by Paul Gilster | Mar 17, 2007 | Autonomy and Robotics |
Lee Gutkind takes a look at the Robotics Institute at Carnegie Mellon in Almost Human: Making Robots Think (W.W. Norton, 2007), a book entertainingly reviewed in this weekend’s Los Angeles Times. Out of which this wonderful clip from reviewer M.G. Lord:
I wish Gutkind had spent more time on an area that I find fascinating: the anthropomorphizing and gendering of robots, which science-fiction author Robert A. Heinlein famously explored in his novel The Moon Is a Harsh Mistress. What Heinlein created was a computer that, depending on circumstances, could switch between masculine and feminine identities. Robots are heaps of hardware, not biological entities, yet humans apparently feel more comfortable if they assign them a gender, regardless of the crudeness of the gender stereotype. The institute, for example, has robot receptionists with gendered personalities: Valerie, a “female” who complains about her dates with vacuum cleaners and cars, and Tank, a “male,” who has blundered so often that he has been placed “where he can do no harm,” — in other words, in a job traditionally for women.
Tank, however, gave me the first real evidence that computers might eventually think for themselves. The robot appears contemptuous of the antediluvian gender roles that engineers (and Gutkind) project upon them. “I saw a very pretty blonde student type Tank an intimate message: ‘I love you,'” Gutkind writes, “to which Tank replied, ‘You don’t even know me.'”
I could never get through The Moon Is a Harsh Mistress. In fact, I had trouble with all the late Heinlein, pretty much everything after Stranger in a Strange Land. But the question about biological vs. machine identity is indeed fascinating, and it’s also instructive to learn that it crops up even with today’s limited robots. The little round vacuum cleaner robot called the Roomba from iRobot inspires owners to assign gender and names to their machines, a phenomenon the company acknowledges. As robots get smarter, we may find them less alien and more ‘human’ than we thought, if only because we can’t resist making them so.
by Paul Gilster | Mar 16, 2007 | Culture and Society |
When you think about it, so much of science involves putting our instruments into the right place at the right time. The transit of Venus across the Sun in 1769 was an opportunity to use triangulation from opposite sides of the Earth to calculate the distance to the Sun more accurately. That effort took James Cook to Tahiti, and though the experiment failed, it remains an inspiring example of the human intellect trying to solve questions by exploration, determination and hard work.
We saw yesterday that if we put instruments into much further places, we may be able to identify oceanic worlds and perhaps map their continents. Peter McCullough (Space Telescope Science Institute) wrote the most recent paper on this concept and presented it at a conference on missions that could be enabled by a return to the Moon. But the Moon itself may not be the best venue for the instruments in question, as McCullough noted in an e-mail after reading yesterday’s entry:
“I might comment (in anticipation of your coverage of the speculative digressions in that same paper) that the polarization-measuring telescope probably would be best as a free-flyer (e.g. at L2 like JWST) instead of on the lunar surface, although the infrastructure to get payloads to the moon will be very helpful for getting large telescopes to L2, which I think was a common theme of the conference held here at STScI…”
So we’re looking at a mission that is enabled by the infrastructure that will boost large payloads to the Moon and other destinations, but which will itself be best placed in a ‘halo’ orbit around the L2 Lagrange point, approximately 1.5 million kilometers from Earth. That’s outside the Moon’s orbit, but it’s clear that tuning up the technologies for lunar missions will make operating at L2 that much easier. The James Webb Space Telescope, as McCullough notes, is already slated for L2.
But even a project as ambitious as tracing the outline of continents on distant exoplanets pales in comparison to the deeper motivations for building up our space infrastructure. Can a lunar base help solve some of Earth’s deepest problems? One possibility is that it could lead by example. A sustainable presence on another world won’t power itself with fossil fuels. It will rely on nuclear and solar power and doubtless develop countless new insights into conservation. All of this returns to Earth in the form of practical technology to preserve our ecosystem.
A lunar colony offers all the benefits of learning to live off the land. The harsh environment forces the issue in ways that can pay off for the home planet. Let me quote McCullough again on this point because I think he has it exactly right:
…solar power is readily and abundantly available on the lunar surface, and a large, slow ?ywheel utilizing compacted regolith for mass could provide for the variable power demands of human habitation and/or store power through the lunar night away from the poles. An alternative approach would be to bring from Earth a high-speed, precision ?ywheel of relatively small mass or a chemical battery, but those are antithetical to the strategic bene?t of utilizing lunar resources. From the opposite perspective, utilizing any water ice mined from lunar craters, for human consumption and/or rocket fuel, could be myopic exploitation and destruction of an important scienti?c resource.
