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Largest Sun Spot In Nine Years Now Viewable
Mazarin writes: "The BBC has an interesting article about the largest sun spot to come around in nine years. 'The spot, which is moving towards the centre of the Sun's disk, covers an area a dozen times larger than the entire surface of the Earth.' The article goes on to talk about other sun spots that have caused minor disturbances and gives a nice little warning about not looking at the sun during this time."
Actually neither the sun nor the moon are magnified when they are at the horizon, it's a really impressive optical illusion whereby our brains interpret the apparent size of the sun/moon relative to features on the landscape. When it's overhead there are no nearby features to compare with and for some reason it then looks smaller.
Get yourself some appropriate household items and measure it. It's another reminder of how tentatively subjective our knowledge of truth is.
:wq
for more information on the type of sunspot (beta gamma delta) try here: spaceweather.com
also, that article from the BBC was posted on friday, the sunspot is now at the center of the solar disk and pointed more directly at earth. the latest magnetograms and intensitygrams are up at the SOHO site here.
- "Hear that?! The percolations are imminent! Cease your ingress!"
Well, it's more likely to cause blindness than masturbation... ;)
Use a filter on top of the lens, which filters the sunlight before it gets into the telescope.
Use your telescope as a projector, and project an image of the sun onto a piece of paper , cardboard, whatever...
But never ever rely on a filter that's put on the eyepiece: due to the high temperatures caused by the focused sunlight in the eyepiece and the fact that a dark filter absorbs all the light == energy == heat, it can crack easily - and once that happens when you're looking through it, you can kiss your retina goodbye.
Okay... I'll do the stupid things first, then you shy people follow.
Okay... I'll do the stupid things first, then you shy people follow.
[Zappa]
Thanks for the link.
It looks like a big round head with two eyes, a little too close set, with furry eyebrows, those pointed up at the ends and down at the middle (which indicates a squinting or frowning or cynical cast of face). You also see the diagonal wrinkles on the forehead. Immediately below the eyes is the tip of the nose. Because the sun is frowning so, the lips are pale and tightly compressed together, and somewhat askew; the right side is up and the left side is down, as if to ask sarcastically "What the Hell are you going to do about it?!" And on the right cheek is the scar he got back when he was a junior in high school, in that fight in the parking lot of the pizza parlor.
Yours WDK - WKiernan@concentric.net
Hmmm... are you sure you're looking at the sun? To verify, use a pair of binoculars and try to eye a big sunspot 100 time larger than earth. Report back.
Physics courses are very nice, but have you ever personally actually measured the width of the sun, or timed it as it marched across a fixed telescope's crosshairs? I've measured the angular width of the sun several times with a surveyor's transit (it's about a two minutes of time, or 32 minutes of angle) and it does not change from midday to sunset. Neither does the image of the moon widen as it nears the horizon. That either one seems bigger to your eye at sunset is only an optical illusion.
If you don't trust that statement, which after all is sound thinking - really, what would you read off a weblog that you'd believe uncritically? - then get hold of a transit and sun filter, or for cheap, get sunglasses, two sticks and a watch with a second hand, and perform the experiment yourself.
Yours WDK - WKiernan@concentric.net
Isaac Newton practically drove himself blind by staring at the sun for hours regularly, watching for sunspots.
To make it vividly clear how dangerous it is to stare at the sun, consider this. Total luminous flux from a given source drops down quadratically with distance; but so does the apparent angle. So the luminous intensity (luminous flux per unit solid angle) does not decrease with distance. In other words, neglecting absorbtion by the atmosphere, and so long as you are not near-sighted, a cell in your retina receives as much intensity from the sun when you stare at it from Earth as it would do if you were three meters from the sun.
(Of course, some would argue the same should hold for the stars. The reason it doens't is that the stars' apparent angle is smaller than one retinal cell. However, if the Universe were infinite in space and time, with stars uniformly distributed among it, the entire sky would be as luminous as the surface of the sun. This is the well known Ober's paradox.)
Normally, pointing out misspellings is a bit rude, but in this case it's a public service for anyone wishing to do a net search for more information.
/.
/. If the government wants us to respect the law, it should set a better example.
What happens if you hold a magnifying lens above ants on the sidewalk?
Your eyes have lenses in the front.
~ radiographite: art by john shepard
Although it's geared towards kids in school, NASA has a great site on Sunspots here.
There is also an interesting article on the recent coronal mass ejection here.
Also read about the cold summer of 1816 here. It is theorized that the earth was extra cool because of sunspot activity.
Fun stuff... brings out the amateur scientist in me.
-Todd
- "When you want something with all your heart, the entire universe conspires to give it to you" -Paulo Coelho
In Surely You're Joking, Mr. Feynman! (are there two Ns or just one in his name? I always forget), Richard Feynman talks about the Trinity nuclear test. He was the only person to look at the nuclear bomb directly, and suffered no permanent eye damage.
:)
:)
According to Feynman (or at least, what's written in his book), it's the ultraviolet light which cooks your retinas, and that visible light simply won't do it no matter how intense it is. He took the simple precaution of watching the nuclear blast through a truck windshield, which is UV-opaque. While he had a big purple blotch in his visual field for several minutes afterwards, he did manage to watch a nuclear blast without permanent damage, which I think is pretty damn cool.
From my own experience, I can submit anecdotal evidence which supports Feynman's UV-is-the-problem hypothesis. Once, while working in a laser holography lab, I wound up getting an eyeful of HeNe. While I was damn near blind in that eye for ten minutes afterwards, I had no permanent effects.
ObWarning: I am not a competent eyecare professional, and don't try either of these stunts at home. Really. Especially not the nuclear one.
