captioning sponsored by newshour productions, llc >> sreenivasan: good evening, i'm hari sreenivasan. gwen ifill and judy woodruff are in milwaukee for tonight's democratic debate. on the newshour tonight, in a pivotal moment, bernie sanders and hilary clinton face off tonight, the first encounter since new hampshire's results. also ahead, in part two of our egypt series, a look at their heavy handed judiciary system. >> they have this crazy idea that you can teach a whole population manners by putting them in jail! >> sreenivasan: plus, einstein was right again. after 50 years of research scientists detect the sound of two black holes colliding, proof gravitational waves do exist. all that and more on tonight's pbs newshour.

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>> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. >> sreenivasan: milwaukee is the center of the democratic political universe tonight. the candidates meet for a pbs newshour presidential debate, and how they perform on stage could influence the next key contests. our political director lisa desjardins is in milwaukee. >> reporter: that's right. newshour staff is finishing up the rehearsals on our debate stage for what is expected to be a powerful and maybe even pivotal debate between bernie sanders and hillary clinton, but the democrats do not have a monopoly on intensity and today republicans were fighting for votes in their next primary state, south korea. >> this is our youngest, dominic. say hello, dominic.

>> hello. >> reporter: all across the palmetto state, the hopefuls are making tracks, and taking their best shots. former florida governor jeb bush marked his 63rd birthday by stumping with south carolina senator lindsay graham and going after frontrunner donald trump. >> do you want an entertainer- in-chief? someone who will say whatever he wants to make it all about him? insult people, divide people, basically just talk trash on his way to the republican nomination? or do you want someone who hs been tested? because if you do, i'm your man. >> reporter: bush's fellow floridian, senator marco rubio, took a different line of attack today, near hilton head. >> donald trump has zero foreign policy experience. negotiating a hotel deal in another country is not foreign policy experience. jeb bush has no foreign experience. period. >> reporter: rubio said he's ready for a long slog to the party's nomination and even a brokered republican convention this summer. likewise, ohio governor john

kasich, who placed second in new hampshire. he told c.n.n. last night he does not expect to win in south carolina. but he said today, he means to keep campaigning. >> we are going to do our best here. i'm a scrappy guy. we are going to go all over the country. >> reporter: meanwhile, trump talked of sweeping away his opponents at a campaign stop in clemson last night. >> we win here, we're going to run the table. if we win here after winning so big in new hampshire, all of these characters are going to give it up. >> reporter: on the democratic side, bernie sanders sized up the state of the race on cbs' "late show with stephen colbert" last night. >> well i think a lot of donald trump supporters are angry. people have the right to be angry. but what we need to be is rational in figuring out how we address the problems and not just simply scapegoating on minorities. >> reporter: rival hillary clinton hopes to draw on her strength with minorities, and she picked up a key endorsement

today from the congressional black caucus pac. >> our brains and our intelligence tells us what our conscience confirms that the best person to be the best president of the united states is hillary rodham clinton. >> reporter: georgia congressman and civil rights veteran john lewis went further, questioning sanders' claim that he worked for racial justice in the 1960's. >> i never saw him. i never met him. i was involved in the sit-ins, the freedom riders, the march on washington, the march from selma to montgomery, and directed the voter project for six years. but i met hillary clinton, i met president bill clinton. >> reporter: both clinton and sanders largely stayed out of sight today as they prepped for tonight's debate here in milwaukee. >> sreenivasan: lisa joins us now, along with amy walter of the cook political report and tamara keith of npr from the site of tonight's debate at the university of wisconsin-milwaukee.

lisa i want to start with you, how close is this race heading into tonight's debate? >> it is a real horse race. it is not the race we thought it was three or four months ago. bernie sanders has momentum, so i don't want to say that there's really a front-runner at this point. hillary clinton has more of what are called super delegates. i know you like to talk about that, amy. but bernie's got momentum. so we have a real race. i don't want to say there is a front-runner right now. >> you have had, obviously, a very contested contest in iowa, that hillary narrowly won. bernie came out of new hampshire, big, big win. the real question now we head to nevada and south korea, which are demgraphicry and stylistically very different. not quite as liberal as those other two. that's why she needs to have a strong debate tonight going into what we will soon see in nevada and south carolina. >> absolutely. today, you can tell how important these voters are because-- and how the landscape

has shifted because bernie sanders was announcing an endorsement from harry belafonte. meanwhile, hillary clinton has a number of members of the congressional black caucus holding a press conference singing her praises. this has definitely shifted to the next states where the electorate-- >> the non-white vote is more important. >> where the electorate reflects the democratic party as a whole. >> sreenivasan: let me get to that question. tam, let me start with you. who do they need to appeal to through this debate and beyond? >> it's all of the democratic electorate, and i think hillary clinton, especially, has work to do, at least based on the exit polls that we saw from new hampshire. she lost-- she lost women. she lost young people-- >> almost every age group. >> basically everybody. >> everybody except people earning more than $200,000 a year. she really needs to come out on on this debate stage. and as he said tuesday night, she has work to do and she needs

