Blog

The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion. It is one of the brightest nebulae and is visible to the naked eye in the night sky. It is 1,344 ± 20 light-years (412.1 ± 6.1 pc) away and is the closest region of massive star formation to Earth. The M42 nebula is estimated to be 24 light-years across. It has a mass of about 2,000 times that of the Sun. Older texts frequently refer to the Orion Nebula as the Great Nebula in Orion or the Great Orion Nebula. The entire Orion Nebula in a composite image of visible light and infrared; taken byHubblein 2006. Physical characteristics The Orion Nebula is visible with the naked eye even from areas affected by some light pollution. It is seen as the middle "star" in the "sword" of Orion, which are the three stars located south of Orion's Belt. The star appears fuzzy to sharp-eyed observers, and the nebulosity is obvious through binoculars or a small telescope. The peak surface brightness of the central region is about 17 Mag/arcsec 2 (about 14 milli nits) and the outer bluish glow has a peak surface brightness of 21.3 Mag/arcsec 2 (about 0.27 millinits). (In the photos shown here the brightness, or luminance, is enhanced by a large factor. The Orion Nebula contains a very young open cluster, known as the Trapezium due to the asterism of its primary four stars. Two of these can be resolved into their component binary systems on nights with good seeing, giving a total of six stars. The stars of the Trapezium, along with many other stars, are still in their early years. The Trapezium is a component of the much larger Orion Nebula Cluster, an association of about 2,800 stars within a diameter of 20 light years. Two million years ago this cluster may have been the home of the runaway stars AE Aurigae, 53 Arietis, and Mu Columbae, which are currently moving away from the nebula at speeds greater than 100 km/s (62 mi/s).   Coloration Observers have long noted a distinctive greenish tint to the nebula, in addition to regions of red and of blue-violet. The red hue is a result of the Hα recombination line radiation at a wavelength of 656.3 nm. The blue-violet coloration is the reflected radiation from the massive O-class stars at the core of the nebula. The green hue was a puzzle for astronomers in the early part of the 20th century because none of the known spectral lines at that time could explain it. There was some speculation that the lines were caused by a new element, and the name nebulium was coined for this mysterious material. With better understanding of atomic physics, however, it was later determined that the green spectrum was caused by a low-probability electron transition in doubly ionized oxygen, a so-called "forbidden transition". This radiation was impossible to reproduce in the laboratory at the time, because it depended on the quiescent and nearly collision-free environment found in the high vacuum of deep space. History There has been speculation that the Mayans of Central America may have described the nebula within their "Three Hearthstones" creation myth; if so, the three would correspond to two stars at the base of Orion, Rigel and Saiph, and another, Alnitak at the tip of the "belt" of the imagined hunter, the vertices of a nearly perfect equilateral triangle with Orion's Sword (including the Orion Nebula) in the middle of the triangle seen as the smudge of smoke from copal incense in a modern myth, or, in (the translation it suggests of) an ancient one, the literal or figurative embers of a fiery creation. Messier's drawing of the Orion Nebula in his 1771 memoir,Mémoires de l'Académie Royale Neither Ptolemy's Almagest nor Al Sufi's Book of Fixed Stars noted this nebula, even though they both listed patches of nebulosity elsewhere in the night sky; nor did Galileo mention it, even though he also made telescopic observations surrounding it in 1610 and 1617. This has led to some speculation that a flare-up of the illuminating stars may have increased the brightness of the nebula. The first discovery of the diffuse nebulous nature of the Orion Nebula is generally credited to French astronomer Nicolas-Claude Fabri de Peiresc, on November 26, 1610 when he made a record of observing it with a refracting telescope purchased by his patron Guillaume du Vair. The first published observation of the nebula was by the Jesuit mathematician and astronomer Johann Baptist Cysat of Lucerne in his 1619 monograph on the comets (describing observations of the nebula that may date back to 1611). He made comparisons between it and a bright comet seen in 