22 minutes after the Protagonist wakes up, the Solar System's Sun reaches the end of its life cycle and explodes into a supernova. In the last 60 seconds before the Sun goes supernova, the song End Times plays, which can be heard from any location. Upon the song finishing, the Sun goes supernova. It collapses in on itself to form into a relatively small sphere for a brief moment before exploding outer ward violently with a blue flash. The supernova grows and accelerates to quickly encompass the entire Solar System. The Protagonist's memories are then sent 22 minutes back in time by the Ash Twin Project, starting another 22-minute loop.
While the player can escape the blast radius of the supernova, they will still die with an alternative screen fade as their memories are uploaded to the Ash Twin Project. Escaping from the supernova after removing the core of Ash Twin will trigger the Isolation Ending.
For more information, see: Supernova (Wikipedia)
Stars generate light and heat by fusing hydrogen into helium. Over time, the star runs out of hydrogen and starts to contract. The star's core contracts and gets hotter, causing the outer layers to expand. The star becomes a red giant. When the core is hot enough, the star starts fusing helium into carbon. If it becomes massive enough, it will fuse carbon into heavier elements such as iron. Eventually, the star collapses under its own gravity and then explodes into a supernova.
281,042 years before the start of the game, the Nomai attempted to prompt the Sun to go supernova to generate enough energy to power the Ash Twin Project. They constructed the Sun Station which would shoot at the Sun and trigger a supernova. This would give the Ash Twin Project enough power to send an order 22 minutes back in time for the Orbital Probe Cannon to shoot a random probe. 22 minutes after this, the Sun Station would cause a supernova again, and the same order would be sent back in time. This cycle would end once a probe found the location of the Eye of the Universe.
However, the Sun Station was not able to trigger a supernova, as the Sun barely responded after it was fired at. 281,042 years later, when the universe started dying and more and more stars went supernova, the Sun reached the end of its natural lifespan and exploded into a supernova by itself. This powered the Ash Twin Project and made it start sending the order for the Orbital Probe Cannon to fire. Over 9 million loops later, a probe finally found the Eye of the Universe. Consequently, a Nomai Statue linked with the Protagonist. This caused the Protagonist's memories to be sent back in time after the supernova, thus making them aware of the time loop.
Models of the Sun's life cycle as shown in the Observatory
- YARROW: Are there other ways to generate this level of power? PYE: Theoretically, yes. Practically, no. I can’t imagine discovering them in our lifetimes... RAMIE: I understand this proposal is unsettling, but the Sun Station must be built if we hope to complete the Ash Twin Project.
- PYE: It fired, Yarrow. But it failed. The sun barely responded; there were infintestimally small surface-level changes, but they were barely visible, even to the third eye. PYE: The Sun Station is useless. It will never, and could never, cause the sun to explode.
- YARROW: We’re nearly ready to activate the Ash Twin Project! Here is what will happen: First, the Sun Station will receive the order to fire at the sun, prompting it to explode. YARROW: Using the energy from the resulting supernova, the Ash Twin Project will send the order for the Orbital Probe Cannon to fire back in time by 22 minutes.
- YARROW: Exactly 22 minutes after these orders are received, the Sun Station will again trigger the supernova to send the probe data from this cannon launch back in time.
- PRIVET: Once the probe determines the location of the Eye of the universe, I’ll send an alert directly to you and Ramie.
- CANNA: It’s clear the universe is dying. There are fewer and fewer resources and safe places within space now, so my clan and I believe the best option is for all of our clans to stay together.
- Eye of the Universe Observatory: At the end of its lifespan, our sun collapsed under its own gravity and then exploded in a violent supernova.
- X MINUTES, X SECONDS AGO: Request to launch probe received from Ash Twin Project. Cannon aligned with randomly selected probe trajectory. Gravity field activated. BEGIN LAUNCH LOG: Orbital Probe Cannon. Launch request received. Probe launch successful. Probe Tracking Module is receiving data from probe.
- Probe Tracking Module: Deep space anomaly matching all known criteria for the Eye of the universe found by probe 9,318,054.