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Live Reporting

Jonathan Webb, Bernadette McCague, Matt McGrath and Paul Rincon

All times stated are UK

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  1. Goodbye

    We're now ending our live coverage of the Pluto flyby.

    If you're in the UK, turn on the ten o'clock news on BBC One.

    Everyone else - check the BBC News website over the coming days, weeks and months for more Pluto developments!

    Illustration of New Horizons over Pluto

    Thanks for reading - and congratulations New Horizons.

    After a frantic couple of days, the little probe is already 1,644,000km away from Pluto and not slowing down.

    Bon voyage!

    Graphic illustrating New Horizons' position
  2. Pluto on the telly at ten

    The Nasa briefing has concluded but if you're in the UK and you can't get enough of the #PlutoFlyby, turn on BBC One for the ten o'clock news.

    Our science editor David Shukman will be summarising the new findings.

  3. Coffee art fights back

    If you've been following our live blog since that dramatic pre-flyby picture arrived, you might remember this...

    Well, today a barista has bitten back:

  4. Nothing quite like it

    Rebecca Morelle

    Science Correspondent, BBC News

    To think that back in 1930, Pluto was a speck of light on Clyde Tombaugh's telescope plates moving against the backdrop of static stars.

    Now, that tiny dot has been transformed - for the first time, we can peer in detail onto Pluto's surface.

    At the base of the "heart" - now called Tombaugh Regio after Pluto's discoverer - is a young surface, unscarred by craters and dominated by ice mountains more than 3,000m high.

    The team here say it doesn't look like anything else in our solar system.

    It seems there's nothing quite like Pluto.

  5. Science at speed

    A spacecraft flew past Pluto for the first time yesterday.

    Today we are discussing the findings.

    As some of the chat on social media points out - this science is raw, to say the least!

    Chris Lintott is an astrophysicist and co-presents The Sky At Night for the BBC.

    Alex Parker is a researcher at the Southwest Research Institute who is involved in image processing for the New Horizons mission.

  6. Buoyant mood

    The mission team are clearly - sorry - over the moon.

    Quote Message: I don't think any one of us could have imagined it would be this kind of toy store." from Alan Stern Principal investigator, New Horizons
    Alan SternPrincipal investigator, New Horizons
    Quote Message: This is what we came for." from Will Grundy Co-investigator, New Horizons
    Will GrundyCo-investigator, New Horizons
    Quote Message: This exceeds what we came for." from Dr Cathy Olkin Deputy project scientist, New Horizons
    Dr Cathy OlkinDeputy project scientist, New Horizons
  7. A startling moment

    David Shukman

    Science editor

    Every now and again you see something that stops you in your tracks - a stunning sunset or a sight so startling that life seems to pause.

    This is one of those moments.

    Sitting in an auditorium, on a hot afternoon, with my notebook poised, all around me are the mission's scientists and engineers who can't stop grinning. For many, this must be the proudest episode of their careers.

    The detail is phenomenal. Tiny worlds that were specks of light or not even known about have suddenly become reality. We're seeing mountains and abundant frozen water on Pluto, giant canyons on its largest moon Charon, smooth surfaces that indicate active geology and a weirdly-shaped mini-moon, Hydra.

    And there's a moving twist too. Naming Pluto's vast pale heart after Clyde Tombaugh who discovered the world in 1930 offers a charming insight into the lineage of astronomy.

    You almost have to keep reminding yourself that the new images are not science fiction, but have been brought to us all the way from the edge of the solar system. And this is only the start.

  8. Active worlds: That's a 'big wow'

    Jonathan Amos

    Science correspondent, BBC News

    Wow, they didn’t disappoint, did they? And the audience in the theatre here at the Johns Hopkins Applied Physics Lab certainly thought so. Every new picture was introduced with and ooh and an ahh, and then a round of applause.  

    Nasa’s science chief John Grunsfeld said earlier this week that there was very little terra incognita left in the Solar System. But in Pluto, Charon and its other moons we are seeing virgin territory. 

    Any analysis at this stage still carries a fair bit of speculation because not all of the complementary data is in. But perhaps the biggest news is the suggestion that some of these bodies are still active, that they are not dull objects that died 4.5 billion years ago.  

    In the highest resolution image of Pluto, which showed a field of view just 250km across, there were no craters. This is indicative of a young surface, one that may well have experienced recent geological activity. 

    Pluto surface

    Now, we’ve seen this kind of thing on moons of giant planets where gravitational tides from the bigger parent can heat up the satellite and deform it. Think of Europa at Jupiter; think of Enceladus at Saturn. But where do you get the heat to drive activity on Pluto? It’s sitting out on its own in the Kuiper Belt with nothing to squeeze it gravitationally. Charon certainly couldn’t do it; it’s too small. 

    So, what this tells us is that you do not need ongoing tidal heating to power geology on icy worlds. In science terms that’s certainly a big wow.  