If you have a telescope with a sun filter/eyepiece, then you should check it out. it is pretty interesting. looks like the sun has a big outta control zit. just make sure you remember to put in the sun filter before checking it out. yowch!
mmmmmmm Shiner Bock
We did a little experiment back in 7th grade or something close to that.. :)
If you take binoculars and turn them so that the large end is facing the sun.. and have a peice of cardboard it will display the sun spot. This one should be large enough to see on the projected image. This is safe for your eyes..
There are three kinds of people, those who can count and those who can't.
Actually, that's the standard problem with cheap sunglasses that don't block UV; the relative darkness dilates your eyes, which are then exposed to more-than-normal levels of radiation.
I'm not sure about the TV Radiation part, but the theory is at least sound.
Dewey, what part of this looks like authorities should be involved?
Everytime I've seen people do it they get really hot and burn up. Weird.
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If the tv image is bright enough, won't that prevent dilation?
And if the image is dark, then dilation won't really hurt, right?
Dilation is something that is self-adjusting according to brightness I think. So I don't know that 'more' or 'less' radiation is allowed in. I don't know at what point the pupil will dilate, but I do know that my monitor right now is bright that I can see across my room, with lights off.
The nick is a joke! Really!
GPL Deconstructed
You probably won't feel any pain, and the resulting damage is not directly visible--it's just like another blind spot. But once a significant part of your fovea (central vision) is damaged, you won't be able to see details anymore.
So, in short, don't look at the sun directly under any circumstances, and get regular eye exams. There are lots of other things that can go wrong with your eyes.
I wonder if they upgraded thier equipment so this would not happen again.
A large sunspot in March 1989 triggered a disturbance in the Earth's magnetic field that knocked out power lines in Canada.
Comment removed based on user account deletion
Yeah - a friend of mine learned this in another way - never wear a white t-shirt when arc-welding (unless one uses those wrap-around goggles, of course one would still need some kind of face mask, unless they liked to get hit in the face with bits of molten metal). He did that one day, and the light creeped up underneath the mask - needless to say, he had a very painful experience not long after he was done welding...
I support the EFF - do you?
Reason is the Path to God - Anon
Ok, I'll bite on this one.
in '77 when I was a kid, there was an eclipse of the sun on the west coast of the United States.
My sister and I were psyched about it, and our parents talked to us about how to view the eclipse and we made pin-hole viewers, etc...
To make a long story even longer, my sister looked at the eclipse several times--trying to focus on the sun to see the eclipse better.
That day she had a blind spot form right in the center of her vision. She didn't tell anyone about it, hoping that it would go away. Finally after several days she 'fessed up about the blind spot and she went to an eye doctor.
The doctor had been inundated by people with stories similar to hers...he said that she should consider herself lucky that she hadn't blinded herself.
Imagine how tough it would be to have a blind spot directly in the center of your vision. It is a dark spot that you can't look around. Imagine trying to focus on someone's face and seeing nothing.
So, Yes, looking at the sun IS really bad
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Seastead this.
Gallileo Gallilei has gone virtually blind after a few years of starring at the Sun into his primitive telescope (he was recorded as the first astronomer that used a telescope to study the sky, he built his own telescope after hearing about the first telescope built by Hans Lippershey (c1570-c1619) of Holland)
So, yes, there is proof that it can be dangerous for your eye sight to look directly into the Sun especially with a telescope!
You can't handle the truth.
I remember that they never used to let me go outside during an eclipse because I would just stand there and STARE at it. God, I miss those days. Why can't we have a good ECLIPSE, instead of some stupid little spot? I can't even see that! A dozen times earth's diameter? WHATEVER! The MOON is bigger than that- I mean, look- it covers the whole sun. I want a frickin eclipse.
that link was very informative. Thanks.
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I am the dot in slashdot.org
When I was a little kid, my mother told me not to stare into the sun, so once when I was six I did. The doctors didn't know if my eyes would ever heal, I was terrified, alone in that darkness. Slowly, daylight crept in through the bandages, and I could see. Something else had changed inside me. That day I had my first headache.
If you look at the Sun at sunset, when its magnified by the atmosphere and dimmer, you will mostlikely be able to see it. It'll look like a freckle.
I have heard carrots *do* have compounds essential for the visual system. I dunno if they help, but they certainly don't hurt!
What makes carrots orange is a pigment called beta-carotene, and this is a precursor to Vitamin A. The scientific name for Vitamin A is retinol because it has a specific function in the retina of the eye. Simply stated, Vitamin A allows the rods and cones in the retina to adjust to light changes, produce visual excitation and send images to the visual centers of the brain.
Carrots are indeed an excellent source of Vitamin A via the beta-carotene precursors, but so are all darkly colored vegetables. Dark green vegetables have lots of beta-carotene but the green of the chlorophyll overwhelms the yellow and orange tones. Some sources of Vitamin A, in descending order, are liver, carrots, sweet potato, spinach, apricots, winter squash, cantaloupe, broccoli, crab, peaches.
Extremely high doses of Vitamin A are known to cause fetal damage. This was discovered through the marketing and use of the popular acne drug, Retin-A, which is a synthetic version of Vitamin A delivered in very high doses. Just eat some dark leafy green every day and you'll be fine.
The british SAS are rumoured to take vitamin A supplements for a week before running planned special operations, to enhance eyesight.
Just my $0.02
Michael Tandy
...another comment from Michael Tandy.
"Goodness me, how unlike the FBI to abuse the trust of the American public." -- The Onion
Anyway, there's a great site run by NOAA (http://www.sec.noaa.gov/SWN/) that has updated images of the Sun, sunspot activity, solar storms, and aurorae activity. Definitely worth checking out, especially if you live in an area that could possibly see aurorae.