this time he meets the superpowered terrorist, Plastique, a recurring part of Nathaniel's life. Early conflicts involve him coming to terms with the lost time he missed with his now grown children, the death of his wife, her marriage to Eiling, and the overall ramifications of his newly acquired powers. Later, he learns that the 'Project: Captain Atom' was repeated, creating the super-villain Major Force, a bloodthirsty madman lacking Captain Atom's morality and classic military/A.F. discipline. In the Post-Crisis DC Comics Universe, Captain Atom's Dilustel skin is tied into the Quantum Field, which enables him to absorb and manipulate theoretically infinite amounts of energy, limited by only his willpower and imagination. This energy can be used for flight (which is generally faster than the speed of sound in Earth's atmosphere and up to half-light speed in the vacuum of space), super strength (shown at times to be on par with Martian Manhunter), durability (he has survived exploding nuclear weapons) self-sustenance and life support (allowing him to live and even speak in space), and controlling energy of any form. In addition to high speed flight he has been shown to possess enhanced reflexes. Atom's abilities stem from his link to the Quantum Field, which provides a virtually infinite source of Quantum Energy, which can be used for a vast number of effects. He commonly manipulates his energy into force field bubbles, or explosive "bombs", but the most common form is a simple energy blast. Atom has been shown to be capable of manipulating even exotic energies such as magic, and has a high degree of resistance to such attacks.
In other media
Appears in Justice League Unlimited, Batman The Brave and the Bold and Superman/Batman: Public Enemies.