Set as Homepage - Add to Favorites

日韩欧美成人一区二区三区免费-日韩欧美成人免费中文字幕-日韩欧美成人免费观看-日韩欧美成人免-日韩欧美不卡一区-日韩欧美爱情中文字幕在线

【vk kar?nla porno izlemek】Scientists find subtle clues ancient Mars had rainy days, too

For the past four years,vk kar?nla porno izlemek NASA's Perseverancerover has rambled over a region of Marswhere scientists say a strong river once emptied into a crater, creating a large delta. 

But for that to have happened, a lot of waterwould have gushed — something difficult to explain if the Red Planet were always frozen.

Computer simulations show that ancient Mars likely experienced regular rain and snow, which helped shape vast networks of river valleys and lakes. The distribution of these land features lines up better with precipitation models than merely the effects of melted ice caps, according to a new paperpublished in the Journal of Geophysical Research: Planets


You May Also Like

The research, performed by geologists at the University of Colorado in Boulder, argues that our planetary neighbor, on average 140 million miles away in space, was warm and wet billions of years ago, challenginga long-held belief that early Mars was mostly cold and icy. 

Most scientists agree that at least some water existed on the surface during a period about 4 billion years ago, but where the water came from has been up for debate, said Amanda Steckel, who led the studyas a doctoral student. 

"We see these valleys beginning at a large range of elevations," Steckel said in a statement. "It’s hard to explain that with just ice."

SEE ALSO: A NASA rover just exposed something on Mars that eluded orbiters Viewing Mars' topography from spaceNASA's Mars Global Surveyor spacecraft created this topographical map of a region near the planet's equator with its Mars Orbiter Laser Altimeter. Credit: NASA

The researchers created a digital version of part of Mars and tested different climate scenarios. In some computer simulations, they added widespread rain or snow. For others, they only tried melting down polar ice. Then, they used the software to simulate what would happen if that water flowed for thousands of years. 

Mashable Light Speed Want more out-of-this world tech, space and science stories? Sign up for Mashable's weekly Light Speed newsletter. By clicking Sign Me Up, you confirm you are 16+ and agree to our Terms of Use and Privacy Policy. Thanks for signing up!

Their goal was to determine whether ancient Mars may have had a more Earth-like climate, at least for a while. 

The results showed when precipitation was part of the climate, valleys and streams formed in many different regions at varying elevation points. When water came only from melted ice, the valleys mostly formed in the highlands, in close proximity to where the ice caps would have been.

The team compared the simulation data to real images from NASA spacecraft that have observed Mars from orbit. The patterns created by rain or snow more closely matched what is actually seen on the Martian surface.

Observing Mars' valley networks from spaceMars' oldest terrains appear to have eroded into branching valleys, similar to regions of Earth where rain and snow have caused runoff. Credit: NASA / JPL-Caltech / Univ. of Arizona

"Water from these ice caps starts to form valleys only around a narrow band of elevations," Steckel said. "Whereas if you have distributed precipitation, you can have valley heads forming everywhere."


Related Stories
  • A NASA rover just exposed something on Mars that eluded orbiters
  • NASA's rovers just found similar gnarly rocks on opposite sides of Mars
  • The best telescopes for gazing at stars and solar eclipses in 2024
  • Past life on Mars? Here's what new NASA evidence points to.
  • Scientists found huge beaches on Mars likely from a long gone ocean

Today, snow occasionally falls on Mars, but only in the coldest extremes, according to NASA: at the poles and under cloud cover at night. So far there's no photographic evidence of Martian snowfall — clouds obscure the cameras on spacecraft — but other instruments are capable of detecting it. 

The Mars Reconnaissance Orbiter, for example, has the Mars Climate Sounder, which has collected data on carbon dioxide snow — aka dry ice — as it fell to the ground. The Phoenix landeralso used a laser-based tool to spot snow made of water near the Martian north pole in 2008. 

The team still doesn't fully grasp how Mars could have stayed warm enough for rain or snow, especially since the young sunwas about 25 percent dimmer than it is today. Despite the mystery, geologist and study coauthor Brian Hynek says without rain, landforms like Perseverance's Jezero Craterjust don't make sense. The dried delta, for example, features scattered boulders. 

"You’d need meters deep of flowing water to deposit those kinds of boulders," he said. 

0.1245s , 10021.21875 kb

Copyright © 2025 Powered by 【vk kar?nla porno izlemek】Scientists find subtle clues ancient Mars had rainy days, too,Public Opinion Flash  

Sitemap

Top 主站蜘蛛池模板: 制服丝袜中文丝袜av | 精品国产乱码久久久久久浪潮小说 | 久久久精品国产sm最大网站 | 国产成人精品午夜福利在线播放 | eeuss在线无码区 | 精品香蕉国产一区二区三区四区 | 久久人妻av无码中文专区 | 91精品免费不卡在线观看 | 日本系列变态另类一区二区三区 | 国产99在线播放免费 | 毛片一区二区在线看 | 四虎精品成人影院在线观看 | riav久久中文一区二区 | 视频一区在线免费观看 | 国产69一区二区三区在线观看 | 狼人亚洲国内精品自拍在线 | 成人a毛片免费观看网站 | 日本无码成人片在线观看波多 | 人妻无码久久久久久久 | 国产精品亚洲精品在线观看 | 天天天天干 | 久久久久久精品成人免费图片 | 亚洲国产成人久久午夜 | 国产成年女人特黄特色大片免 | 中文字幕卡二和卡三的视频 | 在线观看视频观看高清午夜 | 欧美区一区二 | 国产粉嫩泬一区二区三区 | 国产成人精品无缓存在线播放 | 国产精品亚洲自在线播放页码 | 精品国产免费第一区二区三区日韩 | 精品91自产拍在线观看一 | 日韩精品一区二区三区视频网 | 国产亚洲欧美一区久久国产亚洲欧 | 国产午夜亚洲精品一级在线 | 国产91最新欧美在线观看 | 亚洲国产熟妇无码一区二区 | 成人无遮挡裸免费视频在线观看 | 一本大道伊人AV久久乱码 | 韩国免费特一级毛片 | 成av人电影在线观看 |