  9. Zooming in on Pluto

    From a blurry distant object to a close up of Pluto's mountains and other features on the frozen surface

    View more on twitter
  10. Post update

    Alan Stern, the mission's principal investigator, also said he expects there may be ice volcanoes and geysers on Pluto - he and the team are looking forward to hunting for them in the data still streaming back from New Horizons.

  11. Back to the drawing board

    That finding of recent activity on Pluto's surface, mission chief Alan Stern says, is "going to send a lot of geophysicists back to the drawing boards".

  12. Mysterious mountains

    Spencer adds that Pluto has a "very young surface" - i.e. less than 100 million years old - because of the striking lack of impact craters.

    It also has mountains that are at least a staggering 11,000 feet tall.

  13. The first ever Pluto close-up!

    Spencer now unveils the first view from much closer to Pluto's surface.

    It shows what he describes as the dwarf planet's "icy bed-rock" - the team has calculated that these mountainous features must be water ice rather than methane or nitrogen.

    Pluto's surface

    "This is the first icy world we've visited that hasn't been orbiting a giant planet," Dr Spencer says.

    The other worlds like this have all been moons.

  14. A memorial to Clyde!

    John Spencer, a mission co-investigator from the Southwest Research Institute, announces that the heart-shaped region on Pluto is to be named "Tombaugh Regio" - commemorating the discoverer of the dwarf planet, Clyde Tombaugh.

  15. Grander than grand

    Dr Olkin now explains that Charon has a vast canyon four to six miles deep.

    "A small world with much to show us."

  16. Charon comes into focus

    Now we see Pluto's giant moon Charon!

    Pluto's moon Charon
    Quote Message: This image just blew our socks off." from Cathy Olkin Deputy project scientist, New Horizons
    Cathy OlkinDeputy project scientist, New Horizons
  17. Hello, Hydra

    The first image to be revealed is of the Pluto's littler moon Hydra.

    Project scientist Hal Weaver explains that before New Horizons took this picture, we didn't even know how big this moon was.

    Now we can just count the pixels!

    Pluto's moon Hydra

    It's about 45km by 30km, and Weaver said it probably contains water ice.

  18. Good day

    No images yet - but the mission's principal investigator has started with a masterful understatement.

    Quote Message: I had a pretty good day yesterday, how about you?" from Prof Alan Stern
    Prof Alan Stern
  19. Tune in

    The briefing begins!

    Use the Live Coverage tab above to watch.

  20. New things every day

    Dr Cathy Olkin from the Southwest Research Institute was speaking earlier to our science correspondent Jonathan Amos. 

    This is an exciting time for her and the rest of the team. 

    Quote Message: This is all so special. We're learning new things every day.
    Quote Message: Every time the spacecraft communicates with the deep-space network and sends its data down - we learn something new. It's just remarkable to me that all this data is sitting on the spacecraft, just waiting for us to unlock its secrets." from Cathy Olkin Deputy project scientist, New Horizons
    Cathy OlkinDeputy project scientist, New Horizons
  21. 'Like winning the World Cup'

    Jonathan Amos

    Science correspondent, BBC News

    New Horizons is an American mission paid for by American taxpayers (thank you). But run through the team members and you’re sure to find some Brits.  

    Perhaps the best-known are senior scientists like Fran Bagenal, who grew up in my part of the world (Cambridge), and John Spencer, who’s a Lancashire man. He confesses to still listening to the cricket on the radio even though he’s spent most of his career in the US.  

    And then there are the younger scientists like Carly Howett. She hails from Essex and is now affiliated to the Southwest Research Institute, working on New Horizons' Ralph colour camera.  

    When I asked her what the past few days have been like, she said: “It’s like England winning the World Cup at the same time as the Ashes, thrown in with Olympic golds and Murray winning Wimbledon.”

    Yep, she’s a Brit.

    View more on Soundcloud
  22. Post update

    While we all anxiously await the fruits of its labour, New Horizons keeps on moving...

  23. Eye-popping

    This photo shows New Horizons team members looking over newly downlinked data.

    Something seems to have caught Alan Stern's eye! The mission chief is centre right looking rather excited.

    Mission scientists poring over images on a laptop
  24. Seeing a new world in 3D

    Jonathan Amos

    Science correspondent, BBC News

    One of the pictures we'll get in the next release from the New Horizons team will look very similar to the full-frame image of Pluto that was acquired just before the flyby. Indeed it was taken just 15 minutes prior to the view that so wowed the world. 

    The differences between the two will therefore be quite subtle, but they will also be very important. This new image that's coming is the partner image that makes a stereo pair. Stereo is a critical tool to planetary scientists when they're trying to interpret features on the surface. 

     "When you look at an enigmatic surreal terrain, your eye cannot tell which is up and which is down, and the stereo gives you that," explains Will Grundy, a team-member from the Lowell Observatory. 

     "You cannot do shape from shading, because you just have no idea whether the slopes that are tilted towards you are also brighter or are they brighter only because they are illuminated by the sun." 

    If you look at Tuesday's stretched-colour image of Pluto, it revealed that the "heart" had two distinct "ventricles", and the division between the two was very pronounced. But what does it signify? Does it indicate different materials, maybe different surface and atmospheric processes at play? 

