The recommendation is based on 一项新的十大赌博正规老平台 from Rochester scientists about the role of streaming instability in forming moons and planets.
Scientists around the world are constantly on the hunt for planets outside our solar system that could potentially provide a habitable environment for life.
他们的望远镜, 在地面和太空, 倾向于关注比地球大得多的行星, in part because they’re easier to spot than smaller planets and, 因此, 更有利于学习.
但 一项新的十大赌博正规老平台 从 十大赌博正规老平台 发表在 行星科学杂志 suggests scientists ought to be on the lookout for planets that are not much larger than our own. A rocky planet with a large moon may have good potential to host life, 鉴于我们的月球控制着生命的基本方面, 包括一天的长度, 海洋潮汐, 稳定的气候.
“Relatively 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,杨爱瑾及其说, 助理教授 地球与环境科学 他是十大赌博正规老平台的教授，也是这项十大赌博正规老平台的主要作者. “然而, we predict these planets are actually better candidates to host moons.”
The details of the origin of the Earth’s moon are a longstanding debate in planetary science.
流行的理论是月球形成于4月4日左右.5 billion years ago when the Earth was hit by a planetary embryo the size of Mars. The collision threw into orbit a partially vaporized disk of debris that coalesced into the moon. Other models suggest that Earth collided with a much larger object, 会产生一个完全蒸发的圆盘.
有 太阳系中有近300颗卫星, but their masses are typically much smaller relative to their host planets than our moon is to Earth—and that matters when it comes to the formation of life. 卫星可以通过其他过程形成, but these moons are typically small compared to the sizes of their planets. 相比之下，巨大的撞击往往会产生一个巨大的卫星.
While many scientists theorize that a moon isn’t necessary for a planet to sustain life, they also acknowledge that our disproportionately large moon played a crucial role in the development of complex lifeforms on Earth.
毕竟, it is the moon’s gravitational tug that is largely responsible for the tidal flow of the oceans, which scientists believe enabled the formation of the nucleic acids that fostered life as we know it. 月球稳定了地球的轨道倾斜, which keeps the climate relatively predictable so organisms can more easily evolve and adapt.
Scientists have detected more than 5,000 exoplanets—planets beyond our solar system. 但 exomoons—moons that orbit exoplanets—are elusive because they are by nature so much smaller than the planets they orbit. 到目前为止, 目前只确定了几个貌似合理的候选者.
这可能对寻找第二个地球很重要, one that could offer an ideal environment for life—and this is where the latest science conducted by Nakajima and her coauthors comes in.
基础上 previous research that relies on computer simulations of moon formations, they investigated the role so-called “streaming instability” plays in creating moons.
Streaming instability is a process that concentrates particles in a vapor disk to rapidly form planetesimals and moonlets, 行星和卫星的基本组成部分, 分别.
They found that while streaming instability can form self-gravitating moonlets in a vapor-rich disk generated by a giant collision of planets, those moonlets are not large enough to avoid strong drag 从 vapor disk and being hurtled down to their host planet and destroyed.
“These moonlets could grow further once the disk cools enough and the vapor mass fraction of the disk becomes small,报告写道。. “然而, 到这个时候，大量的磁盘质量丢失了, 剩下的圆盘只能形成一个小卫星.”
Nakajima was assisted in her research by Rochester physics professor 爱丽丝Quillen, 前十大赌博正规老平台本科生杰里米·阿特金斯, 雅各布·西蒙, 爱荷华州立大学的助理教授.
Their study supposes that the moon-forming impact has to be relatively “gentle.那就意味着, 以我们的地球为例, the object colliding with it could not be much bigger than Mars. 否则, 撞击会产生一个完全蒸发的圆盘, and such a disk could have only formed a fractionally small moon.
This work also suggests a major difference between planet and moon formation. Sometimes, moon-formation processes are viewed as analogous to the process of planet formation. This research suggests that streaming instability is a critical process for planet formation, 但对于月球的形成却不是这样.
The researchers conclude that streaming instability is not conducive to forming large moons from vapor-rich disks, 还有那些稍微大一点的卫星, 像地球的月亮一样, stem from vapor-poor disks orbiting planets smaller than that of Earth.
太空望远镜科学十大赌博正规老平台所 recently selected two proposals from researchers to use the powerful James Webb Space Telescope to look for exomoons. 一种是关注类木星行星周围的卫星, 另一个在类地行星周围寻找卫星.
These future observations can test the theory developed in this research.
