# The Faint Young Sun and Faint Young Stars Paradox

## TL;DR

This paper investigates the hypothesis that a more massive young Sun with significant mass loss could resolve the Faint Young Sun Paradox, suggesting it is a plausible explanation consistent with stellar observations.

## Contribution

It proposes and supports the idea that a more massive early Sun with sustained mass loss can explain warm ancient planetary climates, challenging previous rejection of this hypothesis.

## Key findings

- A more massive young Sun is consistent with observed stellar spin-down rates.
- Sustained mass loss over billions of years is plausible for Sun-like stars.
- A more massive early Sun could have kept Earth's and Mars's oceans from freezing.

## Abstract

The purpose of this paper is to explore a resolution for the Faint Young Sun Paradox that has been mostly rejected by the community, namely the possibility of a somewhat more massive young Sun with a large mass loss rate sustained for two to three billion years. This would make the young Sun bright enough to keep both the terrestrial and Martian oceans from freezing, and thus resolve the paradox. It is found that a large and sustained mass loss is consistent with the well observed spin-down rate of Sun-like stars, and indeed may be required for it. It is concluded that a more massive young Sun must be considered a plausible hypothesis.