Friday, July 16, 2004


Tehillim 104:24-25:
מָה-רַבּוּ מַעֲשֶׂיךָ השם!
כֻּלָּם, בְּחָכְמָה עָשִׂיתָ
מָלְאָה הָאָרֶץ, קִנְיָנֶךָ.
זֶה, הַיָּם גָּדוֹל-- וּרְחַב יָדָיִם:
שָׁם-רֶמֶשׂ, וְאֵין מִסְפָּר; חַיּוֹת קְטַנּוֹת, עִם-גְּדֹלוֹת.
"How manifold are Thy works, O LORD! In wisdom hast Thou made them all;
the earth is full of Thy creatures.
Yonder sea, great and wide,
therein are creeping things innumerable, living creatures, both small and great."

I just read on Wired about a new discovery. Phyloplankton, tiny creatures (between 1 and 100 micrometers) that live in water can protect themselves from UV radiation by causing a cloud to form over them:

Phytoplankton may be small, but that doesn't mean they can't do big things -- like change the weather to suit their needs.

A recent study funded by NASA's Earth Science Department shows that the tiny sea plants release high quantities of cloud-forming compounds on days when the sun's harmful ultraviolet rays are especially strong. The compounds evaporate into the air through a series of chemical processes that result in especially reflective clouds. This, in turn, blocks the radiation from bothering the phytoplankton.

size of phytoplankton Posted by Hello

This reminded me of a gemara in yershalmi succah.
סוכה דף ה,ב פרק א הלכה ה גמרא ר' יוחנן דו אמר עננים מלמעלה היו דו יליף לה מאספך. רשב"ל אמר עננים מלמטן היו דו יליף לה מעננים. א"ר אבין דין כדעתיה ודין כדעתיה ר' יוחן דו מדמי לה כמשלח לחבירו חבית וקנקנה. רשב"ל דו מדמי לה כהן דאמר לחבריה שלח קופתך וסב לך חיטין

Rabbi Yochanan and Resh Lakish have a dispute whether to derive the rules for kosher Schach for a Succah from the Clouds of Glory that covered the Jews when in the Desert. A perspective on the dispute is that the kosher Succah covering must "grow" from the ground. One holds clouds "grow" from the ground and the other holds they do not. (Growing means that there is some source from below for them.) There is a verse in the beginning of Berishit about a cloud/mist arising from the ground to water the Garden of Eden. In the above cited gemara, R Avin says: R Yochanan who thinks a cloud is entirely from above compares it to one who sends a barrel of wine together with its container. Resh Lakish who thinks there is some input from below compares it to one who says to his friend send me your basket and take for yourself in it wheat.

The specific meaning of these opinions in the gemara aside, it is interesting that there is here some input from below, with the plankton able to create a cloud for protection above themselves on demand.

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