\n<\/p>\n
There\u2019s no perfect way of doing anything, including searching for exoplanets. Every planet-hunting method has some type of bias. We\u2019ve found most exoplanets using the transit method, which is biased toward larger planets. Larger planets closer to their stars block more light, meaning we detect large planets transiting in front of their stars more readily than we detect small ones.<\/p>\n
That\u2019s a problem because some research says that life-supporting planets are more likely to be small, like Earth. It\u2019s all because of moons and streaming instability. <\/p>\n
<\/p>\n Consider Earth\u2019s Moon. While there\u2019s no consensus on every aspect of the Moon and its role, there\u2019s evidence that it helps make life on Earth possible and has helped life sustain itself for so long. As natural satellites go, it\u2019s massive. Of the approximately 300 (and counting) moons in our Solar System, the Moon is the fifth largest. But that doesn\u2019t tell the tale of its relationship with our planet. <\/p>\n The Moon\u2019s diameter is about one-quarter of Earth\u2019s diameter, and its mass is about 1.2% of Earth\u2019s. The four natural satellites in the Solar System that are larger than the Moon orbit the gas giants Jupiter and Saturn. Those moons are tiny compared to their planets. <\/p>\n This means that the Moon has different effects on Earth than other moons do on their planets. <\/p>\n The Moon stabilizes Earth\u2019s orbital tilt, which helps keep the climate stable and allows life to flourish and organisms to adapt. It creates tides, which may have played a role in the formation of nucleic acids and life. The Moon may even help Earth maintain its protective magnetosphere. One way or another, Earth would be a very different place without its huge Moon. <\/p>\n New research published in The Planetary Science Journal shows that we should look for small planets if we want to find life-supporting worlds because small planets are more likely to host larger moons. The research is titled \u201cThe Limited Role of the Streaming Instability during Moon and Exomoon Formation.\u201d The lead author is Miki Nakajima, an Assistant Professor of Earth and Environmental Sciences at Rochester University. <\/p>\n \u201cRelatively small planets similar to the size of Earth are more difficult to observe and they have not been the major focus of the hunt for moons,\u201d said lead author Nakajima. \u201cHowever, we predict these planets are actually better candidates to host moons.\u201d<\/p>\n The leading theory for the Moon\u2019s formation is the Giant Impact Hypothesis. It states that when the Earth was very young, about 4.5 billion years ago, a Mars-sized protoplanet named Theia slammed into Earth. The collision created a rotating torus of molten rock that orbited the Earth. Some fell back down to Earth, and the rest coalesced into the Moon. There\u2019s still a lot of debate over this, but it is the leading theory. <\/p>\n Here\u2019s where streaming instability comes in. <\/p>\n This research questions the role of streaming instability in moon formation. Some scientists think that planet formation is the same as moon formation. However, while streaming instability is important for planet formation, it may not be for the formation of large moons like Earth\u2019s, which help make planets habitable. <\/p>\n \n