Back to Asgard

 

Credit: pitpony.photography

I blogged about this before (see second link). This seems to be the sequel! So there is a hypothesis that the evolutionary ancestors of the eukaryotes (a vast group of organisms including animals, plants and fungi) were Archaea. Asgard Archaea, more exactly. Or perhaps some unknown microbe living in symbiosis with a bacterium *inside* an Archaeon? The content linked below isn´t entirely clear on this topic, but some kind of hybridization is the bottom line. 

The problem, apparently, is that the bacterium participating in the primordial merger needed oxygen to survive. Asgard Archaea, on the other hand, can´t stand oxygen. However, recent research suggests that some of them actually can do so, making the scenario more plausible. 

Personally, I like the fact that our deep evolutionary ancestors might (at least partially) be tentacled micro-organisms named after the abode of the Norse gods, and that some of them have been found in a remote part of the Atlantic Ocean named after Loki. Life looks like a "trickster", somehow...   

Ancient "Asgard" microbe might have used oxygen

This is us now

This is us now

 

There is something strangely reassuring about our ultimate evolutionary ancestors being "Asgard Archaea" found inside "Loki´s Castle" in the Atlantic Ocean midway between Iceland and Svalbard. 

The hypothesis is that an archaeum captured a bacterium...and this became the first eukaryotic cell. All (?) extant living creatures which aren´t Archaea or Bacteria are Eukaryota, including humans. The idea that our evolutionary ancestor was a hybrid between two different lineages (presumably combining the best traits of both) is obviously also appealing. Are you listening, Lynn Margulis? 

Note also that we are no longer bacteria "cladistically speaking", but rather archaea. Thank you. Always considered archaea to be more cool somehow!

This is us now.  

Potentially alive

 

Staggering. 

Potentially alive 830-million-year-old organisms found trapped in ancient rock

Twin world

 

"Cosmic Front: Saturn´s Moon Titan - Another Earth?" is a 2012 documentary about Titan, Saturn´s largest moon (and the second largest moon in the solar system). Titan turns out to be a highly anomalous planetary satellite. It has a dense atmosphere, and large lakes of liquid methane have been discovered at its icy surface. The moon has seasonal variations in weather patterns, clouds, haze and heavy rains. Volcanoes are believed to spew out a mixture of water and ammonia. Apparently, ammonia-rich water can stay liquid at extremely low temperatures. Scientists theorize that an underground ocean exist below Titan´s ice crust. As far as I understand, Titan is unique among moons in having a "real" atmosphere, and at least in 2012, Titan was the only object in the solar system apart from Earth where liquids had been found. 

Even more sensational, Titan may harbor life. While no evidence for such exists (yet at least), organic compounds of various kinds are constantly being produced in the moon´s upper atmosphere. Scientists believe that the sand on Titan´s surface consist of organic compounds. During experiments made on Earth simulating the conditions at Titan, all four nucleobases needed for DNA were created. The speculation is that organisms resembling archaea (archaebacteria) could live on Titan. An exobiologist interviewed wonder aloud if these could be big and flat, despite being unicellular! But could any living being really survive on Titan?

The documentary makes a little detour through Trinidad (here on Earth), where there is a large natural deposite of asphalt, known as Pitch Lake. About 600 new kinds of archaea have been found in the asphalt, despite the fact that it contains almost no water. The microorganism sustain themselves on methane. And methane is abundant on Titan. However, the docu never explains how these life forms could thrive at Titan´s extremely low temperatures between minus 100 and 180 degrees Celsius. 

Most of our knowledge about Titan is due to the 1997-2004 (unmanned) Cassini-Huygens mission. The probe Huygens (named after the astronomer who discovered Titan back in 1655) penetrated the moon´s dense atmosphere and eventually landed on the surface. It picked up the sound of the wind in Titan´s atmosphere - the first sounds ever recorded from an alien environment. Huygens also took the first and only photo of Titan´s surface, showing it to be a desert-like icy landscape with large chunks of "stone". 

The documentary is somewhat boring at times, and the background music is terrible, but you may nevertheless learn a thing or two if you watch all of it. And if there really is some kind of weird life form on Titan, it is probably safe from our prying eyes, being ensconced in an underground ocean on a moon that takes seven years to reach, and then only with unmanned probes...

We will never know the truth about our twin world.