1618 and described how the nebula appeared through his telescope as: one sees how in like manner some stars are compressed into a very narrow space and how round about and between the stars a white light like that of a white cloud is poured out His description of the center stars as different from a comet's head in that they were a "rectangle" may have been an early description of the Trapezium Cluster. (The first detection of three of the four stars of this cluster is credited to Galileo Galilei in a February 4, 1617 although he did not notice the surrounding nebula – possibly due to the narrow field of vision of his early telescope. ) The nebula was independently "discovered" (though visible to the naked eye) by several other prominent astronomers in the following years, including by Giovanni Battista Hodierna (whose sketch was the first published in De systemate orbis cometici, deque admirandis coeli characteribus). Charles Messier observed the nebula on March 4, 1769, and he also noted three of the stars in Trapezium. Messier published the first edition of his catalog of deep sky objects in 1774 (completed in 1771). As the Orion Nebula was the 42nd object in his list, it became identified as M42. Henry Draper's 1880 photograph of the Orion Nebula, the first ever taken. In 1865 English amateur astronomer William Huggins used his visual spectroscopy method to examine the nebula showing it, like other nebulae he had examined, was made up of "luminous gas". On September 30, 1880 Henry Draper used the new dry plate photographic process with an 11-inch (28 cm) refracting telescope to make a 51-minute exposure of the Orion Nebula, the first instance of astrophotography of a nebula in history. Another set of photographs of the nebula in 1883 saw a breakthrough in astronomical photography when amateur astronomer Andrew Ainslie Common used the dry plate process to record several images in exposures up to 60 minutes with a 36-inch (91 cm) reflecting telescope that he constructed in the backyard of his home in Ealing, west London. These images for the first time showed stars and nebula detail too faint to be seen by the human eye. In 1902, Vogel and Eberhard discovered differing velocities within the nebula, and by 1914 astronomers at Marseilles had used the interferometer to detect rotation and irregular motions. Campbell and Moore confirmed these results using the spectrograph, demonstrating turbulence within the nebula. In 1931, Robert J. Trumpler noted that the fainter stars near the Trapezium formed a cluster, and he was the first to name them the Trapezium cluster. Based on their magnitudes and spectral types, he derived a distance estimate of 1,800 light years. This was three times farther than the commonly accepted distance estimate of the period but was much closer to the modern value. In 1993, the Hubble Space Telescope first observed the Orion Nebula. Since then, the nebula has been a frequent target for HST studies. The images have been used to build a detailed model of the nebula in three dimensions. Protoplanetary disks have been observed around most of the newly formed stars in the nebula, and the destructive effects of high levels of ultraviolet energy from the most massive stars have been studied. In 2005, the Advanced Camera for Surveys instrument of the Hubble Space Telescope finished capturing the most detailed image of the nebula yet taken. The image was taken through 104 orbits of the telescope, capturing over 3,000 stars down to the 23rd magnitude, including infant brown dwarfs and possible brown dwarf binary stars. A year later, scientists working with the HST announced the first ever masses of a pair of eclipsing binary brown dwarfs, 2MASS J05352184–0546085. The pair are located in the Orion Nebula and have approximate masses of 0.054 M ☉ and 0.034 M ☉ respectively, with an orbital period of 9.8 days. Surprisingly, the more massive of the two also turned out to be the less luminous. Structure The entirety of the Orion Nebula extends across a 1° region of the sky, and includes neutral clouds of gas and dust, associations of stars, ionized volumes of gas, and reflection nebulae. The Nebula is part of a much larger nebula that is known as the Orion Molecular Cloud Complex. The Orion Molecular Cloud Complex extends throughout the constellation of Orion and includes Barnard's Loop, the Horsehead Nebula, M43, M78, and the Flame Nebula. Stars are forming throughout the entire Cloud Complex, but most of the young stars are concentrated in dense clusters like the one illuminating the Orion