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discover the new sugar shock the baffling rise in childhood diabetes science technology and the future moon surprise it s wet weird and oddly inviting anti-aging drugs birth of the galaxies robot revolution inside an android lab our mechanical destiny warfare on autopilot the power of dust haiti s first responders what slowed global warming may 2010 $5.99 u.s plus your appendix explained diamond prospecting in the ozarks discovermagazine.com

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contents may 2010 robotics the new two decades ago the internet began to make itself felt in our lives subtly at first then with increasing insistence until it became hard to recall how we lived without it two decades from now will we look back on this as the time when robotics made the same leap discover investigates machine dreams 30 an android portrait under construction at hanson robotics from disaster sites to the classroom robots are reaching ever deeper into our lives four robotics experts weigh in on the science and the social implications the terminators 36 in iraq and afghanistan military machines have proved their value at gathering intelligence and disarming bombs now the hard question should robots also be allowed to kill by mark anderson the body shop 42 hanson robotics is creating androids that look and act uncannily like us the way we respond to these creations says as much about who we are as about what the new machines can do by bruno maddox child s plague 50 in the past few years type 1 diabetes rates have soared alarmingly nobody knows why but one man has an idea by dan hurley mail 4 contributors 5 editor s note 6 hot science 20 new books and tv future food art that blurs the line between life and death destination science 22 caves hot springs and diamond fields arkansas is full of surprises vital signs 26 after the haiti earthquake volunteer doctors struggle with a puzzling potentially fatal injury by h lee kagan the brain 28 an olfactory yardstick measures our sense of smell by carl zimmer 20 things you didn t know about water 80 by rebecca coffey new moon 58 the moon is suddenly hot again scientists see a world of mystery adventurers see a place to live and entrepreneurs see a way to get rich data 8 making sense of the earliest galaxies eternal youth probing the appendix better body scans genomes by numbers how water slowed global warming the multitasking tongue and more five questions for babak tafreshi 18 the founder of the world at night photo project explains how the nighttime sky unites us all by andrew grant turning to dust 66 dry weather overgrazing and population growth are transforming grassland into desert around the globe but some smarter planning and a little chicken wire might reverse the tide by michael tennesen discover on the web videos breaking news and more the latest is online at discovermagazine.com ali jarekji/reuters inset timothy archibald cover t a rector i p dell antonio/noao/aura/nsf

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on the cover the moon seen in a color-enhanced composite photograph above a bee collects pollen from a flower in amman jordan.

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m a y 2 0 1 0 corey s powell editor in chief patrice g adcroft editor at large michael f di ioia creative director ed itorial robert keating deputy editor tina wooden managing editor fred guterl pamela weintraub senior editors jennifer barone news editor elise j marton copy chief chris orlow production director reporter/researchers amy barth andrew grant andrew moseman interns seth newman laurie rich nick zautra bo zhang contributing editors jane bosveld sean carroll jared diamond tom dworetzky tim folger susan kruglinski bruno maddox kathleen mcauliffe kathleen mcgowan philip plait karen wright carl zimmer a rt erik b spooner art director rebecca horne photo director randi slatken photo researcher caroline a madigan intern discov er m a ga zi n e .c om amos zeeberg web editor gemma shusterman web producer eliza strickland online news editor smriti rao intern henry donahue ceo publisher a d v ert isingsal es of fices new york suzanne puchalsky advertising director 212 624 4816 detroit lisa budnick account manager 313 640 5638 chicago keith bainbridge account manager 312 236 4900 x1106 los angeles shannon mcandrews account manager 213 624 0900 x1338 direct response amanda young east coast 212 624 4811 joe wholley midwest 312 236 4900 x1102 kim mcgraw west coast 213 596 7215 tricia g mackey marketing director jim capeleris controller leslie guarnieri circulation director t j montilli newsstand consultant debi allen executive assistant aaron payne intern subscrib er inqui ri e s 800 829 9132 dcrcustserv@cdsfulfillment.com ed itorialinqui ri e s editorial@discovermagazine.com w h at isthis hints 1 its tannin content can poison horses 2 the flowerlike features are actually hairy appendages 3 it sure makes a great bookcase for the answer see the june issue or visit discovermagazine com/web/whatisthis last month s answer page 76 reprints e-prints and related items contact pars international phone 212-221-9595 fax 212-221-9195 e-mail discoverreprints@parsintl.com web www.magreprints.com/quickquote.asp submissions we do not accept and cannot be held responsible for unsolicited manuscripts or materials of any kind inter net discover web site www.discovermagazine.com note to subscribers from time to time we provide our subscriber mailing lists to selected companies for their promotional use if you prefer that we not provide your information to these companies please call 800-829-9132 and have your mailing label available dr uma ganesan/olympus bioscapes digital imaging competition

