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今天替Daisy发啦~~【速度】
Learn the constellations
1.If you're a newcomer to amateur astronomy, eager to begin exploring the night s ky, you'll have to overcome one of astronomy's biggest hurdles — learning to identify the constellations. After all, you can't find the Andromeda Galaxy if you can't find Andromeda. Trying to make sense of those myriad stellar specks overhead might seem intimidating, but making friends with the stars needn't be a "mission impossible."
Remember your first day of school — entering that classroom and finding yourself confronted by a roomful of unfamiliar faces? Even on that first day, you probably made a few friends. Through them, and with your day-to-day exposure to the classroom, you gradually became acquainted with all of your classmates. Learning the constellations is like that. With a little help from your friends (easy-to-find guidepost constellations) and a willingness to "show up for class" on successive nights, you'll soon feel comfortable in your nighttime surroundings. So relax. It's time to go to school and meet some new friends!
North circumpolar constellations
We begin in the northern sky, realm of those always-visible star groups known as the north circumpolar constellations. The most prominent figure is the Big Dipper (Note: The Big Dipper is not a constellation). These bright stars — four forming the "bowl," three more tracing out the "handle" — create one of the most recognizable patterns in the night sky, an ideal guide for locating surrounding constellations.
As any good Boy or Girl Scout will attest, you can find Polaris, the North Star, by tracing a line between the stars Dubhe and Merak at the end of the bowl of the Big Dipper and extending it about five times the distance between them. When astronomical newcomers see this celebrated star for the first time, they are astonished that it isn't much brighter than the stars in the Big Dipper. Polaris is the brightest star in Ursa Minor the Little Bear, which contains the Little Dipper. Like its big brother, the Little Dipper is made up of seven stars — four in the bowl, and three in the handle. Because four of its stars are dim, the Little Dipper is hard to see in light-polluted skies.
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2.If you trace a line from the bowl of the Big Dipper past the North Star and continue it an equal distance beyond, you'll arrive at an eye-catching group of stars that form a distinct letter M or W. This is Cassiopeia, Queen of Ethiopia
Winter
To see the constellations that come and go with the seasons, we need to turn our backs on the north circumpolar constellations and face south. If the winter sky seems alive with stars, it's no illusion. Besides the obvious facts that the air is clear and dry then, we're looking at a star-rich region that defines one of the spiral arms of our Milky Way Galaxy. Of the twenty-one brightest stars in the entire night sky (so-called 1st-magnitude stars), seven are in this area.
On a winter evening, the sky is home to what most astronomers agree is the grandest of all constellations — Orion the Hunter. A rectangle of bright stars, which includes, at opposite corners, 1st-magnitude Betelgeuse and Rigel, is bisected by a diagonal row of three bright stars (the "belt"). Beneath the belt hangs a row of three stars — Orion's "sword." Don't be fooled by their uninspiring naked-eye appearance; the middle star in the sword isn't a star at all.
It's the Orion Nebula — one of the grandest telescopic showpieces the night sky has to offer. In binoculars, it appears as a fuzzy patch of light. When you gaze at this wondrous glowing cloud, you view creation itself, for within this luminous glow, stars are being born.
Orion is the focal point of a stunning gathering of bright stars and constellations. The belt points down and to the left to a brilliant white star: Sirius, the brightest star in the night sky, leader of the constellation Canis Major the Great Dog. Sirius always dazzles, but the star especially captivates when positioned near the horizon. During winter, atmospheric refraction causes Sirius to sparkle in a rainbow of colors — a beautiful sight through binoculars or a small telescope.
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3.Return to Orion's belt and continue up and to the right, and you arrive at a V-shaped group of stars called the Hyades. This is the "head" of Taurus the Bull. The reddish-orange 1st-magnitude star at the upper-left end of the V is Aldebaran— the eye of the Bull. Each end of the V extends outward to a star that forms one of the Bull's horns. Continuing past the Hyades, you'll see a little cluster of stars — one of the loveliest naked-eye sights in the night sky. This is the Seven Sisters, or Pleiades. Six are visible to the unaided eye under average sky conditions; binoculars reveal the seventh star, plus dozens more.
The uppermost horn of Taurus is part of a pentagon of stars that includes the bright golden-yellow star Capella. This pentagon is the constellation Auriga the Charioteer. Auriga lies above Orion and is overhead on a midwinter evening. The fact that these five stars。represent a man on a chariot carrying a goat (Capella) attests to the vivid imagination of its ancient discoverers. Oh yes, that little triangle of stars beneath Capella represents the goat's three kids!
