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Notes & Queries 10/6/07

What better way to represent the gorgeous clouds of the Orion Nebula than with hibiscus flowers? Or how about our Sun as a small jewel on the speckled leaf of a gold-dust croton plant? If this sounds surreal, it is, but it’s also a description of part of the Galaxy Garden, a 100-foot in diameter map of the galaxy on the grounds of the Paleaku Peace Gardens Sanctuary on Hawaii’s Big Island. Astronomy artist Jon Lomberg used galactic maps from Leo Blitz (UC Berkeley) to design the project, a leafy, immersive experience accurate enough to satisfy the most demanding. A collaborator of Carl Sagan, illustrator of most of his books and articles, and designer of the cover for the Voyager Interstellar Record, Jon’s accuracy shows through in every botanical detail.

Globular clusters in the galaxy garden

Image: Dracaena trees represent globular star clusters, spherical groups of “only” hundreds of thousands of stars, making them too small to be called galaxies. Most of the clusters have orbits that carry them far above and far below the galactic plane, as represented here in the Galaxy Garden. Credit: Jon Lomberg.


Want to lower the cost of getting into Earth orbit to something not just reasonable but almost trivial? Arthur C. Clarke’s space elevator, popularized first in his 1978 novel The Fountains of Paradise, could be just the ticket, provided we can find the will and money to construct it. IEEE Spectrum recently interviewed Clarke, who had this to say about getting into space the cheap way:

What makes the Space Elevator such an attractive idea is its cost-effectiveness. A ticket to orbit now costs tens of millions of dollars (as the millionaire space tourists have paid). But the actual energy required, if you purchased it from your friendly local utility, would only add about hundred dollars to your electricity bill. And a round-trip would cost only about one tenth of that, as most of the energy could be recovered on the way back!

Once it is built, the Space Elevator could be used to lift payloads, passengers, pre-fabricated components of spacecraft, as well as rocket fuel up to Earth orbit. In this way, more than 90 per cent of the energy needed for the exploration of the Solar System could be provided by Earth-based energy sources. When the Space Elevator becomes a reality in the coming decades, the most expensive components of orbital travel will be in-flight movies and catering.

The world’s most stupendous engineering project awaits, unless we find a cheaper and faster way to leave the gravity well along the way.


AEGIS–the All-wavelength Extended Groth Strip International Survey — comes to Google Sky, the new feature of Google Earth that offers spectacular mapping and imaging of distant celestial phenomena. The region covered by AEGIS has now been surveyed more extensively and with more telescopes than any other region of sky. The release includes color images from multiple satellite telescopes, all of which can be browsed and compared using Google Sky’s rapid browsing capabilities. Sky requires the Google Earth 4.2 release while the AEGIS site provides survey background.

Frank Taylor, that master of all things related to Google Earth, has pointed out to me how we can begin tagging celestial objects discussed in these pages so that Google Sky users can find and investigate for themselves. Lunch with Frank is always fun; he’s constantly pulling up things on his laptop that offer fodder for discussion and thought, and the use of Google’s KML files is something I’ll be glad to take his advice on. More on this as I have time — right now I’m swamped with Tau Zero work and a project for AIAA.


A recent comment by JPL’s Paul Weissman in Scientific American offers answers as to the size of the Oort Cloud, that vast spherical cloud of comets that surrounds our Solar System. Some 1012 comets are thought to be found within, extending halfway to the nearest stars. Are the Centauri stars surrounded by a similar cloud? If so, a region may exist where objects in the two occasionally pass in the night. There’s your cheap ticket to Centauri — one stepping stone to the next, or as my late uncle used to say about TWA, ‘try walking across.’

Comments on this entry are closed.

  • Christopher L. Bennett October 5, 2007, 9:17

    Here’s something I often wonder: if our Oort Cloud and Alpha Centauri’s Oort Cloud are both big enough to overlap at the edge, can we really say they even have edges? That is, how do we know there really is such a thing as a distinct Oort Cloud? Maybe all of interstellar space is pervaded with cometary bodies, a vast Oort field, except for the areas around planetary systems, which have been swept clean.

