‘והיה לכם לציצית, וראיתם אותו וזכרתם את כל מצוות ד
In Keriat Shema we read “And you shall see it and remember all of the mitzvotof Hashem….” Rashi, quoting the Targum Yonatan and the Tanchuma, explains the mechanism whereby one can look at the tzitzit and remember all the mitzvot. The word tzitzit in gematria adds up to 600. Add the eight strings and five knots and you have 613, the number of mitzvot in the Torah.
The Ramban challenges Rashi noting that the number of strings is subject to ahalachic dispute, and that the number of knots is certainly not from the Torah. He therefore suggests that the subject of the posuk is the tekhelet string. By looking at the blue thread, one remembers the sea and the sky and Hashem’s holy throne, and that reminds one of all the mitzvot.
An additional problem with Rashi’s explanation is that the term “And you shall see it” is in the masculine form. The word tzitzit is feminine, and therefore it cannot be the subject. Only the blue thread can be what is meant to remind us of all the mitzvot.
A recent article by two Belgian scientists has revealed a fascinating “coincidence.” J. Wouters and A. Verhecken studied the characteristics of the different dye molecules obtained from the Murex trunculus snail. One of the measurements was the absorption spectrum of the molecule. Light is made up of many colors (the spectrum) measured in units of nanometers (nm). Our eye perceives color in a complex fashion based on the various combinations of colors of light that strike it. For example, gold absorbs blue light and reflects the rest. When our eye sees all the colors of the spectrum with blue taken out, it perceives the color as gold. Ultimately, however, the color we see is determined entirely by what colors something absorbs and what is reflected.
The tekhelet molecule (indigotin) gets its color from a strong absorption peak centered at 613 nanometers!