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+--- Thread: Moving BH + NASA again needs Russian help to get into space + Exoplanet habitability (/thread-9939.html)
Moving BH + NASA again needs Russian help to get into space + Exoplanet habitability - C C - Mar 12, 2021
Astronomers detect a black hole on the move
https://www.eurekalert.org/pub_releases/2021-03/hcfa-ada031221.php
INTRO: Scientists have long theorized that supermassive black holes can wander through space--but catching them in the act has proven difficult. Now, researchers at the Center for Astrophysics | Harvard & Smithsonian have identified the clearest case to date of a supermassive black hole in motion. Their results are published today in the Astrophysical Journal... (MORE)
NASA once again needs Russian help to get into space
https://bgr.com/2021/03/11/space-news-nasa-roscosmos/
INTRO: NASA’s Commercial Crew Program didn’t work out exactly as the space agency had planned, but it has produced at least one suitable spacecraft for taking astronauts to and from the International Space Station. NASA has already flown missions to the ISS using SpaceX’s Crew Dragon, and another mission is already on the schedule, but if you thought that Crew Dragon’s success meant NASA wouldn’t have to secure seats aboard Russian spacecraft to get to the ISS, you were mistaken.
As NASA reveals in a news release, it will lean on Russian space agency Roscosmos for the privilege of using a seat on its Soyuz spacecraft to get an American astronaut into space. The Soyuz MS-18 mission will now include NASA’s Mark Vande Hei thanks to an agreement between NASA and Axiom Space, which secured the seat on the Soyuz vehicle for NASA.
NASA was really, really hoping that it would no longer need to use seats from Russia by this point in the Commercial Crew Program. By now, both the SpaceX Crew Dragon and Boeing’s Starliner should be taking NASA crews (and others) to and from the ISS whenever needed, but Boeing’s utter failure to get the Starliner project to the finish line and NASA’s desire to ensure a constant presence aboard the ISS means that NASA once again needs to use a seat on Russia’s rocket... (MORE)
How the habitability of exoplanets is influenced by their rocks
http://astrobiology.com/2021/03/how-the-habitability-of-exoplanets-is-influenced-by-their-rocks.html
EXCERPT: Sometimes, that atmosphere is primitive and largely consists of the gases that were around when the planet formed - as is the case for Jupiter and Saturn. On terrestrial planets like Mars, Venus or Earth, however, such primitive atmospheres are lost. Instead, their remaining atmospheres are strongly influenced by surface geochemistry. Processes like the weathering of rocks alter the composition the atmosphere and thereby influence the habitability of the planet.
How exactly this works, especially under conditions very different from those on Earth, is what a team of scientists, led by Kaustubh Hakim of the Centre for Space and Habitability (CSH) at the University of Bern and the NCCR PlanetS, investigated. Their results were published today in The Planetary Science Journal.
"We want to understand how the chemical reactions between the atmosphere and the surface of planets change the composition of the atmosphere. On Earth, this process - the weathering of silicate rocks assisted by water - helps to maintain a temperate climate over long periods of time", Hakim explains. "When the concentration of CO2 increases, temperatures also rise because of its greenhouse effect. Higher temperatures lead to more intense rainfall. Silicate weathering rates increase, which in turn reduce the CO2 concentration and subsequently lower the temperature", says the researcher.
However, it need not necessarily work the same way on other planets. Using computer simulations, the team tested how different conditions affect the weathering process. For example, they found that even in very arid climates, weathering can be more intense than on Earth if the chemical reactions occur sufficiently quickly. Rock types, too, influence the process and can lead to very different weathering rates according to Hakim. The team also found that at temperatures of around 70°C, contrary to popular theory, silicate weathering rates can decrease with rising temperatures. "This shows that for planets with very different conditions than on Earth, weathering could play very different roles", Hakim says... (MORE - details)