Tuesday, February 28, 2012
The Eastern Coast of the United States Seen at Night From the Space Station
One of the Expedition 30 crew members aboard the International Space Station took this nighttime photograph of much of the eastern (Atlantic) coast of the United States. Large metropolitan areas and other easily recognizable sites from the Virginia/Maryland/Washington, D.C. area spanning almost to Rhode Island are visible in the scene. Boston is just out of frame at right. Long Island and the Greater Metropolitan area of New York City are visible in the lower right quadrant. Large cities in Pennsylvania (Philadelphia and Pittsburgh) are near center. Parts of two Russian vehicles parked at the orbital outpost are seen in left foreground.
Atlantic sailfish attacking Spanish sardines !
Reinhard Dirscherl, a freelance photographer based in Germany, has won the 2nd Prize in the Nature Single category with this picture of Atlantic sailfish attacking Spanish sardines, off Yucatan Peninsula in Mexico.
Monday, February 27, 2012
Engineers and Mangers
A man is flying in a hot air balloon and realizes he is lost. He reduces height and spots a man down below. He lowers the balloon further and shouts: "Excuse me, can you tell me where I am?"
The man below says: "Yes, you're in a hot air balloon, hovering 30 feet above this field."
You must be an engineer" says the balloonist.
"I am" replies the man. "How did you know."
"Well," says the balloonist, "everything you have told me is technically correct, but it's no use to anyone."
The man below says "you must be in management."
"I am" replies the balloonist, "but how did you know?"
"Well," says the man, "you don't know where you are, or where you're going, but you expect me to be able to help. You're in the same position you were before we met, but now it's my fault."
The man below says: "Yes, you're in a hot air balloon, hovering 30 feet above this field."
You must be an engineer" says the balloonist.
"I am" replies the man. "How did you know."
"Well," says the balloonist, "everything you have told me is technically correct, but it's no use to anyone."
The man below says "you must be in management."
"I am" replies the balloonist, "but how did you know?"
"Well," says the man, "you don't know where you are, or where you're going, but you expect me to be able to help. You're in the same position you were before we met, but now it's my fault."
Does the Universe have an edge, beyond which there is nothing?
Galaxies extend as far as we can detect... with no sign of diminishing.There is no evidence that the universe has an edge. The part of the universe we can observe from Earth is filled more or less uniformly with galaxies extending in every direction as far as we can see - more than 10 billion light-years, or about 6 billion trillion miles. We know that the galaxies must extend much further than we can see, but we do not know whether the universe is infinite or not. When astronomers sometimes refer (carelessly!) to galaxies "near the edge of the universe," they are referring only to the edge of the OBSERVABLE universe - i.e., the part we can see.
Sunday, February 26, 2012
Airline Routes Are a Pretty Good Predictor of Twitter Connections
A study finds that -- surprise! -- the Twitter world mirrors patterns in our offline world.
You know the maps that show the criss-crossing lines of global air routes? Well, if you could make a map of Twitter, with arched lines tracing the connections among the places that tweeters and their followers live, it would look quite similar -- and not just in that it would be a map of connections all around the world, but much more of a direct resemblance: Air routes are a pretty good predictor of relationships on Twitter.
This is the conclusion of a new study from three Canadian researchers, who compared Twitter connections and airline routes. Though local connections make up a good bulk of Twitter ties (39 percent), the frequency of airline connections between two places is a good proxy for ties that go outside of one's hometown. This means "the strength of prior ties between places matters more than the simple distance between them."
Of course, this isn't only because the constant flights provide more opportunities for connection between residents of two distant places; the airline connections are themselves like the Twitter connections -- a manifestation of an existing relationship between two places. In this sense, it's no more surprising that New York and London are well connected on Twitter than it is that they are well connected by air travel.
That it would be any other way makes little sense. As Matthew Battles writes, "Here's the thing: Twitter is part of the 'real world.' The Internet is part of the world." Even though it's online and technically you can follow anyone anywhere in the world, the choices we make -- whom we follow -- are shaped by the "real" world, online and off. Unfortunately, the authors of the study present a world unfettered by geography as their null hypothesis, thus "proving" that Twitter doesn't exist in a vacuum. It would be more interesting to compare Twitter to other networks -- not just airline routes but capital flows, immigration patterns, and so on -- and see how it's different and think about why.
You know the maps that show the criss-crossing lines of global air routes? Well, if you could make a map of Twitter, with arched lines tracing the connections among the places that tweeters and their followers live, it would look quite similar -- and not just in that it would be a map of connections all around the world, but much more of a direct resemblance: Air routes are a pretty good predictor of relationships on Twitter.
This is the conclusion of a new study from three Canadian researchers, who compared Twitter connections and airline routes. Though local connections make up a good bulk of Twitter ties (39 percent), the frequency of airline connections between two places is a good proxy for ties that go outside of one's hometown. This means "the strength of prior ties between places matters more than the simple distance between them."
Of course, this isn't only because the constant flights provide more opportunities for connection between residents of two distant places; the airline connections are themselves like the Twitter connections -- a manifestation of an existing relationship between two places. In this sense, it's no more surprising that New York and London are well connected on Twitter than it is that they are well connected by air travel.
That it would be any other way makes little sense. As Matthew Battles writes, "Here's the thing: Twitter is part of the 'real world.' The Internet is part of the world." Even though it's online and technically you can follow anyone anywhere in the world, the choices we make -- whom we follow -- are shaped by the "real" world, online and off. Unfortunately, the authors of the study present a world unfettered by geography as their null hypothesis, thus "proving" that Twitter doesn't exist in a vacuum. It would be more interesting to compare Twitter to other networks -- not just airline routes but capital flows, immigration patterns, and so on -- and see how it's different and think about why.
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