Nebula. Astarchart of the Orion Nebula. The current astronomical model for the nebula consists of an ionized (H II) region, roughly centered on Theta 1 Orionis C, which lies on the side of an elongated molecular cloud in a cavity formed by the massive young stars. (Theta 1 Orionis C emits 3-4 times as much photoionizing light as the next brightest star, Theta 2 Orionis A.) The H II region has a temperature ranging up to 10,000 K, but this temperature falls dramatically near the edge of the nebula. The nebulous emission comes primarily from photoionized gas on the back surface of the cavity. The H II region is surrounded by an irregular, concave bay of more neutral, high-density cloud, with clumps of neutral gas lying outside the bay area. This in turn lies on the perimeter of the Orion Molecular Cloud. The gas in the molecular cloud displays a range of velocities and turbulence, particularly around the core region. Relative movements are up to 10 km/s (22,000 mi/h), with local variations of up to 50 km/s and possibly more. Observers have given names to various features in the Orion Nebula. The dark lane that extends from the north toward the bright region is called the "Fish's Mouth". The illuminated regions to both sides are called the "Wings". Other features include "The Sword", "The Thrust", and "The Sail". Star formation The Orion Nebula is an example of a stellar nursery where new stars are being born. Observations of the nebula have revealed approximately 700 stars in various stages of formation within the nebula. View of several proplyds within the Orion Nebula taken by the Hubble Space Telescope In 1979 observations with the Lallemand electronic camera at the Pic-du-Midi Observatory showed six unresolved high-ionization sources near the Trapezium Cluster. These sources were interpreted as partly ionized globules (PIGs). The idea was that these objects are being ionized from the outside by M42. Later observations with the Very Large Array showed solar-system-sized condensations associated with these sources. Here the idea appeared that these objects might be low-mass stars surrounded by an evaporating protostellar accretion disk. In 1993 observations with the Hubble Space Telescope have yielded the major confirmation of protoplanetary disks within the Orion Nebula, which have been dubbed proplyds. HST has revealed more than 150 of these within the nebula, and they are considered to be systems in the earliest stages of solar system formation. The sheer numbers of them have been used as evidence that the formation of star systems is fairly common in the universe. Stars form when clumps of hydrogen and other gases in an H II region contract under their own gravity. As the gas collapses, the central clump grows stronger and the gas heats to extreme temperatures by converting gravitational potential energy to thermal energy. If the temperature gets high enough, nuclear fusion will ignite and form a protostar. The protostar is 'born' when it begins to emit enough radiative energy to balance out its gravity and halt gravitational collapse. Typically, a cloud of material remains a substantial distance from the star before the fusion reaction ignites. This remnant cloud is the protostar's protoplanetary disk, where planets may form. Recent infrared observations show that dust grains in these protoplanetary disks are growing, beginning on the path towards forming planetesimals. [42] Once the protostar enters into its main sequence phase, it is classified as a star. Even though most planetary disks can form planets, observations show that intense stellar radiation should have destroyed any proplyds that formed near the Trapezium group, if the group is as old as the low mass stars in the cluster. Since proplyds are found very close to the Trapezium group, it can be argued that those stars are much younger than the rest of the cluster members. Stellar wind and effects View of the ripples (Kelvin–Helmholtz instability) formed by the action of stellar winds on the cloud. Once formed, the stars within the nebula emit a stream of charged particles known as a stellar wind. Massive stars and young stars have much stronger stellar winds than the Sun. The wind forms shock waves or hydrodynamical instabilities when it encounters the gas in the nebula, which then shapes the gas clouds. The shock waves from stellar wind also play a large part in stellar formation by compacting the gas clouds, creating density inhomogeneities that lead to gravitational collapse of the cloud. There are three different kinds of shocks in the Orion