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now in one easy-to swallow pill 24 scientific studies fre sh ipp e ing antioxidants 101 emerging science suggests th hat antioxidants are critically importan to nt maintaining good health because t they protect you from free radicals wh hich can damage your body taking one e p mx pill a day will help protect you from free radicals it s just that simple complicated studies simplified our pmx pills are made from the same pomegranates we use to make omegranates our pm wonderful 100 pomegranate juice on which each of the following medical studies was conducted an initial ucla study on our juice the antioxidant power of our 8oz juice the antioxidant superpill.tm $32 million in medical research illi $32 million n medi l medical science not fiction p mx is made from the only pomegranates backed by $32 million in medical research at the world s leading universities not only has this research documented the unique and superior antioxidant power of pomegranates it has revealed promising results for prostate and cardiovascular health found hopeful results for prostate health reporting statistically significant prolongation of psa doubling times according to dr allen j pantuck in clinical cancer research 2006.1,2,3 additional preliminary study on our juice showed promising results for heart health stress-induced ischemia restricted blood flow to the heart decreased in the pomegranate group dr dean ornish reported in the american journal of cardiology 2005.1,2,4 p mx is powerful naturally pmx is an all-natural ultrapotent antioxidant extract containing a full spectrum of pomegranate polyphenols pmx is so concentrated that a single capsule has the antioxidant power of a full glass of pm wonderful® 100 pomegranate juice try pmx pills for one month when you sign up for pmx monthly delivery free or pompills.com/dvr use discount code dvr30 offer expires 7/30/10 and applies only to the purchase price for the first bottle of pmx monthly following months will be $29.95 per bottle one discount per customer cannot be combined with other offers no substitutions transfer rights or cash equivalents we reserve the right to modify or discontinue this promotion change the product price or change the shipping charge at any time valid only at pompills.com or 1-888-766-7455 not valid on pmx trial or other pm products credit or debit card required order now 888-766-7455 sign up for p mx monthly and we ll send your first bottle free after that you ll continue to receive monthly shipments for $29.95 with complimentary shipping 1pompills.com/research 2these statements have not been evaluated by the food and drug administration this product is not intended to diagnose treat cure or prevent any disease 346 men with rising psa after surgery or radiotherapy drank 8oz 100 pomegranate juice daily for two years 445 patients with coronary heart disease and myocardial ischemia drank 8oz 100 pomegranate juice daily for three months ©2010 pomwonderful llc all rights reserved pm wonderful pmx and antioxidant superpill are trademarks of pomwonderful llc pp3441

