So-net無料ブログ作成

『史上第2位の暑さ』 [科学]


Earth's surface temperatures in 2017 were the second warmest since since 1880, when global estimates first become feasible, NASA scientists found. Global temperatures 2017 were second only to 2016, which still holds the record for the hottest year; however, 2017 was the warmest year on record that did not start with an El Nino weather pattern, as the previous two years did. In a separate, independent analysis, NOAA scientists found that 2017 was the third-warmest year in their record. The minor difference is due to different methods to analyze global temperatures used by the two agencies, although over the long-term the records remain in strong agreement. Music: Sojourner Rover by Craig Warnock [PRS], Lee Ahmad Baker [PRS], Sean Hennessey [PRS] This video is public domain and along with other supporting visualizations can be downloaded from the Scientific Visualization Studio at: http://svs.gsfc.nasa.gov/12822 Credit: NASA's Goddard Space Flight Center/Kathryn Mersmann
NASA Goddard
nasa2017b.jpg

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共通テーマ:趣味・カルチャー

『スペクトルエネルギー分布のシミュレーション』 [科学]


When exoplanet scientists first spotted patterns in disks of dust and gas around young stars, they thought newly formed planets might be the cause. But a recent NASA study cautions that there may be another explanation: one that doesn't involve planets at all. An alternative explanation suggests the dust and gas in the disk can form the patterns themselves when they interact with starlight. When high-energy UV starlight hits dust grains, it strips away electrons. Those electrons collide with and heat nearby gas. As the gas warms, its pressure increases and it traps more dust, which in turn heats more gas. The resulting cycle, called the photoelectric instability (PeI), can work in tandem with other forces to create some of the features astronomers have previously associated with planets in debris disks. A 2013 study suggested PeI could explain the narrow rings seen in some disks. The model also predicted that some disks would have arcs, or incomplete rings, which weren't directly observed in a disk until 2016. The new simulation includes an additional new factor: radiation pressure, a force caused by starlight striking dust grains. Light exerts a minute physical force on everything it encounters. This radiation pressure propels solar sails and helps direct comet tails so they always point away from the Sun. The same force can push dust into highly eccentric orbits, and even blow some of the smaller grains out of the disk entirely. The new research modeled how radiation pressure and PeI work together to affect the movement of dust and gas, and also found that the two forces manifest different patterns depending on the physical properties of the dust and gas. Credit: NASA’s Goddard Space Flight Center/Scott Wiessenger
NASA Goddard
nasa2017b.jpg

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『ロシアのペット』 [liveleak復活]


こんな奴らと戦争して勝てるわけないっス[たらーっ(汗)]
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共通テーマ:ペット