on our broadcast tonight, "we've been hit." the chilling words from the crew of a commuter jet clipped and spun around by a super jumbo at kennedy airport. tonight, why did it happen, and what was it like on the inside? outrage tonight over a new video on the internet showing the tsa pat-down of a 6-year-old girl. tonight, what does the tsa have to say about it? even worse than they thought. japan now says the nuclear disaster is on a scale with chernobyl. and the teen brain. what's going on in there? fascinating new science tonight about teenagers and their digital life.

about teenagers and their digital life. "nightly news" begins now. captions paid for by nbc-universal television good evening. if you fly a lot or even a little, then you've been on them, the so-called regional jets that carry millions of us every year on routes that crisscross the country. the passengers on board one of them were taxiing at new york's jfk last night when they were clipped and rocked and turned around by a passing behemoth. even the grainy cell phone video is incredible to watch. the biggest passenger jet in the sky caught its wing on their tail and treated that regional jet like a toy. it was harrowing for those passengers, while those on the jumbo jet didn't feel much. and yes, while it could have been so much worse considering the jet fuel on board and all those souls on both aircraft, this investigation will be watched closely. nbc's tom costello is at jfk

with the story tonight. tom, good evening. >> reporter: hi, brian. a lot of questions about how this happened. the a380, of course, is a giant. its wingspan alone nearly the length of a football field. comair, owned by delta airlines. but the people on board that double-decker say they barely felt it when it hit that smaller regional jet. rarely do investigators get to watch an accident as it happens. video of the actual moment on the taxiway at jfk when the biggest commercial airplane in the world, an air france a380, clipped and tossed aside a small comair regional jet. the comair pilot quickly called for emergency help. >> we've been hit by air france. >> super a380, i understand he believes he hit the regional jet, and i understand they're evacuating the regional jet. >> reporter: air france flight 7, with 495 passengers and 25 crew members on board, was

taxiing for takeoff, bound for paris, when its left wing tore into the tail of comair flight 6293, just arriving from boston with 66 people on board. from inside the a380, air france passenger lawrence grotts took these pictures of the comair tail. >> oh, my god. >> reporter: but he hadn't seen video of the impact until we showed him. >> it really felt just like a speed bump, you know, or like hitting a pothole, a jolt. but you know, it didn't feel right, like that shouldn't be happening. >> reporter: this ntsb photo shows the damage to the air france wing. the a380 has the longest wingspan of any commercial plane in the world, nearly 262 feet. the taxiways at jfk are the standard 75 feet wide. so the a380's wings always extend well over the taxiway's borders. if another plane is within the a380's reach, it can spell trouble. in just two seconds everyone inside the regional jet was violently tossed aside. the question for investigators,

was the smaller plane blocked, unable to get out of the taxiway and out of the a380's way? >> was there adequate clearance between the taxiway and that ramp area for an aircraft of the a380's size to be taxiing by at that time? >> reporter: no injuries. everybody got off safely. but investigators will be talking to both pilots as well as to ground controllers to see were they watching carefully to see how much spacing was between both planes and also the spacing between the plane as it left the taxiway and onto the ramp towards the gate. a lot of questions here to be answered. brian? >> unbelievable scene at jfk last night. tom costello there for us tonight. tom, thanks. also on the subject of aviation tonight, another grainy cell phone-generated video. but this one makes a lot of people angry. while we only have time to air a short portion of it here and now, we've posted it onto our website tonight, we know that it shows a tsa inspection of a 6-year-old girl.

further checking on our part revealed it happened in new orleans a week or so ago, and especially for some of us parents watching it it just seems somewhere between ridiculous and outrageous, and some folks see this clip as an example of everything wrong with the way we're carrying out airline security a decade now after 9/11. our justice correspondent, pete williams, is on this story. he's been in touch with the tsa tonight. he's with us from our washington, d.c. newsroom. pete, good evening. >> reporter: brian, after tsa began more intrusive pat-downs last fall, it said that children under 12 would receive a modified version of the searches. now an official says tsa is looking at making further changes in how children are treated. it's a response to continuing expressions of concern from parents, the latest coming in that internet video. tsa says it was made a week ago at the airport in new orleans. it shows a girl, said by the unidentified parents to be 6, getting a modified pat-down. the woman doing the screening uses the back of her hand part of the time and also runs a hand

around the inside top of the girl's waistband, explaining every step in advance as the child's mother watches. the mother later called it groping. tsa says tonight that the screener followed the existing protocols and that tsa administrator john pistole is aware of this video. in a written statement tsa says pistole has been pushing the agency to move away from the one size fits all system and that it's reviewing its policies to improve the screening experience for low-risk passengers such as children." but officials say they will never exempt an entire category of passengers from pat-downs, whether by age or physical characteristics, because they say that would invite terrorists to exploit those exceptions. but tonight tsa says it wants to make the process more respectful for families. brian? >> always a hot-button issue with those who fly. pete williams in d.c. tonight. pete, thanks. and tonight there is fresh evidence of what the world has feared and assumed watching this ongoing nuclear crisis day after day at japan's fukushima power plant. it's serious enough now to be put in the same category by the