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mail time travel conundrums sean carroll envisions a loopy time traveler how to travel through time march page 40 who emerges from a gate one day and disappears into it the next this can hardly be considered time travel at all to say that the time traveler experiences the same thing over and over again with no new memories along the way raises the question in whose frame of reference carroll is implicitly invoking an outside observer who can see the loop neither i as gatekeeper nor the traveler can see it so to us there is no time travel mark a durham spartanburg sc the time traveler who travels one day into the past does not reset to his earlier version each time he travels in carroll s loop he ages a day consider bill murray s character in groundhog day each morning phil connors wakes to nd himself starting the same day he completed the night before the other characters reset to the same point in their lives each morning but connors himself is changed as he is accumulating memories and aging one day so too is carroll s traveler aging a day on each trip through the gate and unless a couple liters of water some sandwiches and a bathroom get added to the scenario the traveler will achieve the ultimate state of entropy when he drops dead within a week michael pavlides crown point in author and caltech theoretical physicist sean carroll replies this isn t the scenario described in the article the traveler on the loop has a life span of only 24 hours and he does not accumulate memories to make the journey logically consistent his internal state including his collection of memories has to be the same at one moment as it is 24 hours later you may think this is very unlikely in which case i can only say exactly most people discussing time travel forget one thing space-time is a four-dimensional phenomenon using psychological and brain imaging techniques like those with which we explored the case of mx such research may help explain both the basis of imagery production in the brain and how if at all imagery is useful to us i enjoyed reading about mx and his mind s-eye blindness were mx s dream experiences also affected by this af iction arlene barker homer city pa zeman and della sala reply for about a year after the loss of his mind s eye mx reported that he dreamed without visual imagery but then his visual dreaming recovered at night even though his mind s eye remained blank by day this suggests that the brain mechanisms involved in dreaming can be teased apart from those involved in deliberate imagery formation appreciation for the guinea pig doctor i am so grateful for the work of barry marshall [discover interview march page 66 his discovery that ulcers are not caused by stress but by the h pylori bacterium saved my life i had suffered from recurring ulcer attacks for 35 years then one day in 1983 my husband brought home an article about ulcers and h pylori i took it to my gastroenterologist and demanded a test which came back positive after years of paying $75 per prescription for tagamet i was completely cured for about $20 thanks to marshall i can now glory in ve delightful grandchildren barbara pellegrini hagar township mi send e-mail to editorial@discovermagazine.com address letters to discover 90 fifth avenue new york ny 10011 include your full name address and daytime phone number fabric assuming that i could strap on a time machine in my living room and try to go back to exactly 24 hours earlier i wouldn t reappear in my living room as i had hoped in 24 hours the earth sun and galaxy would have all moved to collectively put me millions of miles from where i was when i left i would last all of ve seconds oating in space before realizing what a fool i was to not take the space part of space-time into account peter vohsemer cambridge ontario carroll replies that is all correct the best we can do is imagine something like a wormhole that takes a traveler from one event in spacetime to another there does not need to be any relationship between the spatial locations of the two events mind s eyeless in march s the brain [page 28 carl zimmer assumes that having a mind s eye is a normal function of the human senses yet i have never had a mind s eye and when i bring this up in conversation others often voice the same complaint how common is this marshall krause san geronimo ca neuroscientists adam zeman and sergio della sala reply we have encountered people who report that they have never experienced imagery they seem little if at all disabled by their deficiency we hope to study this neglected e r r at u m on page 11 of the april issue battle of the lizard kings paleontologist sterling nesbitt of the university of texas at austin was misidentified as steve nesbitt we regret the error 4 discovermagazine.com

