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Spring Starts Sunday, But Why Has the Date Changed?
When a clock is hungry it goes back four seconds.
by Joe Rao
Avid "Seinfeld" fans might remember the episode when Jerry’s friend, George, was desperately trying to find a way to postpone his impending Christmastime wedding with his fiancée, Susan. He finally comes up with a solution: "Have the wedding on 21 March - the first day of spring!" Unfortunately, if George had gone through with the nuptials (and Seinfeld aficionados know why he never did), he would have been a full day late. You see, in America, spring no longer falls on 21 March. In 2005, for instance, the vernal equinox, the first day of spring for the Northern Hemisphere, comes on Sunday, 20 March at 12:33 GMT, or 7:33am EST (4:33am PST).
Now this doesn’t seem right. I mean, when we were all growing up, the first day of spring was always on 21 March, not 20 March, right? Now all of a sudden spring comes on 20 March. How did that happen?
While it’s true that we’ve traditionally celebrated the beginning of spring on 21 March, astronomers and calendar manufacturers alike now say that the spring season starts one day earlier, 20 March, in all time zones in North America. Unheard of? Not if you look at the statistics. In fact, did you know that during the 20th Century, 21 March was actually the exception rather than the rule? The vernal equinox landed on 21 March only 36 out of 100 years. And from 1981 to 2102, Americans will celebrate the first day of spring no later than 20 March. In the years 2008 and 2012, those living in Alaska, Hawaii and the Pacific, Mountain and Central time zones will see spring begin even earlier: on 19 March. And in 2016, it will start on 19 March for the entire US.
There are a few reasons why seasonal dates can vary from year to year.
The current seasonal lengths for the Northern Hemisphere are:
As you can see, the warm seasons, spring and summer, combined are 7.573 days longer than the colder seasons, fall and winter (good news for warm weather admirers). However, spring is currently being reduced by approximately one minute per year and winter by about ½ minute per year. Summer is gaining the minute lost from spring, and autumn is gaining the half-minute lost from winter. Winter is the shortest astronomical season, and with its seasonal duration continuing to decrease, it is expected to attain its minimum value - 88.71 days - by about the year 3500.
Another complication revolving around the vernal equinox concerns the length of day versus night. We have been taught that on the first days of spring and autumn, the day and night are equal to exactly 12 hours all over the world. Yet, if you check the calculations made by the US Naval Observatory or the sunrise/sunset tables in any reputable almanac, you will find that this is not so. In fact, on the days of the spring and fall equinox the length of daylight is actually longer than darkness by several minutes.
Check out New York City. As the table below shows, days and nights are equal not on the equinox, but on Saint Patrick’s Day:
One factor is that the moments of sunrise and sunset are considered when the top of the sun, and not its centre, is on the horizon. This alone would make the time of sunrise and sunset a little more than 12 hours apart on these days. The Sun’s apparent diameter is roughly equal to ½ a degree (.50º). But the main reason that this happens can be attributed to our atmosphere; it acts like a lens and refracts (bends) its light above the edge of the horizon. In their calculations of sunrise and sunset times, the US Naval Observatory routinely uses 34 minutes of arc for the angle of refraction and 16 minutes of arc for the semi-diameter of the sun's disc. In other words, the geometric centre of the sun is actually .83º below a flat and unobstructed horizon at the moment of sunrise. Or, put in another way, when you watch the sun either coming up above the horizon at sunrise or going down below the horizon at sunset, you are actually looking at an illusion - the sun is not really there, but actually below the horizon. As a result, we actually end up seeing the sun for a few minutes before its disk actually rises and for a few minutes after it has actually set. Thus, thanks to atmospheric refraction, the length of daylight on any given day is increased by approximately 6 or 7 minutes.
