Wheat-dogg’s world
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The snippet lasted only a few seconds, and I’ll bet most viewers didn’t even notice the mistake.

It was during a CNN Special Investigation Report on food safety. The camera supposedly was trained on the Sun as it rises above the horizon. Diagonally. Toward the top left of the screen. In California.

Well, it cannot have possibly happened, not in the Northern Hemisphere anyway. Clearly the cinematographer was just running a sunset backwards to create a “sunrise,” a geographically wrong sunrise. Here’s why.

The Sun always rises in the east and sets in the west, no matter where you live, because the entire Earth rotates in the same direction. The path of the Sun across the sky, however, depends on your latitude, because the Earth is round.

If you live in the Northern Hemisphere, facing east, you will see the Sun rise over the horizon and follow a diagonal path toward the upper right (also known as the southern sky). At sunset, facing west, the Sun will slowly dive toward the horizon from the upper left (still the southern sky). The angle of that path relative to the horizon matches your latitude. (Where I live, that angle is about 38 degrees.) As you head north, that angle gets closer and closer to zero. So, during the Arctic summer the Sun cruises above the horizon, never setting.

Heading the other way, toward the equator, the angle of the Sun’s path increases to 90 degrees. At sunrise or sunset, the Sun drives straight up or down from the horizon.

And that’s a big deal because methane is an organic molecule that can be a precursor to life. We know methane exists in our solar system, but the Hubble’s discovery is the first evidence it exists on planets outside our solar system.

Whether it means life is out there remains to be seen. Methane is a simple enough molecule to be created by chemical means. Its existence does not mean living organisms are producing it. (Y’know, like extraterrestrial cow farts.)

Details are at the Hubble Space Telescope site.

At 1:48 am tonight (the 20th), the Sun will be right on the celestial equator. At sunrise, it will come up due east of your location. We northern hemisphere dwellers call this event the vernal (as in spring) equinox. Southern hemisphere types call it the autumnal equinox.

Either way, for one day, we each get about 12 hours of day and 12 of night.

Ancient civilizations held big celebrations around the time of the equinox, since it marked both the end of winter (in the northern hemisphere, anyway) and the beginning of the planting season. Two religious observances, Passover and Easter, are tied to the season. Easter bunnies and Easter eggs are signs of fertility and reproduction, celebrating the rebirth of the land in spring.

Speaking of eggs, it’s a myth that the only time you can balance an egg on its end is during the equinox. In fact, you can do it any old time. The Bad Astronomer, Phil Plait, shows you how here:

It took a while, but the Roman Catholic Church has finally accepted Galileo was right after all. A statue of the 17th century scientist is planned for the Vatican Gardens.

Four centuries ago, Galileo’s image would instead have been on the Vatican’s post office “most wanted, feared armed with pen and dangerous” bulletin board. He stepped on a lot of ecclesiastical toes, including the Pope’s (never a good career move for a Catholic), by stating in print for all to read that the Church was wrong about the Sun orbiting the Earth.

Instead, Galileo, using observational evidence obtained with a telescope of his own design, argued that Polish astronomer and cleric Nicolaus Copernicus was correct. The Earth and the other planets orbit the Sun. Galileo insinuated that the Bible, the Church and Greek philosopher Aristotle were all wrong in teaching the Earth was stationary.

We know now Galileo was correct. In fact, the Vatican might have suspected the same even while arresting and trying Galileo for heresy. After all, Copernicus intended that the Church use his work in developing a new calendar, which it did in 1582. It was Galileo’s attitude that ticked off Church authorities, who were in the midst of dealing with those troublesome Protestants all over Europe.

Under threat of excommunication (or worse), Galileo in 1633 was forced to retract his statements that the Earth was just another planet orbiting the Sun, banned from publishing any further work on the subject and placed under house arrest (in his villa) until he died in 1642. His books (and Copernicus’) were pulled from the shelves of all Catholic libraries and placed on the Vatican’s banned-book list for two centuries.

It’s Feb. 29, the day the Gregorian calendar adds (almost) every four years to bring the calendar in line with the apparent motion of the Sun across the heavens.

Our calendar normally has 365 days in it, but the purpose of the civil calendar is partly to keep the equinoxes and solstices on the same days each year. Trouble is, the Earth takes a little more than 365 days to orbit the Sun, so over time the calendar “runs slow,” losing almost a day every four years. Since we can’t slow down the Earth in its orbit, the Gregorian calendar adds a day every four years to keep it in step with the Earth.