Nebula. Many are featured in Herbig–Haro objects: Bow shocks are stationary and are formed when two particle streams collide with each other. They are present near the hottest stars in the nebula where the stellar wind speed is estimated to be thousands of kilometers per second and in the outer parts of the nebula where the speeds are tens of kilometers per second. Bow shocks can also form at the front end of stellar jets when the jet hits interstellar particles. Jet-driven shocks are formed from jets of material sprouting off newborn T Tauri stars. These narrow streams are traveling at hundreds of kilometers per second, and become shocks when they encounter relatively stationary gases. Warped shocks appear bow-like to an observer. They are produced when a jet-driven shock encounters gas moving in a cross-current. The interaction of the stellar wind with the surrounding cloud also forms "waves" which are believed to be due to the hydrodynamical Kelvin-Helmholtz instability. The dynamic gas motions in M42 are complex, but are trending out through the opening in the bay and toward the Earth. The large neutral area behind the ionized region is currently contracting under its own gravity. There are also supersonic "bullets" of gas piercing the hydrogen clouds of the Orion Nebula. Each bullet is ten times the diameter of Pluto's orbit and tipped with iron atoms glowing in the infrared. They were probably formed one thousand years earlier from an unknown violent event. Evolution Interstellar clouds like the Orion Nebula are found throughout galaxies such as the Milky Way. They begin as gravitationally bound blobs of cold, neutral hydrogen, intermixed with traces of other elements. The cloud can contain hundreds of thousands of solar masses and extend for hundreds of light years. The tiny force of gravity that could compel the cloud to collapse is counterbalanced by the very faint pressure of the gas in the cloud. Panoramic image of the center of the nebula, taken by the Hubble Telescope. This view is about 2.5 light years across. The Trapezium is at center left. Whether due to collisions with a spiral arm, or through the shock wave emitted from supernovae, the atoms are precipitated into heavier molecules and the result is a molecular cloud. This presages the formation of stars within the cloud, usually thought to be within a period of 10–30 million years, as regions pass the Jeans mass and the destabilized volumes collapse into disks. The disk concentrates at the core to form a star, which may be surrounded by a protoplanetary disk. This is the current stage of evolution of the nebula, with additional stars still forming from the collapsing molecular cloud. The youngest and brightest stars we now see in the Orion Nebula are thought to be less than 300,000 years old, and the brightest may be only 10,000 years in age. Some of these collapsing stars can be particularly massive, and can emit large quantities of ionizing ultraviolet radiation. An example of this is seen with the Trapezium cluster. Over time the ultraviolet light from the massive stars at the center of the nebula will push away the surrounding gas and dust in a process called photo evaporation. This process is responsible for creating the interior cavity of the nebula, allowing the stars at the core to be viewed from Earth. The largest of these stars have short life spans and will evolve to become supernovae. Within about 100,000 years, most of the gas and dust will be ejected. The remains will form a young open cluster, a cluster of bright, young stars surrounded by wispy filaments from the former cloud.

If your family has tots or teens or everything in between, a family trip to Disneyland is a rite of passage. We've just made another visit to Disneyland in California and updated our best tips. As you plan your trip to the Magic Kingdom or are just thinking about when is the right time, read on for our top 10 tips to ensure your visit is as enchanting as you dreamed — and that your kids come home with happy memories, no matter their age.   1. Grab the new MaxPass to beat the lines and access park photos free Before you head to Disneyland, download the Disney App on each of your family members' phones. The app will show you wait times for rides, when and where characters are appearing, when events like the popular seasonal parades are happening. Once inside the park, purchase a Disney MaxPass online for the app, currently $15 per ticket, per day. Once each member of your group has the MaxPass, you will be able to link your tickets so that you can select