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  1. #271
    Moderator at Work ilan's Avatar
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    How a global telescope could reveal black holes for the first time
    By Anna Nowogrodzki | Published: Thursday, June 9, 2016

    A new algorithm could finally reveal the splendors of a black hole. The MIT grad student who wrote it just needs a dozen radio telescopes worldwide to do it.


    An illustration via NASA of what a black hole may look like. The stream of ejecta is the hot gas being swallowed by the event horizon.
    M. Helfenbein, Yale University / OPAC.

    Black holes are ready for their close-up, thanks to a new algorithm which could give astronomers a way to take the first image of a black hole by next spring.

    Katie Bouman, an MIT graduate student in computer science, developed the algorithm, which essentially uses Earth as a giant radio wave dish. Bouman will present the research at the Computer Vision and Pattern Recognition conference in June.

    The problem with capturing a picture of a black hole is that even the closest one, the supermassive black hole called Sagittarius A at the center of our Milky Way galaxy, is very, very far away. Any images taken before show the effects of the black hole, rather than the event horizon itself.

    Radio waves are ideal signals for some reasons—they pass through solids, so they can reach Earth across such a vast distance—but they also have very long wavelengths. This means astronomers need a truly huge radio wave dish to capture enough waves to produce an image. To image something the size of the Milky Way black hole, Bouman explains, “You’d need a telescope the size of the Earth.”

    That’s just what the Event Horizon Telescope project is trying to create, by collecting data from radio telescopes all over the world. The project currently includes six radio telescopes, but there are not enough radio telescopes in the world that can observe at the desired frequency (1.3mm), or even enough suitable sites in the world on which to build such telescopes. (They need to be on top of mountains and at sites that limit the interference of water vapor.) Bouman’s algorithm is designed to make up the difference.

    To do this, her algorithm, called CHIRP (Continuous High-resolution Image Reconstruction using Patch priors), first combines the signals from three different telescopes. By using three, instead of two (which most others do), the delays to the radio waves caused by Earth’s atmosphere cancel each other out.

    But even after that, “there’s an infinite number of images that will perfectly describe the data,” Bouman says. So the next step is to use the data to reconstruct an image that looks like an image. That may seem self-evident, but when images are broken up into tiny patches, Bouman explains, “oftentimes there’s a lot of repeating structure: flat patches, an edge.” She built a machine-learning algorithm that identified those repeating patches, called patch models, and used them to reconstruct images.

    Amazingly, the algorithm worked when it was trained on any kind of image, astronomical or terrestrial.

    “We can take images on your phone, we can take black hole simulation images, we can take images of cats,” says Bouman. “No matter if we trained on black hole images, celestial images, terrestrial images—the patch models that we learn are all similar enough that we ended up getting the same image back in the end.”

    Multiple observatories will be used in the project, including the Sub Millimeter Array and James Clerk Maxwell Telescope in Hawaii; the Heinrich Hertz Submillimeter Telescope in Arizona; the Large Millimeter Telescope in Mexico; the Institut de Radioastronomie Millimétrique in Spain; the Atacama Large Millimeter / submillimeter Array and Atacama Pathfinder Experiment in Chile; the South Pole Telescope in Antarctica; and the NOrthern Extended Millimeter Array in France.

    Bouman’s algorithm was better than previous ones at reconstructing an image from the measurements it would yield at different telescopes, and it was better at handling noise in the data. The real test will come in the spring of 2017, when telescopes will begin collecting the data that could stitch together into our first image of a black hole.

  2. #272
    SPACE ACE Capt.Kangaroo's Avatar
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    THIS IS WHERE THE INTERNATIONAL SPACE STATION WILL GO TO DIE
    IN ONE OF THE MOST ISOLATED PLACES ON THE GLOBE, THE 'SPACECRAFT CEMETERY' PROVIDES A WATERY GRAVE




