Moons Beneficial to Life Beyond Earth

Digital simulations of moon formation determine that only certain sizes of planet have the ability to create a moon of similar size ratio to our own system.

IMAGE: In a new study, Rochester scientist Miki Nakajima and her colleagues conclude that the universe’s smaller planets are more likely to host the fractionally large moons that may be helpful for harboring life on those planets. CREDIT: University of Rochester photo / J. Adam Fenster

Recently, I talked about how researchers think the rise of oxygen levels here on Earth helped life come about and how we could use that rise as a potential biosignature on exoplanets. I also mentioned that there are possibly a lot of ingredients that went into allowing life to develop here, and we’re not sure which ones are necessary because of our sample size of one system with life.

And our Moon is unique in our own solar system. Its radius is over a quarter the size of Earth’s radius, which is a larger ratio than other moons and their planets. Our Moon stabilizes Earth’s spin axis, which could have helped create a great environment for the development and evolution of life. When looking for that as yet unfound Earth 2.0, perhaps we need to also find the Moon 2.0 to go with it.

To understand how necessary that aspect of the search may be, Miki Nakajima led a study of moon formations, which was published in Nature Communications, and concluded that only certain types of planets can form a moon similar in size ratio to the Earth-Moon system. Nakajima explains: By…