9.14 Galileo's eyes

(Galileo Galilei [1564-1642], circa 1630)

Well, it is only inevitable in this age of TV CSI shows: Scientists from both UK and Italy are now seeking the Vatican's approval to exhume Galileo's body, so that they can do some DNA analysis to figure out what had ailed Galileo's eyes.

This news has been widely reported, see for example, here and here. The scientists' interest is to explain why Galileo described Saturn as having "lateral ears" rather than rings around the planet. And the theory is that poor eyesight was behind the error.

Galileo's drawings of Saturn are shown on the left:

The one on top was sketched in 1610, and the bottom, 1616.

These "arms" were clarified by Dutch astronomer, Christiaan Huygens, in 1659, as a ring system. He was able to do so because of improved telescope optics. [Note: Huygens also discovered Saturn's moon, Titan, and for this reason, the probe exploring Titan is named after him. And a few years later, Jean-Dominique Cassini discovered 4 other major moons of Saturn: Iapetus, Rhea, Tethys, and Dione.]

So what was wrong with Galileo's eyes and vision? It was actually quite well-documented. According to this site, for example:

"Galileo’s sight began to deteriorate in the middle of 1636 when he was 68 years old, and by the end of June 1637 he had lost the use of his right eye while his left eye was affected by a constant discharge. He described seeing a 'luminous halo' around candle flames. To date there has been little speculation by modern optometrists or physicians about the possible causes of Galileo’s blindness. In July 1636 he wrote to his friend, an Italian lawyer living in France, Elia Diodati, 'I have been in bed for five weeks oppressed with weakness and other infirmities. Added to the (proh dolor!) the sight of my right eye - that eye whose labours (I have no hesitation in saying) have had such glorious results, is lost forever. That of the left, which was and is imperfect, is rendered null by a continual running’. He became totally blind early in December 1637, a few months after using the telescope to discover that the moon wobbles on its axis ('lunar libration') which was quite a remarkable observation to make with only one useful eye. At this point he wrote to Father Castelli noting that 'The noblest eye is darkened which nature ever made, an eye so privileged and so gifted with rare qualities that it may with truth be said to have seen more than the eyes of all those who are gone, and to have opened the eyes of all those who are to come'."

The keywords are shown in red. The symptom/sign suggests active keratitis [discharge] accompanied by corneal edema [halo]. And since both eyes eventually lost vision, it would imply a chronic retinal problem, perhaps posterior uveitis. The left eye was probably further complicated by band keratopathy in his last years. His 20X telescope was actually a low-vision device - at least by 1616, Galilio appeared to still have retained enough vision (at least 20/400) to allow somewhat accurate observation of Saturn's rings/arms.

What the proposed DNA analysis can prove? Probably not much. The project is expected to cost around £282,000, by the way.

Year of Recovery

Happy Lunar New Year

It is a year of 扭(牛)轉乾坤, i.e.,
a year of (bullish) recovery.

Enjoy.

9.13 Five-, 6-, 7-, 8-pointed stars

How many points does a star emanate?

It depends on where you are from.

In the US, five (5). You see 5-pointed stars on a certain sidewalk in Hollywood (e.g., left). Even the Texaco logo has such a star. It is also the basic standard emblem of the US Military. The American flag has 50 such stars. And the national flags of Singapore, New Zealand, Pakistan, Turkey, China, Somalia, and many others all have the 5-pointed star(s) as part of the design.

There are of course the 6-pointed stars, e.g., the Marian star and the star of David.

The municipal flag of Chicago has four 6-pointed stars (right), each commemorating a specific event and each of the 6 points, a special meaning. A fifth star has been proposed on more than one occasion, but none has been realized thus far. Further, the white stripes = north, west and south sides of Chicago, and the two blue stripes = Lake Michigan and Chicago River, respectively.

Interestingly, the 6-pointed star is also a sacred Mongol symbol, seen, e.g., on the entry to Humayun's tomb in New Delhi (below):

Seven-pointed stars? Of course, the Australian flag has 5 of them:

It often puzzles the tourists: 6 states + 2 territories = 7, not 8 points? (Dared to be different, these Aussies?)

Actually, it is a bit more complicated than the simple math. The winner of the original flag design (contest conducted in 1901) had 5, 6, 7 and 8 points (below, left).

King Edward VII approved the current 5- and 7-pointed star version.

There have been many iterations on the significance of these designs which we'll leave to the real historians to contemplate.

