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  1. #1396

    Re: Let's Discuss Science

    ‘It snuck up on us’: Scientists stunned by ‘city-killer’ asteroid that just missed Earth

    By Allyson Chiu July 26

    Alan Duffy was confused. On Thursday, the astronomer’s phone was suddenly flooded with calls from reporters wanting to know about a large asteroid that had just whizzed past Earth, and he couldn’t figure out “why everyone was so alarmed.”

    “I thought everyone was getting worried about something we knew was coming,” Duffy, who is lead scientist at the Royal Institution of Australia, told The Washington Post. Forecasts had already predicted that a couple of asteroids would be passing relatively close to Earth this week.

    Then, he looked up the details of the hunk of space rock named Asteroid 2019 OK.

    “I was stunned,” he said. “This was a true shock.”

    This asteroid wasn’t one that scientists had been tracking, and it had seemingly appeared from “out of nowhere,” Michael Brown, a Melbourne-based observational astronomer, told The Washington Post. According to data from NASA, the craggy rock was large, an estimated 57 to 130 meters wide (187 to 427 feet), and moving fast along a path that brought it within about 73,000 kilometers (45,000 miles) of Earth. That’s less than one-fifth of the distance to the moon and what Duffy considers “uncomfortably close.”

    “It snuck up on us pretty quickly,” said Brown, an associate professor in Australia with Monash University’s School of Physics and Astronomy. He later noted, “People are only sort of realizing what happened pretty much after it’s already flung past us.”

    The asteroid’s presence was discovered only earlier this week by separate astronomy teams in Brazil and the United States. Information about its size and path was announced just hours before it shot past Earth, Brown said.

    “It shook me out my morning complacency,” he said. “It’s probably the largest asteroid to pass this close to Earth in quite a number of years.”

    So how did the event almost go unnoticed?

    First, there’s the issue of size, Duffy said. Asteroid 2019 OK is a sizable chunk of rock, but it’s nowhere near as big as the ones capable of causing an event like the dinosaurs’ extinction. More than 90 percent of those asteroids, which are more than half a mile wide or larger, have already been identified by NASA and its partners.

    “Nothing this size is easy to detect,” Duffy said of Asteroid 2019 OK. ″You’re really relying on reflected sunlight, and even at closest approach it was barely visible with a pair of binoculars.”

    Brown said the asteroid’s “eccentric orbit” and speed were also likely factors in what made spotting it ahead of time challenging. Its “very elliptical orbit” takes it “from beyond Mars to within the orbit of Venus,” which means the amount of time it spends near Earth where it is detectable isn’t long, he said. As it approached Earth, the asteroid was traveling at about 24 kilometers per second, he said, or nearly 54,000 mph. By contrast, other recent asteroids that flew by Earth clocked in between 4 and 19 kilometers per second (8,900 to 42,500 mph).

    “It’s faint for a long time,” Brown said of Asteroid 2019 OK. “With a week or two to go, it’s getting bright enough to detect, but someone needs to look in the right spot. Once it’s finally recognized, then things happen quickly, but this thing’s approaching quickly so we only sort of knew about it very soon before the flyby.”

    The last-minute detection is yet another sign of how much remains unknown about space and a sobering reminder of the very real threat asteroids can pose, Duffy said.

    “It should worry us all, quite frankly,” he said. “It’s not a Hollywood movie. It is a clear and present danger.”

    Duffy said astronomers have a nickname for the kind of space rock that just came so close to Earth: “City-killer asteroids.” If the asteroid had struck Earth, most of it would have probably reached the ground, resulting in devastating damage, Brown said.

    “It would have gone off like a very large nuclear weapon” with enough force to destroy a city, he said. “Many megatons, perhaps in the ballpark of 10 megatons of TNT, so something not to be messed with.”

    In 2013, a significantly smaller meteor — about 20 meters (65 feet) across, or the size of a six-story building — broke up over the Russian city of Chelyabinsk and unleashed an intense shock wave that collapsed roofs, shattered windows and left about 1,200 people injured. The last space rock to strike Earth similar in size to Asteroid 2019 OK was more than a century ago, Brown said. That asteroid, known as the Tunguska event, caused an explosion that leveled 2,000 square kilometers (770 square miles) of forest land in Siberia.

    Although the chances of a large asteroid landing on a city are “modest,” Brown said it is still worthwhile to devote resources toward detection and prevention. Brown said Asteroid 2019 OK proves there are “still dangerous asteroids out there that we don’t know of” that “can arrive on our doorstep unannounced.”