to do that work and present herself as more than a resume and a pile of white papers. >> you know, young people are something she is definitely going to need to do something with. she lost not just by the loss to obama, which are big, but 70y to 80 points. that is really unprecedented. her challenge, i think, is a little bit like a parent at christmas, when you have to admit that there is no santa claus but still keep the magic of the holiday. >> wait. there is no santa claus? >> i'm sorry that's what she's confronting right now with younger people who do want to be inspired, who see bernie sanders as aspirationals. she's trying to say, yes, but, let's try to figure out how we get things done. how do you do that in a way that doesn't undermine the real energy that the younger voters have. >> the pragmatic vision that she has, harry, is not something young people are looking for. one thing i say from hillary clinton coming out of new

hampshire, she did win with people who decided that day at the polls, just by a little bit. so that might give her the idea that standing on this stage tonight, hari, maybe she can turn around some people who are on the fence who are still deciding. that's what she's counting on. >> sreenivasan: amy, i want to start with you. what are you looking for from each of the candidates tonight? >> from hillary clinton's perspective, it is this balance of santa claus and spirit of the holiday that i was discussing. but it's also pressing bernie sanders on specifics. he has been able to talk about this big, inspirational, aspirational message without getting nailed down on how that's actually going to work, how can she get him to specify those things? , and also, looking for her to really hone in on her message. i went back and look at all the hillary clinton ads what have been run since the summer and it's a miive mash, you have guns, pay equity, work she did with children and women. what had ser hedge? we know what bernie sanders' message is. it's all about the economy being rigged and wall street is not on

your side. where is hillary clinton going to find that message? >> and i think for bernie sanders, soot really about can he get beyond the talking points, beyond the slogans, and can he, you know, dig in on foreign policy, beyond saying, "i voted against the iraq war. i've got the judgment." on the-- on health care, on some of these other things, can he really get into the weeds with it? and i think hillary clinton is going to try to press him to do that. >> and, hari, ung our viewers should know in organizing this debate i know the thing gwen and judy care about the most is they want to try to show the differences between these two candidates. they're similar in a lot of ways but they are hoping to focus on issues, and drill down to what kind of president will each make? we'll see. >> sreenivasan: lisa desjardins, our political director, amy walter, and tamara keith, thanks so much. >> sreenivasan: in the day's other news, a federal judge ordered that all of hillary clinton's remaining e-mails as secretary of state be released this month. they were to have been released by the end of january, but the

state department asked for an extension. clinton's use of a private e- mail server during her time at state has dogged her presidential campaign and triggered an fbi investigation. the last four occupiers of a national wildlife refuge in oregon surrendered today, after a six-week standoff. with that, law enforcement pulled back after tense hours of negotiations, and local people welcomed the outcome. >> i just posted hallelujah on my facebook post and i think that says it all. i am so glad this is over. i have lived in eastern oregon and northern nevada my entire life. and i have never, ever in 70 years locked the doors to my house until this happened. >> sreenivasan: authorities also arrested cliven bunden yesterday on charges from a confrontation in nevada. his son ammon led the oregon standoff before being arrested himself. a battle erupted at a prison in northern mexico overnight, and when it was over, 52 inmates were dead.

officials in monterrey said the fighting pitted factions linked to rival drug cartels. tv broadcasts showed part of the facility burning as crowds of inmates' relatives gathered outside. they demanded information from police. pope francis arrives in mexico tomorrow, and will visit a prison in a nearby state next week. nato defense chiefs ordered three warships to the aegean sea today to crack down on gangs smuggling refugees. after a meeting in brussels, the alliance's secretary-general said the ships will assist the turkish and greek coast guards. >> this is not about stopping or pushing back refugee boats. nato will contribute critical information and surveillance to help counter human trafficking and criminal networks. >> sreenivasan: an estimated 76,000 migrants have reached europe by sea since january 1, 10 times more than the same period last year. major powers opened their latest

talks today on syria, where a government offensive and russian air strikes are creating thousands of new refugees. secretary of state john kerry met with russian foreign minister sergei lavrov. but there was little sign that the russians will agree to an immediate halt in their bombing campaign. back in this country, more than 40 georgia prison guards have been indicted on federal charges of drug trafficking and taking bribes. the charges, spelled out today, are the latest in a series of indictments since september. and, a former los angeles sheriff now admits he lied to federal investigators in a probe of jail corruption and prisoner abuse. lee baca pleaded guilty late wednesday to knowing about efforts to obstruct the investigation. to date, 17 members of the sheriff's department have been convicted. the mayor of cleveland apologized today, after the city billed the estate of tamir rice for ambulance services. the 12-year-old boy had been playing with a pellet gun when he was killed by police in 2014. mayor frank jackson says it was a mistake to send the ambulance

invoice, even though the estate's executor asked for it. >> should it have happened? no, because a red flag should have been risen. but that didn't happen. did anybody do anything wrong in this? no. because it's the normal process. it's the way in which we do things internally. but it's also what the law requires you to do. >> sreenivasan: a rice family attorney called the claim filing "deeply disturbing." there's word that utility crews have finally plugged a natural gas leak near los angeles. the leak started nearly four months ago, and drove thousands of people from their homes. they'll be allowed back once state inspectors declare the well permanently sealed. president obama has made his choice for secretary of education. he's dr. john b. king junior, and he's been acting secretary since arne duncan stepped down in december. he's also served as state commissioner of education in new york. and, wall street took another beating over worries about global growth.