    Even if the majority of comets do tend to congregate around star systems in Oort Clouds, I’m sure there’s enough diffusion and blending of those clouds at the outer edges that you couldn’t really draw a dividing line between what’s an Oort Cloud and what’s interstellar space with the occasional cometary body. I think they’d all pretty much blur together.

  • Adam October 5, 2007, 9:35

    Hi Chris

    Both Alpha Cen’s and our own Oort have been shaped by the gravitational tides of the Galaxy itself – many comets from both have been shaken loose as they orbit the Milky Way. That shaping process keeps both clouds smaller than the Sun, or Alpha’s, zones of gravitational dominance. And remember neither star system has been alone during their lives – other stars have intruded to within a light-year (or less) over time.

    Sol’s Oort Cloud is thus roughly 44,000 AU in radius – about 2/3 of a light-year. Alpha Cen’s would be similar, though Proxima complicates things. Thus there’s a pretty big cosmic wilderness between them. In 27,000 years the suns of Alpha Centauri will be at just 3.2 light years from Sol, and our comets may have a chance at mingling then. But by then I’d expect someone to be out in both Oort Clouds.

  • djlactin October 5, 2007, 22:39

    I love the CONCEPT of a space elevator, but the technology required….

    Also, the cost per trip is very much underestimated, because you have to include start-up costs. I would expect the start-up costs to be in the billions (trillions?) of (heh) euros; even if each trip up/down only costs a buck, the cost function is €(nx10^9) + trips*1€/trip. Millions of trips would be required before this function starts to be less than the cost of brute-force rocketry.

    Add in maintenance costs…
    Factor in the fact that such a construction would be a prime military/terrorist target….

  • Adam October 6, 2007, 2:53

    Hi djactin

    In neutral territory and civilian use it’s hard to see it as a target, but then that never stops the fanatics. Ring in with laser defenses?

    As for economics the Space Elevator is only worth doing IF you have a lot of payload to deliver to GEO and beyond. The ideal use for an SE, initially, is to hoist Solar Power Satellite components. Currently there’s no call for hoisting 30,000 tons of payload to GEO, but once there is the SE wins hands down.

    Check out Bradley Edwards’s work on all these issues, particularly his NIAC studies and so forth. I currently think only PowerSats justify SEs, but once it’s a proven concept then further economic factors have to be considered.

    For example, currently it’s an absurd proposition to mine the Moon for things like iron and aluminium, even though they’re as common as dirt there. But install a Luna SE and an SE down to Earth for delivery and the energy costs basically go to zero because the descending leg gains so much more energy than the ascending leg. Wouldn’t be economically feasible early in the development of SEs, but down the road it will be a sound business proposition once the demands of SPS make SEs viable.

    Or lunar storage of transuranic waste? Or delivery of platinum group metals to Earth for fuel cells? Or whatever eventually. However there has to be a market for a LOT of stuff.

  • Administrator October 6, 2007, 7:05

    djlactin’s point about a space elevator as a prime terrorist or military target is well taken. You can imagine the value certain groups would place in bringing such a thing down. But I do like many of Bradley Edwards’ ideas; glad you brought him into the discussion, Adam.

  • djlactin October 6, 2007, 9:46

    Well this definitely blows my mind.
    Despite my earlier negativity, I have thought about how a Space elevator might be constructed. I thought (initially) of an enormously long buckytube, perhaps synthesized/extruded en-route by a chemical rocket. But the weight?

    Based on values in wikipedia: double-walled carbon nanotubes range up to 70 nm in diameter and weigh 1.4 – 1.5 g/cm^2 (use max values in both cases). A space elevator must have its ‘head’ above geosynchronous orbit (let’s call it geostationary, because I assume the creature would be deployed at the equator) of 36000 km (call it 40000 for round figures)). A double-walled buckytube of with these (maximum) dimensions weighs… wait for it…

  • djlactin October 6, 2007, 9:56

    grrr… what IS IT with this text entry system?? I did not mean to end when I did!

    but ok: the tube weighs

  • djlactin October 6, 2007, 10:10

    for **** sakes!! I think the problem is the ‘less than’ sign: administrator: please warn contributors not to use it!! (better yet, get the geeks to fix the problem.)

    the tube weighs “less than” 0.25 g!! (i’ve triple-checked.)

