#planet science

[just-some-troglodyte]

Science side of tumblr, how hospitable would a planet exactly like Earth 121 years ago, except the entire day/night cycle lasts roughly 2 hours? would the planet begin to stretch like taffy?

[quasifractalatomicgeometry]

Massive crater under Greenland’s ice points to climate-altering impact in the time of humans

The 31-kilometer-wide Hiawatha crater may have formed as recently as 12,800 years ago when a 1.5-kilometer asteroid struck Earth

This is a great write-up of the discovery of the 19-mile wide impact crater in Greenland! The object that struck would've been roughly a mile wide (in other words, fucking devastatingly huge).

For comparison, The Tunguska air blast in remote Siberia (the biggest we know of in modern history until now) that caused a 5.0ish magnitude Earthquake and flattened forests over a massive area is estimated to be just 100metres wide.

All I can say is all current evidence points to this impact as a very potential trigger for the Younger Dryas period (a time when the Earth's climate inexplicably plunged backwards into an Ice Age for about 1200years). The evidence of this impact has been spotted in geological and scientific studies all over the Younger Dryas boundary, but until now, a major impact site was unobserved. If the suspected time of this impact is correct, then we have to rewrite history and take all the geological data we see in areas such as the Scablands (one of many large flood markers) and study these sites further for what they are, the result of almost unimaginably large floods from mass Glacier/Ice Sheet Meltwater and debris (largely accepted for the Scablands, but rejected at other sites with the same Geological features).

Can't wait until more data comes in on this, it will change not just geological/Earth's history but the history of us as humans ourselves and all the symbology used in ancient texts/drawings/carvings. Our ancestors were likely documenters of events, just like we are.

[brandochunderdarkseas]

God, what the hell with this fucking military convoy on the interstate system (I-80)

Amelie, just now, laughing about Dwight

[ulaulaman]

Planetary standard model And the future? ...

[geopolicraticus]

Chaotic formation of galaxies

On my other blog I've just written a piece on planetary science -- The Transplanetary Perspective -- suggesting that it might become possible to extrapolate the formation of stars and galaxies backward in time, perhaps eventually tracing individual stars back to the particular stellar nurseries in which they were born. If we could do this, we could determine which stars (and associated solar systems) ultimately derive from the same clouds of gas and dust, and may therefore share certain chemical properties, and therefore share certain mineral resources in their planetary systems. As I said in the above-captioned post, planetary sciences so understood will enable us to find the resources crucial to the development of a future interplanetary or interstellar civilization: this is the petroleum geology of the future.

While this would be admittedly very difficult -- i.e., recovering earlier states of the galaxy, and determining the origins of particular stars -- it is not at all impossible, and after writing The Transplanetary Perspective I recalled an experiment in chaos theory that is particularly relevant in this connection. There was a now-classic episode of the PBS series NOVA from 1989, The Strange New Science of Chaos, loosely based on the now-classic book by James Gleick, Chaos: Making a New Science. The NOVA documentary features the work of Jerry Gollub and Harry Swinney on fluids in turbulent motion (i.e., nonlinear dynamics). There is a sense in which galaxies can be considered a fluid in turbulent motion. Indeed, a galaxy presents a paradigm case of nonlinear dynamics.

Carl Sagan, in Episode 10 of Cosmos, The Edge of Forever, said that, "A galaxy is a fluid of billions suns all bound together by gravity." In the NOVA episode cited above, Jerry Gollub is quoted as saying, "The entire universe is filled with fluids in turbulent motion." We could extend this observation, in the spirit of Sagan's metaphor about galaxies being fluids, and say that the universe itself is a fluid in turbulent motion. Moreover, fluids in turbulent motion not only converge on a strange attractor, that describes the boundaries of the chaotic movement (so that it is not entirely chaotic, or totally random), but also exhibit conservation and restoration behaviors. For example, under controlled laboratory conditions, a fluid in turbulent motion can be reversed and largely (although not perfectly) restored to its original state, prior to being subject to turbulent mixing.

I think that it would be possible, with a sufficiently powerful supercomputer, and a sufficiently exhaustive map (and history) of the stars of the Milky Way (or some other galaxy), to run the nonlinear dynamics of the Milky Way backward and to recover the origins of our own sun and solar system, and to determine its source and what other stars came from the same stellar nursery. This would tell us what kind of stellar nursery produces stars and solar systems that can produce life and civilization. Of course, as noted above, this would not be simple. We would have to account for the gravitational interaction of the Milky Way with other galaxies in its local group, and for the early natural history of the Milky Way, its particular pattern of population I, II, and III stars, the patterns of nucleosynthesis and the dispersal of heavier elements through supernovae, the patterns of supernovae, what kind of supernovae they were (type Ia, Ib, Ic, II-P, II-L, IIn, IIb), and so forth. All of this would be difficult, and would involve a lot of approximation and estimates, but I do not think it is beyond our present capacity to obtain a reasonable approximation of the evolution of the Milky Way.