Testing Your Science Literacy
Science > People steeped in public education swim in a swirling sea of buzzwords and phrases. One of those phrases is "scientific literacy." It seems that we Americans are a wee lacking in the area of scientific literacy, knowledge of the basic terms and facts from the land of science. But we do not have to belong to the Club of Illiteracy, oh no! We can rise above that. So, in addition to the usual sky information that we normally see here in this column, maybe this year we can, on occasion, devote some time to laying down a solid foundation in the grand science of astronomy. Ready?
Which planets have rings? Well, of course we know that Saturn has rings. For hundreds of years it was the only planet with rings. But recently we have discovered that Saturn's neighbors, the so-called gas giants, also have rings. But they are so faint they weren't discovered until a short time ago.
Uranus was the first planet after Saturn to show us its rings, although we first had to pry the fact from it. In the mid-70's astronomers observed that distant stars would flicker just before and after Uranus passed in front of them. The reason must have been faint rings cutting off the starlight. In 1986, the spacecraft Voyager 2 flew by Uranus and sure enough, there were the nearly imperceptible rings.
It turned out Jupiter had them, too. They were discovered in Voyager 1's flyby in 1979. But don't expect to see them with your backyard telescope. They are essentially made of dust. Only the biggest scopes here on Earth can catch a glimpse of them.
Then, not to be left out, Neptune revealed his rings. Suspected to exist by the same flickering of stars as Uranus' rings showed us, Voyager 2 confirmed them in 1989. It appears that all the big guys - not just Saturn - wear rings.
What is the hottest planet? Most would suspect, intuitively, that the planet closest to the Sun would be the hottest, to wit, tiny Mercury. And Mercury is hot, to be sure - very hot. At its equator it can get to 800 degrees Fahrenheit.
But even as hot as that little guy is, it isn't the winner. Venus is actually hotter - averaging almost 900 degrees Fahrenheit.
But how can a planet more than 50 million kilometers father away from the sun than Mercury be hotter? Because Venus is swaddled in an atmospheric blankie. Poor Mercury has no atmosphere to hold onto the heat, which is why its dark "nighttime" side gets to 300 below.
But Venus has an extremely thick carbon dioxide atmosphere. And carbon dioxide has a notorious ability to hold on to heat; it is the prime suspect in global warming here. This is precisely what is happening on Venus, the warmest planet in the solar system.
How does the sun burn? It was believed since time immemorial that the sun was hot because it was burning stuff, just like fires do here on earth. But if that were what was happening it would have had only tens of thousands of years of stuff to burn, not b-zillions. There had to be another, more efficient way. It took Einstein and his contemporaneous colleagues to figure this one out.
A group of really smart people of his time discovered that the nucleus of an atom stores a wealth of energy, a great wealth, a fortune. It seems that if we rip apart giant nuclei, or smash together very tiny ones, a tremendous amount of energy is liberated.
That is what happens up there in the sun. At its very hot and high-pressure center - the core - tiny little hydrogen nuclei are forged together to form helium. In the process, a prolific amount of energy is released and eventually makes its way to the sun's surface, released now into space.
There is enough hydrogen left at the core for our sun to burn nicely for several billion more years. No need to feed those flames, all is well.
Feel a little more "literate"? Hope so.
Until next time, clear skies!
Posted by Mark Ritter at 2008.01.27 03:58 PM | Comments (0)