    Scientists are working on developing at least two approaches to deflecting potentially harmful asteroids, Duffy said. One strategy involves gently pushing the asteroid slowly over time off its course and away from Earth, he said. The other, which he called a “very elegant solution,” is the gravity tractor. If an asteroid is detected early enough, it could be possible to divert it using the gravity of a spacecraft, according to NASA.

    People shouldn’t try to “blast it with a nuke,” Duffy said.

    “It makes for a great Hollywood film,” he said. “The challenge with a nuke is that it may or may not work, but it would definitely make the asteroid radioactive.”

    In light of Asteroid 2019 OK, Duffy stressed the importance of investing in a “global dedicated approach” to detecting asteroids because “sooner or later there will be one with our name on it. It’s just a matter of when, not if.”

    “We don’t have to go the way of the dinosaurs,” he said. “We actually have the technology to find and deflect certainly these smaller asteroids if we commit to it now.”

    Emily Lakdawalla, senior editor of the Planetary Society, which promotes space exploration, said the recent near miss is a reminder that “it’s an important activity to be watching the skies.” The more that can be learned about an asteroid, the better prepared people can be to prevent potential disasters, she told The Post.

    Still, Lakdawalla said that while the asteroid’s close brush with Earth may have sparked some concern, “it is zero percent danger to us.”

    “It’s the kind of thing where you learn about something that you didn’t know about, like things flying close by us, and your inclination is to be scared,” she said. “But just like sharks in the ocean, they’re really not going to hurt you and they’re really fascinating to look at.”

  2. #1397

    Re: Let's Discuss Science

    Quote Originally Posted by JazzNU View Post
    “It should worry us all, quite frankly,” he said. “It’s not a Hollywood movie. It is a clear and present danger.”
    It's not a Hollywood movie, but let me phrase the rest of what I'm going to say using the title of a Hollywood movie. LOL!

    There's a TON of Armageddon jokes floating around about this and should we be calling in Bruce Willis.

  3. #1398

    Re: Let's Discuss Science

    I have always been puzzled about the Nuke it option. How does a nuclear weapon work in space? It has no air to push or heat up, no medium to transfer energy. You would need to "glue" the nuke to the asteroid, detonate it and then see if you moved it.
    For that, might as well land a rocket on it and switch it on. Then push the asteroid.
    No wonder I never made it into NASA.
    (My application for janitor was rejected).
    Missing winter...

  4. #1399

    Re: Let's Discuss Science

    I didn't even make the call-backs for that janitorial job. GH

  5. #1400

    Re: Let's Discuss Science

    So this equation is breaking the internet.

    The Math Equation That Tried to Stump the Internet

    Sometimes BODMAS is just PEMDAS by another name. And no, the answer is not 100.

    By Steven Strogatz
    Aug. 2, 2019

    Mathematical Twitter is normally a quiet, well-ordered place, a refuge from the aggravations of the internet. But on July 28, someone who must have been a troll off-duty decided to upset the stillness, and did so with a surefire provocation.

    It has to do with something that high school teachers call “the order of operations.” The latest blowup concerned this seemingly simple question:

    oomfies solve this

    — em ♥︎ (@pjmdolI) July 28, 2019

    Many respondents were certain the answer was 16. Others heard Yanny, not Laurel, and insisted the right answer was 1. That’s when the trash talking began. “Some of y’all failed math and it shows,” said one. Another posted a photo showing that even two different electronic calculators disagreed. The normally reassuring world of math, where right and wrong exist, and logic must prevail, started to seem troublingly, perhaps tantalizingly, fluid.

    The question above has a clear and definite answer, provided we all agree to play by the same rules governing “the order of operations.” When, as in this case, we are faced with several mathematical operations to perform — to evaluate expressions in parentheses, carry out multiplications or divisions, or do additions or subtractions — the order in which we do them can make a huge difference.

    When confronted with 8 ÷ 2(2+2), everyone on Twitter agreed that the 2+2 in parentheses should be evaluated first. That’s what our teachers told us: Deal with whatever is in parentheses first. Of course, 2+2 = 4. So the question boils down to 8÷2×4.

    And there’s the rub. Now that we’re faced with a division and a multiplication, which one takes priority? If we carry out the division first, we get 4×4 = 16; if we carry out the multiplication first, we get 8÷8 = 1.

