|
science |
|
|
|
A random collection of scientific articles I found amazing to read—Thane  30 April 2002 Faraway Galaxies Provide a Stunning "Wallpaper" Backdrop for a Runaway Galaxy http://oposite.stsci.edu/pubinfo/pr/2002/11/pr-photos.html 
Click the image for a 2.5 Meg JPG that is not to be missed... This picture of the galaxy UGC 10214 was taken by the Advanced Camera for Surveys (ACS), which was installed aboard NASA's Hubble Space Telescope in March during Servicing Mission 3B. Dubbed the "Tadpole," this spiral galaxy is unlike the textbook images of stately galaxies. Its distorted shape was caused by a small interloper, a very blue, compact galaxy visible in the upper left corner of the more massive Tadpole. The Tadpole resides about 420 million light-years away in the constellation Draco. Seen shining through the Tadpole's disk, the tiny intruder is likely a hit-and-run galaxy that is now leaving the scene of the accident. Strong gravitational forces from the interaction created the long tail of debris, consisting of stars and gas that stretch out more than 280,000 light-years. Numerous young blue stars and star clusters, spawned by the galaxy collision, are seen in the spiral arms, as well as in the long "tidal" tail of stars. Each of these clusters represents the formation of up to about a million stars. Their color is blue because they contain very massive stars, which are 10 times hotter and 1 million times brighter than our Sun. Once formed, the star clusters become redder with age as the most massive and bluest stars exhaust their fuel and burn out. These clusters will eventually become old globular clusters similar to those found in essentially all halos of galaxies, including our own Milky Way. Two prominent clumps of young bright blue stars in the long tail are separated by a "gap"—a section that is fainter than the rest of the tail. These clumps of stars will likely become dwarf galaxies that orbit in the Tadpole's halo. The galactic carnage and torrent of star birth are playing out against a spectacular backdrop: a "wallpaper pattern" of 6,000 galaxies. These galaxies represent twice the number of those discovered in the legendary Hubble Deep Field, the orbiting observatory's "deepest" view of the heavens, taken in 1995 by the Wide Field and Planetary Camera 2. The ACS picture, however, was taken in one-twelfth the time it took to observe the original Hubble Deep Field. In blue light, ACS sees even fainter objects than were seen in the "deep field." The galaxies in the ACS picture, like those in the deep field, stretch back to nearly the beginning of time. They are a myriad of shapes and represent fossil samples of the universe's 13-billion-year evolution. The ACS image is so sharp that astronomers can identify distant colliding galaxies, the "building blocks" of galaxies, an exquisite "Whitman's Sampler" of galaxies, and many extremely faraway galaxies. ACS made this observation on April 1 and 9, 2002. The color image is constructed from three separate images taken in near-infrared, orange, and blue filters. 
2000 Immortality 
Shiro Horiuchi writes in the 15 June 2000 issue of Nature magazine (pg 744): For early humans, the average lifespan was around 20 years, as estimated from skeletal remains. Now, in several industrialized countries, it is about 80 years. Much of this increase has happened in the last 150 years. But it was widely expected that as life expectancy became very high and approached the 'biological limit of human longevity,' the rapid 'mortality decline' would slow down and eventually level off.Thought problem: Given these facts (and the paper), estimate the probability that someone born in the year 2001 will live beyond the year 3000. There's a important difference between immortality (probability of death = 0) and unbounded longevity (probability of life beyond any fixed limit > 0) I suppose. It's probably always going to be possible to kill someone using old-fashioned methods. But it also seems possible that some people, in the not too distant future, are going to be lucky (cursed?) enough to live 500 or even 1,000 years.
