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[whisperer]

Skulptura “Cannot Let Go” (ne mogu otpustiti), autora Hsieh Tong-Liang.

Zove se nostalgija i podsjeća nas da smo, srećom, i krhki.
Cesare Pavese

[whisperer]

Na današnji dan 2020, u 50 godini, umro je posljednji afrički slon kljovaš - posljednji slon sa mamutskim kljovama koje su nekada krasile sve alfa titane i vođe krda.
Zbog masovnog lova i ubijanja, upravo njih zarad slonovače, izumrli su svi mužjaci koji su nosili ovaj gen.



* prenosim sa FB stranice Niste znali, znaju ponekad biti zamimljive objave

[Tomica]

Pluto's moon Charon* also has a desolate region called Mordor,



..  and Pluto itself has a mysterious dark region called Cthulhu.


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Mordor mystery: scientists solve puzzle of the strange, dark north pole on Pluto's moon Charon

The remarkable moon has a mysterious dark-red stain over its north pole, called “Mordor Macula” by the New Horizons team – where Macula means “dark spot” and Mordor refers to the “black land” in Tolkien’s The Lord of the Rings. While many bodies in the solar system have polar caps or hoods of some sort, these are typically bright, due to reflective ice or frost of some kind, rather than dark. So what’s going on at Charon? A new study, published in Nature, has proposed an answer.

One of Charon’s most interesting features is a vast chasm system, which cuts across the middle of Charon’s Pluto-facing hemisphere and reaches a maximum depth of 7.5km. This speaks of an era of upheaval when slabs of Charon’s icy crust were ruptured, tilted and then partially flooded by a type of lava produced by icy volcanism.

Charon’s surface is mostly dirty, grey water-ice, and the red stain around the north pole looks to be a thin film, coating but not burying the underlying topographic features such as craters.

Mordor Macula resembles the red-stained areas of Pluto. This led to early suggestions that they share a similar origin. However, Pluto’s red stuff is understood to be tarry molecules called tholins, which form in the atmosphere when sunlight strikes molecules and makes them sufficiently reactive to link together. This forms haze particles, which eventually settle to the ground. Unlike Pluto, however, Charon has no trace of an atmosphere, so how can tholins form there?

Molecules of Mordor Macula

The researchers behind the new study think they have the answer. The New Horizons probe detected two sorts of molecules leaking away from Pluto: methane and nitrogen. Although nitrogen is the most abundant gas in Pluto’s atmosphere, methane is lighter and is being lost about 500 times faster. Tholins and their precursors are far too heavy, and cannot escape Pluto in the same way, so Charon’s tholins must be somehow made from methane arriving from Pluto.

Charon orbits very close to Pluto, and quite a lot of Pluto’s escaped methane falls onto its surface. If a methane molecule strikes the night side of Charon it will stick, particularly near the winter pole where the temperature is lowest (less than 30 degrees above absolute zero). This is because at lower temperatures surface molecules vibrate more slowly, and atmospheric molecules travel more slowly, so collisions are gentle. However, if a methane molecule hits a sunlit part of the surface, it will tend to bounce off and fly away into space because of Charon’s weak gravity (which has long since allowed it to lose any atmosphere that it may once have possessed).

(nastavak na linku)

https://www.google.com/amp/s/theconversation.com/amp/mordor-mystery-scientists-solve-puzzle-of-the-strange-dark-north-pole-on-plutos-moon-charon-65194

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