    Before you can start to answer those kinds of questions, you need elevation information. One half of the heart could be a basin, one half could be a plateau - and different things can happen in such diverse settings. 

    I don't know if the team will present the pair together, but if they do we'll likely need some of those funny glasses to see the stereo effect. 

  25. 90 minutes to go

    Not long now until we hear from the mission scientists again! You'll be able to watch the briefing right here - scheduled to start at 20:00 BST.

    Expect to see Pluto and Charon in apparently spine-tingling detail, 10 times better than this (and from a slightly different angle).

    Pluto seen by New Horizons before the craft's flyby
  26. Fluid situation on Pluto

    Speculation is growing about some of the details that images, expected in a few hours from New Horizons, will reveal about the surface of Pluto. 

    Co-investigator Will Grundy has been quoted on social media as saying that Pluto is covered in exotic ices - Nitrogen, methane and carbon monoxide - in fact, he says, we've not even made some of these ices in the lab yet! 

    No tell-tale signs of liquid on the surface, but he can't rule out sub-surface liquids.

  27. 'In for a treat'

    This sounds promising!

    Andy Rivkin is a researcher at the Johns Hopkins University Applied Physics Laboratory, home of the New Horizons operations centre. 

    View more on twitter
  28. Calm before the storm

    Our science editor David Shukman is also at the operations centre in Baltimore, looking forward to the new results. 

  29. 'Spectacular' images... soon

    Rebecca Morelle

    Science Correspondent, BBC News

    The scientists here can't stop smiling this morning.

    The data is back. The images are processed. And we've been told that they're spectacular: a full frame shot of Pluto in the best resolution yet, extreme close-ups of its surface - and a snap of its largest moon Charon too, revealed in all its glory.

    But... the world will have to wait a little longer to see them! We'll have to hang on until 3pm local time (20:00BST) when they'll be unveiled at mission HQ.

  30. Trickle of results

    The New Horizons spacecraft is now splitting its time between taking more measurements and sending priority data home.

    It will take more than a year to send all of its Pluto payload - not only is the distance vast, but the maximum transmission speed is one kilobit (125 bytes) per second.

    NPR science correspondent Geoff Brumfiel makes an earthbound comparison:

    Remember you can check when and where signals from New Horizons (code NHPC) are being received on the web page for Nasa's Deep Space Network - currently the goods are coming via Australia...

    Screengrab from Deep Space Network live site
  31. Pluto's heart inspires

    Social media has really taken Pluto to heart - especially the heart shaped region that dominates yesterday's spectacular image. It's been the subject of countless tweets and even members of the New Horizons mission team are getting in on the act.

    View more on twitter
  32. Science never sleeps

    It didn't all end yesterday! New Horizons is still moving at more than 30,000mph...

  33. Data delivery

    The "first look" batch of data, including close-up photos of Pluto and Charon from the flyby, has been spotted by Prof Chris Lintott from the BBC's The Sky At Night.

    (He has been watching - closely - the live website for Nasa's Deep Space Network of antennas, which receive the signals after their 5bn km journey...) 

  34. Good night from London

    You can expect a lot more from New Horizons over the next day or so - especially at the next main Nasa announcement, expected at 20:00 BST on Wednesday. 

    But particularly if you're in the UK (like the online team running this live page) it is probably time for some shut-eye!

    Check back tomorrow for more updates - and write down this time:

  35. Woman of the hour

    The name of mission operations manager (MOM) Alice Bowman is now trending on Twitter.

    It was also chanted in the auditorium during the briefing - and the journalists in attendance were all on board...

  36. Hold the front page

    Alan Stern tells the room that the packet of data his team expects to receive on Wednesday morning, US time, has been dubbed "the New York Times data set".


    Quote Message: We think it's going to be pretty interesting." from Prof Alan Stern Principal investigator, New Horizons
    Prof Alan SternPrincipal investigator, New Horizons
  37. Just quietly...

    Alan Stern, New Horizons mission chief, is speaking now at the briefing (use the Live Coverage tab above).

    Half an hour ago he sent this tweet.

  38. So much more to come

    Nasa science chief John Grunsfeld emphasises that this is just the beginning - comparing today's flyby event to the landing of the Curiosity rover on Mars.

    All the science is still on its way.

    Quote Message: If you think it was big today, wait until tomorrow. And the next day." from John Grunsfeld Associate administrator for science at Nasa
    John GrunsfeldAssociate administrator for science at Nasa
  39. 'Pluto kids'

    Sitting among the journalists and other visitors to the operations centre are some special guests...

    Children at the Nasa briefing who were born on the day New Horizons launched
  40. 'It's still busy'

    Jonathan Amos

    BBC Science Correspondent

    Boy, are there some happy people here in Laurel, Maryland!

    I've just spoken with Hal Weaver, the New Horizons project scientist. Like me, he was waiting for the call on the autonomy logs. Unfortunately, neither of us could then hear the next call (because of the cheering), which concerned the status of the solid-state recorder. No matter, it was clear from the faces in the mission operations centre that the recorder was full of data.