1997 Internet Spectators Find A Draw for Kasparov Reprinted from The King's Messenger, courtesy of the Internet Chess Club by Tim McGrew  Sunday, May 4th, well over two thousand people watched online as the human race took a drubbing. The Internet Chess Club put a lot of effort into the coverage of the widely-publicized match between Garry Kasparov and the IBM supercomputer Deep Blue, sending a representative to New York with a laptop and a modem so that chess players from all over the world could watch. They even brought on board a raft of internationally titled players to give live commentary on the games and kept a log of the comments for each game as it unfolded. Though I am not a GM or an IM, I teach chess online and have given some lectures here. As a perk, the ICC gave me a special _Ersatz_ title for the match so that people who wanted to hear "just the titled players" (filtering out the deafening cross-chatter from the assembled fans) would be able to hear my comments as well. Now I almost wished they hadn't. Kasparov, widely acknowledged to be the best chess player in the world, had made some bad decisions early in the second game and was being pushed back across the board as the machine outplayed him in astonishingly "human" fashion, building up positional pressure with iron control. Black's position seemed to grow more desperate with each passing move until finally both the Grandmasters watching and the microcomputers we had online to provide move-by-move analysis indicated that Black was lost. As we contemplated the position after White's 45th move, Matej Guid, the 18 year old Slovenian Junior Champion, suggested that Black should send his Queen deep into White's territory in a desperate bid for a perpetual check -- a maneuver that, if successful, would turn defeat into a draw. An IM commenting on the game immediately dismissed it, and Matej gave up the idea. But it seemed to me that the concept had value, so I followed up on it and questioned the IM's off-the-cuff dismissal: after Black's Queen penetrates and White snaps off an undefended Bishop, Black should, paradoxically, play another quiet move. (See the analysis below). Kasparov 
Deep Blue Here are the highlights of the analysis generated by the discussion on the ICC. After 45...Qe3: a) 46 Qxd6 Re8 47 Bf3 loses the Bf3 to stop the perpetual, and then after Black takes the Bf3 he still threatens a perpetual. b) 46 Qxd6 Re8 47 Qc5 keeps the game alive, but 47... Qxe4 48 d6 Qb1+ looks tenable for black. c) 46 Qd7+ Kg8 (46...Be7 47 Qe6+ eventually wins for White) 47 Qxd6 Rf8 is similar to 46 Qxd6 Re8. [Editor's note: To see the entire game do "examine Deep-Blue 2" on ICC.] The central idea is not the sort of thing that a chess computer, even one that can evaluate 200 million positions per second, will come up with. It runs something like this: Given the pawn structure, the board is essentially divided into two independent parts. In one of those parts White is trying to checkmate Black, but at the price of cutting off his pieces from defense of his own King; in the other, Black is trying to snag a perpetual check. White has more force on hand but he can't put a Rook on a7 -- the ideal square from which to try to force checkmate --because Black's Queen looks back down the diagonal at that square. After 46...Re8, any series of moves by White that ends without a threat of immediate mate will give Black a free hand to go after White for a perpetual. In effect, this sorts out the horrendous multiplicity of variations into a set of equivalence classes. One doesn't have to worry exactly how one gets to a quiescent position; one merely needs to get to one or another of them. Then it will be Black's move, and he can pursue his perpetual essentially unhindered. The real situation is slightly more complicated since White has a few ways to avoid the complete bifurcation of the position (Qc5, or Ra1), but that was the essential insight that struck me as Garry was thinking over his 45th move. It is the sort of thing that one would have expected Garry himself to come up with -- he is, after all, vastly superior to the rest of us as a chess player and is well known for his incredible resourcefulness in tough positions. It is also a "human" approach to the position; rather than sorting through countless variations, most of which is utter rubbish; a human master tries to find ideas that lead through the labyrinth to the desired outcome. Instead of giving the Queen move a shot, Garry resigned. I was baffled and frustrated, and I vented these feelings on the ICC with a string of question marks and comments to the effect that I didn't see a win. At first, most of the strong players online were dismissive: one very strong Grandmaster went so far as to say that the whole draw idea was "nonsense." But I persisted in my heresy and managed to pique the interest of a few other players. Within half a minute of Kasparov's resignation we had begun an impromptu online analysis session on the idea. Sometime early in this process John Hartmann, a foresighted ICC member, realized that we were serious and began to log the analysis as it unfolded. Ironically, the first people to give the idea a fair hearing were for the most part not the famous Grandmasters but rather people