Answer:
Every week, the launch goes up by one. Below is how to get Jirachi!
Jirachi is one of the hardest Pokemon to obtain. Here are ways how you get it:
Pokemon Colleseum bonus disc
Pokemon event
Pokemon channel
Other downloads
Trade
Illegal cheats: gameshark codes etc. (not recommended)
In-game (this is the hardest way), How to do this:
1.Beat league.
2. Complete Hoenn pokedex (200 Pokemon not including Jirachi and Deoxys).
3. Contest, have 5 pictures on second floor of Lilycove Museum.
4. Battle tower, beat 50 trainers in a row without losing.
5. Pokemon Master Challenge:(beat league at least 50 times, complete national dex this does not include event legendaries, after you have 5 museum pics look at it without pressing A you will see a different Pokemon get that Pokemon and get a picture of it and it will overlap the previous one, beat at least 100 trainers in a row without losing in battle tower) You also have to beat every trainer in the game this does not include e-reader trainers. You have to also obtain all visible items (pokeball shaped items you find on your journey). You have to have at least 200hrs play time and the launch must be at least 100. If you have used gameshark or cheat codes it will lock jirachi and you won't be able to obtain it using the in-game method. In Emerald, instead of of beating trainers in Battle Tower, just obtain all symbols!
After all this talk to Birch and he will say your rival is in Mossdeep. Go there to the space centre and just in front of the door the rival will come out and you will be pushed back then he/she will say sorry, talk for a while and battle you. Your rival will have 6 Pokemon all around level 70s and 80s. Your rival says that he/she will go home and you should too. Screen fades. You are in your bedroom. Walk downstairs and your father will give you a Space Ticket (key item). Go to the space centre talk to the scientist. He will lead you (one of the machines is actually a secret door). Now you are behind the space centre in front of a rocket! Press A on the scientist and you will be lead inside the rocket! There are around 5 pretty tough trainers and some items. After that talk to the captain on the top floor and he will tell you to go to an assigned bed. Sleep there and the screen fades. The rocket lands on the moon. The bright side of the moon has Jirachi and the other side has Deoxys. Explore the moon, have fun and catch the Legendaries!
Good luck!!!!!