the dow jones industrial average lost more than 250 points to close at 15,660. the nasdaq fell 16 points, and the s&p 500 dropped 22. and, the senate has given final approval to blocking state and local governments from taxing internet access. seven states now collect taxes for online access, but under this measure, they'll have to stop by 2020 still to come on the newshour: the fight for freedom of speech, five years after egypt's revolution. proof of einstein's universe-- changing theory on gravitational waves. the first puppies created using in-vitro fertilization. and much more. >> sreenivasan: five years ago today, egypt's longtime ruler hosni mubarak was removed from power, and he was soon jailed by egypt's judicial system.

today he is held in a military hospital, charged with ordering the killings of protesters and awaiting retrial. the court system in egypt has played an essential role in the turbulent times that followed mubarak's ouster. the elected president after mubarak, mohamed morsi, who was deposed by the army, sits in prison today, sentenced to death. under current president abdel fattah el-sisi, the courts have jailed tens of thousands of opposition figures, he claims the decisions are out of his hands. tonight, special correspondent nick schifrin examines the role of the justice system in egyptian society, for our series, five years on. >> reporter: no egyptian family has fought for justice more tirelessly than the seifs. alaa abdel fattah is a symbol of the revolution, imprisoned by the current government. his sister mona seif leads campaigns against military trials of civilians. and last month sanaa seif was the only left-wing demonstrator

to commemorate the revolution, the siblings have learned their lessons from their parents. the justice apparatus, is completely failed at the moment. >> reporter: their mother is laila soueif, one of egypt's most prominent activists. that's her on the right, yelling at plain clothes police. she has protested against six governments over 42 years. >> it's my duty to do this so that at least everyone remembers that they do not have the right to push people around >> reporter: their father ahmed seif was egypt's leading human rights lawyer. today, laila believes the judiciary is out of control. >> they have this crazy idea that you can teach a whole population manners by putting them in jail! >> reporter: a judge sentenced alaa to five years in prison for protesting against what he saw as the military taking over the courts. sanaa was sentenced to three years for protesting against a

law that bans protests. mona has been detained, and is currently awaiting a suspended sentence. >> the judges have become self- motivated to squash opposition movement. and to imprison any rebelling youth that they don't think are accommodating to the conservative ideas. >> reporter: those conservative to the point of iron-fist ideas are embodied by the man they call the executioner judge: nagy shehata. last january he ratified a mass death sentence of 183 suspects, despite evidence they'd been tortured. he sentenced 230 people at once to life in prison, for demonstrating, even though police killed many of the demonstrators. >> i confirm the execution, and the accused of obliged to pay the trial fees. the session is >> reporter: and when activist ahmed douma asked shehata

whether he used facebook, the judge added three years to his sentence. >> this is just sloppy work. and when you're a judge, sloppy work is a crime. >> reporter: it wasn't always like this. before the revolution, egyptians took pride in their judiciary as fiercely independent. today judges and their defenders say the judiciary is still independent, but focused on one specific thing: maintaining peace and security. >> both the government and the judiciary, perhaps for different reasons, value order and public safety almost above everything else. >> reporter: for four years david risley was the u.s. legal advisor and diplomatic attache to egypt's judiciary. he believes egyptian judges see violence on the streets, and believe their job is to restore stability. >> some judges simply felt they are doing what needed to be done for the good of the country, judicious or not. >> reporter: pbs newshour called dozens of egyptian judges. each declined to be interviewed. western diplomats say the

judges, in private, argue egyptians are willing to give up some rights to keep order. but the seifs argue even if that's true, today's judges fail to deliver. >> they have had their 100% freedom to do whatever they want to do for the past two years. and order has not returned. and justice has not prevailed. >> you do not bring security or stability by being unprofessional. okay, you bring security and stability by behaving like the judge who sentenced my husband. that that is bringing security and stability. >> reporter: when ahmed seif was arrested in 1983, his judge investigated whether he had been tortured. >> and he threw out the evidence that was obtained by torture. so, there was a certain amount of adherence to the law. >> reporter: and now? >> now, now you have judges who are not just unprofessional, they're ignorant. they don't know the, they don't know the statues of the law. >> reporter: but just like in

