Timeline of Sol 2

Sol_2 is the 2nd planet from the sun in the So star system, it is next Sol_1 which is small with no atmosphere, and Sol_3, also known as Earth...

4700 MYA

 * Proto-Precambias Vienosis is formed and is the size of the moon, at 0.4 AU. Where Sol_1 is today.

4600 MYA

 * The planet is now 90% of its present size, it shifts to 0.3 AU due to Earth being formed at 0.7 AU.

4450 MYA

 * Planet drifts back to 0.4 AU as Sol_1 is formed at 0.3 AU.

4200 MYA

 * Planet drifts to 0.6 AU and Earth drifts to 0.9 AU.
 * Planet forms crust, contenental rifts fail and the planet has no way to recycle carbon...
 * Late-Heavy Bombardment begins.

3800 MYA

 * Late-Heavy Bombardment ends, Sol_1 is pushed to 0.4 AU after it was partly destroyed by a solar flare, reducing Sol_1 to it's present day size rather than about same size as Sol_2. Earth drifts to 1 AU and Earth starts to form life.
 * Sol_2 drifts to it's present day position (0.7 AU) after it and the other rock planets were damaged by the star's activity and meteorite storms.
 * Sol_2 is first atmosphere-measured, it has 96% CO2, 1% Argon, 1% Nitrogen, 1% Uranium and 1% Other. It was evaluated unhabitable to Carbon Based life, which was the only known life base at the time as well as Oxygen-Based life.

3500 MYA

 * The core and the crust of the planet goes to critical level, melting it, after 5 million years it resolidifies.

3450 MYA

 * Very simple Nitrogen-Based life starts to form on Precambrias Vienosis. They breath in CO2 of the atmosphere and breath out Nitrogen and poop sulphur...
 * The planet is atmosphere-measured and the life is discovered. The atmosphere is 95% CO2, 1% Argon, 2% Nitrogen and 2% Other; the uranium had depleted at that point.

3000 MYA

 * For a short time Sulphur-Based life also appeared, It breathed in CO2 and breathed out Argon, however most went extinct due to them being extremely allergic to Argon above 2% in the atmosphere.

2500 MYA

 * Multicellular life begins.  The carbon recycling is unnecessary due to the atmosphere being; 65% CO2, 6% Argon, 3% Other and 26% Nitrogen.

2230 MYA

 * The planet is put under Fast Change Status as it's atmosphere was measured with 32% CO2, 60% Nitrogen, 1% Sulphur 5.9% Argon and 1.1% Other gases. (Previously Sulphur was apart of other gases)

1980 MYA

 * The first plants on Vienosa Jurassica are noted.

1510 MYA

 * The planet is put under an at risk status as the CO2 in the atmosphere was being replaced by the Nitrogen, going under 5%. Sulphur and Argon decreases due to plants and bacteria which breath them and exhale Nitrogen and Oxygen becoming common.

1320 MYA

 * The first animals form which breath in Oxygen and Nitrogen and breath out CO2.
 * The atmosphere is heavily monitored. Having 12% Oxygen, 6% CO2, 1% Argon, 1% Sulphur, 79% Nitrogen and 1% Other Gases as the air content.

1200 MYA

 * There is a mass extinction all CO2 Breathing life is killed due to CO2 becoming rare. However after this, CO2 levels explode due to Nitrogen breathing life becoming too common...