Water Arrived in the Final Stages of Earth’s Formation

Roughly 4.6 billion years ago, the Sun was born from the gas and dust of a nebula that underwent gravitational collapse. The remaining gas and dust settled into a protoplanetary disk that slowly accreted to form the planets, including Earth. About 4.5 billion years ago, our planet was impacted by a Mars-sized body (Theia), which … Read more

Are there liquid water brines on Mars? New study casts doubt

View larger. | An example of weird, dark streaks called recurring slope lineae on the slopes of Mars’ Horowitz crater. Do liquid water brines form these streaks? A new study suggested brines on Mars are less likely to occur than scientists thought. Image via NASA/ JPL-Caltech/ University of Arizona. 2025 EarthSky lunar calendar is available … Read more