Sure, watching planets gettingblowed upreal good is fun and all, but it takes a lot longer to create something than to destroy it. Sometimes, it's nice to see a world take shape, rather than become rubble.
This trope occurs whenever a planet is born.
Some form of this occurs in every religiousCreation Myth. It's also fairly common inScience Fiction. Sometimes it's a naturally occurring event, sometimessomeone just possesses the technology to make planets. Typically is used as a symbol for birth and renewal, usually with a hefty amount ofScenery Porn special effects thrown in for good measure, while the sheer amount of energy required can stretchWilling Suspension of Disbelief.
Due to the precarious nature of this trope, writers tend toavoid using it, even when it would be appropriate or interesting to do so.
At one point the canonical source of the Marvel Universe was thatEternity sent Reed Richards back in time to design it. At other times it was caused naturally by a "Big Crunch" of the previous universe or by the Phoenix Force.
And due to the circumstances that it happened in, also becomes a case ofOutrun the Fireball
The plot of the movie is driven by the fact that if the Genesis Device is aimed at a lifeless rock (or nebula), it will create a living, breathing planet... if aimed at a living, breathing planet, it'll erase it entirely and create a brand-new living, breathing planet. Which makes it a weapon of mass destruction as well as mass creation.Subverted; we later learn that Genesis doesn't work. Completely the opposite of its creators' intention, it's only a weapon of mass destruction.
InTitan A.E., the Titan (a giant spaceship) can make a planet out of a comet field almost instantly, with water, oxygen and plants and everything.
In the novelization, formation of the new planet took almost exactlyseven days. Cale thinks his father programmed it to take that long as a joke.
The first part of the "Rite of Spring" segment fromFantasia.
During theDoctor WhoChristmas Special "The Runaway Bride", the Doctor takes Donna back in time to witness the formation of the Earth.
Video Games
It's almost as easy to create planets in theSpace Empires games as it is toblow them up. So easy, in fact, that you can keep destroying and reforming planets if you don't like the atmosphere.
Planets inMaster of Orion II can be constructed from asteroid belts or gas giants in already-colonized systems (tough luck with a system that only has asteroid belts or gas giants). They always turn out Barren-class. Since there's no way to terraform Toxic planets, it may be sometimes beneficial toblow up an enemy's Toxic colony with aStellar Converter, conquer/colonize the neighboring planet, and rebuild the resulting asteroid belt into an improvable Barren world.
InSpore, there are a multitude of different tools for use in making worlds habitable. The easiest to use of these is the Staff of Life, which will instantly transform any planet into a lush paradise, but it only has42 uses.
Not the funnest part ofDwarf Fortress, or the most dramatic use of the trope, but a world has to be born and grow up a little before play.
The Hungry Lumas fromSuper Mario Galaxy andSuper Mario Galaxy 2, if fed enough starbits or coins, will actually transform into either a new planet or galaxy.
Other
There are a few professional 3D procedural world generation applications, some which render planet-birth to stunning real-time effect similar toStar Trek II.
Every religion or mythology ever has had its version of the Creation Myth.
The formation of the Earth inReal Life makes thisliterally older than dirt.