    The cold void of the ocean floor is the closest thing Earthlings can come to the conditions of space. Nothing really lives there, and nothing ever visits. It’s freezing, dark and empty. However, off the coast of New Zealand, the Pacific Ocean is home to what may be the most exclusive scientific burial ground in the world: the so-called Spacecraft Cemetery has become the final resting place for hundreds of manmade space objects.
    There are thousands of satellites and pieces of debris orbiting the Earth at any given moment, but what happens when they run out of fuel or complete their missions? Essentially, they need to get out of the sky and out of the way of other spacecraft.
    The risk of leaving a large metal object the size of a car orbiting the Earth is, well, physics. The Earth’s mass creates a gravitational pull on anything in orbit around it, gradually dragging them closer and closer to Earth. Eventually, without proper disposal, all of the orbiting spacecraft (including the gigantic International Space Station) would threaten to come hurtling down on our heads.
    The Spacecraft Cemetery has become the final resting place for hundreds of manmade space objects
    Luckily, there are scientists who know how to prevent an Armageddon scene like this from happening. Space agencies around the world carefully plan out the re-entry of these large bodies, and they’ve even chosen a place on Earth where these spacecraft can go to safely rest, far from the likes of any humans.
    Roughly 3000 miles off the Eastern coast of New Zealand, 2000 miles north of Antarctica, and 2.5 miles deep, the Spacecraft Cemetery is truly in the middle of nowhere. This isolated spot in the ocean is technically called the Oceanic Pole of Inaccessibility--the point on Earth farthest from any land mass. This spot was chosen for obvious reasons, as it greatly reduces the risk of human casualties from scorching hot space debris. (According to NASA’s Orbital Debris Office, any objects re-entering Earth’s atmosphere cannot exceed a 0.0001 chance of impact with humans, meaning that if the entry were to occur 10,000 times, there would only be one human casualty expected.)

    To date, over 263 spacecraft have been crashed here since 1971, and the number is continually growing. The Spacecraft Cemetery's most famous resident is MIR, the 142-ton Russian space station. MIR was de-commissioned in 2001 and subsequently sent into what is called orbital decay, or spacecraft death. Other spacecraft in the graveyard range from rockets' secondary payloads to spy satellites, small Russian space stations, fuel tanks, and hundreds of cargo ships that carried supplies to astronauts in orbit.
    Russian objects far outnumber every other space agency when it comes to the Pacific Ocean; there are more than 190 Russian objects alone. The US is next with 52 objects, then Europe with 8, Japan with 6, and finally SpaceX dropped its second stage here in September of 2014.
    There is a roster of objects lined up to break up over this area, but the next big ticket item likely won’t make it there for another 12 years. The International Space Station will eventually crash into the Pacific Ocean upon its decommissioning, expected sometime around 2028.



    Each line is an individual satellite or space debris and the dates in which they fell to Earth. Russia (shown in blue) has dropped the majority of objects into the Spacecraft Graveyard, but in recent years, the U.S. (red) has been catching up.

    MIR was a massive object to bring back to Earth, requiring intensive calculations to make it back safely. By comparison, the ISS is four times larger, weighs almost 500 tons, and is the size of a football field. The scientists who have to plan the re-entry of the ISS acknowledge that the entry angle for this maneuver will have to be extremely precise but should result in all surviving debris ending up in the Pacific Ocean.
    It will be a sad day when the ISS meets its demise in the cold waters of the Pacific. However, this incredibly complicated task is sure to create quite the spectacle. The re-entry of any spacecraft through the Earth’s atmosphere doesn't tend to leave anything in one pristine piece at the bottom of the ocean. It’s a pretty violent scene as the friction of the atmosphere heats metal up to thousands of degrees, forcing a once meticulously engineered craft to explode into pieces.
    As the world's space agencies and private spaceflight companies continue to grow and launch things up, eventually those things must also come back down, and the Spacecraft Cemetery will be there to welcome them upon their fiery return.
    The Spacecraft Cemetery is literally littered with a rich space history from NASA to Russia, Europe to SpaceX--it’s just too bad no one will ever get to visit.

    By Shannon Stirone Posted June 13, 2016
    popsci.com
    I gather darkness to please me...

  3. #273
    SPACE ACE Capt.Kangaroo's Avatar
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    I gather darkness to please me...

  4. #274
    SPACE ACE Capt.Kangaroo's Avatar
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    Quote Originally Posted by Captainkangaroo View Post

    Looked nice tonight
    I gather darkness to please me...

  5. #275
    Super Moderator at Work Marley's Avatar
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    i seen it when moon was coming up after that changed back

  6. #276
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    Excellent! information ...as always Guy`s.

    Thank you all.

    Regards

  7. #277
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    Quote Originally Posted by anon2599 View Post
    Excellent! information ...as always Guy`s.

    Thank you all.

