Nisi cognitio finitas, infinitum sit necesse est ignoratio
For his gigadollar earning movie “Avatar” James Cameron wanted as plausible a design as possible for the interstellar vehicle featured, the ISV “Venture Star”. Advised by his good friend Charles Pellegrino, Cameron has given us, in film, a starship design that could really work – or close to. Check-out Winchell Chung’s detailed description and discussion at his “Project Rho: Atomic Rockets” site…
ISV Venture Star at “Atomic Rockets”
The 100-year leap – O’Reilly Radar.
Very interesting discussion of construction of a working version of Charles Babbage’s Analytical Engine, the general purpose computer design that extended his work on the Difference Engine (an automatic calculator that instantiated difference computation), a working version of the latter was finally constructed according to Victorian Era engineering and tolerances in 1991.
An Analytical Engine would have been the ultimate Steam Punk machine, a general purpose computer built from 19th Century materials and powered by steam. It was also the first example of a general purpose computer planned over 100 years before it finally became realised in c.1950.
The take-away lesson of the article is that blue-sky thinking has real value, even if it isn’t realised for another 100 years…
from here. Courtesy of Invader Xan.
The Solar System centered on Gliese 581 (Zarmina’s Sun) is very compact. All the currently known planets almost fit inside the orbit of our Venus and four are closer together than Mercury is to the Sun. Of course Gliese 581 is much dimmer than our Sun, so even though Zarmina orbits a mere 0.146 AU from its Sun the climate is reasonably clement. So all those planets crowded together must make for a very interesting view in the sky. The inner three worlds would look roughly as large as our Moon does from each other’s location, while from there even Zarmina would show a disk. From Zarmina the inner 3 planets are all bigger than the planet Venus appears in our sky, but smaller than our Moon. All should appear as disks or crescents during their whole orbits around Gliese 581 and because Zarmina is exterior to them, they would all cluster around the Sun in the Zarminan sky.
The next planet out, dubbed the unpoetic Gl 581 d, is on a quite elliptical orbit (e=0.38) just 0.22 AU out from the Sun. Zarmina and Gl 581 d could come very close together, just 0.00961 AU, though whether they get so close at present is unknown. If they do, then Gl 581 d would appear in Zarmina’s sky more than twice the size of our Moon. Gl 581 d is bigger than Earth and potentially very bright from clouds or oceans. If it’s a true water planet, or mini-Neptune, then it will be a rather impressive sight in Zarmina’s sky, especially from the Night Side. From that vantage it would be the brightest source of light and likely to dominate the view, as the inner planets would never be visible, and the outer is barely a disk. Imagine that blue-white giant lighting up an otherwise star-light icy wasteland…
(ok so a bit of artistic license. That’s a Bonestell Classic from Fabio Femino’s online gallery)
It’s all over the news! Earth-like Planet Found (for real)!
Of course we don’t know much about Zarmina (Gliese 581 g) other than some very bare basics, but her discoverer, Steve Vogt, has expressed his near 100% certainty there’ll be Life on Zarmina of some kind. While I agree with his sentiment I think we should stay skeptical of all claims of inhabitants on that distant world. But that hasn’t stopped some from going further. For example, this “Daily Mail” piece…
Does ET live on Goldilocks planet? How scientists spotted ‘mysterious pulse of light’ from direction of newly-discovered ‘2nd Earth’ two years ago
…covering the 2008 claim of signal detection by Dr Ragbir Bhathal (University of Western Sydney) who is an active member of SETI, particularly OSETI – the Optical Search for Extra-Terrestrial Life. At the time he didn’t let out a lot of information, but now it seems his positive signal came from Gliese 581, the star, or close to it. Or did it? I’m not entirely impressed by the article because it’s both vague and inaccurate. At the time of Dr. Bhathal’s initial claim the constellation of Tucanae was quoted as the region in question. Now the story has changed. Until Dr. Bhathal releases more information or someone else makes another positive detection the claim can only be “under investigation”.
Yet what if it was true? Zarmina is being called a “ribbon world” – a planet tidally locked to face its star forever with the same face, thus endless day on one side and endless night on the other. The ribbon refers to the border between night and day, the Terminator, which is in a state of never-ending twilight. Duncan Lunan’s discussion of the Green Children of Wolfpit, who were mentioned by Francis Bacon [erratum: Robert Burton, in his “Anatomy of Melancholy” (1651)] as possible extraterrestrials, suggests such a world. Their story comes from the 12th Century and Lunan did a write-up for “Analog” some years ago. The children were found disoriented and speaking a foreign language in the town of Wolfpitt/Wolpitt. The strangest thing about them, aside from their curious story, was their bright green skin, which eventually returned to normal. They claimed to have come from “St Martin’s Land”, but gave a description of their homeland as always being in twilight. This fits the concept of a ribbon world, but their undeniable humanity caused Lunan to make the SF leap that they were from a human colony on a ribbon world accidentally time-space transported to Medieval Earth. Of course there’s an alternative mundane explanation, but their twilit homeland is terribly evocative and hard to explain as an earthly locale.
We’ll only ever know the truth if we go looking for it… Part II.
For those who don’t know, SKYLON is a fully reusable spaceplane with Ramjets for speeds up to Mach 6. The current version is a bit beefier than the original design, now promising about 16 tons of payload delivered to LEO from a suitably low inclination launch site. Further north or south, or tilted to the equator, and the payload is less.
