Skip to main content



To sort out the biological intricacies of Earth-like planets, astronomers have developed computer models that examine how ultraviolet radiation from other planets’ nearby suns may affect those worlds, according to new research published June 10 in Astrophysical Journal.

“Depending on the intensity, ultraviolet radiation can be both useful and harmful to the origin of life,” says Lisa Kaltenegger, Cornell associate professor of astronomy and the director of Cornell’s new Carl Sagan Institute: Pale Blue Dot and Beyond. “We are trying to ascertain how much radiation other young Earths would get and what that could mean for the possibility for life.”

The study, “UV Surface Environment of Earth-like Planets Orbiting FGKM Stars Through Geological Evolution,” was prepared by lead author Sarah Rugheimer, Cornell research associate at the Carl Sagan Institute; Antigona Segura of Universidad Nacional Autonoma de Mexico; Dimitar Sasselov of the Harvard Smithsonian Center for Astrophysics; and Kaltenegger.

“We’re going to see all kinds of planets in all kinds of stages in their own evolution, but we wanted to take four kinds of epochs from Earth history, as samples of what we might see,” said Rugheimer. “With the next generation of missions, we expect to observe a wide diversity of extrasolar planets.”

Borrowing from deep into Earth’s history, Rugheimer and co-authors modeled the first epoch, a pre-biotic world with a carbon dioxide-dominated atmosphere, similar to early Earth 3.9 billion years ago. The second epoch – about 2 billion years ago – spawned the first whiff of oxygen, an active biosphere and the process of biosynthesis. Oxygen started to rise from the first cyanobacteria to the 1 percent concentration of current levels.

“It’s not just the amount of ultraviolet radiation, but also the specific types of ultraviolet radiation which will impact biology,” Rugheimer said. “We consider which wavelengths are most damaging to DNA and other biomolecules in addition to just looking at the total amount of radiation.”

Multicellular life started about 800 million years ago, and the group modeled a third epoch, where oxygen rose to about 10 percent of today’s levels. The fourth epoch corresponds to modern Earth, where the atmosphere features a carbon dioxide ratio of about 355 parts per million with current oxygen levels.

The researchers noted that for all epochs after the rise of oxygen the hottest and coolest stars have less biologically effective radiation. For the hottest stars, this is due to increased ozone shielding from higher UV environments, and for the coolest stars this is due to less absolute UV flux.

Rugheimer, who conducted the research while she was a doctoral student at Harvard University, explained that astrobiology draws researchers across disciplines and noted: “This work provides a link from the astrophysical conditions we expect to find on other planets to the origin-of-life experiments happening on here on Earth.”

The Simons Foundation provided funding for this research.


金鱼直播app下载 可乐视频下载app 尤蜜视频app下载 主播福利下载app 咪咪直播下载app 柠檬视频app下载 后宫视频下载app 蜜桃直播app下载 小蝌蚪app下载 AVBOBOapp下载 秀儿直播下载app 菠萝蜜下载app 葡萄视频下载app 酷咪直播app下载 泡芙短视频下载app 小可爱下载app视频免费最新 樱桃视频app下载 蓝精灵直播下载app 橙子视频下载app 月色直播app下载 樱花雨直播下载app 丝瓜草莓视频下载app视频免费最新 柚子直播app下载 AVnight下载app 考拉直播app下载 可乐视频下载app 茄子视频下载app 微杏下载app 恋人直播下载app 卡哇伊下载app视频免费最新 咪哒app下载 斗艳直播app下载 BB直播下载app 菠萝蜜下载app 火辣直播下载app 小蝌蚪app下载 iAVBOBOapp下载 fi11含羞草下载app 月光宝盒直播下载app 杏趣直播app下载 丝瓜草莓视频下载app视频免费最新 小姐姐直播下载app 快播破解下载app 红杏视频下载app 成人直播app下载 草莓视频app下载 Kitty直播app下载 玉米视频下载app 葡萄视频下载app 快喵下载app 灭火卫视app下载 花样视频下载app 草莓视频app下载 名优馆app下载 6房间视频直播下载app 初恋视频下载app 荔枝下载app 西瓜直播app下载 冈本app下载 花粥直播app下载 小v视频下载app视频免费最新 九尾狐视频app下载 雨云直播app下载 ML聚合直播下载app 压寨直播app下载 久草视频app下载 富二代f2下载app 小蝌蚪视频app下载 含羞草视频app下载 火爆社区app下载 丝瓜下载app 梦露直播下载app 豆奶视频下载app 夜猫视频app下载 夜夜直播app下载 小v视频下载app 豌豆直播下载app 雨云直播下载app 一对一直播下载app 6房间视频直播app下载 左手视频下载app 望月直播app下载 十里桃花直播下载app Kitty直播下载app 秀儿直播app下载 梦露直播下载app 尤蜜下载app 宅男之家app下载 AVBOBO下载app 97豆奶视频app下载 香蕉app下载 木瓜视频app下载 蘑菇视频下载app 初恋直播下载app 97豆奶视频app下载 6房间视频直播app下载 花椒直播app下载 红楼直播下载app 夜狼直播下载app 花姬直播app下载 久草视频app下载 Avnight下载app 杏趣直播app下载 荔枝app下载 久草视频下载app 大秀直播app下载 成版人抖音富二代下载app视频免费最新 9uu下载app 秀色小抖音下载app 泡泡直播下载app 麻豆传媒映画下载app 丝瓜视频污下载app 西瓜直播下载app 大小姐直播下载app 微杏app下载 JOJO直播下载app 木瓜视频app下载 夜猫视频app下载 小怪兽直播下载app 望月直播app下载 橙子视频app下载 黄瓜视频人app下载 么么直播下载app 丝瓜视频污下载app 木瓜下载app 盘她直播app下载 Avnight下载app 青草视频app下载 棉花糖直播下载app 心上人直播下载app bobo直播app下载 尤蜜视频app下载 久草视频app下载 食色短视频app下载 小可爱下载app 夜猫视频下载app 咪哒直播下载app 葡萄视频app下载 花秀神器app下载 音色短视频下载app 草鱼app下载 免费黃色直播下载app 皮卡丘直播app下载 小蝌蚪app下载 宅男之家app下载 牛牛视频下载app 小小影视下载app 桃花直播app下载 樱花直播app下载 7秒鱼直播app下载 蝴蝶直播下载app 小蝌蚪下载app BB直播app下载 西瓜直播app下载 富二代app下载 樱花视频app下载 火爆社区下载app 春水堂视频app下载 笔芯直播app下载 嘿嘿连载app下载 葫芦娃app下载 菠萝菠萝蜜视频app下载 柠檬直播下载app 云上花app下载 A头条下载app 夜夜直播app下载 内裤直播app下载 初见直播下载app 佳丽直播视频下载app 七秒鱼直播app下载 小奶狗下载app 小狐仙app下载 可乐视频下载app ML聚合直播下载app 食色app下载 奶茶视频下载app 小小影视下载app 夜猫视频app下载 葡萄视频下载app 铁牛视频下载app 一对一直播app下载 恋夜秀场app下载 成版人音色短视频下载app视频免费最新 成版人短视频下载app视频免费最新 香蕉视频app下载 富二代f2app下载 豆奶下载app 花姬app下载 豆奶抖音短视频app下载 梦幻直播app下载 遇见直播下载app