who know something about the strengths and weaknesses of chess computers. Bruce Moreland, the programmer of Ferret (the world microcomputer chess champion), brought his machine to bear on the analysis of my idea. Though Ferret was initially giving evaluations favorable to White, Bruce knew enough to find this unconvincing. "I've seen too many positions," he said, "where the computer initially thought it was up by two pawns but on closer examination it turned out that the other side could give a perpetual." Bruce waded into the analysis session and soon, instead of two-pawn advantages for Deep Blue, Ferret was finding perpetual check buried deep in line after line. Grandmaster Jonathan Tisdall may have been the first GM to be won over to the idea; he stuck with the analysis session for hours as other strong players came, scoffed, tried to find a win, and were unable to do so. I couldn't stay long: I had already spent too much time online and was late for dinner. But when I returned some hours later the analysis was still going strong and the entire mood had changed. Most of the strong players thought that a draw really was there for the taking, and skeptics were the outsiders. The entire session lasted some six hours. When it was over, John Hartmann edited the log he had been making for readability and fired it off to a couple of key people on the net --an analysis package that bounced across the Atlantic and then back to New York where, at about 2 a.m., it landed in the laps of Kasparov's astonished seconds. It is impossible to overestimate the impact of the Internet on chess. Just a few years ago I would have had to wait for the arrival of the New York Times just to get the moves of the game. Like the majority of chess fans, I can't afford a trip to New York City for the privilege of seeing the event live, and apart from the ICC there would be no question of my hearing live Grandmaster commentary. The Internet not only enabled us to have live coverage and instant analysis: it also made possible the transfer of our discovery around the world in just a few hours. But there is another and potentially more significant way in which the Internet affected this event. Most chess clubs are fortunate if they have one or two masters showing up on a good night. A marathon analysis session like ours required a certain critical mass: three or four enthusiastic players would have been unlikely to have the staying power to keep going for six straight hours, verifying line after line until the outcome was beyond dispute. The ICC brought together nine Grandmasters, as many International Masters, some of the world's strongest microcomputer chess programs, and a host of other interested participants all focussed on the same problem, fresh minds taking over when others had to leave, computers working out the details when the position became too obscure for human intuition to be sure of itself. The collaborative potential when that many experts are brought into real-time contact is overwhelming. It may have been the first time in history that a group of armchair quarterbacks in any field outsmarted both the world's greatest living authority and the world's fastest computer -- and received confirmation within 12 hours from the experts themselves. IBM got a tremendous publicity boost out of the match because of its unexpected outcome, and this was not entirely unwarranted. The machine does a remarkable job of playing chess at a level that used to require human understanding. If one accepts the Turing test, then Deep Blue is, at least on the chessboard, intelligent. But should we accept the Turing test? It seems ridiculous to do so when one considers the vastly different ways in which Deep Blue and Garry Kasparov produce chess moves. The speed difference in favor of the computer is enormous: eight orders of magnitude, a difference greater than that between the speed of the most advanced tactical fighter jet and that of an average inchworm. The amazing thing is not that Deep Blue won this match but that the human race has managed to hold it at bay for so long in what is, stripped of its noble associations, an abstract full-information mathematical problem of a sort accessible, in principle, to computational solution. Obviously something is going on in Kasparov's mind that is not only different from Deep Blue's computations but also, for all its human fallibility, inconceivably more efficient. Seen in this light, the Turing test looks like what it is: a quaint leftover of Logical Positivism that leaves all of the really interesting questions untouched. Instead of bemoaning the downfall of the human race or deifying Deep Blue, we should be celebrating this match as the occasion when we first discovered that the Internet enables the real-time coordination of human expertise -- a sort of massive biological parallel processing -- on a level we never dreamed possible. Commercial sponsorship isn't required. Coors is unlikely to take out commercial spots on the ICC. But on the Internet, even a game like chess that has limited popular appeal can flourish thanks to a scattered but enthusiastic group of fans. The possibilities on the horizon for collaboration on problems of greater urgency are simply dazzling. 7 September 2002 NGC 1232 
|