    "What you heard means the flyby must have worked perfectly," he said.

    "All the pictures must be onboard. But obviously I won't quite believe it until I see some of them. We have to make sure that they're not affected by streaking or some other artefacts."

    New Horizons dropped the link to Earth at nine minutes past the hour. It's still busy making observations of Pluto and its moons. But it will phone home again during the night, and that will be a much longer pass.

    In that contact we'll get a first look at some really high-resolution pictures from the flyby - far more detailed than the spectacular pictures we were shown on Tuesday as a preview to the main event.

    Standby for something special from Pluto, its main moon, Charon, and its minor moons Hydra and Nix.

  41. Rock stars

  42. Don't go away!

    Another briefing is due to start at 02:30 BST.

    We will hear a mission status update from the scientists who just flew a probe past Pluto.

    Stay tuned...

  43. Indications of a triumph

    Jonathan Amos

    Science correspondent, BBC News

    The crucial call came over what were called the autonomy logs - these recorded any upsets that New Horizons might have had during the flyby. 

    The fact that it had none meant the observation sequence must have run without a hitch. 

    Controllers will not know until they examine what is in the memory that they did indeed have the data - but all the indications are that this historic fly by was a triumph. 

  44. Ain't seen nothing yet

    Rebecca Morelle

    Science Correspondent, BBC News

    Well, the cheer this morning for countdown was pretty incredible, but it wasn't a patch on the wave of joy - and relief - that just swept through the auditorium here at mission HQ.

    They have heard back: they have a healthy spacecraft with a memory full of images and other science data. Wow.

    If you thought the image today was amazing - we haven't seen anything yet...

  45. Still talking...

    If you go to the website for Nasa's Deep Space Network you can still see the signal coming through from New Horizons to Madrid.

    It will drop shortly, Jonathan Amos explains:

  46. Smiles all round

    Our correspondents at mission control are enjoying the atmosphere.

  47. Tick, tick... and tick

    Quote Message: We have a healthy spacecraft, we have recorded data from the Pluto system, and we are outbound from Pluto.
    Quote Message: I can't express how I feel! It's just like we planned it!" from Alice Bowman New Horizons mission operations manager
    Alice BowmanNew Horizons mission operations manager
  48. Post update

    "We are in lock with telemetry from the spacecraft," said mission operations manager Alice Bowman.

    And the house came down.

    Waiting for a few more details from New Horizons now...

    mission control room
  49. BreakingThe probe phoned home!

    First post-flyby signal received at mission HQ

    Celebrations have erupted among mission scientists and the hundreds of assembled journalists and visitors - including relatives of Clyde Tombaugh, who discovered Pluto, and James Christy who discovered its moon Charon.

  50. Packing them in

    Our science editor David Shukman is on the scene...

  51. Three minutes to go!

    All we can do is wait...

  52. Quite a contrast!

    This is the view a few moments ago in the mission control room.

    Mission control room awaiting "phone home"

    Bustling with excited scientists and engineers!

    Remember what it looked like when New Horizons actually soared past Pluto 13 hours ago? 

  53. Watch live

    You can now watch the Nasa briefing - awaiting the "phone home" from New Horizons - using the Live Coverage tab above.

    "We are flying through the safest part of the Pluto system," says project scientist Hal Weaver - explaining that New Horizons' path should have been cleared by Pluto's chunky moon Charon.

    So the chances are good that we will hear from the probe.

    But cross your fingers anyway...

  54. Last of the nine, or the first of the Kuiper Belt?

    Many people are keen to use today's history-making flyby as an excuse to welcome Pluto back onto the list of our Solar System's nine "official" planets.

    This image, and others like it, have had thousands of retweets.

    Whether or not Pluto's status is still official - it's inspiring to think that today we've added a significant chunk of knowledge to our understanding of the Solar System.

    Read more about the planet-or-not-a-planet controversy here:

  55. Relive the countdown

    While we are waiting for the Nasa briefing to start at 01:30 BST (you'll be able to watch it right here on this page), why not relive the excitement of today's countdown?

    This was the moment of New Horizons' closest approach - which it made in radio silence. 

    View more on Soundcloud
    View more on vine

    If New Horizons stays silent, these celebrations may have been premature! But all the mission scientists sound very confident that they will get a "phone home" signal in about half an hour's time.

  56. Less than one hour to go!

    Jonathan Amos

    BBC Science Correspondent

    New Horizons' call home is due at 00:53 GMT Wednesday (01:53 BST). It will come through a giant dish in Madrid, Spain - part of Nasa's Deep Space Network of communications antennas.

    You can watch it come in yourself at the Nasa Eyes DSN webpage.

    screengrab from the NASA Deep Space Network's website

    Receipt of signal should appear on the page no more than about five seconds after the real event.

    'The phone will ring'

    Now, while we've talked about this tiny concern over New Horizons being damaged in a collision with some icy or dusty debris during its flyby, everyone you speak to on the mission is confident the "phone will ring". But it might not, and if it doesn't there are plenty of benign reasons.