    Which way is correct? The standard convention holds that multiplication and division have equal priority. To break the tie, we work from left to right. So the division goes first, followed by the multiplication. Thus, the right answer is 16.

    More generally, the conventional order of operations is to evaluate expressions in parentheses first. Then you deal with any exponents. Next come multiplication and division, which, as I said, are considered to have equal priority, with ambiguities dispelled by working from left to right. Finally come addition and subtraction, which are also of equal priority, with ambiguities broken again by working from left to right.

    To help students in the United States remember this order of operations, teachers drill the acronym PEMDAS into them: parentheses, exponents, multiplication, division, addition, subtraction. Other teachers use an equivalent acronym, BODMAS: brackets, orders, division and multiplication, and addition and subtraction. Still others tell their pupils to remember the little ditty, “Please excuse my dear Aunt Sally.”

    Now realize, following Aunt Sally is purely a matter of convention. In that sense, PEMDAS is arbitrary. Furthermore, in my experience as a mathematician, expressions like 8÷2×4 look absurdly contrived. No professional mathematician would ever write something so obviously ambiguous. We would insert parentheses to indicate our meaning and to signal whether the division should be carried out first, or the multiplication.

    The last time this came up on Twitter, I reacted with indignation: It seemed ridiculous that we spend so much time in our high-school curriculum on such sophistry. But now, having been enlightened by some of my computer-oriented friends on Twitter, I’ve come to appreciate that conventions are important, and lives can depend on them. We know this whenever we take to the highway. If everyone else is driving on the right side of the road (as in the U.S.), you would be wise to follow suit. The same goes if everyone else is driving on the left, as in the United Kingdom. It doesn’t matter which convention is adopted, as long as everyone follows it.

    Likewise, it’s essential that everyone writing software for computers, spreadsheets and calculators knows the rules for the order of operations and follows them. For the rest of us, the intricacies of PEMDAS are less important than the larger lesson that conventions have their place. They are the double-yellow line down the center of the road — an unending equals sign — and a joint agreement to understand one another, work together, and avoid colliding head-on. Ultimately, 8 ÷ 2(2+2) is less a statement than a brickbat; it’s like writing the phrase “Eats shoots and leaves” and concluding that language is capricious. Well, yes, in the absence of punctuation, it is; that’s why we invented the stuff.

    So on behalf of all math teachers, please excuse us for drilling your younger selves on this tedium. My daughters spent weeks on it each school year for several years of their education, as if training to become automatons. No wonder so many students come to see math as an inhuman, meaningless collection of arbitrary rules and procedures. Clearly, if this latest bout of confusion on the internet is any indication, many students are failing to absorb the deeper, essential lesson. Perhaps it’s time to stop excusing dear Aunt Sally and instead embrace her.

    Better still would be to teach everyone how to write unambiguous math expressions, and then all of this would go away. For those students destined to become software designers, writing code that can handle ambiguous expressions reliably whenever they arise, by all means exhume Aunt Sally from her crypt. For everyone else, let’s spend more time teaching our students the more beautiful, interesting and uplifting parts of mathematics. Our marvelous subject deserves better.

    Steven Strogatz is a professor of mathematics at Cornell and the author of “Infinite Powers: How Calculus Reveals the Secrets of the Universe.”
    "Even if you dance for your enemy on the rock, he will accuse you of splashing water on him." ~ African Proverb

  6. #1401

    Re: Let's Discuss Science

    I know what I was taught in junior high and high school, reminding you that was in the late 1960's. We were taught that, in this equation, parentheses go first, then multiplication and division are considered equal (as are addition and subtraction), and would proceed from left to right, so the answer would be 16. I am not saying that I know beyond any doubt that 16 is clearly correct to mathematicians, I'm merely saying that I am certain that in my high school math class, 16 was correct. GH

  7. #1402

    Re: Let's Discuss Science

    The age of hyper-mega-super-hyperbole.
    THIS is breaking the internet? Some people really need to get a life.
    Missing winter...

  8. #1403

    Re: Let's Discuss Science

    Study: many of the “oldest” people in the world may not be as old as we think
    A new paper explores what “supercentenarians” have in common. Turns out it’s bad record-keeping.

    We’ve long been obsessed with the super-elderly. How do some people make it to 100 or even 110 years old? Why do some regions — say, Sardinia, Italy, or Okinawa, Japan —produce dozens of these “supercentenarians” while other regions produce none? Is it genetics? Diet? Environmental factors? Long walks at dawn?

