Big Rip is unlocked when buying the relevant mastery study. You will need 2e98 time theorems and the "The Challenging Day" achievement. In Big Rips, everything except normal dimensions and post-quantum mechanics is disabled. You are also stuck in PC6+8. When you exit Big Rip, you gain Space Shards based on your best antimatter while in Big Rip (log10(AM)/200, 1.5 * ( DT + 1 ^ 0.05). There are 20 upgrades you can buy that cost Space Shards and some of them disable others.
Infinity Points boost Normal Dimensions, but is repealed by all other upgrades except for the 2nd.
Start with 1e5 eternities and all ECs completed.
Gain 5 TT.
Replicanti multiply the gain of IP at a reduced rate and replicate speed is 10x faster.
Gain 20 TT.
Space Shards boost EP gain.
You start with TS192.
Each replicated galaxy doubles EP gain.
Gain 1350 TT but reset the study tree and repeal upgrades 3 and 5 through 8.
Start with dilation unlocked but activate the 9th Big Rip upgrade.
Start with tachyon particles but reset the study tree, all upgrades can boost dilation except for your best TP, and repeal all others.
You keep your time studies, dilation studies, and mastery studies.
Replicanti boost TDs at a greatly reduced rate.
TS101 is stronger based on your Space Shards but doesn't work on dilation.
EP start Distant Antimatter Galaxy scaling later.
DT boosts TD7.
Reactivates the first upgrade and makes it 2.9x stronger.