The Kryptonian Expansion, referred as the "Great Age of Expansion" by Kryptonians, was a campaign to explore the known universe and beyond. Due to the advancement in genetic engineering on Krypton, the program was ended and the colonial outposts were abandoned.
The species was rendered critically endangered after almost all Kryptonians died when their main civilization center on Krypton exploded due to the instability of the planet's radioactive core.
As it turned out, all Kryptonians are born with a genetic bond to Krypton itself, which prevents them from leaving the planet. However, Jor-El was able to successfully remove the bond from his son's DNA, allowing Kal-El to safely travel all the way to Earth.
Almost all Kryptonians were killed when the planet exploded shortly after the infant Kal-El was sent to Earth. In some continuities, he is the planet's only survivor. In other versions of canon, there is a last daughter of Krypton Kara Zor-El. She is a cousin of Superman and known as Supergirl.
Depictions of Superman's homeworld of Krypton have varied wildly over the years, and in one version, Kryptonians were kept from colonizing the rest of the galaxy thanks to a genetic alteration made to the species by a being called the Eradicator, a being who would go on to a play a role in Superman's death and rebirth.
According to the comics, Superman can fly because of a combination of powers he derives from Earth's “yellow” Sun and from his extraterrestrial biology. On his birth planet, Krypton, gravity was much stronger than it is on Earth, so Kryptonians developed a physique that could resist its pull.
Due to the success of living in a sustainable atmosphere with little to no complications, a Kryptonian's body can remain in the same physical state for as long as possible. This can enable them to live well into their hundreds to even thousands of years with every detail of their appearance remaining unchanged.
As awful as it sounds, Zod's plan is likely to have worked. By forcefully rationing more resources, the Kryptonian elites could have created Jor-El's device in time to at least postpone Krypton's destruction, if not curtail it entirely.
In most retellings, Jor-El wanted Lara to accompany their son to Earth, but Lara refused, saying their son would have a better chance of reaching Earth without her extra weight. Kal-El's spaceship then took off, leaving Lara and Jor-El to perish.
Kara was sent to Earth to protect her then-infant cousin, Kal-El. Krypton exploded just seconds after her pod took off, sending it into the Phantom Zone. The episode "Hostile Takeover" revealed that the planet was destroyed due to over-mining its core.
It seems that Superman's ultimate destiny is to revive Krypton is an unconventional way. A surprising history lesson hints that the Man of Steel could one day bring the long-dead planet back in a way fans won't see coming.
As the projection of Jor-El tells his son, the 'S' marking the chest of their family's clothing means hope. "The symbol of the House of El means hope." Most of DC's origin stories have Superman's suit and respective "S" appear before Superman even receives his name.
The reason Darkseid doesn't invade krypton like earth is because their technology was far superior so instead he played it sneaky and messed with the planets core, which the kryptonians assumed was decaying due to lack of resources.
A lot of races are so powerful or stronger than kriptonians. Kryptonians are only as strong as the sun is in their galaxy. If they were so powerful their world would still exist. There are plenty of races in the d.c. universe with out such limitations, Atlanteans are one.
Kara Zor-El, a.k.a. “Supergirl”! She's not only the strongest female Kryptonian…she's also the kindest… most beautiful, and compassionate among them…as Kara is willing to protect a people not hers biologically, and a planet she wasn't born on…as much as she would have done for Krypton itself!
Which version of Superman is immune to Kryptonite?
In this dark future, an older Man of Steel had grown impervious to kryptonite's radiation after years of living in a yellow sun solar system. The Golden Superman of DC One Million was at an even greater power level, having spent several decades within the sun itself.
Captain Atom has proven in past battles that he is stronger than Superman and has better fighting skills. He can also weaponize red sun radiation, which can weaken Superman like Kryptonite and magic. His sometimes uncontrolled nature has earned him a reputation as one of the most dangerous DC heroes.
Some might assume that General Zod sees Superman as his biggest enemy due to their fighting over the years, but that's not actually true. While Zod dislikes Superman, his hatred for Superman is due to Superman's father, Jor-El, whose defeat of Zod haunts him to this very day.
Mutated Hybrid Physiology: Doomsday, due to being the genetic amalgamation of General Dru-Zod, a Kryptonian, and Lex Luthor, a human, is a terrifyingly powerful being of potentially apocalyptic proportions, thereby (along with Zeus and Darkseid) being one of the only known beings to surpass the power and might of ...
Although he was angered at Jor-El's refusal to restore the Kandorians' powers, Zod nevertheless regretted Jor-El's death, executing the Kandorian responsible and showing some respect for Kal-El out of recognition of his relationship with his father.
This means that once exposed to a yellow sun, Kryptonians will age normally up to their prime, but the aging process will slow down considerably when their bodies reach a peak level of maturity. They are not immortal per se, but they age so slowly that they may as well be.
In most DC movies, Superman is around his mid-20s or 30s. So far, it appears that Superman has never reached 40 on the big screen. Here are the different ages Superman has been in all of his DC films.
Self-Sustenance: Thanks to their ability to absorb, reprocess and metabolize varied solar ray frequency energies. Kryptonians do not need to eat or sleep (but are still capable of doing so) and don't require oxygen to breathe, which enables them to travel in space and underwater easily.
