Showing posts with label meteorite. Show all posts
Showing posts with label meteorite. Show all posts

Tuesday, March 30, 2021

Geology Through Literature - Han Christian Andersen's: Ole The Tower Keeper

Geology Through Literature: 

Hans Christian Andersen's: Ole, The Tower Keeper (1859)



For the third entry we continue on through Hans Christian Andersen's oeuvre to our next geological reference.

For other Geology Through Literature entries, please check them out compiled on my website.

Ole, The Tower Keeper (1859)

First Visit
Listening to the Rocks
Among the books I had recently lent Ole was one about pebbles, which had greatly pleased him.

"They are truly veterans from olden times, those pebbles," he said, "yet people pass them by without thinking, and trample them down in fields or on beaches, those fragments of antiquity. I have done so myself. From now on I shall hold every paving stone in high respect!...

"The romance of the Earth is truly the most fascinating of all romances. It's a shame we can't read the first parts of it; but they're written in a language we haven't learned yet; we have to dig away among strata and rocks, puzzling out bits here and there from the early acts of earth's drama.... The crust on which we move remains solid so that we never fall through, and so it is a story of millions of years, with steady progress. 

"Many thanks for your book on pebbles; those old fellows could tell us so much if only they could talk.... And it makes you feel so ridiculously young, compared with the millions of years of these venerable stone!"

"...I was rolling through millions of years with my rocks, watching them break loose up in the North, drift along on icebergs ages before on a reef, and at last peer up through the water and say, 'This shall be Zealand!'..." 

What Andersen is describing is exactly what geologists hope to decipher. Geologists read the rocks. They listen to what the rocks have to say and have been doing it far before Andersen's time period. Which he should be aware of with his comments about the earth being millions of years old, since geologists are the reason that we even thought that the earth was millions of years old at that time (we now know it to be ~4.543 billion years old).  

Layers of the Earth

The scientist that is often touted as the father to modern geology is James Hutton, who lived from 1726 to 1797. He is the one who came up with some of the first principles of geology, which are his way of essentially listening to what the rocks had to tell us. James Hutton's primary theory that he developed was the Principle of Uniformitarianism, which stated that the present is key to the past and that all processes happening on Earth today are the same ones that happened on the Earth in the past. This means that when we have ripples and mud cracks in modern day sediments, they can help us identify ripple marks and mud cracks in the rock record. Since everything happening today has happened in the past and erosion and deposition are incredibly slow processes then the age of the Earth must be very, very old. Although he couldn't be sure of an exact age of the Earth, one could easily assume the Earth was millions or even billions of years old based on the rates of modern day erosion and sedimentation.

His research continues today with geologists "reading the rocks" and listening to their life stories. Then taking this information and combining it with the histories of other rocks, until we have a full and complete global history dating back to the beginning of the earth. We aren't fully there yet, and we may never get fully there, but it is an ever hopeful promise that we may.

Shooting Stars

"Then three or four beautiful shooting stars fell; they shone brightly, and started my thoughts off in an entirely different direction. Does anybody know what a shooting star really is? The learned do not know!..."

Although Andersen claims that the "learned do not know", we do know today what they are. They are bits of cosmic debris that burns up when it enters our atmosphere, technically called a meteor. The meteor is the flash of light that we see when the debris enters the atmosphere and the debris itself is called a meteoroid. 

Illustration of a "fireball" from a 1771 publication by Le Roy (Marvin, 2007). 

What interests me about this statement is when did scientists begin to learn about meteors and shooting stars. One of the first scientists to suggest that the fireballs were real events was Ernst Chladni in 1794. He hypothesized that shooting stars, fireballs that came crashing to earth, and the physical meteorites were all related phenomena. Although there was resistance to the idea at the time, he persevered until his death in 1827. It was not until 1834, that scientists had been able to start piecing together that meteor showers were tied to specific orbital events, and from here to realize that shooting stars were actually pieces of orbiting materials burning up in the atmosphere. 

It took until 1862 when the hypothesis that shooting stars had an extraterrestrial origin had firmer proof with the prediction and the tying of comets to specific orbits and times of the year. With these observations, future meteor showers were able to be predicted including the 1866 Leonid shower. So, even though the story was written in 1859, there still was significant evidence at that point that meteoroids were the cause of the shooting stars with firmer proof only a few years away.  

References

Thursday, January 26, 2017

What are....Meteorites, Meteoroids, Meteors, Asteroids, and Comets

I occasionally do a set of blogs called "What are...". Here is the next one in the series.

I was reading a book with my daughter, book 8 of the Magic Tree House series - Midnight on the Moon (her current favorite series of books to read) and I came across this passage that seemed off to me:


The main part I was stuck on was:
"Rocks of all sizes crash into the moon from outer space. These rocks are called meteorites."
From what I could remember, meteorite is a term specifically reserved for rocks that crash into Earth. But did it apply to rocks that crashed into the moon (or other planets for that matter) as well? Looking into it, no. This was incorrect. Meteorites are rocks that specifically have traveled through our atmosphere and crashed into the Earth.

So what would be an object that crashed into the moon?  Turns out that NASA scientists just refer to them as meteoroids, as can be seen in this story - A Meteoroid Hits the Moon.

So what are the differences between a meteor, meteorite, meteoroid, asteroid, and comet?

Meteoroid - These are chunks of rock that are floating in space that are smaller than a kilometer in diameter (Hubblesite.org).

Meteor - This is just the flash of light, a shooting star, that you see in the night sky as a meteoroid falls through the atmosphere and starts to burn up. This is not the physical object that is falling (Hubblesite.org).

Meteorite - A meteorite is a meteoroid that has survived entry through the Earth's atmosphere and has crash landed on the surface of the Earth (Hubblesite.org). This term seems to be exclusive to rocks found on Earth, since terms like "Martian meteorite" or "lunar meteorite" are for meteorites found on Earth that originated from Mars or the moon respectively.

Comet - A comet is a body of ice, rock, and organic compounds that can be up to several miles in diameter. "Comets are thought to originate from a region beyond the orbits of the outermost planets. Scientists believe that gravitational perturbations periodically jar comets out of this population, setting these "dirty snowballs" on orbital courses that bring them closer to the Sun. Some, called long-period comets, are in elliptical orbits of the Sun that take them far out beyond the planets and back. Others, called short-period comets, travel in shorter orbits nearer the Sun" (Nasa.gov).

Asteroid - "Most asteroids are made of rock, but some are composed of metal, mostly nickel and iron. They range in size from small boulders to objects that are hundreds of miles in diameter. A small portion of the asteroid population may be burned-out comets whose ices have evaporated away and been blown off into space. Almost all asteroids are part of the Main Asteroid Belt, with orbits in the vast region of space between Mars and Jupiter. In space, a large rocky body in orbit about the Sun is referred to as an asteroid or minor planet whereas much smaller particles in orbit about the Sun are referred to as meteoroids" (Nasa.gov).


Sunday, February 17, 2013

CBS Sunday Morning - Hunting for Meteorites

A nice piece was played this morning on CBS Sunday Morning discussing the Russian Meteor of yesterday and linking it to the meteorite hunting that goes on in Antarctica. They mention that the meteorite hunting was little known, but I thought it was common knowledge. I guess that is part of the problem of being so in to geology that I don't realize what other people don't know.


 
Or go here if the video doesn't seem to be working:
 
(but it does take a minute or 2 to load).