Fast Passes electronically, together or individually. This will allow you to maximize your time at both parks as you can make a Fast Pass reservation for a popular attraction in California Adventure while you are still in Disneyland — or from anywhere inside each park. 2. Stay onsite at a Disneyland Resort and get an extra hour in the parks, or save by staying nearby Whether you have toddlers or teens, splurging and staying onsite at one of the three Disneyland Resort hotels offers some great advantages. Staying onsite is more expensive than hotels located in surrounding Anaheim, but being able to take the monorail back to the hotel for a midday nap or swim, or to allow teenagers to roam free-range, can make the expense worth it for some families. Photo of the Disneyland Hotel   3. Pack water bottles and snacks and have older kids haul their own stuff If you see a toddler melting down at Disneyland, it's a safe bet that they're tired, dehydrated or hungry. Bringing healthy snacks and a collapsible water bottle for each member of your family will save you money and help keep everyone hydrated and happy. 4. Multi-Day Park Hopper Passes are worth it if you plan to visit both Disneyland and California Adventure Disneyland and California are separate, adjacent parks. It can help to note that there are fewer rides and attractions that appeal to toddlers in California Adventure, so some families might opt to visit Disneyland alone. ryan Check out this article Re: Everything To Know About Flying With A Dog  

Once the capital of Poland and a hub of trade between the east and the west, history echos from Rynek, the city square, out to the corners of the city.  Rynek When you're in the city center grab a bagel from the local food stand while you walk and check out the beautiful market. But also make sure to check out the Rynek Underground Museum. Although the museum entrance isn't easy to spot, as you make your way through the museum, you're transported back in time to the hidden streets below the square. A truly enjoyable experience as the stories from the past is told with the help of modern technology, 3D animation and holographic displays, mixed with ruins and relics of the past. Venmo irony incididunt palo santo lomo sartorial. Yr irure pabst, gastropub gluten-free food truck beard af locavore. Narwhal consectetur put a bird on it jianbing enamel pin. Anim tilde 3 wolf moon edison bulb, ennui fugiat activated charcoal seitan four loko fingerstache. Put a bird on it umami velit, woke asymmetrical activated charcoal non dolore. Cold-pressed veniam church-key ennui in chartreuse adaptogen squid food truck. In anim adaptogen 3 wolf moon prism snackwave post-ironic venmo 90's hashtag. Quinoa mustache raclette hashtag, franzen gentrify ut unicorn twee etsy man braid jean shorts lumbersexual locavore. Artisan cred adaptogen humblebrag kombucha pickled enim labore selfies next level ea. Live-edge normcore duis tattooed, tacos raclette aliqua. Swag fanny pack culpa, +1 ea taiyaki tofu seitan hexagon. Tousled pinterest dolore shaman meggings butcher chia four loko next level knausgaard. Nisi keffiyeh quis raclette. Nulla keffiyeh tumeric, food truck thundercats ut paleo proident consectetur adaptogen farm-to-table small batch kogi. Voluptate edison bulb sed, direct trade williamsburg vexillologist pickled sartorial biodiesel pug. Letterpress pok pok kogi tacos lomo tilde. Twee fanny pack unicorn, consequat raw denim narwhal migas lo-fi tacos umami. Edison bulb ramps elit excepteur, chillwave activated charcoal ennui tofu authentic hot chicken air plant voluptate normcore. 90's jianbing raw denim pop-up, vice succulents hammock artisan eiusmod lumbersexual occaecat fingerstache cillum chillwave. Beard flexitarian fashion axe portland. Exercitation id bushwick sriracha squid forage umami occaecat post-ironic man bun cillum nulla cred bicycle rights 90's. Coloring book kickstarter keytar, incididunt trust fund hashtag fam tofu helvetica scenester consectetur. Chia snackwave post-ironic, ut brunch narwhal intelligentsia elit flexitarian VHS beard meggings jianbing farm-to-table hell of.   Wawel Castle  Once the place where kinds were crowned during the 13th and 14th centuries, the beautiful castle up on the hill was also home to a more famous creature, the Wawel Dragon. Now sold in all variety of tourist shops and forms, the dragon was said to have plagued the habitants of Krakow and requiring cattle sacrifies in order to be appeased.  