    A new working paper released on bioRxiv, the open access site for prepublication biology papers, appears to have cleared up the mystery once and for all: It’s none of the above.

    Instead, it looks like the majority of the supercentenarians (people who’ve reached the age of 110) in the United States are engaged in — intentional or unintentional — exaggeration.

    The paper, by Saul Justin Newman of the Biological Data Science Institute at Australian National University, looked at something we often don’t give a second thought to: the state of official record-keeping.

    Across the United States, the state recording of vital information — that is, reliable, accurate state record-keeping surrounding new births — was introduced in different states at different times. A century ago, many states didn’t have very good record-keeping in place. But that changed gradually over time in different places.

    Newman looks at the introduction of birth certificates in various states and finds that “the state-specific introduction of birth certificates is associated with a 69-82% fall in the number of supercentenarian records.”

    In other words, as soon as a state starts keeping good records of when people are born, there’s a 69 to 82 percent fall in the number of people who live to the age of 110. That suggests that of every 10 supposed supercentenarians, seven or eight of them are actually younger than that, but we just don’t know it because of poor record-keeping.

    This doesn’t mean that any of these false supercentenarians are lying. It could be that they lost track of their age a long time ago, accidentally double-counted some years, or were told the wrong birth year. But it does mean that the majority of people claiming to be supercentenarians, born in areas that didn’t keep reliable, accurate birth records, are probably not quite as old as they say they are.

    As a result, most of the studies we’ve conducted on them — trying to divine the secrets of old age from genetic tests and diet surveys — may be no good. But this isn’t just a funny little accident of old-age science: It actually illustrates a serious challenge in science.

    Why we may have to question what we know about supercentenarians
    The paper also looks at the phenomenon in Italy and Japan, where something different seems to be happening.

    Italy keeps better vital statistics than the United States does, and has had reliable vital statistics across the country for hundreds of years — yet in Italy, too, there are clusters of the country where lots of supercentenarians pop up. Maybe the Italian supercentenarians are for real?

    Newman’s analysis suggests not. He starts out by noticing something fishy: The parts of Italy that claim the most supercentenarians overall have high crime rates and low life expectancy. Isn’t that weird? Why would an area generally have low life expectancy but also produce an extremely disproportionate share of the world’s oldest people?

    The same pattern repeats itself in Japan: Okinawa has the greatest density of super-old people, despite having one of the lowest life expectancies in the country and generally poor health outcomes.

    The paper puts forward a controversial proposal. It seems unlikely that living in high-crime, low-life-expectancy areas is the thing that makes it likeliest to reach age 110. It seems likelier, the paper concludes, that many — perhaps even most — of the people claiming to reach age 110 are engaged in fraud or at least exaggeration. The paper gives a couple of examples of how this might come about; some of it might be reporting error, and some of the supercentenarians might be produced by pension fraud (someone might be claiming a dead person is still alive for pension benefits, or claiming the identity of a parent or older sibling).

    Newman’s overall conclusion: “Remarkable age attainment is predicted by indicators of error and fraud,” and isn’t correlated with things like a healthy population of 80-year-olds or high-quality access to medical care. “As a result, these findings raise serious questions about the validity of an extensive body of research based on the remarkable reported ages of populations and individuals.”

    In other words, all of our research into the biomarkers, habits, and diets that predict extreme old age? Probably worthless, because a significant share of the sample was not actually as old as we thought.

    The paper still needs to undergo peer review, but if its findings hold, it does illustrate an interesting statistical phenomenon: When you’re looking for something exceptionally rare, your data set will be dominated by errors and false positives. For example, if you’re looking for a disease that affects only one in a million people, and your test for the disease is 99.99 percent accurate, then it’ll turn up 100 false positives for every true positive. Even though you used a highly accurate test, most of your “positives” don’t have the disease!

    Similarly, supercentenarians are extremely rare. Only about one in 1,000 people who live to the age of 100 make it to 110. The vast majority of people would never impersonate their parent or older sibling for benefits, or forge a birth certificate, or participate in identity theft, or get confused about how old they even are. But if one in 1,000 people would do that, then fraudulent supercentenarians will be more common than bona fide supercentenarians. When you’re looking at an exceptionally rare phenomenon, you have to be exceptionally careful — or you’ll mostly find yourself studying something else entirely.
    Roger forever

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