Sunday, October 25, 2009

Meteor, Meteoroid, Meteorite: What's the Difference?

It wasn't until I took my first astronomy class in college that I learned that a meteor, meteoroid, and meteorite are not the same thing. Previously I had supposed that "meteor" was short for the word "meteorite," which to me was simply a rock from outer space. I also speculated that the term "meteoroid" was a sort of geeky nickname for the same rocks, since adding "oid" to the end of any word makes it sound like it's associated with little green men from a distant planet. While it is true that all three terms refer to a space rock, they can not be used interchangeably. Each term has it's own specific meaning and appropriate usage.

Firstly, the website Solar Views explains that the term meteoroid is reserved for matter in outer space which revolves around our sun. Of course, however, not everything that revolves around the sun is a meteoroid. "
A meteoroid is matter revolving around the sun or any object in interplanetary space that is too small to be called an asteroid or a comet. Even smaller particles are called micrometeoroids or cosmic dust grains, which includes any interstellar material that should happen to enter our solar system," reads the site.

Though this explanation makes sense, it raises the question, "what's an asteroid?" The website explains, "A meteoroid is anything from the size of a grain of sand up to a boulder. Anything bigger than that is considered an asteroid. "

OK, now what is a meteor? Well, the term "meteor" actually refers to the reaction that occurs when a falling meteoroid passes through Earth's atmosphere. The website Space Today explains that, "Meteors are the streaks of light associated with the burning of small chunks of rock or interplanetary debris [meteoroids] as they arrive in Earth's atmosphere from space." Just to clarify, the actual space rocks/debris are the meteoroids, and when they contact our atmosphere, they create meteors. "A sky-watcher under a dark clear sky might see a few [meteors] per hour on an average night. On the other hand, during one of the annual meteor showers, a sky-watcher might see up to 100 per hour," reads Space Today.

Now come the meteorites. According to Space Today, "A meteorite is a meteoroid large enough to survive the fall to Earth's surface." Basically, space debris can only be meteoroids while they are in outer space. Once they touch Earth's soil, they technically become meteorites.

File:Meteoroid meteor meteorite.gif

Monday, October 12, 2009

How did the domestication of cats come about?

If you have a pet cat, you may often wonder, as I do, how such a playful, affectionate, and generally easy to live with creature could have evolved from the feral feline beasts that lurk in the jungles of Africa and Asia. Even my utterly domestic cat, who knows no predators and has never had to hunt a day in his life, has painfully sharp teeth and claws that he not only knows how to use, but that he rather seems to enjoy using at times. So how did humans and cats end up forging such a docile relationship? How did these fierce hunters end up in our homes?

According to the informational domestic cat website,, interactions between cats and humans go way back. The bones of cats have been found next to the bones of humans, dating back to the Stone Age. "It is unclear what kind of relationship they had – possibly the cats were just drawn to the food and warmth of human settlements, but didn’t hang around longer than it took to forage scraps," reads the site.

It was the Egyptains, however, that first documented a relationship between humans and cats. According to the aforementioned website, "Tomb scenes dating from 1540 BC showed that cats played a large part in everyday Egyptian life." There is agreement among researchers that the Egyptians were the first to domesticate wild cats into house pets; however, it is unclear exactly when this happened. The website says, "There is no exact date that one can conclude when the cat was domesticated in Egypt, but researchers believe that the act took place around 2000 BC. Researchers have tried many times to pinpoint a date when the domesticated cat emerged, but ancient Egyptians did not indicate the differences between wild and tame cats in their records. Interestingly, the Egyptians had one word to refer to a cat (miu or mii), which translates into 'he or she who meows.' "

The species of cat that Egyptians befriended was the African Wild Cat, or Felis Libyca, according to This species is, "one of the closest wild relatives of the modern cat, explains the site, adding that it was slightly larger than today's house cats, and, "had yellow-gray fur,
striped markings, and a long tail that tapered off." Though these cats (pictured at right) are undoubtedly less intimidating than a lion or tiger, they are still very much wild, carnivorous, and territorial. So how did they make their way into the hearts and homes of Ancient Egyptians?

It seems the Egyptians actually appreciated the felines' predatory nature rather than fearing it. explains that, "The villages of ancient Egypt faced a number of poisonous snakes, rats and mice that attacked food supplies within the households and snuck into the village granaries. The wild cat would come into the villages and hunt down the vermin, ridding the community of one of their number one threats. Some researchers theorize that the Egyptians would leave pieces of food out to bring in more wild cats."