japanese themselves as the 1986 disaster at chernobyl. nbc's john yang is with us tonight from tokyo. john, good evening. >> reporter: good evening, brian. for many japanese when the government put the nuclear crisis in the same category as chernobyl it was the strongest psychological aftershock yet. from a remote-controlled mini helicopter, one of the closest, most dramatic looks yet at the wreckage of the fukushima power plant, now officially one of the two worst nuclear accidents ever. today japanese officials raised it from level 5 to level 7, defined by the international atomic energy agency as a major accident with widespread health and environmental effects. only chernobyl was worse. that disastrous 1986 explosion released ten times the radiation that fukushima has leaked so far. >> in fukushima we haven't seen

that level of release yet. we've seen some of the environmental levels, particularly in the air and some in the water, but not the full core blowing up and polluting the atmosphere. >> reporter: officials say the change is the result of a fuller, more accurate picture of how much radiation is being released, not because anything's gotten worse at fukushima. still, it's one more body blow for japan. "for the first time i'm a bit shocked," said tokyo vegetable vendor kiichi kobayashi. "they don't seem to be making progress," said fukushima resident fusako nakahara. "if makes me uneasy." prime minister naoto kan went on television to say progress is being made, claiming radiation leaks are declining. he urged people to focus on recovery and rebuilding and to buy products from the disaster zone. in tokyo officials made a show of eating fukushima-grown vegetables, shunned by consumers. despite a small electrical fire

and another strong aftershock today, workers began pumping an estimated 14 million gallons of highly radioactive water from the plant. a key hurdle in restoring cooling systems and stopping the radiation leaks. scientists say conditions at the fukushima plant may not be getting worse but they're certainly not getting any better. they say completely containing the radiation could take as long as ten years. brian? >> john yang in tokyo for us tonight. john, thank you. in libya tonight, as the gadhafi regime bombards the city of misrata, there are new strains in the nato campaign. as you may know, the rebels have been saying they need more air support, and now both britain and france urge their nato allies, that includes the u.s., to step up this campaign by air against the libyan regime. nato's chief of allied operations disagreed, saying, "we're doing a great job." in egypt former president hosni mubarak is in the hospital with heart problems. he experienced an irregular

heartbeat earlier today while being questioned by prosecutors about his role in violence against the protesters we witnessed during that egyptian uprising. and we are hearing tonight from saudi arabia, a nation that has a lot at stake as change rocks across the arab world. late last week on this broadcast you'll recall tom brokaw reported that the saudi arabian monarchy is so unhappy with the obama administration for the way, as they see it, it pushed out mubarak that they sent senior officials to china and russia to seek expanded business opportunities with those countries. continuing his reporting there over this past weekend, tom was given rare access inside the kingdom. here now his report from riyadh. >> reporter: saudi arabia is the richest and most powerful country in the arab world, hugely important to the u.s. because of its oil reserves, and now surrounded by populist rage on all sides.

a sunni country, it is the home of mecca, the birthplace of islam, and takes pride in its orderly society. even so, there have been protests by the country's shiite minority against saudi rule. but they were quickly put down. saudi's king abdullah surprised almost everyone by sending his country's military into bahrain to suppress shiite demonstrations in that country. the king and other saudi officials are known to be unhappy with the obama administration for pushing egyptian president mubarak out so quickly. but until my weekend interview with prince saud, the foreign minister, there has been no public comment. >> the evidence is overwhelming now that people are demanding more change and a greater voice at a faster pace.

>> reporter: and the influence of the united states on saudi affairs? >> reporter: recently, king abdullah spread $125 billion among workers, the military, and for housing, a giveaway that prince saud insists was long planned and not an attempt to buy loyalty. when king abdullah spread all that money around, it didn't hurt his standing with the saudi people, of course. but then in fairness to him, he's always been a very popular monarch. >> we have good country, we have safe country, and we trust the government about what going to do. ♪ >> reporter: the kingdom is quiet for now, still pumping oil

every day and talking about reform. >> reporter: even so, he emphasized that saudi arabia will not be rushed into change. >> tom brokaw's reporting from his trip from riyadh. and now back in this country he took part in a ceremony in washington today honoring former senator bob dole. the dedication of a new plaque at the world war ii memorial in washington honoring his service. dole, as you may know, was a big driving force behind that memorial. as a young man from kansas, he was severely wounded while serving with the 10th mountain division in italy in the po valley in 1945. he emerged publicly today after months in the hospital on and off following surgery, and today he talked about those he served with.

