(Roughly) Daily

Posts Tagged ‘Milky Way

“I’m sure the universe is full of intelligent life. It’s just been too intelligent to come here.”*…

Email migration should now be complete; email subscribers should now be getting (Roughly) Daily via Mailchimp, and should not be getting a duplicate from Feedburner. If you are getting a dupe, please let me know (roughlydaily@gmail.com). Note that this new service may be landing in your Gmail “Promotions” folder; you can move it to your main folder. With apologies for the turbulence over the last few days, and thanks for your continued reading, on to today’s post…

A new computer simulation shows that a technologically advanced civilization, even when using slow ships, can still colonize an entire galaxy in a modest amount of time. The finding presents a possible model for interstellar migration and a sharpened sense of where we might find alien intelligence.

Space, we are told time and time again, is huge, and that’s why we have yet to see signs of extraterrestrial intelligence. For sure, the distances between stars are vast, but it’s important to remember that the universe is also very, very old. In fact, I’d go so far as to say that, in terms of extremes, the Milky Way galaxy is more ancient than it is huge, if that makes sense. It’s for this reason that I tend to dismiss distances as a significant variable when discussing the Fermi Paradox—the observation that we have yet to see any evidence for the existence of alien intelligence, even though we probably should have.

New research published in The American Astronomical Society is bolstering my conviction. The new paper, co-authored by Jason Wright, an astronomer and astrophysicist at Penn State, and Caleb Scharf, an astrobiologist at Columbia University, shows that even the most conservative estimates of civilizational expansion can still result in a galactic empire.

A simulation produced by the team shows the process at work, as a lone technological civilization, living in a hypothetical Milky Way-like galaxy, begins the process of galactic expansion… Things start off slow in the simulation, but the civilization’s rate of spread really picks up once the power of exponential growth kicks in. But that’s only part of the story; the expansion rate is heavily influenced by the increased density of stars near the galactic center and a patient policy, in which the settlers wait for the stars to come to them, a result of the galaxy spinning on its axis.

The whole process, in which the entire inner galaxy is settled, takes one billion years. That sounds like a long time, but it’s only somewhere between 7% and 9% the total age of the Milky Way galaxy.

As noted, the new model is constrained by some very conservative rules. Migration ships are launched once every 10,000 years, and no civilization can last longer than 100 million years. Ships can travel no farther than 10 light-years and at speeds no faster than 6.2 miles per second (10 kilometers per second), which is comparable to human probes like the Voyager and New Horizons spacecraft. 

“This means we’re not talking about a rapidly or aggressively expanding species, and there’s no warp drive or anything,” said Wright. “There’s just ships that do things we could actually manage to do with something like technology we can design today… Even under these conditions, the entire inner part of the simulated galaxy became settled in a billion years. But as Wright reminded me, our “galaxy is over 10 billion years old, so it could have happened many times over, even with those parameters.”…

A new simulation published by the American Astronomical Society suggests that aliens wouldn’t need warp drives to take over an entire galaxy in (relatively) short order, as George Dvorsky (@dvorsky) explains.

[Image above: Andromeda Galaxy, source]

* Arthur C. Clarke

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As we spread out, we might spare a thought for Jacobus Cornelius Kapteyn; he died on this date in 1922. An astronomer, he used photography and statistical methods to determine the motions and spatial distribution of stars (especially with the Milky Way), the first major step after the works of William and John Herschel. He introduced absolute magnitude and color indexing as standard concepts in cataloguing stars.

Kapteyn was also among the first to suggest the existence of dark matter (which he deduced from examining stellar velocities).

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Period, Full Start…

Computersherpa at DeviantART has taken the collected wisdom at TV Tropes and that site’s “Story Idea Generator” and organized them into an amazing Periodic Table of Storytelling

click here (and again) for a larger image

[TotH to Brainpickings]

Along these same lines, readers might also be interested in the “Perpetual Notion Machine” (which includes, as a bonus, the story of Dmitri Mendeleev and the “real” Periodic Table…)  See also the Periodic Table of Typefaces (“‘There are now about as many different varieties of letters as there are different kinds of fools…’“) and the Periodic Table of Visualization Methods (“Now See Here…“).

As we constructively stack our writers’ blocks, we might wish a thoughtful Happy Birthday to Immanuel Kant; he was born on this date in 1724 in Königsberg, Prussia (which is now Kaliningrad, Russia).  Kant is of course celebrated as a philosopher, the author of Critique of Pure Reason (1781), Critique of Practical Reason (1788), and Critique of Judgment (1790), and father of German Idealism (et al.).

But less well remembered are the contributions he made to science, perhaps especially to astronomy, before turning fully to philosophy.  For example, his General History of Nature and Theory of the Heavens (1755) contained three anticipations important to the field: 1) Kant made the nebula hypothesis ahead of Laplace. 2) He described the Milky Way as a lens-shaped collection of stars that represented only one of many “island universes,” later shown by Herschel. 3) He suggested that friction from tides slowed the rotation of the earth, which was confirmed a century later.  Similarly, Kant’s writings on mathematics were cited as an important influence by Einstein.

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Stepping on the scale(s)…

In their introduction to the book version of Charles and Ray Eames’ Powers of Ten, Philip and Phyllis Morrison wrote elegantly of the importance of the evolution of the tools of science to scientific progress.  It’s the continuous improvement in these “instruments of vision” that pushes back the frontiers of knowledge, and allow us to know, and ultimately to understand, more and more of the universe around us.

The frontiers of this vision are at the extremes of scale– the very small and the very large.  Readers have recently visited the territory of the tiny, where the Large Hadron Collider is at work finding the smallest (at least for now) of the small.  Today we turn to the very large– and the very distant…

The Sloan Digital Sky Survey (SDSS) was the most ambitious astronomical survey ever undertaken.  Over an eight-year period, an array of the world’s most sophisticated astronomical resources have been devoted to mapping and imaging the cosmos.  In the first five years, Phase One,

SDSS-I imaged more than 8,000 square degrees of the sky in five bandpasses, detecting nearly 200 million celestial objects, and it measured spectra of more than 675,000 galaxies, 90,000 quasars, and 185,000 stars. These data have supported studies ranging from asteroids and nearby stars to the large scale structure of the Universe.

Phase Two is addressing “fundamental questions about the nature of the Universe, the origin of galaxies and quasars, and the formation and evolution of our own Galaxy, the Milky Way.”

While we wait for those answers (peer-reviewed journals take their time :-), we can share the wonder…  an extraordinary gallery– SkyServer— is available online.  Our SDSS hosts:  “We would like to show you the beauty of the universe, and share with you our excitement as we build the largest map in the history of the world. ”

See them all (or as many as time allows… it is, after all, the biggest map in history) here.  And check out the Hubble Space Telescope’s peeks into deepest space here.

As we crane our necks, we might wish a stylish birthday to Edith Head, Hollywood wardrobe mistress and costume designer extraordinaire; she was born (Edith Claire Posener) on this date in 1897, in Searchlight, Nevada.  Ms. Head, who was nominated for the Oscar 35 times, and won eight (more than any other woman), had this sensible advice: “Your dresses should be tight enough to show you’re a woman and loose enough to show you’re a lady.”

 

Edith Head and Pixar’s homage: Edna Mode in The Incredibles (source)

Written by (Roughly) Daily

October 28, 2008 at 1:01 am

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