Day: July 24, 2021

The Edge of Space

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Where does space begin? For purposes of spaceflight some would say at the Karman line, currently defined as an altitude of 100 kilometers (60 miles). Others might place a line 80 kilometers (50 miles) above Earth’s mean sea level. But there is no sharp physical boundary that marks the end of atmosphere and the beginning of space. In fact, the Karman line itself is near the transition between the upper mesophere and lower thermosphere. Night shining or noctilucent clouds are high-latitude summer apparitions formed at altitudes near the top of the mesophere, up to 80 kilometers or so, also known as polar mesopheric clouds. Auroral bands of the northern (and southern) lights caused by energetic particles exciting atoms in the thermosphere can extend above 80 kilometers to over 600 kilometers altitude. Taken from a cockpit while flying at an altitude of 10 kilometers (33,000 feet) in the realm of stratospheric aeronautics, this snapshot captures both noctilucent clouds and aurora borealis under a starry sky, looking toward planet Earth’s horizon and the edge of space. via NASA https://ift.tt/2W4wvDR

Wikipedia article of the day for July 24, 2021

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Wikipedia article of the day is The 1975 (2019 song). Check it out: Article-Link Summary: “The 1975” is a song by the band of the same name and the first track on Notes on a Conditional Form (2020), their fourth album. In the song, Greta Thunberg (pictured) calls for civil disobedience in response to climate change, to reduce greenhouse gas emissions. Each of their three previous albums began with a track titled “The 1975” that used the same lyrics, beginning “Go downย / Soft sound”, but the lead vocalist Matty Healy thought it was important to give a platform to Thunberg, the “voice of this generation”. After the recording in Stockholm, they released the song earlier than intendedโ€”on 24ย Julyย 2019. Proceeds from the song were donated to the grassroots environmental movement Extinction Rebellion, at Thunberg’s request. The band opened encores at their performances with the song, before the COVID-19 pandemic halted their touring. It was received positively by music critics, many of whom praised the album’s transition from the end of “The 1975” into the punk rock song “People”.