    One of the main ones is just the general difficulty of picking up what is a very faint signal. The ground antenna and the probe will go through a series of "handshakes" before a stable link is established. It may take a little while for that process to be completed. Be patient. When it is established and the telemetry starts to come down, controllers will also need a bit of time to understand what it all means.

    So, what will they be looking for? They won't be able to see any images or other types of science data. All they'll look for is evidence that the spacecraft is healthy - that in its logs there are no records of any upsets during the period of flyby. And - and this is key - they'll want to see that the memory storage onboard has been filled, because that will suggest all the precious pictures were indeed acquired.

    And what if the phone doesn't ring? Or the handshakes are made too late for controllers to get the information they need? Well, we'll all have to come back eight hours later when there is another opportunity for a connection.

  57. Precision putting

    Pete Marshall got in touch with another suggested analogy relating to today's historic flyby (see our question three posts ago):

  58. 'We all have our fingers and toes crossed'

    Our science correspondent Jonathan Amos has been speaking to John Grunsfeld, Nasa's head of science.

    He was full of excitement and pride, but said the team will be "a little bit concerned" until they hear from New Horizons tonight.

    Quote Message: In just 50 years, we've gone from the first flyby of Mars with Mariner 4 to the first flyby of Pluto. 50 years! That's pretty short when you consider that making the first map of the Earth and understanding its continents took hundreds of years.
    Quote Message: In 500 years from now in Encyclopaedia Galactica, if such a thing exists, I think historians will look back at this time and say that it truly was the golden era, or the classical age, of space exploration.
    Quote Message: We still wonder whether New Horizons survived the encounter. We all have our fingers and toes crossed. But every indication is that it should have, and we'll know tonight. It's not exactly the 'seven minutes of terror' (a reference to landing probes on Mars), but we are all a little bit concerned until we actually get the signal from the spacecraft. Lots of things can go wrong.
    Quote Message: But as to the question about whether this is going to inspire - I think we've answered that. Just the mission to Pluto was intriguing, and I think we're already inspiring millions and millions of people around the world with the little probe that could." from John Grunsfeld Associate administrator for science at Nasa
    John GrunsfeldAssociate administrator for science at Nasa

    When Jonathan sent us these quotes he summed it up as follows:

    "We wait for a great day to become a perfect one."

  59. Socks blown off

    Jonathan Amos

    BBC Science Correspondent

    It's gone pretty quiet here at the Johns Hopkins Applied Physics Lab - the mission operations centre for the New Horizons probe.

    I can hear a cocktail party in the background as VIP guests while away the time before the expected receipt of the spacecraft's "phone home signal".

    Whatever the outcome - and I don't really expect much drama - this has been one of those good days for science, for engineering and just putting it out there.

    Principal investigator Alan Stern called it right this morning when we saluted the ingenuity of the human species.

    Think about it. It's little more than 110 years since the Wright brothers made the first successful powered flight in an aeroplane, and here we are today with another vehicle - albeit a robot - flying past Pluto at 14km/s at a distance of 4.7 billion km.

    The idea that it can go all that way, taking nine and a half years, and arrive at a pre-determined point ready to make the flyby, arriving just 70 seconds early - well, that blows my socks off.

    Pluto and Charon in stretched Ralph images
    Image caption: Hello Pluto, hello Charon
  60. Broken-hearted?

    Prof Chris Lintott, astrophysicist and presenter of BBC's The Sky at Night, has filed this video round-up of today's events.

    "It's been a busy one," he says, demonstrating remarkable powers of understatement.

    View more on twitter
  61. Choose your analogy

    BBC Two's Newsnight just compared New Horizons' buzzing of Pluto today (a separation of 12,472km at last estimate) to the distance from London to Jakarta. 

    That's not bad: 11,715km. 

    What's your best analogy? You can tweet Jonathan or Paul with suggestions.

    We like saying the craft got within one Earth diameter (about 12,735km on average) - which, apparently, is also about half the total length of the Great Wall of China !

    Not bad after travelling five billion km...

  62. Just over two hours to go...

    Nasa's now world-famous probe has (hopefully) already sent its "phone home" message! That much-anticipated signal should be received at approximately 01:53 BST.

    There will be a live broadcast from mission control starting at 01:30 BST.

    Meanwhile - this graphic from the official New Horizons Twitter account is a nice reminder of how far away the little spacecraft is, and the vast territory that it is headed into...

  63. Hawking's congratulations

    In a recorded message to the New Horizons team, Cambridge University astrophysicist Prof Stephen Hawking congratulated them on their "pioneering mission"....

    Quote Message: Billions of miles from Earth, this little robotic spacecraft will show us the first glimpse of mysterious Pluto

    He noted that it was 50 years since Mariner 4, the first successful mission to Mars, sent back 21 images of Earth's neighbour. Now New Horizons will uncover new details of a much more distant red planet.

