October 19 – A New Low

Today’s factismal: The most intense Atlantic hurricane ever recorded was Wilma, with a low pressure in the eye of just 882 mbar.

If you are a meteorologist, then 2005 is probably your favorite year. Over the course of the year, there were so many tropical storms that they ran out of names and had to resort to using Greek letters. Of the 28 storms that developed, a record high of 15 would go on to become hurricanes and seven of those would become major hurricanes. And none of those was more major than Wilma.

Wilma at peak strength (Image courtesy NASA)

Wilma at peak strength
(Image courtesy NASA)

Wilma started as a tropical depression off of Jamaica on October 15. Two days later, she had become a tropical storm. By the 18th, she was a full-fledged hurricane and showing no signs of getting any weaker. Indeed, where most hurricanes are big, ungainly monsters with large eyewalls (which often indicates a weaker storm), Wilma had a fairly compact eyewall just two miles across (the smallest known) and peak winds of 185 mph! Those factors combined to give Wilma the lowest known pressure of any hurricane at just 882 mbar; to put that in perspective, remember that normal air pressure at sea level is 1013 mbar. In effect, the center of Wilma was at the same air pressure as Denver!

Naturally, a storm this intense caused lots of damage. Wilma killed at least 62 people (mostly through flooding and landslides) and caused $29 billion dollars in damage. Many of the deaths happened because Wilma’s path was unusually unpredictable; she changed directions several times, making it harder to know where she would hit. What the meteorologists needed was more observations in order to give better predictions. What they needed was people like the members of the Citizen Weather Observer Program who send in reports about severe weather (and the other kind, too) that is then used to make better predictions. If you think that you’ve got what it takes to be a CWOP member, head over to:
http://wxqa.com/

October 18 – Winner By A Landslide

One of the amazing things about science is how often things at one scale apply at another as well. For example, you can measure the way that a cup of lye reacts with a cup of water and know how much heat will be produced if you use a ton of lye and a ton of water instead. Or you can simulate an earthquake using a piece of spaghetti and that will teach you something about how the San Andreas behaves. Or, as Peter and Mary are about to discover, you can use a pile of rice to discover why the Earth is round.

 

The images on the television were both frightening and fascinating. There had been a heavy rainfall in California and the runoff was rapidly eroding the base of a cliff, causing parts of the cliff to collapse in large chunks that splashed mud and mayhem when they fell. That would have been fascinating enough but on top of the cliff were several multi-million dollar mansions that were following the formerly stable cliff on its downward plunge.

“Wow!” said Peter as he watched a particularly large chunk of a swimming pool fall twenty stories into the surf below. “That was amazing!”

“Yes,” agreed Mary. “I’m glad that they got all of the people out. But what about their stuff?”

“I guess they’ve got insurance,” Peter replied. “But why did they build on the cliff?”

“Probably for the view. But what I want to know is why isn’t the cliff still still standing?” Mary puzzled. “It was doing OK before the rain, so why fall now?”

“I dunno. Who could we ask?” Peter wondered.

“Well, Mr. Medes is on vacation this week, so we can’t ask him,” Mary said. “And your mom is an astronomer, so she wouldn’t know. That just leave my dad. But he’s an engineer. He probably won’t know either.”

“Well, there’s only one way to find out,” Peter said. “Let’s go ask him!”

With that the two young scientists left the den where they had been watching television and sought out Mary’s father. Since it was Saturday, the first place they checked was the kitchen; in addition to being a popular engineering professor at the local university, he was also an amateur gourmet chef who liked to make special meals on weekends. Sure enough, he was in front of the stove, cooking raw rice in oil and fragrant spices.

“Oh, boy!” Mary exclaimed. “Costless Rican Rice again?”

“You betcha!” her father replied. “I wanted to use up the last of that roast chicken and we had enough vegetables to make this interesting. Peter, would you like to stay for dinner?”

“I’ll ask my mom,” Peter said as his belly rumbled in response to the smell of the cooking. Mary’s father laughed at the sound.

“It sounds as if your stomach has already decided the answer will be ‘yes'”, he said as he stirred the rice. “So what may I do to help you two? Or are you just drawn to the sight of a master turning leftovers into a meal fit for a king?”

“We had a question about cliffs,” Mary said. “Why do they fall down?”

“That is an excellent question!” Her father boomed in response. “And I’ll tell you the answer just as soon as I toss these odds and ends into the rice.”