The only national flag that has an 8-pointed star seems to be that of Azerbaijan (below). This star is supposed to be the symbol of Rub El Hizb (Arabic: رب الحزب‎). And the design here was modified in 1991:
Seriously, how many points of a real heavenly star are we supposed to see? Let's see:

In the human eye, the crystalline lens is composed of a single-cell-layer epithelium in the front and a cortex that envelopes the nucleus. The epithelial cells elongate into cortical fiber cells and the ends are jointed at the front and the back, known as the sutures. The front suture is shaped as an upright Y and the posterior, an inverted Y. Superimposing the two Ys, what do you get? Yes, 6-points. This is the basic pattern. Often there are branches off the basic Ys. In other words, stars (in effect, point sources of light) should appear 6-pointed (with/without branches) to most of us. If you see 5 or 7 points, have your eyes examined.

Occasionally, something goes wrong with the sutures, then you'd end up with sutural cataracts. A real bad case is shown here:

(From: http://www.eyesonline.com.au)

See the huge Y within the dilated pupil? Most sutural cataracts are, however, less dramatic than the one shown here. Most have no significant impact on vision except the 6-pointed stars look even more prominent.

You'll shoot your eye out

(A Christmas Story, Warner Bros, 1983)

(Click arrow to start the video)

Merry Christmas and

Happy New Year!

9.12 Panda myopia

Two giant pandas, Tuan-Tuan and Yuan-Yuan, both from Sichuan arrived in Taiwan today.

Panda-mania now begins. Kids are overjoyed. And adults are busy analyzing the political implications of such precious gifts.

The happiest people are the merchants who peddle everything panda, from cookies, candies, to clothing.

What, pandas are near-sighted? -4.00D? Based on cycloplegic refraction?

9.11 Lobster eyes

On the left is a normal 2-clawed Maine lobster. Newport Daily News (12/3/2008) reports that a 1.5-lb 4-clawed lady lobster is caught this week by a Mr Patrick Marks in the waters 60 miles south of Newport, RI. It has one crusher claw and three pincher claws, all functional. After showing it off most of the day, Mr Marks let her go, explaining that he "sometimes lets lobsters go out of guilt when they look at him funny."

Yes!! Lobster vision at work.

Lobster eyes are structurally very different from that of other animals (including the mantis shrimp). The cornea actually contains an array of mirror-like reflectors, each arranged at a specific angle, that ultimately focus incoming light rays onto the retina.

The optics is reflection rather than the more conventional refraction.

Presumably in the dim deep sea where sharp vision is less important than acute sense of smell and touch, the lobsters do not rely on vision to hunt, they only need to detect motion.

Under bright lights, the lobsters probably cannot not see much as everything is blended into the background and "washed out". Lights reflected from their eyes, on the other hand, will give you an impression that you are being stared at, inquisitively. If you were a lobsterman, you'd probably let them go, too.

Earlier this summer, another 4-clawed lobster was caught by a Mr Jimmy Whitty based in Morell, PEI, Canada. It was nicknamed Mothra and kept in an aquarium at a restaurant. It was, alas, lost to follow-up.

And in Taiwan (local news, 11/25/2008, reported in www.nownews.com), fisherman Mr Chen caught a 3-kg male crab with a 50-cm "wing" span, estimated at 10 years old, at the mouth of Chen-wen Brook in Tainan Hsien (台南曾文溪河口). When caught with a net, it protested loudly with a hissing sound, fought gallantly with its claws, and with the eyes extending from the protective grooves, it was looking to escape at the same time. Mr Chen eventually let him go, so it can continue to propagate.

The first Thanksgiving

(In November of 1621) when the Wampanoags helped the Pilgrims (who had arrived on the Mayflower, in 1620) bring in their first crop in the new world, there was a great feast during that harvest time. According to the Pilgrims, about 90 Wampanoags crashed the party and brought with them all sorts of delicacies. The Wampanoags usually celebrated their harvests, with food and rejoicing. They brought venison (deer meat), wild turkey, rabbit, woodchuck, lobster, clams, mussels, potatoes, sea bass, bluefish and many other delicious foods. Wampanogas also brought corn, beans, and squash to the feast, and even showed the Pilgrims how to cook the food. The Pilgrims were very appreciative of the gifts, and the 90 Wampanoags who crashed the party had a wonderful time (extracted from http://content.scholastic.com/browse/article.jsp?id=7587).

Thanksgiving is celebrated in the US on the 4th Thursday of November every year. Happy Thanksgiving !!