Orion's heavenly court includes Gemini the Twins. From Orion, extend a line upward from Rigel through Betelgeuse to this neat rectangular constellation, which contains the bright stars Pollux and Castor. In 2005, Gemini will be more aptly called the "Triplets," for Pollux and Castor will be joined by a third bright "star" — Saturn. Midway and slightly left of a line between Sirius and the stars Pollux and Castor is the 1st-magnitude star Procyon. Procyon forms an equilateral triangle with Betelgeuse and Sirius. It's about all you'll see of Canis Minor the Little Dog.
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Spring
4.As the days lengthen and the weather warms, Orion and his wintry retinue process slowly into the western sky. Leo the Lion now assumes center stage high in the south. Leo's most noticeable feature is an asterism (a grouping of stars) that reminds observers of a sickle or a backward question mark. The period on the question mark is the 1st-magnitude star Regulus. To the left of the Sickle are three stars that form a right triangle. We see the Lion from the side; the Sickle outlines his head, and the triangle, his hindquarters. Viewed with a little imagination, Leo definitely sports a feline profile.
During spring, the Big Dipper appears nearly overhead from mid-northern latitudes. If you follow the handle of the Dipper away from the bowl, you'll "arc toArcturus," a golden-yellow 1st-magnitude star in the constellation Bo?tes the Herdsman. The constellation itself is shaped like a huge kite, with Arcturus at its base. Continuing the arc, you'll "sprint to Spica." This blue-white 1st-magnitude star is in Virgo, which is a huge, sprawling constellation.
If you look below and to the right of Spica, you'll spot a neat little group of four bright stars that resembles the outline of a sail. This is the constellation Corvus the Crow. I'm always impressed at how stately this little constellation looks, perched above the treetops to the south on a clear spring evening.
Summer
Summer is a season of mixed blessings for astronomers. The nights are warm but short and often hazy. As if that weren't bad enough, we have to contend with swarms of blood-sucking mosquitoes! Haze and insects aside, the summer sky is a veritable gallery of cosmic masterpieces. The Milky Way arches high across the sky, which is richer than its winter counterpart because we now look toward the heart of our galaxy. Dominating the evening sky are three 1st-magnitude stars forming the Summer Triangle. Vega is the brightest of the three and is located in a nifty little constellation called Lyra the Lyre.
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5.Our second Summer Triangle star, Deneb, is the tail of Cygnus the Swan. Deneb and four other bright stars of the Swan form an asterism called the Northern Cross, which is immersed in the Milky Way. Deneb is at the top of the cross, the star Albireo is at the base. Albireo is a double star famous for its rich colors of golden yellow and sapphire blue. The star pair can be split with binoculars, but the colors can be seen only through a telescope.
Farther south on the Milky Way is the bright star Altair and its parent constellation, Aquila the Eagle. If you follow the Milky Way from Aquila toward the southern horizon, you should find a group of stars that looks like a teapot. This asterism is part of Sagittarius the Archer. This constellation marks the location of our galaxy's center. The area teems with deep-sky treasures — especially bright nebulae and star clusters. To the right of the teapot is the ruddy 1st-magnitude star Antares, the "heart" of Scorpius the Scorpion. Like the winter star Betelgeuse, Antares is a red supergiant star in the last stages of its life. A fishhook-shaped row of stars trailing down and to the left of Antares forms the Scorpion's tail and stinger, while an upright row of three stars to Antares's right marks the location of its claws.
Autumn
As the nights begin to lengthen and a chill pervades the air, the summer Milky Way exits center stage (although the Summer Triangle remains visible in the west until early winter). Following the Summer Triangle is one of the night sky's prettiest constellations — Delphinus the Dolphin. Four stars, arranged like a diamond, form the Dolphin's head, while a fifth creates the tail. You can imagine a dolphin leaping out of the water as you gaze at this constellation.
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自由阅读 ：In its wake is a rather barren expanse of sky whose most prominent feature is the Great Square of Pegasus the Winged Horse.
Alpheratz is at the top left corner of the Great Square. From here, two rows of stars branch out and up. This is the constellation Andromeda the Princess. And yes, it is home to the great Andromeda Galaxy. At a distance of 2.7 million light-years from Earth, it's the most remote object readily visible to the naked eye. Through binoculars, however, you'll see an elliptical glow (the galaxy's bright nucleus), which appears larger in small telescopes.
Now that I've introduced you to some of the constellations, it's time to head out and make your own friends. The expansive night sky will become more familiar to you after spending quality time learning the "faces" of the constellations. Class dismissed!
【越障】【字数：1071】
Inventive warfare
Battles over patents are becoming fiercer and more expensive
THIS deal is all about patents. That was the near universal view of Google’s announcement this week that it was taking over Motorola Mobility, a maker of handsets and other devices, for a colossal $12.5 billion. Indeed, the purchase will provide Google with an awful lot of patents: around 17,000 of them issued and another 7,500 pending. They should help Google in its efforts to get more smartphones and other mobile devices running on its Android operating system (see article). But it could also make the battles over patents nastier and more costly.