With that, Mary’s father scrapped chunks of cooked chicken and vegetables that were left over from the previous week’s meals into the rice. Pouring in a carefully measured amount of water, he gave the mass a final stir and put a lid on top. He then turned the heat down and turned to his daughter and her friend.

“So you want to know why cliffs fall down,” he said. “Why do you ask?”

“Well, we saw these cliffs in California that were falling apart and dragging the houses that were on top of them into the mud,” Mary said. “But the cliffs were only about two hundred feet tall. We’ve got skyscrapers that are ten times as tall. So why do the skyscrapers stand up and the cliffs fall down?”

“It turns out that you have come to exactly the right person to answer that question,” her father replied. “Though Peter’s mother might have done just as well; this applies to her field as well.”

“It does?” Peter asked. “How?”

“You’ll see!” Mary’s father replied. “To start with, we’ll need a couple of plates, some toothpicks, and some uncooked rice.”

Mary quickly went to the pantry and grabbed the things that her father had listed off. Her father took the plates from her and placed on in front of each of the scientists. He then gave them each a toothpick and poured a cupful of rice onto each plate.

“In front of each of you is a pile of rice,” he said. “What I want you to do is to make the tallest cliff of rice that you can by scraping away the rice at the bottom of the pile with the toothpick. When you are done, what do you think the cliff will look like?”

“It will be just like a real cliff,” Peter confidently said. “It will go straight up.”

“I’m no so sure,” Mary countered. “I think it will be a lot slope-ier. It will probably lean over more.”

“Well, there’s only one way to find out,” her father said. “Start scraping!”

What do you think will happen? Try the experiment yourself!

The two started scraping at the base of their rice piles. But as soon as they would start to build up a small cliff, the bottom would slide out and a small cascade of rice would flow down, turning the vertical wall into a horizontal slope. After a few minutes of diligent scraping, Peter tossed down his toothpick in disgust.

“I give up!” he declared. “The rice won’t make a cliff! It is even worse than what we saw on TV!”

“Peter’s right,” Mary agreed. “You can’t make a tall cliff out of rice.”

“You are both right,” her father said. “You can’t make a tall cliff out of rice and you can’t make a skyscraper out of sand. And in both cases, the reason is the same.”

“It is?” Mary asked.

“Yes,” her father replied. “What is happening is that every stack of stuff is a balance of two things. There is gravity, which is pushing down on all the parts of it and there is cohesiveness which is trying to keep everything together. When gravity pushed on the center of a pile of rice or a cliff or a skyscraper, the force is straight down. That creates pressure on the grains of rice which gets bigger as you go deeper into the pile. The rice on top feels very little pressure while the rice at the bottom feels a lot. If the pressure on a grain of rice is about the same as the pressure on the grains around it, everything is stable and nothing moves. But if the pressure is lower on one side, then things naturally try to move in that direction. And when the difference in pressure is greater than the cohesiveness, then -”

“You get a landslide!” Mary exclaimed.

“That’s right!” her father agreed. “If you watched carefully during your experiment, then you probably saw that the rice-slides only happened on the side where you were scraping. That was because that was the only side where the pressure was changing.”

“Oh!” Peter said with a look of sudden understanding. “And that’s why the cliffs were falling. When the water eroded enough of the base, the pressure from the dirt piled up in the cliff was more than the strength of the stuff holding the cliff together and – pow! – we got a landslide!”

“That’s right. And that should also tell you why you can’t build a twenty story cliff of rice or a two hundred story cliff of sand,” Mary’s father said.

“Because rice isn’t as strong as sand and that’s not as strong as the steel in a skyscraper!” Mary said. “But why could Peter’s mother have told us this, too?”

“Because she works with planets,” her father replied. “And the one part of the definition of a planet that everyone agrees on is that they are round thanks to their own gravity.”

“I don’t get it,” Peter said.

“Imagine that you are building a cliff of sand,” Mary’s father said. “What happens if it gets too tall?”

“Some of it collapses,” Peter said.

“OK, now imagine that you’ve got a pile of sand as big as a planet,” Mary’s father said. “What happens to that cliff?”

“It will collapse,” Mary said.

“And if the cliffs that creates are too tall?”

“Then they will collapse too,” Peter said.

“And what happens if you keep doing that all around the planet-sized sand pile?” Mary father asked.

“I get it!” Mary said. “No matter where you look, the sand piles can only be so tall. And that means that everywhere you look, everything is about the same distance from the center of the planet. And that makes it -”

“Round!” Peter and Mary chorused together.

“That’s right,” Mary’s father said. “And now, if you two will clean up your budding planets and if Peter will call his mother, we can eat dinner.”