For Europe, spring will begin on 21 March in 2007. That, however, will be the last time until 2102. For places much farther to the east, such as Tokyo, Japan (9 hours ahead of Greenwich), spring will fall on 21 March in 2 out of every 4 years from 2006 through 2023 (2006, 2007, 2010, 2011, et cetera), then once every 4 years from 2027 through 2055. But then that’s it until 2101.
Joe Rao is the Night Sky Columnist
Source: space.com 18 March 2005
Some People Do not Understand Mirror Reflections
Psychologists at the University of Liverpool have found that people still find it difficult to understand how mirrors work. Dr Marco Bertamini, from the University's School of Psychology, conducted a number of experiments by covering a mirror on a wall and inviting participants to walk along a line parallel to the mirror. He asked them to guess the point at which they would be able to see their reflection. Results showed that people believe they can see themselves even before they are level with the near edge of the mirror. Dr Bertamini said: "People tend not to understand that the location of the viewer matters in terms of what is visible in a mirror. A good example of this is what we call the Venus Effect, which relates to the many famous paintings of the goddess Venus, looking in a small mirror. If you were to look at these paintings, you would assume that Venus is admiring her own face, because you see her face in the mirror. Your viewpoint, however, is rather different from hers; if you can see her in the mirror then she would see you in the mirror."
Participants were also asked to estimate the image size of their head as it appears on the surface of the mirror. They estimated that it would be a similar size to their physical head. However, participants based their answer on the image they saw inside the mirror rather than on the image on the surface of it. They failed to recognise that the image on the surface of the mirror is half the size of the observer because a mirror is always halfway between the observer and the image that appears inside the mirror.
Dr Bertamini added: "Mirrors make us see virtual objects that exist in a virtual world; they are windows onto this world. On the one hand we trust what we see, but on the other hand this is a world that we know has no physical existence. This is one of the reasons why throughout history people have been fascinated by mirrors."
Contact: Samantha Martin firstname.lastname@example.org University of Liverpool
Source: eurekalert.org 21 December 2005
Do You See What Eye Mean?
This benefit of seeing... can come only if you pause a while,
- Dorothea Lange
Seeing is not always believing.
- Martin Luther King Jr
Source: the web
Also, on the subject of sex and eyes, read this:
An Eyeful a Day Keeps the Doctor Away
by Jonathan Hayter
Staring at women's breasts is good for men's health and makes them live longer, a new survey reveals. Researchers have discovered that a 10-minute ogle at women's breasts is as healthy as half-an-hour in the gym. A five-year study of 200 men found that those who enjoyed a longing look at busty beauties had lower blood pressure, less heart disease and slower pulse rates compared to those who did not get their daily eyeful.
Dr Karen Weatherby, who carried out the German study, wrote in The New England Journal of Medicine: "Just 10 minutes of staring at the charms of a well-endowed female is roughly equivalent to a 30-minute aerobics workout. Sexual excitement gets the heart pumping and improves blood circulation. There is no question that gazing at breasts makes men healthier. Our study indicates that engaging in this activity a few minutes daily cuts the risk of a stroke and heart attack in half. We believe that by doing so consistently, the average man can extend his life 4 to 5 years."
She added that sexy stars like Dolly Parton, Heather Locklear, Anna Nicole Smith and Demi Moore had proved to be especially good for the men's health.
Source: the web again - but wait! See email and two articles below.
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Comments: The Jonathan Hayter article about the women's breasts doesn't pan out. A pubmed search reveals no such article in the New England Journal of Medicine, nor any author by that name...
What Do You Mean I Won't Live Forever?
by Cory Farley
Oh, boy. I'm going to live forever. At least I am if a study alleged to have been done in Germany by Dr Karen Weatherby, and alleged to have been reported in the New England Journal of Medicine, is valid. The researchers supposedly found that staring at women's breasts for 10 minutes is "as healthy as half an hour in the gym." A "5-year study" showed that men who copped a look had "lower blood pressure, less heart disease and slower pulse rates (than) those who did not get their daily eyeful."