the u.s., egypt's higher courts can overrule lower courts harsh sentences. and that is exactly what has happened in egypt, where the >> on appeal, these sorts of injudicious, expedient, including mass convictions, mass death penalties, are being consistently reversed. the consistency of those reversals seem to me by now to be so predictable, that it makes one wonder whether the real purpose of mass convictions is not an expectation that the defendants convicted will ultimately be punished, but rather they are tied up and detained for an extended period of time. >> reporter: mona fights those lengthy detentions. attempted to document egypt's 40,000 political prisoners. they're trying to shine a light on a system they say is usually a black box. >> you can have a first degree relative who is now detained, faces prosecutiond gets a sentences. and you can't, you don't even know. and you don't even check on him or get a lawyer to attend on him. >> reporter: because no one has access to it at all. >> because no one has access to

it. ahmed died when they were both in prison. the campaign was entitled, "injustice has taken them away from us." what is it like to have two of your children in prison? how can you even handle that? >> you turn it into practicalities. >> reporter: because if you didn't... >> reporter: one bright spot: alaa's son, four-year-old khalid. his toys fill her living room. >> i like it very much. that's about the only thing that's consistently, that makes me consistently happy at the moment. >> reporter: your grandson. laila shows me her favorite family photos.

in one, khalid is laughing with his mother. his father, above them, is actually just a poster. khalid was born when alaa was in prison. mona was born when her father was in prison. >> reporter: despite that, all of the sacrifices your family's made, it's been worth it? >> reporter: she says it'll be worth it if their sacrifices today mean her grandson doesn't have to fight the same battle, and go to the same jail, tomorrow. nick schifrin, pbs newshour, cairo. >> sreenivasan: tune in tomorrow night for nick's final piece on the role of women in the tumultuous five years since the revolution. >> sreenivasan: now some truly cosmic news, the sound of two black holes colliding more than a billion years ago was recorded by a team of scientists at the ligo observatory. proof of gravitational waves, or

ripples in time and space, first theorized by albert einstein. we explore this monumental moment in physics with dave reitze of cal tech, executive director of the ligo labratory. now, that was a rudimentary attempt at explaining what a gravitational wave is. but what are they and why is it such a big deal to find one? >> actually, you did a pretty good job. dprafitational wraefs fluctuations in space time, and any time you have a mass, something that has matter in it, accelerating, it produces a gravitational wave. and that's a consequence of einstein's theory of general relativity. now, these particular gravitational waves, in order to be able to detect them, you need really, truly massive objects. in this case, these were black holes that had 30 times the maz of the sun in them. why gravitational waves are so interesting is they tell us something about the universe you can't get from any other kind of astronomy. if you think about optical astronomy, that looks at certain

classes of light. if you look at radio astronomy-- so gravitational waves are completely different. they come from a different sector of the universe, and that's why they're so exciting. >> sreenivasan: so einstein is sitting at his patent clerk's office thinking about this big thought, and what is the connection between space time? does time and space bend? if you heard or saw, so to speak, this moment, does that mean time and space bent just a little bitta those points? >> oh, in fact, this particular event was as a colleague called it, a storm in space time. they really disrupted space time and produced a burst of gravitational radiation. gravitational waves were first predicted actually 100 years ago. and einstein himself thought it was an interesting consequence of a theory of relativity, but didn't think it had any practical value because he said the effect is so tiny that we'll never be abe to measure them. and it took 100 years from the

time he predicted to the time we have been able to measure them. >> sreenivasan: and also to measure them, you have very giant antenna that most people probably haven't heard about until today, one in louisiana and washington. >> these two interferometers, a type of laser measuring device. a laser going gz out, it could split, it goes along the arms of the interferometers. the arms are very long, two and a half miles long, comes back. we do a lot of tricks to make the interferometer very sensitive. as the wave passes it stretches and squeezes the light between the arms in the interferometer, and because light is made up of waves, we use the fact that that stretching and squeezing changes the relative relationship, the phase, if you will, between the waefdz. >> sreenivasan: so is it that we got this sound? i mean, these are laysers and you're seeing the disruption, or change in light. what does that mean to say we heard two black holes? >> right. so the ferrometers are very nice.

the light goes on to the detector, and the frequencies fs that these gravitational wavees were generated by the two block holes are an audio band. it's like a cd player you can put a plug in the detector and put headphones on, and after a little data processing and filtering you can hear the signal. it's an interesting signal. it goes whoop! actually, it's a little lower. >> sreenivasan: what does this mean for science? ask does this mean new branches of study have opened up? >> i think there are two things that reporter. here. first of all, it's really a big confirmation that gravitational waves exist. now, woe knew they were they existed. there was a nice experiment done early on, but this is the first direct measurement, so that's exciting. but i think the thing that's more exciting is this opens up a completely new way of looking at the universe. so everything we know about the universe we know from light, electromat nettic radiation.