It’s not precise, actually. Earth refuses to observe our petty attempts at scheduling the solstices and equinoxes, and actually takes about 365.2422 days to orbit the Sun, instead of the more convenient 365.25 days. So the additional leap day every four years, over the course of 400 years, means the calendar would be about 3 days ahead of the Earth’s motion. The Gregorian calendar fixes that little detail by adjusting the add-a-day rule.

The rule is a bit obscure. It goes like this (sing along if you know the melody). Years that are divisible by 100 are also divisible by 4, so they would normally be leap years, as they were in the old Julian calendar. But we only apply the leap-day fix on those 00 years that are also divisible by 400. So, 1600 and 2000 were leap years, but 1700, 1800 and 1900 were not. So in the 400 years after 1600, the calendar “lost” 3 days — the right amount to keep it and the Sun in line with one another.

Caption: Áurea (Fernanda Torres) talks to Luiz (Enrique Diaz) in Casa de areia.

On our day off Monday, I ended up watching TV in the afternoon and stumbled upon a Brazilian movie on Starz, Casa de areia (House of Sand), that to my surprise had references to Einstein’s relativity theory in it.

The plot is minimal. The movie’s effect comes from the acting and the ironic turns in its main characters’ lives.

Áurea is a young, city-bred woman whose husband has the crackbrained idea of moving to a godforsaken plot of land on Brazil’s arid northeast (O Nordeste). Her mother, Dona Maria, accompanies them. The husband dies before the birth of Áurea’s only child, Maria, leaving the women essentially stranded in the middle of nowhere.

Áurea wants to leave in the worst way, while Dona Maria would prefer to stay. There are no men to tell her what to do, Dona Maria says. After nearly a decade stuck in O Nordeste, Áurea arranges to leave with a wandering peddler who sells salt and other sundries to the few people living in the region.

But the peddler dies en route to the women’s house. Áurea and their neighbor, a reserved man named Massu, go in search of the peddler. Along the way, Áurea tells Massu she will finish the trip on her own, following tracks in the sand. After two days, she comes across the campsite of a group of scientists photographing the solar eclipse of 1919.

MESSENGER took about 1,200 images during its flyby of Mercury earlier this week. Here’s another nifty one. (Click on the image to see a larger version.)

It may be a barren surface, but I find it fascinating to see pictures of another world. They make Mercury seem like a place, instead of some abstract location. By the way, the large crater at the lower right is named “Sholem Aleichem,” the Yiddish author who created the Fiddler on the Roof. The large craters on Mercury are named after authors, artists, and musicians.

The MESSENGER probe captured this image of Mercury yesterday from 27,000 km away, giving us our first view of this previously unseen side of the planet. At the time, the probe was receding from its first flyby approach. [Click on the image to see a larger version.]

As MESSENGER passed by, it snapped this image of the “near side” of Mercury, showing the crater Vivaldi on the right. Mariner 10 had imaged this part of Mercury on its pass in 1974.

NASA will be releasing more images as MESSENGER sends them for processing.

The MESSENGER probe zipped past Mercury yesterday in the first of three flybys needed before it settles into a regular orbit. NASA scientists say the probe survived the encounter, which brought it to within 200 km (124 miles) of the planet’s surface.

MESSENGER is the first probe to visit Mercury in 30 years, so planetary scientists are excited to see what new data the new probe returns. MESSENGER (short for “MErcury Surface Space ENvironment GEochemistry and Ranging” — NASA must have a special office to devise names like this one) will investigate Mercury in ways that were not possible when Mariner 10 paid it two flyby visits in 1974. Mariner 10 was able to image only one side of Mercury.

Here’s an image of Mercury taken by MESSENGER on its approach Sunday, from 760,000 kilometers away (about twice the distance from the Earth to the Moon). (Click on the image to see a larger version.)

After two more flybys this year and next, MESSENGER will settle into a regular orbit in 2011 when it will begin a longterm study of the innermost planet, the first in its history. The peculiar trajectory is a fuel-saving measure, to enable the probe to “catch up” to Mercury in its fast orbit around the Sun. [Earth travels at an average of 30 km/s; Mercury at 48 km/s. A more direct route would require burning a lot of fuel to speed the probe up and change its orbit.]

You don’t need to cancel any Martian vacation plans. The chances of asteroid MD5 colliding with the Red Planet are now 1 in 10,000, according to Near Earth Object Program experts. The image below shows the envelope through which the asteroid will likely pass on Jan. 30, when it intersects Mars’ orbit.

Earlier estimates had the envelope overlapping Mars itself, and experts as late as yesterday had given MD5 a 1 in 40 chance of hitting the planet. Better telescopic observations of MD5’s path have narrowed the size of the envelope, reducing the odds of a collision.