How Thin is 8.55 millibar? May 28, 2008
Posted by physics309 in Science.add a comment
Yesterday’s weather report from Mars said the air pressure was 8.55 millibar. This got me wondering, ‘Just how thin is that?’ One way to answer that is to calculate how high you would have to go in our atmosphere to get that air pressure. As it turns out, this is a pretty easy calculation and uses what is called the scale height, something I use to do fairly often when I was in graduate school.
When I did the calculation (shown below), I found you would need to go to an altitude of about 38 kilometers in our atmosphere to get the same pressure. This is about 23 miles, or roughly 120,000 feet. In comparison, long-range aircraft routinely fly between 35,000 and 40,000 feet and even high-altitude spy planes fly at less than 100,000 feet. So, 120,000 feet is extremely high (and with extremely thin air). Obviously, you would need a spacesuit at that altitude.
The equation I used was
P = Po*exp(-Z/H)
where
P = the measured air pressure (8.55 millibar, in this case),
Po = standard air pressure (about 1000 millibar at sea level),
Z = the altitude (what we want to solve for in this case), and
H = the scale height (about 8000 meters for Earth).
Solving for Z gives you
Z = -H*ln(P/Po) = 38,095 meters
While its not exact, it is a very good approximation. If you’re at 8.55 millibar, do you really care if the altitude is actually 121,000 feet or 120,000? Either way, you’re really way up there.
Brrrr! May 27, 2008
Posted by physics309 in Science.add a comment
The first weather report came back from the Phoenix lander. The report said the temperature ranged between a minimum of minus 80 degrees Celsius (minus 112 degrees Fahrenheit) in the early morning and a maximum of minus 30 degrees Celsius (minus 22 degrees Fahrenheit) in the afternoon. But, that really wouldn’t have been your biggest concern because the report also said the average pressure was 8.55 millibars, which is less than a hundredth of the sea level pressure on Earth. Tough to breathe under those conditions.
What was going on in the 1300s? May 26, 2008
Posted by physics309 in Musings, Science.add a comment
I love Bill Bryson’s books. I will be reading one of his books and people will ask me what I’m reading because I’m sitting there laughing out loud like some kind of maniac. If you’re not familiar with him, he writes these travelogs that are hilarious and informative. I find both his sense of adventure and humor to be exhilarating. While they are mostly funny and pleasant, there are also times he discusses the unpleasant. I have also found that he does his homework quite well. Like this quote that I recently read in his book neither here nor there:
I tend to think of life as bleak when I can’t find a parking space at the supermarket, but imagine what it must have been to be an Italian in the fourteenth century. For a start, in 1345 it rained nonstop for six months, turning much of the country into a stagnant lake and making planting impossible. The economy collapsed, banks went bust, and thousands died in the ensuing famines.
I found this to be an amazing statement. I did some research to verify this (sorry, Bill) and, sure enough, it’s in the historical record just as he said. Which immediately made me wonder what was going on? There are places in the world where six months of rain is considered normal, but Italy isn’t one of them. What set of circumstances could have caused this? I would give an initial guess that a low-pressure system was trapped over the middle Mediterranean basin, but what could have caused it to be trapped like that? This is obviously very unusual because I could find no other reference in the record to any similar event occurring in Italy, and there is a lot of record on Italy.
What I did find was that the 1300s was a period of very strange and severe disasters. There were incredible floods and droughts leading to massive famines throughout the world. Entire regions of China were recorded to have flooded, drowning thousands and thousands of people at a time, just to be followed by horrible droughts and locust plagues. The same in Europe. The pattern of droughts and floods was recorded even high in the mountains. All to be followed by famines. A famine in Poland was recorded to have been so bad that people were eating the criminals that had been hung. Italy wasn’t the only one afflicted with long-term rain. England suffered nearly non-stop rain for two years starting in 1316. Winters were so severe that the Baltic froze over several times during the century.
Volcanic eruptions were common worldwide, burying villages with lava and ash. And everywhere there were earthquakes. Monstrous ones that leveled entire cities. Granted, the building codes weren’t so hot back then, but it was still unusual to see city after city being leveled.
But, that’s not even the weirdest part about what was going on. There are several recorded instances of fetid fogs that killed the fruit on trees and even people that breathed it.
And, during it all was the Black Death. Recorded to have killed one-third of the people in Europe, it also ravaged China and other countries.
What could have been going on here? It is easy to question the record by saying they didn’t keep good records in the 1300s, but that would be incorrect. China kept very good records, and by the fourteenth century Europe was very well organized and managed with very good records that are still referred to today. The evidence has shown that these records are accurately reporting events to the best of their abilities at the time.
A possible clue for some of this is where the records show that aurorae were visible in even southern Europe. Some of the auroral displays lasted for considerable lengths of time when a normal display may last a few hours, at most. This would indicate some very violent solar activity. While this may explain a few things, it can’t explain it all.
So, I still have to wonder, what was going on during the fourteenth century? Whatever it was, it sure seems to be out of the ordinary to me.
Now, let me ask, ‘Can it happen again?’
