In three to five sentences, explain the evidence that supports the idea that water on earth may have come from comets

3 answers

One piece of evidence comes from the study of isotopes in water molecules on Earth. Isotopes of hydrogen and oxygen can provide insight into the origin of water. The ratios of certain isotopes, specifically deuterium and oxygen-18, in Earth's water closely match the ratios found in comets.

Another line of evidence comes from the analysis of cometary material brought back to Earth by sample return missions. The analysis of these samples revealed the presence of water ice and various organic compounds, supporting the idea that comets contain water.

Additionally, observational data from space missions such as the Rosetta mission have directly observed water vapor and ice in comets. This strengthens the hypothesis that comets could have delivered water to Earth during the period known as the Late Heavy Bombardment.

Lastly, computer simulations and modeling of the early solar system also support the idea of cometary delivery of water. Certain models suggest that comets from the outer solar system possess enough water to account for the amount of water on Earth, and their impact on our planet during its early stages could have released this water onto the surface.
I meant in three to five sentences, not paragraphs
Water on Earth may have come from comets based on isotopic analysis, which shows that the ratios of certain isotopes found in Earth's water closely match those found in comets. Analysis of cometary material brought back to Earth also reveals water ice and organic compounds in comets, further supporting this idea. Observational data from space missions and computer simulations of the early solar system both provide evidence for the cometary delivery of water.