Those of us who find ourselves in front of audiences trying to justify space exploration would do well to review McCullough’s arguments with care. Here’s another, which speaks to the objection that the money we spend on space could better be applied to solving problems here on Earth. Weigh NASA and its expenses against what goes on on Wall Street. The pharmaceutical company Pfizer had a 2005 annual revenue of $51 billion, spending some $7 billion on research and development.
By contrast, NASA’s 2005 budget as allocated by Congress was $16 billion. In other words, the NASA budget that year was less than one-third the annual revenue of a single company of the thirty that make up the Dow Jones Industrial Average. Nobody is saying that Pfizer isn’t huge, or that $16 billion is a small amount of money. But the idea that diverting NASA’s budget will solve global warming or shelter the world’s homeless is a fantasy. Whereas exploration properly conducted may provide benefits far outreaching what might be accomplished by keeping those dollars here on Earth.
McCullough quotes Freeman Dyson on the nature of exploration, a passage he draws from George Dyson’s wonderful Project Orion: The True Story of the Atomic Spaceship:
We shall know what we go to Mars for, only after we get there…. You might as well ask Columbus why he wasted his time discovering America when he could have been improving the methods of Spanish sheep-farming. It is lucky that the U.S. Government like Queen Isabella is willing to pay for the ships.
Of course, paying for the ships is always problematic, and remains so today given the eternally fluctuating budgetary situation. It may be that getting us back to the Moon and continuing our work on a space-based infrastructure will take prompting from China’s determination to do the same — competition is always a sure driver, as it was during the Apollo days. Whatever the trigger, though, the benefits of space exploration are tangible if all too rarely part of current discourse. Consider McCullough’s paper a short primer marshaling many of the needed arguments.
by Paul Gilster | Mar 15, 2007 | Exoplanetary Science |
If you want to put the hunt for planets around other stars in perspective, consider this. For almost all of our species’ time on this planet, we have looked at the planets in our own Solar System as unresolved points of light that seemed to move upon a celestial sphere. The brief time that we have been able to see more is measured since the invention of the telescope, a tiny window compared to the millennia that went before.
We are now working hard to see extrasolar planets as unresolved, moving points of light. In doing so, we’re looking at ways to image these planets that would yield the greatest scientific return. Recall former NASA administrator Dan Goldin’s wish to actually see the surfaces of distant exoplanets — he talked to putting such images on the walls of our schools. One day, starshade technologies coupled with space-borne telescopes may make that possible. For now, though, there is the real potential of something closer: identifying exoplanets with oceans.
The beauty of such an identification, writes Peter McCullough (Space Telescope Science Institute) is that we don’t actually need to resolve the planet to find out whether it has an atmosphere and an ocean. Here the scientist writes about what we can do with near-term technologies:
…we propose to exploit the linear polarization generated by Rayleigh scattering in the planet’s atmosphere and specular re?ection (glint) from its ocean to study Earth-like extrasolar planets. In principle we can map the extrasolar planet’s continental boundaries by observing the glint from its oceans periodically varying as the rotation of the planet alternately places continents or water at the location on the sphere at which light from the star can be re?ected specularly to Earth.
Got that? We’re talking about mapping continents on planets around other stars, using equipment that could be within our capabilities soon. The ‘Rayleigh scattering’ McCullough talks about is what happens when light is scattered off molecules in the air. It’s more effective at short wavelengths and is in fact responsible for the blue color of the sky. A surprising amount of work has gone into the study of Rayleigh scattering and specular reflection — glint — on extrasolar planets already.
Both oceans and atmospheres polarize reflected light. The important point here is that Rayleigh scattering and glint off an ocean can be differentiated, allowing us to mine data from their interplay. Mccullough uses a parallel with lighting techniques in our own oceans. A laser can be used to light up the sea floor, with ocean water scattering the light to create a haze visible to a camera. The laser light that does hit the sea floor creates a well-defined spot as well. Let me quote McCullough again:
By scanning the laser across the sea ?oor and simultaneously recording the location and brightness of the peak of the image, the light scattered by the turbid water is suppressed and detection of objects on the sea ?oor is enhanced. In the proposed technique for imaging extrasolar planets, the glint acts like the localized spot of the laser beam, and the rotation of the planet under the glint serves much the same purpose as the scanning of the laser beam.