    Quote Message: We explore because we are human and we want to know

    You can see the video message in its entirety here:

    View more on youtube
  64. Planetary love affair

    A lot of messages of affection for Pluto have been shared on social media today, in response to the "heart" it flashed at Earth.

    This one has been shared so widely it's hard to know where it started...

    Pluto picture with "Thanks for visiting" message

    Meanwhile US astronaut Scott Kelly, who is four months into a year in space, sent this one from the International Space Station!

  65. Switch on the telly

    If you're in the UK, tune into Newsnight now on BBC Two!

    Our science correspondent Rebecca Morelle is about to give a live update from Baltimore...

    And if you missed Rebecca's short film all about Pluto on Newsnight yesterday, you can find it in the "Key Video" tab above...

  66. Send us your views


    Adham Fisher, Leicester:

    As far as we know, Adham, yes - that portion of Tombaugh's ashes are the farthest-flung human remains, by quite some distance!

  67. Spin, Pluto, spin

    While we're waiting for New Horizons to spin around and ping a message home - look at Pluto itself spinning! 

    Amateur space imager  Björn Jónsson created this animation showing Pluto rotating in all its new high-resolution glory.

    View more on youtube

    It is built up from images taken during New Horizons' approach, right up to - and including - the full-frame shot snapped just before the flyby and released today.

  68. 'Refreshingly raw'

    David Shukman

    Science editor

    There's something refreshingly raw about covering this extraordinary and uplifting story. As we catch the scientists in the corridors or listen in to their briefings, one impression is overwhelming: that they're blissfully ignorant about what's hitting them and are rather enjoying the novelty of not being able to explain anything.

    This is because the Pluto venture is discovery in its purest, least processed and most thrilling form. We're experiencing the cosmic equivalent of landing on a totally unexplored shore. I keep picturing someone like Charles Darwin startled by a strange animal and having no frame of reference to even begin to understand it. Pluto and its moons are so unknown that every hour seems to bring more surprises. And, when we ask questions, we no longer expect confident answers but have become used to hearing an amused "don't know".

    Other favourite phrases include "well, that's just an idea" and "this is our first attempt on the back of an envelope". One that may become classic was the scientist who started to offer an explanation before admitting with a chuckle that he was only thinking of a theory and that "he was making it up right now". Everyone laughed with him. And this makes the mission all the more exciting. Usually us journalists are dealing with finished, polished research findings. Not here. We all feel like we're on the journey of discovery too.

  69. A waiting game

    Jonathan Amos

    BBC Science Correspondent

    Very soon, New Horizons will start to transmit a signal to Earth to tell the mission team it has achieved its objectives. That's a slight exaggeration: it's a report on the health status of the probe, but this will be enough for controllers to know the flyby was very likely successful.

    But the thing you should try to grasp is the vast distance this radio message must cover. Today, New Horizons is 4.7 billion km from Earth. At this separation, a light signal takes a shade over four hours and 25 minutes from transmission to receipt. Therefore, if the probe sticks to the plan and starts to send its telemetry at 20:27 GMT, it should be hitting Nasa's antenna at 00:53 GMT, Wednesday (01:53 BST).

    But the eye-opener is how long the signal takes just to cross the orbits of the outer planets on its way into the inner Solar System. It takes almost half an hour to cross the orbit of Neptune, and it's almost two hours before it crosses the orbit of Uranus. And by the time it gets to Saturn, it's been in flight for just over two hours and fifty minutes. The Solar System really is a big place, and Pluto really is a long, long way from Earth.

  70. Onward and outward...

    New Horizons is now soaring away from Pluto but it is still working to collect information.

    It hasn't even paused yet to send its "phone home" message to say all is well!

  71. Psychedelic colour comes to Pluto!

    Jonathan Amos

    Science correspondent, BBC News

    So, now we’ve got some proper colour images of Pluto and its main moon, Charon, taken on Monday and returned prior to the flyby. 

    They come from New Horizons’ Ralph camera. It’s the information from this camera that was used to colour the spectacular black-and-white image of Pluto released earlier on Tuesday, taken with the long-range camera, Lorri. The advantage of Lorri is that it has four times the resolution of Ralph, but Ralph has some special tricks up its sleeve that Lorri doesn’t.  

    Pluto and Charon in exaggerated colour

    One of the things you can do with its pictures is stretch the colours to amplify property differences in surface materials. You wouldn’t ordinarily see such differences in just a black-and-white image. When you do this stretching with Pluto, you see its “heart” is actually two very distinct regions. Two distinct ventricles, if you like. The north pole of Pluto looks very yellow in this treatment, and we also see linear features starting to emerge. 

    All of this can hint at differences in composition and surface processes.  

    “From the ground, we knew there were a lot of colours on Pluto, but we never imagined anything like this,” said Cathy Olkin, the New Horizons deputy project scientist. 

    But remember, these colours are exaggerated.  

    The same approach to Charon highlights its unusual dark pole. Quite why it is so dark is a mystery, but the Ralph data is opening ideas. One is that atmospheric molecules are coming off Pluto and hitting Charon. They bounce around and stick to where it’s coldest – the poles. Once stuck, they get processed by ultraviolet light and cosmic rays to produce more complex – and darker – molecules referred to as tholins. 