this is the first time the universities is communicating to us using gravitational waves. it's like the codz moas is talking to us. >> sreenivasan: this makes he think of all the sci-fi movies that will sphin off from this. if we can measure that space and time are bending and it's happening all around us, we just happen have to have these two antenna on had planet it's probably happening all over the universe. >> oh, sure, and we hope to be able to hear more of these gog. i should point out. this is only the beginning. there are projects undergoing in japan. there's one in italy right now undergoing. we're hoping to put a gravitational wave detection in india. the more you have of these things the more ears you have and it's a huge advantage. >> sreenivasan: dave reitze from caltech, thank you for joining us. >> my pleasure. >> sreenivasan: we have more on einstein' >> sreenivasan: we have more on einstein's theory and why it was so revolutionary when he posed it more than 100 years ago. theoretical physicist sean carroll wrote about the twists

and turns of spacetime in the universe, and you can read that essay, on our homepage, pbs.org/newshour. >> sreenivasan: stay with us, coming up on the newshour. the economics of online dating. "city of thorns," a look inside the world's largest refugee camp. and comedian billy eichner explains why he ambushes people on the street. but first, now to another scientific breakthrough. the planet is currently in the midst of an extinction crisis. as gloabl climate changes and habitats disappear, species all over the world are at risk of being lost. breeding these endangered animals is one of the tools researchers can use to combat this decline, but that can be difficult to accomplish. but a recent innovation here in the u.s. has given new hope for some wolf species. newshour science producer nsikan akpan has the story of the young puppies that may help save the

rest of the pack. >> reporter: it may be hard to believe but these adorable puppies and how they came into the world might be the key to saving a whole host of endangered species. at the smithsonian conservation biology institute in front royal, virginia, scientists are developing state-of-the-art reproduction techniques to try to save endangered species. at the institute, you'll find everything from cheetahs to blackfooted ferrets. the scientists here are perfecting tools like artificial insemination and in vitro fertilization to help the breeding of those endangered animals. a marquee case is these wolves. they're from south america. smithsonian conservation biologist says most of the wolves' habitat has been lost to farming and human development. >> right now, we estimate about 15,000 of them in the wild. but the problem with this

species is that their habitat is gone. 85% is lost, and only 2% of their natural habitat is protected. so the pop haitian in the future is not looking very bright because that's no home for them. >> reporter: to save the species, she and her colleagues are trying to breed the wolfs in captivity for future reinto the wild, but thee says that's tricky. >> we hope they will breed memorially, but sometimes that's not always the case. sometimes they have incompatibilities, and they may not like each other, and not want to have anything to do with each other. >> reporter: maine wolves are monogamous, and females tend to be very particular when it comes to choosing a boyfriend or partner. that's why scientists need in vitro fertilization, or i.v.f. i.v.f. is commonly used in humans. it involves harvesting an egg from a female and putting it into a dish. you then insert the male into

the egg, creating an embryo. but reproductive biologists say for decades scientists have struggled to make it work with dogs. >> dogs have a unique reproductive physiology and part of why i.v.f. has been a challenge to develop over past 40 years. >> that's in part because canine reproductive systems have some particular quirks, like the fact that females just don't produce that many eggs. >> female dogs only cycle once or twice a year, and it's even more dramatic in wild canines who are seasonal. so you only haveap ovulation event once a year. and even when that egg is ovulated it requires two or three days in the reproductive tract to mature and become fertilizable. so the result of these two things means that aren't that many mature eggs available to develop technologies such as i.v.f. >> reporter: what they did was troubleshoot the entire reproductive process. they started with basic dog

breeds like being cells and coark spaniels and then they figured out the best way and time to harvest the eggs. they even found a way to give male sperm a little boost by adding magnesium. >> when we added magnesium, it improved the motility of the sperm. >> the embryos were then frozen and the team had to determine the best time to implant the embryos into a surrogate mom. the would-be moms had to be exactly in sync with the development of the embryos. after implantitation, the team had to constantly monitor the health of the surgats to make sure nothing went wrong with her pregnancies and two months later, success. seven healthy puppyes were born. >> the puppies were born july 10, 2015, so they're just over five months old right now, and they are adorable, healthy, bundles of terror and joy. >> reporter: the time technique was published in the

journal "plos" and the story received worldwide attention. now the hope is to tiewz on threatened species. >> the hope for the maine wolves and other endangered canine species is we'll be able to use this technology to help their reproduction, to produce pups where otherwise we may not be able to. so, for example, a lot of times in these very small populations, if you have a female that passes away before she's been able to breed, we would really like to be able to take her ovaries, collect the eggs, mature them, and use i.v.f. to produce embryos that would represent her as a mother. >> reporter: most of the litter were adopted by the researchers themselves because, "a," who wouldn't want one of these scientific marvels. and, "b," just look at them. >> this is cannon. he is a cocker spaniel-beagle mix. >> this is buddy. he is a little bunch of joy. >> okay! >> reporter: do you tell your