    Regards
    Thanks......
    I gather darkness to please me...

  8. #278
    Moderator at Work ilan's Avatar
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    Dual Supernovae Light Up June Nights: Part 1
    By: Bob King | June 8, 2016

    Supernovae are popping up everywhere! Two stars flamed out millions of years ago and at least one is an easy catch right now in amateur telescopes.


    Type Ia Supernova 2016coj in NGC 4125 is now bright enough to see in amateur telescopes.
    You'll find it 11.7″ NE of the galaxy's nucleus. NGC 4125 lies about 72 million light-years from Earth.
    William Wiethoff


    Recent years have seen a blizzard of new supernovae discoveries from dedicated robotic searches by both amateurs and professionals. If you have any doubt, David Bishop's excellent Bright Supernova site lists 3,471 reported in 2015. Already this year, we're up to 2,910!

    Sorting through them to find visual candidates takes more time that it used to, but I'm not complaining. Among the ubiquitous 18th- and 19th-magnitude candidates there are always a few bright enough to spot in an 8-inch or larger telescope. On May 28th, two new exploding stars were discovered, SN 2016coj in NGC 4125 (a 10th-magnitude elliptical galaxy in Draco) and SN 2016cok in the bright spiral M66 in Leo, by the automated Lick Observatory Supernova Search (LOSS).

    SN 2016coj's initial brightness of ~15.5 magnitude didn't immediately shout "Hey, look at me!" But in recent days, the Type Ia supernova brightened steadily to its present magnitude of 13.6, making it fair game for 10-inch and even 8-inch telescopes.

    Several nights back, I took a look at the host galaxy in my 15-inch (37-cm) reflector. Its location near a 6th-magnitude star a short distance north of the Big Dipper's bucket made the finding easy. When I used 142×, the supernova presented itself almost immediately as a "second nucleus" about 11.7″ northeast of the true nucleus, a tiny kernel of light buried in the galaxy's core. When the seeing steadied, the supernova stood out crisply, a sharp point compared to the slightly fuzzy galactic nucleus. Here before me eyes was the end of a life, a white dwarf blown to bits in a tremendously powerful explosion brought on by ... weight gain.
    Out With a Bang


    This illustration shows the stages of a Type Ia supernova explosion like that in SN 2016coj.
    From left: a white dwarf accretes matter from a close companion until it reaches a super-critical
    state when it exceeds 1.4 solar masses; a thermonuclear explosion ensues, wiping out the star;
    and an expanding cloud of debris is all that's left.

    NASA / CXC / M. Weiss

    After feasting on its close companion star's atmospheric gases, the Earth-sized star accumulated enough material on its surface to exceed the Chandrasekhar Limit of 1.4 solar masses and undergo rapid gravitational collapse. Dire consequences followed as a runaway fusion reaction from the crushing heat and pressure raced through the star, destroying it in one titanic blast.

    Since then, SN 2016coj has continued to brighten and should be an even easier target by the time you read this. Meanwhile, SN 2016cok in the familiar galaxy M66 in Leo has taken another path.
    Another Dwarf Bites the Dust


    Supernova 2016cok (beween the tick marks) was discovered in the bright, nearby galaxy M66
    in Leo on May 28th, the same day as SN 2016coj was discovered. Unlike the latter, SN 2016cok's
    brightness has remained nearly constant at about magnitude +16.5. The new object is located 61″
    east and 34″ south of the galaxy's nucleus in an outer spiral arm. East is up and north at right.
    Gianluca Masi


  9. #279
    Moderator at Work ilan's Avatar
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    Dual Supernovae Light Up June Nights: Part 2
    By: Bob King | June 8, 2016

    Ordinarily, the words "supernova" and "M66" heard in the same sentence would make a deep-sky hunter's blood pressure spike. It was here in February 1989 SN 1989B peaked at 12th magnitude, within range of even a 4-inch. Given the galaxy's relative proximity to Earth of 36 million light-years, any supernovae there have the potential to become bright, but this one has so far remained faint.


    In a Type II supernova, an aging supergiant star runs out of nuclear fuel in its core,
    leading to a sudden collapse followed by a rebounding shock wave that rips the star
    apart. Some Type II events leave a neutron star or black hole remnant.
    NASA / CXC / M. Weiss


    Discovered by Ohio State's All-Sky Survey Automated Survey for Supernovae (ASAS-SN) at magnitude +16.6, SN 2016cok hasn't gotten any brighter than +16.4 as of June 4th.