    This is science on the go!  

  72. Will Pluto's orange be the new black?

    Rebecca Morelle

    Science Correspondent, BBC News

    It's only lunchtime here, but some of the scientists are starting to look a little bleary eyed.

    I just chatted to John Spencer - part of the New Horizons science team - who said he'd had about an hour's sleep last night.

    He was up until 3am processing the Pluto image that has so wowed the world today. It involves combining information from the probe's black and white hi-res camera with what was captured by the lower-res colour imager, Ralph. But - and I think everyone would agree - it was worth losing a bit of sleep over!

    Later we might see some more colour images coming back - with patches of deep orange and black standing out against the soft beige backdrop.

  73. Add to the debate


    Alan Puckey:

  74. Send us your comments


    Timothy Smith:

  75. Pluto features prompt speculation

    As they endure the long wait before receiving confirmation from New Horizons that it has safely flown past Pluto, scientists at mission headquarters have been outlining some of the features that might become apparent on the dwarf planet when the probe begins to download images tomorrow evening. There have been discussions about the red colour, tectonic plates, even mountains!

    The bright white area at the bottom of the most recent image, rapidly dubbed the "heart" has provoked much comment on social media. 

    View more on twitter

    Others have been using the flyby as an opportunity to re-open old wounds about Pluto's status - planet or dwarf planet?

    View more on twitter

    And some have used the long gap between flyby and "phone home" to polish their artistic skills....

    View more on twitter
  76. Take part


    Richard Bevan:

  77. Add to the debate


    Tom Spencer:

  78. Take part


    Siobhán, Norwich:

  79. In on the action

    Jonathan Amos

    Science correspondent, BBC News

    Here’s looking at you, kid! The Rosetta probe has taken a picture of Pluto.  Okay, Europe’s spacecraft, which orbits Comet 67P, is a long, long way away from the dwarf planet, but the dot-like picture is still neat. Why? Because both objects – Comet 67P and Pluto – are Kuiper Belt objects.  

    The comet likely originates from that same zone of the Solar System where the dwarf planet continues to live. Somehow, the icy dirt-ball got disturbed and sent into the inner Solar System. In fact, we think there are quite a few KB objects that have done this, and not just comets.  

    Triton, the moon of Neptune, is very probably a one-time Kuiper Belt resident that got thrown inwards, only to be captured in the gravity of the gas giant. Today, Rosetta and Comet 67P are 194 million km from the Sun. New Horizons and Pluto, on the other hand, are 4.9 billion km from the Sun. Both are great space missions. If 2014 was the “year of the comet”, then 2015 is very definitely the “year of Pluto”.

    Rosetta image of Pluto
  80. Anxious hours ahead

    Rebecca Morelle

    Science Correspondent, BBC News

    After the elation and cheers at the moment of closest approach and the gasps after the incredible picture was revealed - things are now starting to get a tiny bit tense.

    The scientists here won't find out for many hours whether this flyby has actually worked or not.

    At a press briefing, Alan Stern said there's a chance of about one in 10,000 that New Horizons could fail. But he said he's confident that won't happen.

    After nearly a decade of waiting, I reckon these last few hours will feel like an eternity for the New Horizons team...

  81. 'Nervous and proud at the same time'

    Head of mission operations Alice Bowman
    Quote Message: I am feeling a little bit nervous like you do when you set your child off, but I have absolute confidence that it is going to do what it needs to do to collect that science, and it's going to turn around and send us that burst of data and tell us that it's ok. I'm nervous and proud at the same time. from New Horizons mission operations manager Alice Bowman
    New Horizons mission operations manager Alice Bowman
  82. Send us your reaction


    Caol, Glasgow:

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    Paramjit Grewal:

  84. On your feet

    Jonathan Amos

    BBC Science Correspondent

    In some ways, this will be one of the most memorable pictures this week. It shows New Horizons team members at the moment they first saw the full-frame image of Pluto released today.

    The team saw it hours before the rest of the world, at their morning briefing. What you see is unbridled joy after nine-and-a-half years of flight across the Solar System, and many more years of development before that.

    New Horizons probably has its origins in scientific meetings held in the late 1980s. If you'd worked all that time just for this moment, you'd jump out of your seat as well.

    New Horizons team members celebrating
  85. Send us your comments


    In response to our earlier post about New Horizons radio signals being received in Australia,  Frank Desmond emails:

    Actually Frank, that dish was in Parkes in New South Wales. The tracking station receiving New Horizons data is just outside Canberra.

    Coincidentally, it would take about as long to drive between the two as it does for NH radio signals to transmit home from Pluto!

  86. 'Aren't we an amazing species?'

    Jonathan Amos

    Science correspondent, BBC News

    The world’s media descend on to the stage after the press briefing to talk to Alan Stern, New Horizons’ principal investigator. 