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contributors dan hurley a medical journalist who has had type 1 diabetes for more than 30 years was frustrated by the multitude of inspirational diabetes books out there self-help books can be useful but there s a time to step back and say `maybe we shouldn t be feeling good about a pandemic what s wrong with this picture he says while researching his book diabetes rising which formed the basis for child s plague page 50 hurley says he spoke with hundreds of people and read more than a thousand studies to analyze why the number of people with type 1 or juvenile diabetes is rapidly increasing i had no idea until i got into it that type 1 is rising the number of cases of type 2 is increasing incredibly quickly as well and now more and more kids are getting it he says it was really challenging when i started asking why this was happening i felt like a detective hurley has also written for the new york times psychology today and neurology today he lives in new jersey with his wife and daughter and a dog named sugar interviewed military experts scientists and philosophers for his feature on the mechanization of warfare the terminators page 36 the biggest decision a military robot can make is whether or not to shoot someone he says some researchers say we should never never let that happen others say it s going to happen and we need to introduce these machines to some rudimentary ethics anderson who has studied astrophysics and worked as a programmer/analyst at the supercomputer company cray research remains wary of giving robots autonomy arguing that even the smartest fastest computer in the world is still a box that does only what you tell it to do he was impressed however by the involvement of philosophers in this research some of whom even wrote reports for the u.s navy about autonomous robots they weren t just standing on a hill stroking their chins they were actively engaged examining some nittygritty questions of design and risk he says fundamentally this is about ethics what s right and wrong for a robot to do when it wields a weapon anderson a freelance writer based in massachusetts also writes for ieee spectrum and wired he is currently working on a book about 18th-century astronomy mark anderson grew up fishing in california s owens valley at the base of the sierra nevada an area prone to thick dust storms which is how he became intrigued by the idea that windblown dust can change landscapes and have a tremendous environmental impact for turning to dust page 66 he traveled in the 105-degree heat of las cruces new mexico with geology professor and dust expert greg okin scientists at las cruces set up a wind tunnel and a bunch of instruments on a at area tennesen says the wind started blowing and i had my contacts in but no sunglasses i was instantly blinded and bumping into things in the course of his research for this article tennesen learned that dust can affect everything from the cattle business to the dispersion of nutrients in the environment the bottom line he says is that dust is a lot more complicated than it sounds when he is not chasing a story tennesen loves running over mountain trails and along the paci c ocean near his home outside los angeles his work also appears in scientific american smithsonian and science michael tennesen having math problems we can help subjects basic math 7 hours $26.99 8 hours $26.99 award winning math physics tutorial dvds basic math word problems pre-algebra/algebra 1 10 hours $26.99 algebra 2 6 hours $26.99 algebra word problems 6 hours $26.99 geometry 9 hours $26.99 advanced algebra 7 hours $31.99 7 hours $31.99 5 hours $31.99 matrix algebra trig/precalculus calculus 1&2 8 hours $36.99 visit our website to view sample video clips of every course ventured into a chaotic garage lab at pittsburgh s carnegie mellon university to photograph discover s robotics panelists who share their thoughts in machine dreams page 30 the giant room was a robot tinkerer s dream jampacked with robots carbon fiber motor parts wires and a modi ed hummer suv to avoid the cluttered jumble though truglia decided to move inside the newly constructed robotics laboratory across the way shooting from the ground oor up toward an elevated conference room with large glass windows where the scientists could look down on the work area i couldn t communicate with them easily because of the thick plate of glass between us says truglia who eventually secured two radios leaving one in the room with his subjects while he broadcast directions from below this vantage point looks momentous he remembers thinking kind of retro-nasa based in chicago truglia is a freelance photographer who enjoys road cycling and home improvement projects his images have been published in time and rolling stone much more of his work can be seen on his web site www.saveriotruglia.com saverio truglia amy barth advanced calculus 2 14 hours $49.99 10 hours $44.99 11 hours $49.99 calculus 3 vol 1 calculus 3 vol 2 physics 11 hours $39.99 probability statistics 10 hours $39.99 4 hours $21.99 unit conversions all topics taught entirely through worked example problems raise grades or your money back order by phone 877-math-dvd order online www.mathtutordvd.com