being whale he might mean for the survival of future relatives? >> actually, i do. i tell him every day that he is very important, he is a superstar, but, you know, he's still a puppy. i'm not really sure he understands what that means yet. but hopefully one day he will understand. >> reporter: for the pbs newshour, i'm nsikan akpan, in front royal, virginia. >> sreenivasan: leading up to valentine's day, paul solman takes an encore look at the economics of dating, how some people are using market principles to overcome the traditional impediments to finding the perfect match. its an updated presentation of our making sense series, which airs every thursday. >> reporter: facebook software engineer mike o'beirne, aka" cirrusly" online, had been looking for a date since moving to new york four months earlier. >> it was really at my brother's

urgings. he told me i need to start going out and dating people. >> reporter: ad agency art director priyanka pulijal, also new to new york, her love handle was "brbeatingcupcake." the brb is webspeak for "be right back." >> i think you have to meet a lot of different people to first understand what you want. and i think, once you understand what you want, you have a lot of different options. >> reporter: so what did they want? each other? >> hi. nice to meet you. >> reporter: last february, they agreed to let us record their very first date. >> do you guys mind leaving now? >> reporter: ok, we would brb. but while we gave our daters some alone time, we checked in with their online matchmaker, okcupid. founded a decade ago by four harvard math majors, the site was owned by i.a.c., the same media conglomerate that ran match.com, which charges a monthly fee, and the mobile app tinder.

>> between okcupid, tinder or match, we will sign up easily over 30 million people this year alone. >> reporter: that was okcupid co-founder christian rudder, nine months before i.a.c. spun off the dating websites, selling stock in them to the public via an i.p.o. there was already plenty of competition, though; eharmony was big. and niche sites were trending, for jews, christians, farmers, sea captains, mimes, the gluten- free, the incarcerated, the unhappily married, and, of course, accompanied by mozart. >> welcome to purrsonals.com. as a fellow cat owner, i know how finicky we are. >> reporter: but no matter how finicky, you're better off with more than less. >> imagine a mixer with three people. that would be a pretty rough, pretty rough hour if you lasted even that long there. but okcupid, metaphorically speaking, is a mixer with four million people.

>> in the language of economics, the study of maximizing human welfare, this is what's known as a thick market. >> where would you rather buy a pair of pants, at the mall of america or on the streets of a small town in oklahoma? >> reporter: economist paul oyer has actually written a book," everything i ever needed to know about economics i learned from online dating," based on his own adventures looking for love. >> so, i found myself back in the dating market in the fall of 2010, and, immediately, as an economist, i saw that this was a market like so many others. >> reporter: well, not any old market, like the one for pants. this is a market for what economists call differentiated goods. >> no two potential life partners are the same. every single one of them is different. from an economics perspective, searching for a partner is just cost-benefit analysis. (laughter) this isn't funny. (laughter)

this is economics. >> reporter: and that analysis includes, in the lingo of economics, search costs. >> it takes time and effort to find your mate. you have to set up your dating profile. you have to go on a lot of dates that don't go anywhere. these frictions, the time spent looking for a mate, lead to loneliness or, as i like to say, romantic unemployment. >> reporter: oyer found himself romantically unemployed when he first took the online dating plunge, as it happens, on okcupid, and had written" separated" on his profile. but at least he didn't say he was actually unemployed or drug- happy or a glutton, even bigger turnoffs. those are among the tidbits gleaned from the millions of responses in okcupid's database, shared by christian rudder in his book "dataclysm," not that all are exactly shockers. >> when people come to a dating site, all they look at is the pictures, for the most part. >> reporter: rudder has since

left okcupid, but beneath the sidewalks of new york, erika christensen is still hawking what is arguably a more discriminating approach. >> you are very handsome. are you single, by any chance? if you find yourself single, i'm a matchmaker. >> reporter: yes, a real live matchmaker whose turf happens to be the subway. >> you are very handsome. >> reporter: the days leading up to valentine's day are the busiest of the year for this hello dolly of the l train, who was looking for lasting love on behalf of two 30-something female professionals. >> what we're dealing with is the biological clock, and these women want the 35-to-45-year old man quick. they want him yesterday. >> so you mean that you're sizing up these guys as... >> potential baby daddies, that's right. >> reporter: since time is money, clients are willing to pay a couple of grand or more, sometimes much more. okcupid, by contrast, is free. but, to christensen, you get what you pay for. >> i think online dating is

great, but it's basically humans as commodities. >>there's another objection to online dating as well. >> okcupid, by making a huge universe of people available to you at any minute, doesn't that work against a rational decision about whether to invest in the relationship you have? >> reporter: writer r.d. rosen, who's used online dating, is working on a book about middle- aged courtship. >> there's an enormously addictive quality to online dating that has never existed before in the culture. you want to keep going back, because you think you're going to hit the jackpot eventually. >> reporter: rudder doesn't deny it. >> whether you're gay or straight, we're constantly showing you people. there might be someone better looking or who has a cooler profile or whatever it is just right around the corner always. >> reporter: and not just gay or straight. >> at ok cupid we have 22 genders and 13 orientations. >> reporter: that's right, 22 genders and 13 orientations, including our favorite, sapiosexual: attracted to intelligence.

