The Speed Cycle achievement in Solar 2 requires that you go from Big Crunch to another Big Crunch in under 20 minutes without using any God or Physics options. In order to do this you will have to focus solely on gaining mass as fast as possible, ignoring everything else. Your best time will be saved.
First things first, to start the Speed Cycle timer, you will have to basic spawn as a Black Hole and gain enough mass to hit the Big Crunch. The second you respawn as an asteroid, the Speed Cycle timer begins to count down, but is not visible yet. Use the tactics you’ve learned so far to burn through each stage as fast as possible.
As both an asteroid and planet you will want to stick to harvesting large clusters of asteroids, ignoring more sparse groups as they take too much time to capture for the payoff. As a Star you will want to make sure you stick to a single star system and keep the number of planets in orbit low as to spawn more loner planets and less large star systems. Always avoid hostile lifeforms and nomad ships as both aren’t worth your time and can prove hazardous to your end goal.
Once you hit the Star stage, the timer will show up allowing you to keep track of your progress from that point on. Just stay safe and quick about your way to growing in size, keep your interface on, and use the path and orbit keys to assist you wherever applicable. Upon triggering your next Big Crunch the timer will stop and if its under 20 minutes, the Speed Cycle achievement will unlock.