As an influential archetype of the superhero genre, Superman possesses extraordinary powers,
with the character traditionally described as "faster than a speeding bullet, more powerful
than a locomotive, and able to leap tall buildings in a single bound", a phrase coined by Jay
Morton and first used in the Superman radio serials and Max Fleischer animated shorts of the
1940s[111] as well as the TV series of the 1950s. For most of his existence, Superman's famous
arsenal of powers has included flight, super-strength, invulnerability to non-magical attacks,
super-speed, vision powers (including x-ray, heat-emitting, telescopic, infra-red, and
microscopic vision), super-hearing, super-intelligence, and super-breath, which enables him
to blow out air at freezing temperatures, as well as exert the propulsive force of high-speed
winds.[112]
As originally conceived and presented in his early stories, Superman's powers were relatively
limited, consisting of superhuman strength that allowed him to lift a car over his head, run
at amazing speeds and leap one-eighth of a mile, as well as an incredibly dense body structure
that could be pierced by nothing less than an exploding artillery shell.[112] Siegel and
Shuster compared his strength and leaping abilities to an ant and a grasshopper.[113]
When making the Superman cartoons in the early 1940s, the Fleischer Brothers found it
difficult to keep animating him leaping and requested to DC to change his ability to flying;
this was an especially convenient concept for short films, which would have otherwise had to
waste precious running time moving earthbound Clark Kent from place to place.[114] Writers
gradually increased his powers to larger extents during the Silver Age, in which Superman
could fly to other worlds and galaxies and even across universes with relative ease.[112]
He would often fly across the solar system to stop meteors from hitting the Earth or sometimes
just to clear his head. Writers found it increasingly difficult to write Superman stories in
which the character was believably challenged,[115] so DC made a series of attempts to rein
the character in. The most significant attempt, John Byrne's 1986 rewrite, established several
hard limits on his abilities: He barely survives a nuclear blast, and his space flights are
limited by how long he can hold his breath.[116] Superman's power levels have again increased
since then, with Superman currently possessing enough strength to hurl mountains, withstand
nuclear blasts with ease, fly into the sun unharmed, and survive in the vacuum of outer space
without oxygen.
The source of Superman's powers has changed subtly over the course of his history. It was
originally stated that Superman's abilities derived from his Kryptonian heritage, which made
him eons more evolved than humans.[85] This was soon amended, with the source for the powers
now based upon the establishment of Krypton's gravity as having been stronger than that of the
Earth. This situation mirrors that of Edgar Rice Burroughs' John Carter. As Superman's powers
increased, the implication that all Kryptonians had possessed the same abilities became
problematic for writers, making it doubtful that a race of such beings could have been wiped
out by something as trifling as an exploding planet. In part to counter this, the Superman
writers established that Kryptonians, whose native star Rao had been red, possessed
superpowers only under the light of a yellow sun.[117]
Superman is most vulnerable to green Kryptonite, mineral debris from Krypton transformed
into radioactive material by the forces that destroyed the planet. Exposure to green
Kryptonite radiation nullifies Superman's powers and immobilizes him with pain and nausea;
prolonged exposure will eventually kill him. The only substance on Earth that can protect
him from Kryptonite is lead, which blocks the radiation. Lead is also the only known substance
that Superman cannot see through with his x-ray vision. Kryptonite was first introduced to
the public in 1943 as a plot device to allow the radio serial voice actor, Bud Collyer, to
take some time off.[83] Although green Kryptonite is the most commonly seen form, writers
have introduced other forms over the years: such as red, gold, blue, white, and black, each
with its own effect.[118]