    So here’s the plan: “synthesize a 40000 km-long buckytube” (he said, avoiding your querulous gaze [could this be an application of genetic engineering — bacteria that synthesize shiga wire?]). Launch a chemical rocket at exactly the right trajectory to ascend orthogonal to the Earth’s rotation. Release the far end and counterweight it. (Wait for the vibrations to dissipate.) Release an army of nanobots at one (the far?) end that synthesize a layer (cords?) of buckytubes around the seed tube. Adjust counterweight as required. Eventually, the elevator becomes viable.

    (anybody want to collaborate on a sci-fi story?)

  • Administrator October 6, 2007, 10:32

    Unfortunately, the text entry problem is a WordPress ‘feature’ that causes problems. You’re exactly right about using the ‘less than’ sign, which I will not type for obvious reasons — it truncates the text. I hope the latest WordPress version will have a fix for this. As far as the SF story, Stanley Schmidt’s eyebrows are probably dancing at your description — Analog will want to see it.

  • andy October 6, 2007, 11:01

    Testing HTML entities. <

  • andy October 6, 2007, 11:02

    Ok, to insert the less than symbol you have to type &lt;

    (To get the ampersand you type &amp;)

  • ljk January 19, 2008, 18:10

    2008 space elevator goals, 1 kilometer height

    The Spaceward Foundation announces the goals for the 2008 Space Elevator Power Beaming Challenge. Building on the results of the 2007 Challenge, the goals for 2008 have been set at 1 km height, 5 m/s minimum speed, for a prize level of $2M. An intermediate prize level of $900k will be given for a speed of 2 m/s. Additionally, teams that can reach an altitude of 1 km at between 1 and 2 m/s will be awarded a prize of up to $50k. In the last two competitions in 2007 and 2006, teams have come close to winning the robotic climbing prize.

    2008 Space elevator proposed 1 kilometer high test track graphic if over asteroid crater

    The pyramid is as tall as it is wide, and with a 4-Ton lift balloon at its apex can withstand winds above 30 MPH. The cables are 1/2″ diameter Spectra lines, similar in feel to Nylon rope. The central climb tether is between 3/8″ and 1/2″ in diameter, and will be tensioned to approximately 200kg.

    Here is what the pyramid would look like over the 2007 test site (the orange circle).

    The target date for the competition is early September 2008.

    A world leader in disc laser technology, TRUMPF took a natural interest in the power beaming games, and is providing both hardware and expertise to enable the 1-km climb. TRUMPF is contributing a top-of-the-line TruDisk 8002 high power laser for use at the 2008 and 2009 games, as well as on-site operation and engineering support for participating teams.

    Dilas supplied the two Laser Diode power sources in the 2007 games, and is offering this year an integrated light source designed specifically for power beaming application to the 1 km range.

    2007 entrant in the climbing competition


  • ljk February 28, 2008, 12:46

    WorldWide Telescope peers into Big Dipper

    CNET News.Com Feb. 27, 2008


    Microsoft presented its WorldWide
    Telescope (WWT) program today at the
    TED conference. WorldWide Telescope,
    which is similar to the sky feature
    in Google Earth but much more
    expansive, is a virtual map of space
    that features tens of millions of
    digital images from sources like the
    Hubble telescope and the Sloan
    Digital Sky Survey. From the…


  • ljk February 29, 2008, 7:05

    A video of the WWT seak preview. To quote:

    Science educator Roy Gould and Microsoft’s Curtis Wong
    give an astonishing sneak preview of Microsoft’s new
    WorldWide Telescope — a technology that combines feeds
    from satellites and telescopes all over the world and the
    heavens, and weaves them together holistically to build
    a comprehensive view of our universe (Yes, it’s the
    technology that made Robert Scoble cry).

    The video is here:


  • ljk March 13, 2008, 22:58

    Google Earth is no longer required to view Google Sky:


  • ljk June 27, 2008, 10:08

    Space elevator games and Lunar lander contest 2008 preview

    The Space elevator power beaming (climber) competition is on
    Sept 27, 2008

    Vertical Distance: 1 kilometer (ten times the 2007 distance)

    Speed for prizes: 2 m/s for $900,000 and 5 m/s for $2 million

    11 teams have entered the 2008 power beaming / climbing contest.