and to further complicate, chief product officer jimena almendares has just added another option. >> earlier this year we launched a feature that if people are searching for someone else in their relationship they can actually publicly state that and people that are interested can respond. >> reporter: to paul oyer, though, a surfeit of choice is just another search cost, for which economists have a fairly simple solution: >> what you need to do is you need to settle, to say, i have somebody who's good enough. people hate it when we say that. but it's the way-- it's the way a rational economist would think about it. >> reporter: but wait a minute. after my first date with my now wife, i knew she was the perfect mate. and last year was our thirtieth anniversary. >> the perfect one for you doesn't exist. but there's a very important idea in labor economics called firm-specific human capital. and that is, as you work at a company for a longer time, you

have certain skills that are valuable at that company and not elsewhere. well, you have built up something we will call marriage- specific human capital. you have developed your life around your wife, such that she probably is the best match for you at this point. >> reporter: meanwhile, our daters had to get back to their jobs. so, how had it gone? >> so, we both found out that we had like way more in common than we expected. >> i felt we really connected about a lot of different things. >> i will probably e-mail her later. >> reporter: actually, he didn't. that same week, he met a new flame. meanwhile, priyanka began dating an old friend; a year later, they're still going strong. as for me, paul solman, economics correspondent for the pbs newshour, i'm still ever-so- happily married and wishing all of you, online and off, another welfare-maximizing valentine's day.

the newest addition to the newshour bookshelf takes a most intimate look at one of the world's oldest refugee camps administered by the the united nations, originally established in 1991 as temporary haven for somalians fleeing their civil war. author ben rawlence recently talked to judy woorduff about his book, "city of thorns: nine lives in the world's largest refugee camp." what drew you to kenya. what drew to you this camp? >> for 10 years i worked, for human rights watch. and i first came to the refugee camp in 2010. and the place just blew my mind.

it was a complete shock to me they hadn't heard about it before and in fact that this place should still exist. at that time, it was 20 years old. and now it's 25 years old. >> it started out as something much smaller. refugees-- one group of refugees. it's grown into something much bigger and, frankly, much worse. >> yes, dadab is the world's biggest. somali refugees came in 1991. sunshine then, somalia has been through different phases of civil war, and there have been waves of refugees, more and more coming, until it peaked in 2011, with around half a million refugees living in one place. it's a bit like new orleans, it's that many people, but spread over 30 square miles. the tents are made of-- or the houses are made of tents or sticks and mud. and it's-- there's no permanent structures. so there's no plumbing. there's no concrete. there's no running water.

it's a humanitarian disaster still, even after 25 years. it's constructed on temporary liewns, and yet it's become permanent. >> people living in conditions, it's almost impossible to imagine. and yet, you write about how there's organization there. there's structure there. >> well, you can deny a city permanent structures, but you can't deny the people the right to associate and to make societies. and, of course, that's what's happened. people have made their own soccer leagues. they've fallen in love. there are many love stories in this book, people have had children. and then sometimes those children have had children. so we're now on to three generations. and, of course, they're going to school. there are hospitals. there's a market, a black market. lots of smuggling and so on. so people have nonetheless made a life for themselves. >> you picked just a few individuals to write about and you tell their stories in a very powerful way. why did you choose these

individuals, these people? >> well, firstly, i was trying very consciously to sort of break open the media on-- you see the eyes glaze when you talk about refugees and famine. because we think we've seen it all before. we think we know what a refugee camp look likes with the lines of tents. we see angelina joelet and celebrities doing their thing. but actually, what was interesting to me is what happens when she goes? what's daily life like for all of these people? so i wanted to really give you a ground-eye view of what's whatgoes on. and i chose those nine through a long process, really. i start with about 50 people, and nine made the cut. >> the world is-- has virtually forgotten about this place if it ever knew about it. what do you want people to take away from this? >> well, the first thing i wanted to do was to make you feel, to make you care about the people stuck in this place, because certainly they feel forgotten. in large part they have been

ignored by the international media. so to get beyond the headlines, to actually see-- make you see these people as humans with all the normal struggles you would imagine of trying to find a job, make a living, things like that, to try and bridge the gap, to make people feel connected. these are not just numbers but these are face. these are real people with hopes and dreams. and if we start thinking of refugees more in those ways, hopefully then we can start seeing a bit more intelligent policy, a bit more humanity at the political level as well. >> and we're look at the faces of a few of the people. >> yes, these are the some of the people in the camp. this is my friend nisho, the taller guy, and mahat is his young side kick, and they work as porters in the market. they offload the trucks coming in smuggling goods from somalia because they're not allowed to work. refugees can't leave. they can't work. so they have to find these