With that reminder, Peter’s stomach once more rumbled threateningly and all three laughed as they set the table for dinner.

 

October 17 – Live! On TV!

Today’s factismal: The first earthquake to be shown live on television happened in 1989.

It was a balmy October evening in San Francisco. The Giants were competing with the Oakland A’s for the pennant, and the two teams were warming up in preparation for game three. As the television sports casters searched for something to add a little local color to the broadcast, they were given the greatest exclusive in history: an earthquake struck the area. And not some piddly little 4.0; this was a 6.9 Mb earthquake! As the anchors tried to describe what was happening, the world saw buildings shake, highways fall, and homes crumble into rubble.

A section of the collapsed highway (Image courtesy USGS)

A section of the collapsed highway
(Image courtesy USGS)

Amazingly, there were only 63 people killed in the earthquake (the 1905 temblor was about 30 times stronger and killed 3,000 people). Most of these happened in Oakland where a double-decker highway collapsed on itself. Interestingly, many credit the baseball game for the low fatality count. Because many people had left work early in order to watch the game, the highways were relatively uncrowded which meant that fewer people were hurt.

California is almost certain to have another large earthquake in the next three decades (Image courtesy SCEC)

California is almost certain to have another large earthquake in the next three decades
(Image courtesy SCEC)

But what is even more amazing is that the danger isn’t over. There is a 99.7% chance that California will have another earthquake at least as powerful as this one in the next thirty years. So we know when the next big on will happen (soon); what we don’t know is where. And that’s where you can help. The USGS and Stanford University are developing a new type of distributed seismometer that uses the accelerometers in tablets, smartphones, and computers to provide more complete coverage of earthquakes; the data that this Quake Catcher Network gathers will then help them to narrow down when we can expect the next big one. If you’d like to take part, head over to:
http://qcn.stanford.edu/

October 16 – Almost Home

Today’s factismal: The closest known extrasolar planet is Alpha Centauri Bb, a mere 4.4 light years away!

There’s an old astronomy joke that goes “What is the name of the closest star?” Ask that of most people and they will say “Alpha Centauri”; of course they would be wrong (the correct answer is “Sol” or “our Sun”). But there is a newer joke that just became possible a year ago; it asks “What is the name of the closest Earth-like planet?” Though the correct answer is “Terra”, “Tellus”, “Dirt”, or “Earth” (they all mean the same thing), the best answer is “Alpha Centauri Bb”.

That’s because astronomers have discovered a planet just slightly larger than Earth (1.13 times our mass, 1.04 times our size) that is orbiting the second brightest star in the Alpha Centauri system. The three stars that make up Alpha Centauri are a bit strange; the two brightest (A and B) orbit each other at a distance ranging from that of Saturn to that of Pluto while the dimmest of the three (Proxima centauri) orbits the AB pair at what would be the distance of our Oort cloud (home of the comets). Using highly tuned spectroscopes, the astronomers were able to sort out a slight shift in the light from Alpha Centauri B that indicated a planet which they gave the designation of Alpha Centauri Bb.

An artist's deception of what the Alpha Centauri Bb system might look like (Image courtesy ESA)

An artist’s deception of what the Alpha Centauri Bb system might look like
(Image courtesy ESA)

Of course, there is some skepticism in the scientific community over whether or not Bb actually exists (hey, we’re scientists; skepticism is just what we do), especially given that no-one has observed Bb passing across the face of Alpha centauri B. However, that just means that we’re spending a lot more time watching that part of the skies right now. If you’d like to join in on the fun but don’t happen to have a 30 meter telescope in your backyard, then why not become a Planet Hunter? Using Keppler data, you’ll be able to discover planets of your very own!
http://www.planethunters.org/

October 14 – Acid Trip

Today’s factismal: Acid rain has about the same pH level as wine or beer.

In the late 1800s, the fogs of London were notorious not just for their thickness (“pea soup” being about the kindest appellation that they were given) but also for their effect. Going out in a London fog would leave you with a raspy voice, itchy eyes, and a dry, chapped skin. How could a little fog do so much damage? It was because at that time, London was powered almost exclusively by high-sulfur coal. When the sulfur from the coal combined with the water in the fog, it created a weak sulfuric acid solution (about as acidic as wine or beer); walking in the fog was literally like walking in acid!