SKYLON User’s Manual
A notable feature is the suborbital delivery mode promises 30 tons at SKYLON’s release of the payload. To then circularize the orbit we can use the figures for the SKYLON Upper Stage (SUS) to get an estimate of payload that can be orbited. The SUS masses 0.95 tonnes empty and can carry 7 tonnes of propellant (LH2/LOX) with an Isp of 4562 N.s/kg – to circularize the payload in LEO needs another 900 m/s delta-vee, thus meaning a mass-ratio of 1.21 and after we subtract the SUS that leaves 23.7 tonnes of payload. Expanded slightly that would mean an SUS based space-tug with ~23 tons of propellant and about 1.5 tonnes dry mass. Reaction Engines Ltd is designing just such a space tug it dubs Fluyt.
Fluyt has a larger propellant load (~47 tons) and higher payload, but a simpler interim space-tug might prove useful even before an orbit tanker facility is available to support larger FLuyt operations. Back in the early 1970s the European Launcher Development Organization (ELDO) designed an even smaller space-tug system massing just 12.5 tons fully tanked, which in a tandem configuration could deliver 7 tons to Lunar Orbit. Thus a “small” SKYLON tug system could deliver ~12 tons to Lunar Orbit, potentially enough to provide support for a Lunar base. The ELDO tug is featured on Adrian Mann’s “This is Rocket Science” art gallery …
If Adrian’s work looks very familiar, that’s because he’s the chief graphic visualiser for Reaction Engines Ltd. Bringing SKYLON to virtual life is something we can thank him for!
What’s eating the stars out of our galaxy’s heart? – 15 September 2010 – New Scientist.
The Galactic Centre is home to a massive black-hole, estimated at ~4 million solar masses, meaning it’s event horizon is 12 million kilometres in radius. Not the biggest – there are multi-billion solar mass black-holes in the cores of other Galaxies – but big enough. And now there’s this mystery of the Missing Stars. The astrophysicists are modelling natural explanations, as that’s a reasonable assumption, but I’m with Greg Benford – the Core is full of mass and energy. If advanced civilizations are astroengineering on a large-scale, then the Core is where it’s at.
One possibility is that the black-hole is surrounded by collapsed remnants of stars, like stellar black-holes and neutron stars. In my mind if there’s any chance a natural black-hole can be made into a wormhole, then that’d be the place to do it. That ETIs might be shepherding the stars in that region, could also explain the odd lack of visible stars near the Core. Carl Sagan’s old image (in the 1985 “Contact” novel, not the 1997 movie) of a Galactic Grand Central Station for wormholes might actually be true!
xkcd: Exoplanets
Just how many exoplanets are now known? Oodles. Topping 500 this week with 400 more odd promised over the next year from “Kepler” and who knows how many being watched prior to the discoverers going public…
Exoplanet Encyclopedia
SpaceX has outlined its concepts for the next generation of Heavy-Lift Launch Vehicles, the Falcon X and Falcon XX…
…notice the jumps in capability by replacing the bank of 9 Merlin 1 engines by a single Merlin 2. That’s going to be a HUGE engine, akin to the Saturn V I-C stage’s main engines. The single-engine concept is a step-down in reliability because an engine-out is fatal, but with the right engineering that might be a manageable risk.
The human brain as a linearly scaled-up primate brain.
There are truisms in brain-science which hide more than they reveal. For example, the old line that there’s 100 billion neurones in the brain and ten times as many non-neurones as neurones. It’s true, and not true, but the details are complicated. From the diagrammed average brain we have the following breakdown…
Whole Brain:
1500 grams, 170 billion (170 B) cells
86 B neurones
84 B non-neurones
ratio non/neurone: 0.99
Cerebral Cortex: 81.8% mass, 19.0% neurones
1233 grams, 77 B cells
16 B neurones
61 B non-neurones
ratio non/neurone: 3.76
Cerebellum: 10.3% mass, 80.2% neurones
154 grams, 85 B cells
69 B neurones
16 B non-neurones
ratio non/neurone: 0.23
Rest of Brain: 7.8% mass, 0.8% neurones
118 grams, 8.4 B cells
0.7 B neurones
7.7 B non-neurones
ratio non/neurone: 11.35
…which is interesting because the even ratio of neurone to non-neurone (which includes glial cells and blood vessels etc.) is not evenly distributed. Surprisingly the cortex isn’t the main show for neurones – the “Back-up Brain”, the cerebellum, has more. Which makes sense because of its intensive role in fine-motor control and similar real-time computation heavy work. If the cortex is the repository of cognition and memory, with the hippocampus as the “pattern buffer” of memorising processing, then the higher glial component is needed for its support role for the chemical and hormonal changes needed by memory and “higher level” thinking.
The cerebellum is the “robot controller” which has to smooth out the commands from the cortex and monitors them in real time. Thus lots of neuronal circuits working to keep “body programs” running smoothly in dynamic response to external conditions , thus the neurones are all squeezed close together for maximum speed.
More glial are needed in the brain-stem and cortex because they contain more “cabling” – longer neuronal ‘wires’ feed-up from the body, and back to the body, through the brain-stem and fan-out into the different cortical areas, as well as cross-wiring the different cortical areas.
Ok. Enough description. Part 2 will explore some of the implications.