If the method works, we should be able to tell the difference between terrestrial-size planets and terrestrial worlds with oceans. That’s a big step forward for exoplanet studies and it’s one available in the near-term. And if we can extend that model to learning about the shapes of continents on such worlds, we’ve moved a bit closer to making Goldin’s vision a reality. Space telescopes or the Moon itself could provide an ideal base for pursuing such studies, and tomorrow I want to turn to McCullough’s ideas on lunar exploration and its implications for this work.
The paper is McCullough, “Observations of Extrasolar Planets Enabled by a Return to the Moon,” to be published in Astrophysics Enabled by the Return to the Moon, Ed. M. Livio (Cambridge: Cambridge University Press), 2007 (abstract here). For greater detail, see the same author’s “Models of Polarized Light from Oceans and Atmospheres of Earth-like Extrasolar Planets,” submitted to The Astrophysical Journal and available here.
by Paul Gilster | Mar 14, 2007 | Outer Solar System |
I remember talking to the exuberant astrophysics professor Sheridan Simon about a football-shaped planet he had created one Super Bowl eve. This was at a science fiction convention and it must have been fifteen years ago. Simon frequented such venues because he had built a cottage industry around creating planets for various science fictional settings. As a lark, he had run the numbers on what would happen to the atmosphere of a world shaped like a pigskin and wound up announcing the result: “It’s plaid! That’s what you would see. A plaid football!”
I think he was pulling my leg, and that wouldn’t have been out of character either for this generous, gregarious man who died all too young. But Mike Brown’s new paper in Nature brought back memories of that conversation with Sheridan Simon in spades. Brown (California Institute of Technology), who specializes in the exotica at the fringes of our Solar System, has been examining an object his team originally found. 2003 EL61 is also shaped like a football, though having no atmosphere, it doesn’t offer as many opportunities for fun as Simon’s planet did.
Brown now believes this Kuiper Belt object was the result of a catastrophic collision sometime around the time Earth was born. The original KBO was doubtless spherical and of roughly Pluto size until it was rammed by a body not much smaller than itself. The rapdily spinning (every four hours) football shape we see today is the result, along with two moons and many other fragments that have long since dispersed.
2003 EL61 plays interestingly into our understanding of how the Solar System evolved. For the area of space we’re talking about isn’t very stable. Here’s Brown on the matter:
“In most places, things go around the sun minding their own business for 4.5 billion years and nothing happens. But in a few places, though, orbits go crazy and change and eventually objects can find themselves on a trajectory into the inner solar system, where they would be what we would then call comets.”
So many of the shattered pieces of 2003 EL61 doubtless made their way in close to the Sun, and Brown believes some have probably hit the Earth at one time or another. And 2003 EL61 itself may become what Brown calls ‘…the largest comet in eons,’ although this won’t happen for a billion years. How big? Brown figures the incoming football will shine about 6000 times brighter than the Hale-Bopp comet did just a few years ago. If Sheridan Simon were still around, he could have some fun with that.
The paper is Brown et al., “A collisional family of icy objects in the Kuiper belt,” Nature 446 (15 March 2007), 294-296. Abstract here.
by Paul Gilster | Mar 13, 2007 | Outer Solar System |
If the dark features Cassini has found near Titan’s north pole really are filled with liquid, they’re seas more than lakes, one of them larger than any of the Great Lakes in North America. The image below says it all, comparing the largest of these features with Lake Superior. This work is being done through radar imaging, detecting dark radar surfaces that imply smoothness. Cassini’s visual and infrared mapping spectrometer is also at work as the liquid hypothesis at Titan’s surface is explored.
Image: This feature on Titan is at least 100,000 square kilometers (39,000 square miles), which is greater in extent than Lake Superior (82,000 square kilometers or 32,000 square miles), which is one of Earth’s largest lakes. The feature covers a greater fraction of Titan than the largest terrestrial inland sea, the Black Sea. The Black Sea covers 0.085 percent of the surface of the Earth; this newly observed body on Titan covers at least 0.12 percent of the surface of Titan. Because of its size, scientists are calling it a sea. Credit: NASA/JPL/GSFC.
Assuming these are bodies of liquid, they’re most likely filled with liquid methane and ethane. That jibes with current thinking that methane is continuing to move between the surface and the atmosphere, a cycle that will be further explored in Cassini’s May flyby, when we’ll get a more targeted pass over these dark areas. See JPL’s mission news for more.