informal jobs, scrab ling a living as best they can. >> what is it in these young boys and everyone else that gives them the strength to keep going? what is it inside them? >> well, that's one of the questions that drew me to write about the place in the first instance. i couldn't understand how do you put up with this? you know, why are there not some kind of mass riots and protests and burning downtown u.n. office and so on? but people do put up with it because they have no option. they can't go back to somalia. kenya doesn't want them. the resettlement system are countries share the burden of refugees through the quota system is completely broken because the birth rate in the camp, for example, is 1,000 a month. the international community takes around 2,000 a year of people from dadab. so that's why people are choosing the illegal route to come to europe or elsewhere instead of waiting for the formal legal process. >> what is the future for them? what's the hope for them?

>> i'm afraid the reality is it's pretty bleak. i see now real solution for dadab. and as long as there's no international solution or political solution, the camp will continue. we're now on to our third generation of people living in this situation. this is one city. there are many other temporary cities like this in ethi don't knowia, sudan, yemen, these cities going on and on. which is why i think we need to hear about this place. we need to understand it. and then we need a marshal plan for refugees that people are talking about. we need to fix this broken system but world has gotten a bit harder, a little less generous. >> ben rawlence you certainly shined a light to what's happening there and more people will know about it from the book. the book is "city of thorns: nine lives in the world's largest refugee camp." thank you very much. >> thank you.

>> sreenivasan: finally, another installment of brief but spectacular-- our series where we ask interesting people to describe their passions, tonight, we hear from comedian billy eichner, star of "billy on the street" on tru tv and the hulu original series "difficult people." he opens up about his comedic style and process. >> we were filming recently and someone yelled out from across the street, "billy, please harass me." which is a really strange request. ♪ ♪ >> "billy on the street" is a game show in new york city where i ambush people on the street with pop culture trivia. it also features celebrity guests helping me ambush people. my favorite segments are the super bowl, where i asked the new york giants what they thought of the madonna half time

show. sir, are you exied exooited about madonna? >> madonna? absolutely not. >> why, she's the half time show. >> she's an old hag. >> you're an old hag. >> did you see madonna. >> no, i was in the locker room. >> we did a segment with the first lady this year, michelle obama, and i had her push me around in a shopping cart while i read gwyneth paltrow's oscar acceptance speech. i would like to thank the academy from the bottom of my heart. i would like to thank our miraculous cast and crew. for $1, be honest, who is hotter, abraham lincoln owe barack obama? >> oh, barack obama. >> sorry, abraham lincoln! "billy on the street" is a persona. it's a performance. it's pretty much my id as a 12-year-old kid, like, blown up. "difficult people," which is a scripted half-hour show on julio, created by julie klausener, great writer, performer. >> i am starving! >> i know. i'm trying to order food. there is no wifi.

>> what are we supposed to do wander around the neighborhood. >> you know what kind of food they'll have, turkish and tapas. >> a moment of silence for the deceased, please. >> it's "will and grace" but more unattractive and more unlikable. it's what america wants. i am gay and i'm in comedy. i don't know what to say about it. i was so blind to homophobia. i grew in new york, i went to sivessant. when anyone asked me was it a conscious choice to be out of the closet and a comedian? i don't know. is it a conscious choice to be white? it's what i bring to the table. it's not that big of a deal. my gay, married friends with kids are just as boring and annoying as my straight married friends with kids now and i don't want to hang out with any of them, to be honest. hi, i'm billy eichner, and this is my brief but spectacular take on the most difficult person i know, me.

>> sreenivasan: you can find more brief but spectacular videos on our facebook page-- facebook.com/newshour. on the newshour online, how do you capture the majesty of a place like yosemite national park in one frame? it's a feat the national parks service is hoping someone will master when it hires an official photographer this summer. so how do you do it? we asked national geographic senior photo editor kathy moran for some tips. see those, plus a photo gallery of some of the most stunning park photos, on our home page. and remember, you can watch tonight's democratic debate on pbs, and also in our live stream, that's on our homepage. pbs.org/newshour. and that's the newshour for tonight. tune in to this pbs station at 9:00 p.m. eastern. gwen ifill and judy woodruff moderate the democratic presidential debate from milwaukee. plus, analysis from shields and brooks. i'm hari sreenivasan. for all of us at the pbs newshour, thank you and see you later tonight. >> major funding for the p newshour has been provided by:

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>> this is "bbc world news." >> funding of this presentation is made possible by the freeman foundation, newman's own foundation, giving all profits from newman's own to charity and pursuing the common good, kovler foundation, pursuing solutions for america's neglected needs, and hong kong tourism board. >> want to know hong kong's most romantic spots? i will show you. >> i love heading to repulse bay for an evening stroll. it's the perfect, stunning backdrop for making romantic momentut