The website explains further the popular theory that the Egyptians eventually allowed the wild cats into their homes because the cats became known as pest controllers, rather than pests themselves. Once the cats became familiar with human surroundings and realized that humans were not a threat to them, "[they] allowed themselves to be tamed and raised their kittens in a human environment. As soon as the Egyptians began supplying the cats with food, thereby significantly changing their diet, and breeding them for certain characteristics, the cats were domesticated. They were perfect pets-playful, intelligent, affectionate and helpful to the farmers who sustained life in ancient Egypt," reads the website.

As a result, the Egyptains came to consider the cat to be a very sacred animal. points out that the Egyptains actually went through the trouble to mummify some cats, and it even became popular to name children after the cat. "Many Egyptian parents named their children after cats, especially their daughters. Some girls were called Mit or Miut," states

Very few purely wild African Wild Cats still exist in the world today, according to South Africa Explored. The site explains that, "Pure genetic stock of the African Wild Cat is today only found in remote areas [of Africa and the Middle East]. Elsewhere interbreeding with domestic cats has taken place." Still, it is quite likely that the cat you share your home with (if you share your home with a cat) is a descendant of an African Wild Cat domesticated by the Ancient Egyptians. points out that much of the characteristic aloofness of modern house cats was inherited from their wild ancestors.

Sunday, October 4, 2009

Article critique

I enjoyed the article "Stephen Hawking is Making his Comeback" from Discover magazine. It especially sparked my interest because I've taken some astronomy classes and I enjoy learning about the cosmos. However, I can see how someone that doesn't know much about the topic might find the article long and complicated. At the very least, it was a well-written biographical tribute to an interesting man.

Lede: I give the lede a 17 out of 20. It drew me in and was somewhat creative, but there's room for improvement.

Content: The content was great. The author obviously did his research and was able to convey an essence of Hawking and his ideas to readers. 20 out of 20.

Organization: I was also very impressed with this aspect of the article. There is so much info in the article, and I'm sure when the author sat down to write, he really had to wrap his mind around everything he wanted the article to say. He was able to get it all down in a logical way. 20 out of 20.

Writing Style: I enjoyed the style. It managed to be authoritative and conversational at the same time. 19 out of 20

Clarity: I didn't have too much trouble understanding the science in the article, but I have a bit of astronomy background. I think some of the science in the article is over a lot of people's heads. The author tries to explain things in simple terms, but concepts such as singularities, event horizons, and quantum uncertainty can take some time to wrap your head around. 15 out of 20.

Saturday, October 3, 2009

Why are flamingos pink?

Flamingos are known for their brightly colored pink feathers, but the truth is, they are actually born white. But how does this happen? After all, unless you're Micheal Jackson or a chameleon, you must learn to live with the skin, feather, fur, or scale color you are born with. But flamingos have options. If they don't fancy their white feathers, they can simply eat themselves pink, giving a whole new meaning to the phrase, "you are what you eat."

According to Cecil Adams of the website The Straight Dope, flamingos eat a diet high in carotenoid compounds. The most well known of such compounds is probably Beta Carotene, which is found in a variety of vegetables including carrots. "Carotenoids tend to be a persistent red orange in color," explains Adams. "Depending on formulation, they impart a red, pink, orange, yellow, or even green cast to some plants and to the higher links in the food chain by which those plants are consumed."

Though it is unlikely to see a flamingo snacking on a carotenoid packed broccoli stock or a carrot, flamingos are big fans of brine shrimp, and brine shrimp are big fans of algae, which contains carotenoids. In short, the shrimp act as carotenoid carriers for flamingos. Catherine Side explains on the African Conservation Foundation website that when flamingos ingest shrimp the carotenoid chemicals, "are not broken down and have extremely low water solubility, [so] they are deposited in the feathers of flamingos."

So what happens when flamingos don't get their recommended dose of carotenoids? They turn white. R.P Dales of the University of London explains on the African Conservation Website, that when the birds shed their feathers (a habit known as moulting), they shed the pink pigment also, so if that pigment is not replenished via carotenoid consumption, the flamingos will become pale.

Interestingly enough, flamingos are not the only animals whose hue comes from their food. "The pink color of some other birds, such as spoonbills and the pink ibis, is also due to carotenoids," says Dales. In addition, Adams points out that, "Salmon caught in the wild are orange because of their diet of crustaceans that contain carotenoid. The flesh of farm-raised salmon, which don't feed on crustaceans, is an unappetizing gray unless the fish are given the carotenoid astaxanthin."

So are human skin pigments affected by carotenoids? According to Adams, they certainly can be. "If [humans] eat enough carrots (which, duh, contain carotene), they'll turn orange," he says. "And if they have no interest in eating vegetables but would still like to be orange, they can take beta carotene pills providing 10 to 30 times the normal dietary amount."