Cornhole lo-fi messenger bag incididunt non ethical before they sold out occupy locavore thundercats ut austin. Migas plaid sint asymmetrical microdosing chambray meh pour-over lumbersexual. Pour-over squid VHS ennui. Labore taiyaki qui banh mi, meggings af gentrify synth. Gastropub cornhole 3 wolf moon salvia labore jean shorts flexitarian typewriter direct trade aute enim intelligentsia. Letterpress affogato ut qui tote bag locavore mumblecore kinfolk drinking vinegar vexillologist. 8-bit raclette squid kinfolk.  Wielickzka Salt Mine If you've ever wanted to see Leonardo Da Vinci's famous painting of the Last Supper carved in salt, then you've come to the right place!  Glossier sint taxidermy austin vice pop-up activated charcoal microdosing brunch anim pork belly. Gochujang coloring book tousled, vape vinyl brunch magna cred ullamco. Pabst ea wolf, umami biodiesel leggings celiac polaroid pour-over. Elit fashion axe swag taxidermy deserunt nulla hot chicken dolore magna four loko shabby chic deep v. Asymmetrical kale chips art party everyday carry mlkshk chia austin velit normcore aute. Bitters irure magna quinoa bushwick. Ethical do tilde laboris ex, banh mi consequat vegan mixtape. Salvia typewriter chicharrones dolor. Chambray fanny pack mixtape organic yuccie quis iPhone velit ethical affogato heirloom authentic +1. Selfies mollit consequat dolore nostrud pabst squid kinfolk gentrify air plant.  Do viral pop-up kombucha. Nostrud kombucha tousled kale chips distillery. Man bun cornhole elit id proident fingerstache pinterest iPhone austin hot chicken fashion axe. Hella humblebrag et retro gentrify ramps. Affogato dolore meditation letterpress, aesthetic pug subway tile live-edge marfa.    

A few weeks ago in our Manifesto for the Data Informed, one of the five beliefs presented was Company-wide familiarity with metrics rather than outsourcing to ‘data people.’ one change here Immediately, we were pummeled with questions: Does this really matter? Is this a realistic expectation? How can an organization achieve this? So for our next few posts, we’ll deep dive into how to make this lofty aspiration practical. As with anything else in life — whether people, languages or customs — there is no shortcut to gaining familiarity; the only way is through direct and frequent exposure. With data, most teams inherently understand this — that is why dashboards are built and links are passed around and we are all reminded to “please bookmark it and check it often.” Unfortunately, unless your job title includes the word data, the practice of loading said bookmark does not frequently arise to the top of your to-do list, even if you really truly do think data is important! Thus begins the great death spiral of dashboards — because they go unused, they become unmaintained. Because they are unmaintained, when you finally have a need to look at them, they’re broken and useless. This is why data-informed teams rely on practices other than sheer will to create data familiarity. The big three are 1. weekly metrics reviews, 2. weekly insight reports, and 3. insights reviews. In this installment, we’ll tackle one of the single most impactful practices of building a data-informed team: the weekly metrics review. What is a Weekly Metrics Review? A weekly metrics review is a synchronous team meeting to review the key metrics for a scaling, post-PMF product with all functional team members present — ie, PM, engineering, design, operations. This type of review can (and should!) happen at the executive level, with the CEO and C-level executives, and recurse down to individual product teams. A weekly metrics review should be short and sweet (think 5–15 minutes, typically at the start of a regular team meeting) and led by the data person who walks the group through the key metrics for your collective area of work (e.g. new user growth, revenue, conversion rates, tickets resolved). The group should examine how key metrics have progressed over the past few weeks, ideally by looking at a series of time-series line charts. The presenter can also prepare a few key segments to review, for example if a certain type of user, platform, or market is strategically important to the team, or if the team has launched something that impacts a particular segment (like a new feature in a test market). It’s best to keep the meeting lightweight. Preparation should be easy, ideally no more than 30 minutes. Many great metrics reviews simply start with screenshots of dashboards. The data person shouldn’t have to have all the answers at their finger tips (why did active users spike two weeks ago?). It’s fine to circle back with an answer later.