>> i want to most of all thank the citizen soldiers, the farm and city boys and factory workers and recent immigrants as diverse as america itself for all you did to preserve civilization when it was most endangered. >> bob dole thanking those he served with and thanking those who made that memorial in washington what it is today. we'll take a break. when we come back in just a moment, new science on what all those electronic distractions are doing to the brain of the average teenager. and later, just as it was 150 years ago, today the shots that started the war between the states.

a new study out tonight which, as they often do, tells a lot of folks what we already know. this one says when you get older multitasking gets tougher. the younger you are, and it's

called life in 2011. and now there's a new major study looking at how all of that, all of the electronics affects the brain of the average teenager. nbc news chief medical editor dr. nancy snyderman has the first of two reports on the teen brain, a work in progress. >> reporter: it's after school at the cohen house. a sea of computers, cell phones, and notebooks. it's how homework is done these days, with constant text messages. >> you don't know if it's work, if it's play, if it's homework or if it's chatting. >> reporter: a generation that has never known a world without the internet or cell phone. >> sometimes i'll fall asleep with my phone with me in bed. i'll just be like holding on to it. >> reporter: and the headlines reflect the concern. are we raising kids who are constantly distracted by technology? the average child now spends 7 1/2 hours a day with media. but since some of that is done with multiple devices, it's actually almost 11 hours of

media every day. >> a lot of the memory system -- >> reporter: that's why neuroscientist jay giedd is scanning the brains of thousands of teenagers. >> this is an incredible gusher of information pouring into the teen brain from all these different sources. >> reporter: it's a critical time for the brain, becoming more specialized by getting rid of information it doesn't use. it's like pruning branches, allowing the brain to strengthen the connections that will last until adulthood. dr. giedd scans the teens every two years as they grow up and tests their distractibility. the surprising news? all this multitasking might be making their minds stronger and serves as a cross-training exercise for the brain. >> there does seem to be a plasticity for the younger adolescents that allows them to get better at multitasking to a point. >> reporter: and dr. giedd also sees this outside his lab. he's a parent of three teens himself.

but he limits how much screen time his kids get. >> as a parent we all want to do the best for our children. how do we parent better? how do we live better? >> reporter: it's that balance, he says, that will help teens learn in this ever-changing world. >> the doctor's poor kids are under constant scrutiny. >> constant scrutiny. >> can you imagine? first of all, i find it believable that it's at some level probably good brain exercise. but do we know enough to do any long-term studies? >> well, that's exactly where they're going. in fact, dr. giedd says right now if you look at college kids there are no alarming findings their brains are turning into mush. they seem to be handling all this incoming data, and that pruning seems to be working. and that's what they could be learning. so for parents keep your eyes on their grades, and one thing we're really going to talk about, and that's tomorrow night, brian, is the sleep deprivation. because sleep absolutely has an effect on brains, and that's going to be the subject of tomorrow night's segment. >> all right. nancy snyderman, as always, thanks. and by the way, we should point out, much more on this topic on the web. dr. nancy will host a live chat

tomorrow afternoon on nightly.msnbc.com. but she won't be performing any primary care. up next, what does april 12th mean to you? in the history business it means a lot of things.

and now a word about today. this day, the 12th of april, in history. in the history business this is a big one, from small events to

large. on this date the union jack was first flown in britain. in this country it is national grilled cheese day. celebrity birthdays include the author tom clancy, david letterman. joe louis died on this date in 1981. also on this day in 1945 word arrived from warm springs, georgia that fdr had died. some people thought he'd be president for life. harry truman took over the job at a dicey time for the u.s. and the world. we were at war, after all. yuri gagarin woke up the world on this day in 1961 as the first man in space. just 20 years later the first space shuttle flew, the shuttle "columbia." and on this anniversary the remaining shuttles were handed out today by nasa as tourist attractions when the program is all over. l.a. will get the shuttle "endeavour." the kennedy space center will get "atlantis." "discovery" will go to the smithsonian aerospace collection just outside d.c. and the shuttle will finally

land here in new york. we'll get the "enterprise." but in the life of this country this day will always mean just one thing, the start of the civil war. the first shot was fired 150 years ago today. the civil war killed 2% of the population of the united states. it tore our nation apart and reformed it later. and when we come back, we'll show you how it was remembered today where it started.

>> reporter: a crackling predawn fire for confederate re-enactors ready for battle, while across charleston harbor this morning just past 4:30 a single beam of fired into the night sky became two, a nation that had become on this, the sesquicentennial of

the assault on fort sumter, which started america's bloody four-year civil war, wreaths for more than 600,000 people who lost their lives in those years. recognition that such sacrifice proved necessary to form a more perfect union. today's events were cast not as a celebration but a commemoration. >> this obviously was the opening shots of what took the united states of america into a terrible civil war. i think in order for us to understand our own people, our own history, we have to understand what that civil war was about. >> reporter: slavery of course was at the heart of the fight between north and south, and though the confederates quickly routed union forces here on fort sumter the union ultimately won the war, forever changing the course of american history. president lincoln freed the slaves before war's end, beginning a new kind of struggle for african-americans. what one historian calls a work in progress. >> we must always remember that there's great potential in this country, its institutions, in

the constitution to further the interests of civil rights and equality and justice. that's the beauty of america. >> reporter: a beauty born of painful, self-inflicted wounds ever healing and a flag still flying, united. ron mott, nbc news, fort sumter, south carolina. that's our tuesday broadcast, april 12th. thanks for being here with us. i'm brian williams. we hope to see you right back here tomorrow evening. we hope to see you right back here tomorrow evening. good night. that led to the suspected killer. now new information into the newsroom on charges against the 15-year-old accused in the killing. and setting our sights on a brighter future, the governor going green. why some say it's the biggest thing he's done