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editor s note prediction is very difficult especially about the future again in popular culture the image of robot technology is still pretty much what it was half a century ago an attempt at making convincing human doppelgängers and not much else look at some of the smartest of today s science ction and then look for the robots in the new star trek movie nada in avatar amazing biological devices but in robotics nothing more than mechanical ghting suits iron man more ghting suits even in battlestar galactica a series about robots the machines are just human analogues and honestly who needs a complicated arti cial version of an ordinary person even if it doesn t go off on a homicidal spree the bots at cmu on the other hand don t look human at all howie choset has two machines that look like snakes the big one is designed to slither into a disaster zone after an earthquake say to locate and make contact with survivors the small one may one day wriggle around inside a patient s body to operate on the heart eliminating the need to cut open the chest seth goldstein s robots look like little ecks of metal he is trying to shrink them down to the size of a grain of sand so that huge numbers of them could link together into what he calls claytronics an intelligent material that can be programmed to take on any desired shape or color red whittaker director of cmu s field robotics center has a whole hangar of robots that mostly look like dune buggies and suvs but each has its own clever function one can map mines one can harvest grain one is designed to land on the moon and beam back reports and tweets about what is going on there and all of this is just one small selection of the research going on at just one university the total taxonomy of robots is huge and bewildering the variety of forms re ects some basic truths about evolution that apply to technology as much as they do to biology one is that form follows function faces and limbs are great for robots designed to interact with people like the ones from hanson robotics see page 42 but they do you no favors when you are trying to navigate constricted spaces there is a reason that a snake looks like a snake indeed choset says that he taught his zoologist colleagues new things about snake locomotion while learning to program his robot wheels on the other hand are great for covering long distances if there were any obvious way to grow a biological wheel you can bet that some creature would have evolved it which leads to a second truth new forms always make use of what came before evolution is incremental since the present always builds on the past modern humans take a lot of their design from homo erectus it should come as no surprise that many of the current mobile robots similarly take much of their mechanical inspiration from bulldozers hummers or ultralight planes then again i try not to take these lessons too seriously for fear of failing to heed that opening quote the collective imagination of humanity like the collective imagination of nature is too much for any one person to presume to understand much less to project forward and for that i am eternally thankful corey s powell his quote strikes down so many forms of hubris that it has been attributed to everyone from niels bohr to yogi berra it is often invoked these days to mock the vision-impaired visionaries who failed to foresee the rise of the personal computer the internet and our whole information-linked society the quiet implication is that this time surely we are smarter and more self-aware better able to see the limitations of our imaginations and more important better able to make clear-eyed forecasts after spending a day touring the various robotics labs at carnegie mellon university in advance of our robotics roundtable see page 30 i was dumbfounded by our failure of imagination all over t 6 discovermagazine.com saverio truglia

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i m sorry i waited so long w ha twehear is bose® acoustic wave® music system ii our best-performing all-in-one music system we hear a lot of enthusiastic comments from our customers about the acoustic wave® music system particularly how they wish they had not waited so long to order they tell us how natural and lifelike the sound is and how it completely changed the way they listen to music their only regret is that they didn t try it sooner when we introduced the original acoustic wave® music system sound vision said it delivered possibly the best-reproduced sound many people have ever heard and our latest system is even better if you care about music why not take advantage of our risk-free trial right now and ask us to ship one of these award-winning systems to you we ll give you 30 days to try it wherever you want better sound inside and outside use it to enjoy your music with the built-in cd player and fm/am tuner or connect your mp3 player you ll be able to start listening in minutes because this system is so easy to use when you call please ask about making 12 easy payments with no interest charges from bose also ask about adding the optional 5-cd changer for hours of uninterrupted music at home or take the system with you using the free travel case and power pack ­ a $299 value the power pack includes a rechargeable battery and charger that fits easily into the travel case creating a portable self-powered system for hours of music use our 30-day risk-free trial to discover what you have to say about the acoustic wave® music system ­ our best-performing all-in-one music system and why so many other people say they wish they d acted a lot sooner free travel case and power pack when you order by may 31 2010 to order or learn more 1-800-314-3416 ext g8726 www.bose.com/awms2 bose payment plan available on orders of $299 1500 paid by major credit card separate financing offers may be available for select products see website for details down payment is 1/12 the product price plus applicable tax and shipping charges charged when your order is shipped then your credit card will be billed for 11 equal monthly installments beginning approximately one month from the date your order is shipped with 0 apr and no interest charges from bose credit card rules and interest may apply u.s residents only limit one active financing program per customer ©2010 bose corporation patent rights issued and/or pending the acoustic wave® music system ii design is a registered trademark of bose corporation financing and free travel case and power pack offers not to be combined with other offers or applied to previous purchases and subject to change without notice if the acoustic wave® music system ii is returned the travel case and power pack must be returned for a full refund offers are limited to purchases made from bose and participating authorized dealers offer valid 4/1/10-5/31/10 risk free refers to 30-day trial only and does not include return shipping delivery is subject to product availability quotes reprinted with permission sound vision 3/85.

