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Archive for the ‘astronomy’ Category

A Solar Eclipse Deserves A Blessing

Thursday, August 3, 2017 @ 09:08 PM
posted by Roger Price

Credit: USAF/Museum of Aviation

We are on a fantastic journey, over which we have precious little control. As our universe expands, we are pushed deeper and deeper into space. We travel along, like some pebble carried with the tide. Our own galaxy, like hundreds of millions of others, rotates, and it does so at about 168 miles per second. On one of the spiral arms of our galaxy, our solar system has its own rhythms. Within the solar system, our home planet goes around our local star, the Sun, and our moon orbits around our home planet, even as the Earth and the Moon spin too.

Once in a while, in the midst of all this motion, the Moon travels between the Earth and the Sun in such a way as to block the light of the Sun from reaching us. It casts a shadow on our planet. The blockage may be partial or complete. We call this event a solar eclipse. In a total eclipse, when the Moon obscures the entire solar disk, the fullest form of the Moon’s shadow, the umbra, lasts no more than a few minutes in any one spot, but the effects are stark as darkness literally covers the Earth and the temperature drops.

We will ooh and ah as the eclipse begins, but we know that this too shall pass. All that was will be again and soon. Normalcy will return. One might think that it would be an occasion for a blessing, a b’rakha. After all, Jews seemingly have blessings, or b’rakhot, for every event and circumstance, from the sublime to the mundane, and from the time they arise to the time they go to sleep. And there are well recognized blessings for similar occurrences. For instance, when one sees a comet or lightening, there is Barukh atah Adonai, Eloheynu melekh ha’olam, oseh ma’aseh v’reyshit (Blessed is the Eternal One, Sovereign of the universe, maker of the works of creation). When one sees something beautiful like a tree or an animal, one might say Barukh atah Adonai, Eloheynu melekh ha’olam, she’kakha lo b’olamo (Blessed is the Source of wonder, Ruler of the cosmos, that such things are in the world). There are blessings on reaching the ocean, on smelling fragrant grasses and spices, even on witnessing an earthquake. But traditionally, there is no blessing for an eclipse. Why? To answer that question, we need to understand some science and some Judaism. read more

In the Beginning and In the End

Thursday, October 15, 2015 @ 02:10 PM
posted by Roger Price

Credit: NASA/ESA Hubble Space Telescope.

When the cosmos was about to be created — the fundamental forces of nature being unified in an exceedingly hot, dense point and galaxies, stars, planets, even stable matter itself yet unformed — there was no recognizable space, no measurable time. There was no darkness over the surface of the deep because there was no deep, no surface, no over and no under. No wind hovered over any water, as there was not yet any hydrogen or oxygen, much less any combination of them in the form of water. And there was no wind, either. What there was — all that there was — was chaotic, pulsating Potential.

At some moment, for reasons yet unclear, what was began to change into what is. Gravity separated first from the combined strong nuclear and electroweak forces. Then the strong force emerged and the electroweak force devolved into the electromagnetic force and weak nuclear force. The nascent universe, still small and unbelievably hot and turbulent, was an ever changing soup of energy and sub-atomic particles. It was all good, and about to become better.

Within one second from the mystery of beginning, our mini-universe inflated, and then started to expand. Its temperature dropped from an unfathomably hot state of 100 nonillion degrees Kelvin to only one trillion degrees, but that relative cooling was sufficient for sub-atomic particles to become protons and neutrons and other heavier particles. At the three minute mark, with the temperature now down to a cool billion degrees, particles fused into atomic nuclei, mostly hydrogen nuclei, some helium nuclei and other kinds as well. This, too, was good. read more

Sagan, Stars and Grains of Sand

Monday, February 23, 2015 @ 02:02 PM
posted by Roger Price

Pandora’s Cluster

Credit: NASA/JPL-Caltech

Who could look at the stars and yawn? Certainly not astronomer Carl Sagan.  Sagan, a serious scientist, popularized a journey though the universe just over a third of a century ago with his award winning TV series, Cosmos. To impress upon his viewers how many stars existed, Sagan would enthusiastically assert that there were “billions and billions” of them, stressing and drawing out the first syllable each time.

As he acknowledged at the outset, however, the “size and age of the Cosmos are beyond ordinary human understanding.” So, to try to make such an enormous quantity understandable, he said that “the total number of stars in the universe is larger than all the grains of sand on all the beaches of the planet Earth.” (Watch here; see also, Sagan, Cosmos (Random House 1980) at 4, 196.) It was a wonderful reference.

We may sense that there are a lot of stars in the sky, but with the naked eye it is hard to pinpoint and count them, even or maybe especially on a clear night. Sand is somewhat different. We can take a fistful of it at a beach, survey the area, think about the coast lines of the various continents, and then factor in countless interior beaches. Sagan says that our hand will hold about 10,000 grains of sand. (Cosmos, at 196.) Without help, we may not be able to do the math or know the result of the equation, but we can understand that the beaches hold an enormous number of grains of sand.

What Sagan did not say is that his two subjects, stars and sand, were invoked long ago in the Hebrew Bible as metaphors for abundance. They appear first in the book of Genesis, each separately and once together. read more

An Earth-like Exoplanet, Extraterrestrial Life and the Messianic Age

Sunday, April 27, 2014 @ 11:04 AM
posted by Rabbi Allen S. Maller

The most Earth-like planet yet discovered has been found right in our neighborhood according to a report in an April 18, 2014 issue of the L.A. Times from the journal Science. By sifting through observations from more than 100,000 distant stars, astronomers say they have discovered the first definitive Earth-sized planet that orbits in a habitable zone where water could exist in liquid form — a necessary condition for life as we know it.

Scientists don’t know whether the planet has water or a protective atmosphere. But they said the landmark discovery gives astronomers great hope that a bumper crop of Earth-like planets is waiting to be found nearby. “This is really a tip-of-the-iceberg discovery,” said Jason Rowe, an astronomer who spent a year analyzing data gathered by the Kepler space telescope.

The planet is 10% bigger than Earth, and its parent star is a red dwarf, smaller and dimmer than our sun but that is good news because red dwarfs are the most common star in our galaxy. UC Berkeley astronomer Geoffrey Marcy, who discovered the first exoplanet said. “This is the best case for a habitable planet yet found. The results are absolutely rock solid.” read more