How acid rain forms (Image courtesy EPA)

How acid rain forms
(Image courtesy EPA)

The fogs of London are now nothing but a memory, thanks to improved power generation methods, but acid rain is still with us. There are many places around the world (e.g., China, India) where it is cheaper and easier to burn high sulfur coal and oil to generate energy, which means that there is still plenty of sulfuric acid being formed. And, because the atmosphere doesn’t stop at a country’s borders, the pollution that one nation creates can easily affect other nations across the globe. However, quantifying that damage can be frustratingly difficult.

This fountain has been damaged by acid rain (My camera)

This fountain has been damaged by acid rain
(My camera)

And that’s where you come in. A group of scientists in Sydney (Utah) are looking for volunteers across the globe to go out and look at old gravestones in order to measure the effects of acid rain. The sulfuric acid created by sulfur pollution will slowly eat away at a marble gravestone; by measuring the amount of damage that’s been done, they can tell how much sulfur pollution the area has had. If you’d like to help, then head over to:
http://www.earthscienceeducation.org/Dj-AnthrosphereUT/EarthTrek%20-%20Gravestone%20Project.htm

October 19 – A New Low

Today’s factismal: The most intense Atlantic hurricane ever recorded was Wilma, with a low pressure in the eye of just 882 mbar.

If you are a meteorologist, then 2005 is probably your favorite year. Over the course of the year, there were so many tropical storms that they ran out of names and had to resort to using Greek letters. Of the 28 storms that developed, a record high of 15 would go on to become hurricanes and seven of those would become major hurricanes. And none of those was more major than Wilma.

Wilma at peak strength (Image courtesy NASA)

Wilma at peak strength
(Image courtesy NASA)

Wilma started as a tropical depression off of Jamaica on October 15. Two days later, she had become a tropical storm. By the 18th, she was a full-fledged hurricane and showing no signs of getting any weaker. Indeed, where most hurricanes are big, ungainly monsters with large eyewalls (which often indicates a weaker storm), Wilma had a fairly compact eyewall just two miles across (the smallest known) and peak winds of 185 mph! Those factors combined to give Wilma the lowest known pressure of any hurricane at just 882 mbar; to put that in perspective, remember that normal air pressure at sea level is 1013 mbar. In effect, the center of Wilma was at the same air pressure as Denver!

Naturally, a storm this intense caused lots of damage. Wilma killed at least 62 people (mostly through flooding and landslides) and caused $29 billion dollars in damage. Many of the deaths happened because Wilma’s path was unusually unpredictable; she changed directions several times, making it harder to know where she would hit. What the meteorologists needed was more observations in order to give better predictions. What they needed was people like the members of the Citizen Weather Observer Program who send in reports about severe weather (and the other kind, too) that is then used to make better predictions. If you think that you’ve got what it takes to be a CWOP member, head over to:
http://wxqa.com/

October 18 – A Hint Of Basel

Today’s factismal: The strongest recorded earthquake in the Europe took place in 1356; it was as strong as the 1989 Loma Prieta earthquake!

If you ask the typical person where we have earthquakes, odds are that they’ll say “California” and leave it at that. But the truth is that California just gets all of the press (and bad movies); earthquakes happen all over the world, anywhere that there are two parts of the crust moving against each other. In fact, only about 4,100 (5%) of the 28,000 earthquakes that are recorded each year happen in California!

And earthquakes have been a problem since the world first formed, even if we’ve only been recording them for a few thousand years. One of the most notable “early” earthquakes happened in Switzerland nearly a thousand years ago. Switzerland’s famous Alps exist because the European plate was the victim of a hit and run by the African plate; the mountain range is the “dents” caused by the collision. Over time, the mountains have eroded down and are slowly settling. As they do so, they release a little energy from time time time; this is why Switzerland averages one earthquake a month. And in 1356, Switzerland had its biggest earthquake ever

The 7.1M earthquake destroyed the town of Basel and leveled the churches and villages in the thirty miles surrounding it. It was strong enough to be felt in France and to crack chimneys in Zurich. More than 300 people died in the main shock; many more were frightened out of their wits and out of the area by the year-long series of aftershocks that plagued the region.

What is most interesting about the earthquake is how we learned about it. Because the recording seismometer hadn’t been invented yet, seismologists have had to pore over old records and traveler’s accounts to identify the damage that was done and estimate the strength of the earthquake from that. But they need your help in calibrating their work.

If you experience an earthquake, then head over to the USGS “Did you feel it?” website and tell them what you felt. That will help them map out faults and improve our understanding of how earthquakes cause damage so that historical data like this can be used to predict future events.
http://earthquake.usgs.gov/dyfi