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riverdance the moment asian carp leap from the waters of the illinois river near the town of havana as researchers with the illinois natural history survey use electroshock equipment to stun the fish so that they can be captured and counted the carp often jump when startled zapping the water seems to intensify the reaction asian carp were imported in the 1970s to remove pond algae from catfish farms and quickly spread north along the mississippi ohio and illinois rivers over the past decade electric barriers have been installed to keep the hungry giants which can grow to 100 pounds from invading the great lakes the shot photograph by jason lindsey using a nikon d2x camera and nikon 17-35mm lens f/8.0 iso 250 1/250 sec may 2010 9

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data red rover the moment flight technician the shot photograph by spencer lowell using a canon eos-1ds mark iii with an ef16-35mm lens f/5.0 iso 1600 1/80 sec spencer lowell previous pages jason lindsey errin dalshaug adjusts a model of the robotic arm for the next mars rover curiosity in preparation for testing at nasa s jet propulsion laboratory the rover is slated to launch in late 2011 and will reach the red planet the following year its arm will bear a magnifying camera a sample scoop a spectrometer to identify chemical composition and a drill to bore into rocks the testing shown here carried out last october evaluated vibrations caused by running the drill.

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data big picture building the galaxies a detailed account of the 13.7-billion-year history of the cosmos is finally within reach in the beginning there was light the hot reball of the big bang but the story of the universe really begins more properly with dark the rst structures to emerge from that early conflagration were enormous strands of dark matter a material unaffected by the radiation still ricocheting around the early universe over millions of years the gravitational pull of these strands attracted normal matter which gradually collapsed into stars and galaxies smaller galaxies merged to form larger ones giving rise to massive elliptical blobs and to shining pinwheels like our milky way or so the current view holds astronomers have created a detailed theory of how the universe evolved from its ery origins to the galactic zoo we see today this picture of cosmic evolution known as the cold dark matter cdm model fits remarkably well with most observations until recently though a few stark problems stood out some galaxies have shapes that look nothing like astronomers predictions while other galaxies nasa esa j english u manitoba and the hubble heritage team stsci/aura national science foundation that they expected to see never showed up supercomputer simulations and new images from the world s great observatories are nally lling in the gaps as a result scientists can for the rst time ever provide a detailed life history of the cosmos one of the most vexing mysteries has concerned the shape of dwarf galaxies the cdm model predicts that they should accumulate bulges of stars at their centers surrounded by halos of dark matter held in place by gravity in reality observations showed that most dwarfs lacked this structure a recent study may explain why the key ingredient is violent stellar explosions or supernovas inside the developing galaxies because visible matter including stars is thought to make up just one-seventh of all the matter in the universe many simulations left it off the table but supernovas can blow material out of the dwarf galaxies inner regions so fabio governato an astronomer at the university of washington and his colleagues simulated dwarf galaxy formation on super adventure with purpose planning a summer getaway consider all that the trip has to o er whether you are hiking or biking hunting dinosaurs or on an underwater adventure think about all that we know about the places you visit and all the discoveries we have yet to make parks museums and universities across the country o er a multitude of activities and adventures that can add unique purpose to the place you visit nsf sponsors outreach and education programs that can give you a new perspective on the environment around you and the science behind what you might nd there for more fun science explore www.nsf.gov nsf ­ where discoveries begin dwarf galaxies like the ones in hickson compact group 31 small blobs at right have presented a big challenge to cosmology adventurers learn about snowy river in fort stanton cave new mexico photo lisa van pay nsf

