# apparent horizon

> surface that is the boundary between light rays that are directed outwards and moving outwards, and those directed outward but moving inward

**Wikidata**: [Q4780925](https://www.wikidata.org/wiki/Q4780925)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Apparent_horizon)  
**Source**: https://4ort.xyz/entity/apparent-horizon


## References

1. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)