Should be good news for me. I'm not a toucher, nor a stalker, nor, you know, creepy. But I will take a peek. According to published reports, the doctor theorised that staring "accelerates the heart rate and improves circulation. There is no question that gazing at breasts makes men healthier," she supposedly said. "Our study indicates that (it) cuts the risk of stroke and heart attack in half."
Once again ahead of my time: I was drinking the now-recommended "moderate amounts of alcohol" when that was considered a sin, and I thought smoking was a bad idea long before the Surgeon General verified it. And now this. If 10 minutes of staring equals 30 in the gym, I've averaged a 20-hour workout every day since about 1960.
Before I revised my fitness regimen, though, I decided to verify the report. A Google search for "Dr Karen Weatherby" yielded 933 hits, so at least she existed. Apparently she didn't exist, though, before this study. I didn't read all 933 entries, but those I scanned mentioned her only in connection with breast observation. Could a person go to medical school and pursue a research career without generating a single Web reference? Not likely.
Still, hope springs eternal in the human ... never mind. I was dubious, but I wanted to believe. And I'm a trained researcher, so I employed a professional tool: I went to the website of the New England Journal, crossed my fingers and typed "Weatherby." Let it be there...
It was: one entry, one "Weatherby" in what apparently was the entire electronic history of the Journal. One could be enough, though. If it panned out, I could continue to ogle, which I was going to do anyway, and I could feel good about it. Which I was also going to do anyway, but this would justify it. Eagerly, I clicked it up.
"Early Goal-Directed Therapy," was the title, "in the Treatment of Severe Sepsis and Septic Shock." No breasts, at least none I'd want to look at. I was shocked, at first, but now I'm just disappointed. I mean, wouldn't you think a prestigious medical journal, breaking an important story like this, would keep better records?
Cory Farley’s column appears on Sunday, Tuesday and Friday. He can be reached at email@example.com.
Source: news.rgj.com Reno Gazette Journal 30 March 2007
Don't give up yet - there's hope!...
Pretty Faces Get Men's Brains Going
New York - A beautiful woman's face is like chocolate, cash or cocaine to a young man's brain, according to Harvard University researchers. Their brain-imaging study revealed that while young heterosexual males are indeed capable of finding beauty in another man's face, only a lovely female visage can set off the "reward centres" in their brains.
When men in the study were shown pictures of various faces, only the female faces deemed beautiful triggered activity in brain regions previously associated with food, drugs and money, according to findings published in the November 8th issue of Neuron. The unique effect of the comely female face occurred despite the fact that the men also rated some male faces as "beautiful."
"It looks like there can be a difference between what the brain 'likes,' an image that is judged to be attractive, and what the brain 'wants,' something that is regarded as a reward in and of itself," study author Dr Hans Breiter, of Massachusetts General Hospital in Boston, said in a statement. In their experiments, the researchers first asked a group of men to rate how attractive they found the faces - which, unbeknownst to the participants, had already been placed into the categories "beautiful" or "average." The men's ratings, it turned out, fell in line with the categories, and attractive male faces garnered ratings similar to attractive female faces.
But in the next phase of the study, men in another group were allowed to control how long they viewed a particular face by pressing a key. Breiter's team found that they "expended effort" to see the beautiful female faces for a longer time, but for all other faces they tried only to "make the faces disappear faster." Finally, in a third group of men studied with brain imaging known as functional MRI, the investigators found that only the attractive female faces set off the brain's "reward circuitry."
"It's particularly interesting that the attractive male faces actually produced what could be considered an aversion response, even though they had been recognised as attractive," Breiter said. His co-author, Dr Nancy Etcoff, noted that this research echoes previous work suggesting the human perception of beauty may be "in-born." "While we know that experience, learning and personal idiosyncrasies all have an impact on attraction between particular individuals, these results show that this basic reward response is deeply seated in human nature," she said in a statement.
Source: nzherald.co.nz 10 November 2001 © New Zealand Herald via Reuters
The Dangers of Deafness
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