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data big picture billion numbers by jeremy jacquot genomics computers this time with supernova explosions in the mix they found that their virtual dwarf galaxies mimicked the genuine article lacking both a central bulge and a darkmatter halo this is a simple mechanism that we know exists and it explains two long-standing puzzles in dwarf galaxy formation governato says understanding the origin of small galaxies turns out to be important for understanding how all galaxies form dwarf galaxies are the building blocks for galaxies like the milky way governato notes getting the bricks right is important the notion that large galaxies were built up from smaller pieces is called hierarchical formation in the cdm model this theory predicts that galaxies in the early universe should have been much smaller than modern ones as researchers harvest light from the far reaches of space in effect looking back billions of years through time they are nding evidence con rming their expectation this past january a new hubble space telescope image revealed the deepest view of the universe yet it shows galaxies dating to just 700 million years post­big bang ivo labbé a hubble fellow at the carnegie observatories examined the color and brightness of the edgling galaxies to estimate their masses and ages the galactic infants appear to have just 1 percent of the mass of our milky way matching astronomers predictions these little galaxies are just what cold dark matter predicted says joel primack a physicist at the university of california at santa cruz and one of the model s architects but along with the con rma 3 approximate length of the human genome in base pairs letters of the dna sequence the human genome project launched in 1990 produced the first complete map of our dna covering 99 percent of the genome at its completion in 2003 the project cost about $2.7 billion in 1991 dollars roughly $1 per base pair $48,000 price to have your entire genome sequenced today by the san diegobased company illumina in january it announced a new system that will be able to sequence two full human genomes for $10,000 each and do the job in about a week a $10 million archon x prize awaits the first group that can sequence 100 human genomes in 10 days for less than $10,000 each tion came a new surprise it appeared that these cosmic building blocks had already been forming stars for a few hundred million years meaning we are not yet reaching the zero hour of galaxy formation labbé says but we ve just about exhausted what we can do with current telescopes to understand the birth of the earliest galaxies astronomers eagerly await the next generation of instruments the james webb space telescope is slated for launch in 2014 its 21-foot mirror will gather nearly seven times as much light as hubble and its detectors will be optimized to pick up infrared rays from very distant galaxies whose buzzwords dark matter invisible material thought to make up the majority of the mass of the universe astronomers infer its existence from its gravitational effects on normal matter cold dark matter model a leading model of the universe s evolution since the big bang in which slow-moving dark-matter particles clumped together seeding the formation of galaxies and galactic clusters hierarchical formation creation of large structures from many smaller ones a likely mechanism for forming big galaxies warm dark matter model an alternative to cdm with faster-moving particles it resolves a major problem in cdm but does not describe existing galaxies as accurately 12 discovermagazine.com nasa esa and the hubble heritage team stsci/aura 2

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423 number of genes in the human genome that have been implicated in cancer according to the sanger institute s cancer gene census the world health organization estimates that more than 10,000 human diseases result from changes to a single gene the number of base pairs that differ from one person to another according to the human genome project all individual human variation amounts to just onetenth of 1 percent of the entire genome the fbi maintains a database of more than 7.8 million individual dna profiles 5,831 160,000 number of genome sequencing projects registered with the genomes online database as of late 2009 4,172 are devoted to bacteria 443 to fungi 233 to plants 37 to primates 84 to other mammals 41 to fish and 8 to birds number of base pairs in the smallest known cellular genome belonging to the bacterium carsonella ruddii which lives symbiotically inside insects called psyllids it does not have the genes required to survive on its own the largest known genome at 133 billion base pairs belongs to the marbled lungfish above sagittarius dwarf irregular galaxy left the whirlpool spiral galaxy merges with its companion ngc 5195 light has been stretched and reddened by the expansion of the universe webb may be able to spot protogalaxies as they were just 250 million years after the big bang supersize ground telescopes such as the thirty meter telescope planned for mauna kea hawaii and the european extremely large telescope spanning 42 meters 140 feet will help astronomers probe the properties of the rst galaxies starting around 2018 the new tools could help resolve another long-standing mystery known as the missing satellite problem cdm predicts that galaxies like the milky way should be orbited by tens of thousands of clumps of dark matter says beth willman an astronomer at haverford college yet the latest studies which push current telescopes to the edge of their limits have turned up only two dozen of these faint satellites so where is the other 99.9 percent alternative warm dark matter models of cosmic structure in which galaxy formation was seeded by lighter faster-moving particles that would not have clumped together as readily as cold dark matter could eliminate the need for the missing galaxies unfortunately warm dark matter models fail to reproduce the galaxies we see today governato says willman thinks that the swarm of dark galaxies is out there waiting to be uncovered by sensitive sky surveys the nearly invisible satellites may be among the best places to nail down the identity of the enigmatic dark-matter particles thought to drive galactic evolution high-energy gamma rays perhaps a product of collisions between dark-matter particles may stream from these wraithlike satellites the fermi gamma-ray space telescope launched two years ago is on the hunt for such signals if successful it could give physicists insights into the properties of dark matter and help nail down the identity of the mysterious unseen stuff that has so dominated the development of our universe adam hadhazy may 2010 13

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