    I reach out to grab his hand to offer congratulations.  He hangs on to it, and we discuss the significance of the day. 

    “Aren’t we an amazing species, a truly amazing species?” he says.

  87. Snows of Pluto

    Mission chief Alan Stern says there is evidence of "surface activity" on Pluto, a tantalising hint of earth-like tectonics "in its past or even its present".

    But might it snow?

    Quote Message: “It is clearly a world where both geology and atmosphere, climatology, play a role. Pluto has strong atmospheric cycles, it snows on the surface, the snows sublimate and go back into the atmosphere each 248 year orbit…” from Alan Stern, New Horizons principal investigator
    Alan Stern, New Horizons principal investigator
  88. 'Earlier and closer than planned'

    Jonathan Amos

    BBC Science Correspondent

    You have to take your hat off to the space navigators. The ability today to drive probes precisely around the Solar System is extraordinary.

    To get into position for today's flyby, New Horizons had to hit a "keyhole" in space just 100km by 150km, and arrive at that location within a set margin of 100 seconds.

    The last indications were that New Horizons was on the button of that aim point, being perhaps 70km closer to the surface of Pluto than anticipated, and arriving about 72 seconds early. But, hey, that's pretty good going after a multi-billion-km flight lasting nine and a half years.

    It does mean of course that with a closest approach of 12,472km from the surface (rather than 12,542km as planned), the best images will have just a little bit better resolution than expected.

    We can live with that.

  89. Chances are good

    A reminder, as mentioned earlier, that there is a very small chance New Horizons will come a cropper. 

    The team, led by principal investigator Prof Alan Stern, sounds confident!

  90. Behind the scenes

    Nasa has released some images showing tension and jubilation among members of the New Horizons team, waiting to see the fresh image of Pluto.

    New Horizons team members await news
    New Horizons team members celebrating
  91. Tense excitement

    David Shukman

    Science editor

    The cheering and jubilation are phenomenal. There's a powerful sense of achievement at sending a robotic craft three billion miles to Pluto.

    But there's also something much more instinctive: the thrill of witnessing and sharing a great moment of discovery. Most moving for me has been catching a few words with the son of the man who first found Pluto.

    Al Tombaugh is obviously delighted that a sample of his father Clyde's ashes is on board New Horizons, speeding past Pluto and now heading into the unexplored realm of the Kuiper Belt. I asked Al if his father would have wanted to visit the tiny world. Maybe, he said, but he was always worried about the physical strain of life as an astronaut.

    Al Tombaugh and David Shukman

    Another thought that's very striking here today: so many scientists and engineers and technicians have had a hand in making this mission work, and their excitement is totally justified.

    So what about the coming hours? No one here will truly relax until the next signals reach home as the spacecraft slips beyond Pluto.

  92. Busy bee

    As word of its flyby, and the last image it took beforehand, travel around the world - it's worth remembering that New Horizons is still frantically acquiring photos and measurements.

    Shortly after passing Pluto, it made its closest approach to the dwarf planet's biggest moon, Charon, at 13:04 BST.

    Illustration of Pluto and New Horizons

    We'll hear from it again - with any luck - in just over 12 hours' time.  

  93. True exploration!

    The briefing is underway - click the "Live Coverage" tab above to watch.

    It's a very, very big day for the New Horizons team.

    Quote Message: This is true exploration...that view is just the first of many rewards the team will get. Pluto is an extraordinarily complex and interesting world. from Alan Grunsfeld, Nasa associate administrator
    Alan Grunsfeld, Nasa associate administrator
  94. Radio silence

    Wow. 15 minutes out from New Horizons' closest approach - this is what the mission control room looked like!

    As you've heard from our science correspondent Jonathan Amos - the probe is too busy to phone home until much later tonight.

    You'll get all the updates right here!

  95. Quite a legacy

    A tweet from our science editor David Shukman, also at the operations centre in Maryland:

  96. Stay tuned...

    Coming up at 13:15 BST there will be a briefing direct from the New Horizons operations centre - including an update on what the team received from the probe last night, before it went silent for the flyby.

    You can watch using the "Live Coverage" tab above.

  97. Pluto part of 'historic cycle'

    Quote Message: “We have completed the initial reconnaissance of the Solar System, an endeavour started under President Kennedy more than 50 years ago and continuing to today under President Obama. It’s really historic what the US has done, and the New Horizons team is really proud to have been able to run that anchor leg and make this accomplishment.” from Alan Stern, New Horizons principal investigator
    Alan Stern, New Horizons principal investigator
  98. A spectacular vista

    Jonathan Amos

    BBC Science Correspondent

    A "love note" from 4.7bn km, they're calling it. Do you like it?

    This is the last full-frame image that New Horizons sent down to Earth before going radio silent for the flyby. What you see is a combination of data - of a high-resolution, black-and-white image from the probe's Lorri camera, and colour information from the spacecraft's lower-resolution Ralph camera.

    In this view, Lorri sees the surface at about 4km per pixel, while Ralph's information is roughly 28km per pixel. So, it's a bit of clever work on the part of the image processors.