A scramble for patents had already begun. In December four companies, including Microsoft and Apple, paid $450m for around 880 patents and applications owned by Novell, an ailing software firm. In July those two and four others, including Research in Motion, maker of the BlackBerry, spent $4.5 billion on 6,000 patents owned by Nortel, a bankrupt Canadian telecoms-equipment maker. Before its latest deal, Google bought 1,000 patents from IBM. Firms are also suing each other. Apple claims its technology has been copied by Samsung and Motorola in their Android phones. Oracle is suing Google for up to $6 billion, claiming that Android infringes its patents. Microsoft is suing Motorola over Android too. Nokia recently settled a similar quarrel with Apple.
What is going on? Some say companies are attaching more value to intellectual property. Indeed, the Google deal seems to have been priced on a cost-per-patent basis, causing the share prices of other firms with lots of patents to rise. Others, however, think the battles reflect deficiencies in the patent system forcing firms to pay vast sums to protect technologies they have developed. The answer is a bit of both.
System failure
Kent Walker, one of Google’s senior lawyers, grouses at being forced to spend a lot of money defending the company against frivolous lawsuits by rivals. Others counter that as computing goes mobile, it favours information-technology firms that have invested in research for years and that Google was naive—or idealistic—to broaden its IT business without having a stack of patents. There is a retort to that, too: that incumbents can use patents as barriers to entry, which is why America’s antitrust regulators are showing interest in them. In April the Department of Justice demanded changes to Novell’s patent sale to protect open-source software.
Nowadays, innovations in IT usually rely on many small improvements involving numerous technologies, which means it is not always clear precisely which inventions a patent covers. The open secret is that everyone infringes everyone else’s patents in some way. This creates an incentive for firms to build up their patent portfolios to strengthen their position in negotiations, leading to what some liken to an arms race. The legal tussles usually end in cross-licensing deals, in which small sums of money change hands. This is considered preferable to a mutually destructive exchange of endless lawsuits.
The patent battle has become more contentious than ever. One reason is the mobile phone has provided a new platform of computing that firms want to dominate. Also, such a backlog of applications built up at America’s patent office (now more than 1m, with a waiting time of around three years) that standards slipped. Dubious patents were granted, helped in part by court rulings that allowed patents to stand on some software and “business methods” that many thought no one could lay claim to. In Europe and Japan, where patentability standards are higher, this is less of a problem.
Making things even more troublesome is that as lawsuits became particuarly lucrative some companies entered the fray to feed off them. Non-practicing entities (NPEs), which have intellectual property but no actual products, include such august bodies as the Harvard Medical School. But some NPEs are derided as “trolls” because their sole purpose seems to be to exploit the legal system by demanding licensing fees from companies, sometimes for questionable patents. Over the past 15 years, the median award to NPEs of damages for patent infringement has doubled while that for other firms has declined (see chart).
Court rulings in America have begun to clip the trolls’ beards by making it harder to win injunctions and by strengthening the criteria for whether an invention is truly “non-obvious”. Microsoft has seen the number of suits filed in the famously plaintiff-friendly district court of Eastern Texas fall from 17 in 2007 to just two so far this year, says Brad Smith, Microsoft’s general counsel. However, as big companies have improved their defences, the trolls have changed their tactics and are now going after start-ups.
New legislation could change things. David Kappos, director of America’s patent office, says the America Invents Act could amount to “the most sweeping reforms to the US patent system in 175 years.” It is expected to be passed this autumn, Barack Obama has indicated that he will sign it, and big IT and drug companies support it. But many entrepreneurs and venture capitalists do not, arguing that it does not fix any of the system’s big problems and risks creating new ones.
The most contentious point is a change to determine who is the rightful inventor. Instead of being the “first to invent”, the successful applicant would be the “first to file”, the standard used worldwide. Harmonising America’s rules with those in other countries would be a step towards greater co-operation and efficiency in patent examinations globally. Big companies like the proposal because it gives them more legal certainty that someone will not appear claiming they came up with the idea first. But inventors like Steve Perlman, the founder of WebTV and other firms, argue that it forces companies to file for patents before their inventions are fully developed. That, says Mr Perlman, would lead to yet more incremental improvements rather than big innovative steps and put a toll on America’s competitiveness.
For the moment, though, companies are amassing ever larger arsenals of patents. Google, for one, was hit by eight lawsuits in April alone—more than in the first five years of its 13-year existence, says Mr Walker. “See how far we have strayed from the notion of innovation, that we need to acquire patents to fend off potential suits,” he says of the firm’s overall strategy. “That money could have been spent on engineers, to much more productive use.” |
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发表于 2011-8-31 18:58:50
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发表于 2011-9-1 18:02:38
