In Pokémon Legends: Arceus, you first learn about Space-Time Distortions once you’ve reached Star Rank two and access to Crimson Mirelands. They appear occasionally and will often spawn Pokémon you can't find in Hisui, such as Magnemite and Johtonian Sneasel, powerful ones you can only capture late into the game, and evolution items like Upgrades. They’re also the only place where you can collect shards needed to craft Star Pieces.
Fully formed Space-Time Distortions last for around 10 to 15 minutes. The clock to their disappearance will start ticking down faster, however, once you’ve entered it. The clock stops temporarily when your satchel is open. So, if you need a break, it’s fine to take one.
It will disappear if you save and exit the game though!
Space-Time Distortions, even those that are just starting to form, will also disappear if you rest for a period that will change the in-game’s time (such as Midday and Night). If you need to recharge your team to full health, only rest for a little while.
Moreover, these Distortions don’t form immediately. Once the game gives you a notification that one “is forming,” you have five minutes to get ready before it does. There’s no need to rush that much, so take your time preparing for it.
For more help with Pokémon Legends: Arceus, we at Pro Game Guides have you covered.