    It may still be on the rise, though. According to a recent notification from The Astronomer's Telegram, the supernova's spectrum indicates it was caught a few days before maximum.

    While a perfect target for astrophotographers, the star presents a tough visual challenge at the moment. Maybe a 24-incher can pry this one loose, but until it cracks magnitude +15.5, I'll be sitting on the sidelines watching with interest.

    SN 2016cok is a Type IIp supernova involving the collapse and explosion of an evolved supergiant star. But instead of fading at the regular rate, the IIp variety slows or “plateaus” (hence the p) for many days before resuming its normal decline in brightness. Has the supernova already plateaued or does a "brighter future" lie ahead?
    M66 Wide and Detailed


    This dual map will help you find the 9th-magnitude spiral galaxy M66 and SN 2016cok
    located midway between the naked-eye stars Theta (θ) and Iota (ι) Leonis. The left
    half shows a wide view, the right half is zoomed in. Stars at right shown to magnitude +7.5.
    Bob King, Source: Stellarium


    You can keep track of the progress of both supernovae at the Bright Supernova site. Click and search for "M66" or "NGC 4125" or go out the next clear night and have a look for yourself. When it comes to stellar explosions, M66 is a real champ with five recorded supernovae to its name since 1973.
    Explosion Over the Bowl



    Use the bowl of the Big Dipper to navigate to NGC 4125 and its bright supernova. Stars shown to magnitude +7.5.
    Bob King, Source: Stellarium


    I wish you much success in your supernovae hunt. As you slowly twist the focusing knob to bring SN 2016coj into sharp focus, consider that this pinprick of light shines some five billion times brighter than the Sun while material within the expanding debris cloud rushes outward at 9,500 miles per second (15,300 km/s). How fortunate that you and I just happened to be around to see it 72 million years later.

  10. #280
    Moderator at Work ilan's Avatar
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    An ocean for Pluto and a thinner ice shell on Enceladus
    Plenty of good news for our ocean worlds!
    By John Wenz | Published: Wednesday, June 22, 2016



    NASA/JHUAPL/SwRI

    Once, we thought earth was the only planet with oceans. But now, we're seemingly finding them everywhere in our solar system, including possibly the last place on anybody's mind: Pluto.

    New evidence published in Geophysical Research Letters shows that the icy dwarf planet may still have a liquid ocean lurking underneath its frozen exterior. Tectonic activity on the surface of Pluto, revealed by NASA's New Horizons spacecraft, shows an absence of contraction in the surface. Contraction is the kind of thing that would be expected if the ocean had, at the depths it's believed to be at, frozen completely into a dense form of ice called Ice II. That seems to indicate it's liquid or at least slushy down there.

    Radioactive elements in the core (along with some motion from the tug-o-war between Pluto and Charon) would keep the ocean warm. There's still some chance, though, that the ice crust of Pluto is thinner than anticipated, which would lead to formation of less dense forms of ice. But flows of nitrogen ices seem to come from much deeper below, placing the ice shell as much as 300 km (186 mi) from the surface. At those depths, if there was water, it would almost certainly form Ice II. That is, unless something made it not freeze.

    Of course, we already know that Enceladus, a moon of Saturn, is an ocean world, with warm water under the ice shell spewing into space thanks to the gravitational tug of Saturn. Pluto joins that pantheon now, along with worlds like Ganymede, Europa, and Titan. But unlike Pluto, new evidence seems to indicate that Enceladus may have a much thinner ice shell than once believed.

    The research, also published in Geophysical Research Letters, suggests that the crust at the south pole of Enceladus may be as little as 3 km (1.86 mi) deep. That would also make drilling under the ice shell a more distinct possibility for a future space probe, or to have an orbiter penetrate the ice shell with radar to find out more of what's going on down below. Previous measurements of the ice shell, which placed it as much, much thicker, didn't line up with gravitational data collected by the Cassini probe.

    It's a lot of excitement for two small places in our solar system. Many astrobiologists already think Enceladus may be a high probability place to find life. But now that Pluto is on the radar, we're seeing that liquid water is even more abundant than we thought. On Earth, where there's water there's life. And now we have to recognize that there might be a chance for life on Pluto.

 

 
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