Que la figura mítica del kraken es real -o, al menos, muy parecida físicamente a lo que relataban las leyendas escandinavas- se sabe desde hace tiempo. El calamar gigante, que mora en las oscuras profundidades del océano, y que puede crecer hasta 12 me…
Here's why it's so difficult to know for sure.
It is estimated that between 90 and 95% of the indigenous population of the Amazon died after 1492, because, when Europeans first arrived on the coasts of South America, brutal waves of disease, war, slavery and genocide followed.
However, new measurements suggest that, in many places, land abandonment and reforestation began between 300 and 600 years before the arrival of Europeans.
The Amazon is a vast region in the horizontal and northern part of South America that includes the rainforest of the Amazon River basin.
According to this new study published in ScienceTherefore, depopulation and subsequent reforestation in the Amazon began centuries before the arrival of Europeans and did not contribute to the decline observed atmospheric CO2 during the 17th century.
The data suggest that, in many places, land abandonment and reforestation began between 300 and 600 years before the arrival of Europeans.
To reach these conclusions, researcher Mark Bush and his colleagues at the Florida Institute of Technology, in Melbourne (Australia), evaluated fossil pollen records from 39 places in the Amazon that record changes in forest cover over the last 2,000 years.
That does not mean, of course, that the cascading effects of environmental change, pre-European pandemics and/or social strife may have contributed as well. Nevertheless, It is possible that indigenous populations in some areas of the Amazon were already declining when Europeans arrived..
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The news
More than 300 years after the arrival of Europeans to the New World, the Amazon had already been depopulated and reforested
was originally published in
Xataka Science
by
Sergio Parra
.
It took off at 3:23 UTC, from the Wenchang Space Launch Center on Hainan Island, southern China, the central capsule of your space station.
The central capsule, called Tianhe, or Harmony of the Heavens, is 16.6 meters long and 4.2 meters in diameter. The construction of the space station marks the beginning of the third stage of China's manned space program, which was approved by the government in 1992.
Specifically, a Long March 5B heavy-lift carrier rocket has been launched, with a central stage and four side boosters, an equivalent height to an 18-story building and a takeoff weight of 849 tons.
Watch: #China launches “Tianhe,” core module of space station🚀🚀 pic.twitter.com/zAFZ5uaDWm
— CGTN (@CGTNOfficial) April 29, 2021
The launch is intended to transport the 22.5-ton capsule, the largest and heaviest spacecraft China has ever built, to a low Earth orbit about 400 kilometers above Earth to place the first piece of the country's space station.
The multi-module space station, called Tiangong, or Heavenly Palace, will be mainly composed of three components, a central module attached to two space laboratories, with a combined weight of almost 70 tons. The entire Tiangong station is expected to be fully operational by the end of 2022 and is scheduled to operate for about 15 years.
The module sent will be essential for the future operations of the space station, since the astronauts will live there and control the entire station from the inside. Next year, Tiangong's two space laboratories, two manned missions and two robotic cargo flights to continue station construction.
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The news
China launches the central capsule of its future space station, one of the largest and most sophisticated space facilities
was originally published in
Xataka Science
by
Sergio Parra
.
Previously unobserved extreme amounts of atmospheric hydroxyl and hydroperoxyl radicals (HO2), which have been generated directly by lightning sparks, are involved in cleaning our atmosphere.
This is what it suggests a new study published in Science. These amounts are much higher than expected, and that's a good thing.
We already knew that lightning increases the atmosphere's ability to clean itself by producing reactive nitric oxide (NO), which, through subsequent atmospheric chemistry, ultimately leads to the formation of atmospheric oxidants, including ozone ( O3) and hydroxyl radicals (OH).
OH is the most important oxidizing species in the atmosphere, controlling the concentrations of toxic and climate-relevant gases such as carbon monoxide and methane.
According to the researchers, these quantities are several orders of magnitude above any previous measurement of atmospheric OH or HO2.
Although the results are uncertain, perhaps by a factor of ten, they suggest that the OH generated by lightning in all storms occurring globally at any given time could be responsible for between 2 and 16% of the oxidation capacity of the Earth's atmosphere.
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The news
Lightning produces more hydroxyl radicals than expected and that is very good for our atmosphere
was originally published in
Xataka Science
by
Sergio Parra
.