Phoenix Lander May 25, 2008
Posted by physics309 in Science.add a comment
Congratulations to the Phoenix lander team on a successful touchdown on Mars! I was watching on NASA TV and the level of tension and excitement as as great as with any movie, except that it was real. Years of hard work by the thousands of people involved in this project have resulted in this landing and the beginning of the scientific examination of the Mars north polar region.
Summer Season Starts May 25, 2008
Posted by physics309 in Old Lyme.add a comment
Well, the annual seashore migration has started here in Connecticut with the roads and beaches both loaded. Its nice to see the families back. It provides a nice diversion to sit on the porch and see the kids playing in the street and the good-looking women on their power walks. The sunbathers are all out at the beach again. I could even smell sunscreen, so at least some of them are protecting themselves. A lot of people think that they don’t need it because it isn’t very hot. The breeze coming in from the Atlantic Ocean is quite cool and keeps the temperature down, even a little chilly at night. But, we are less than a month from the summer solstice, so the sun intensity is actually the same as it will be in the middle of July.
But, there is one thing that drives me nuts. Why is it that people will make the effort to come out here for a nice quiet weekend at the beach, just to fire up all of their noisemakers as soon as they get here? It has been constant lawn mowers, leaf blowers and high-pressure water jets since Friday evening. My landlord lives a couple of doors down from me in the summer. He got into a lawn-mowing groove one day and mowed my lawn for me. Really nice. But, then he pulled out the leaf blower to clean up the grass cuttings. I said I would be glad to clean them up, but he kept saying it wasn’t a problem with the leaf blower. Finally, I had to tell him that the sound of that thing was so annoying it was driving me crazy. It took me less time to do it by hand and it looked just a good.
I know what you’re thinking. You’re thinking I should just suck it up and stop whining. OK, you’re right. So, I’ll stop now.
ISS Sightings May 23, 2008
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We went out last night to watch the International Space Station go by. We had been planning this for a few days because last night was such a good viewing opportunity. We were disappointed when it was stormy all day and still very cloudy as evening approached. We had already decided that it wasn’t going to happen and made other plans for the evening. Then, it just cleared up completely. It actually turned out to be perfect for viewing.
The sighting started at 9:31 with the space station way out west and coming almost right at us, eventually passing overhead at an angle of about 70 degrees (90 degrees is directly over head). As it got closer, it got brighter and brighter, eventually getting brighter than even Venus, making it the third brightest body in our skies. This is bright enough that it would have been visible even in the day time. The space station is visible because of the sunlight it reflects and it is now so large that it reflects a lot of light. We can see it in the dark because it is still up in the sunlight. Normally, as you watch a satellite orbit, it will suddenly disappear as it enters the Earth’s shadow. But, because of the season and the inclination of the ISS’s orbit relative to the equator, we never saw it disappear last night. It just kept going farther and farther away until it was so faint we couldn’t see it anymore. The whole thing lasted more than two minutes and was very spectacular.
So, how did we know to go out at the appropriate time? There are some good websites to provide that information. One is SpaceWeather.com, which can give you the viewing information for places around the world. Just enter you zip code and it will provide the viewing data. Another good one is Heaven’s Above. NASA has a very good site that not only provides viewing information, but shows where the ISS is right now. You can also find information about other satellites at both Heaven’s Above and NASA.
It is a great sight, one well worth the small effort it takes to see. And, you don’t even need to do any traveling and spend any money. Its right there, just waiting for you.
USS Utah May 17, 2008
Posted by physics309 in Pearl Harbor.add a comment
I’ve always been fascinated with the history of the Pearl Harbor attack of December 7, 1941. When I was stationed at Pearl Harbor I enjoyed going around the island and seeing the sights associated with the attack. My command, FICPAC, was located right across the street from the Arizona Memorial. I’ve read a number of books about the attack and will catch a show every now and then on TV. I recently saw one on the Military History Channel about the ‘Myths of Pearl Harbor’ and was interested in one particular statement they made. They said that only one battleship was lost in the attack – the Arizona. I always thought there was a second. Well, after checking I’ve learned that they were technically correct, the second ship was no longer classified as a battleship at the time of the attack. And therein lies a story.
One of the great places I enjoyed going to while in Pearl Harbor was Ford Island. This is the big island in the middle of the harbor. Today, it is a military housing complex with a few small commands. There’s a bridge connecting it to the main island today, but when I was there in the early-1980s the only way to the island was by ferry, which made it very private. I would take the ferry over and just walk around the island. It was very peaceful and tropical and no one ever bothered me when I went looking around at the sights.
Ford Island was a seaplane facility before and during the war and had large hangers and a runway. The runway has houses built on it now and no planes have landed there in decades. The hangars were still there, long since abandoned but not secured. I would walk around in these hangars, passing through the ready rooms and offices, imagining what it was like on that morning with the men scrambling to respond to the attack while avoiding the bombs and strafing runs at the same time. There are still bullet holes visible from the attack that made it easier to visualize. Standing there and seeing the ghosts in my mind, the attack was a lot less history and a lot more reality.
Working my way around the island, I came across some wreckage a memorial on the western side of the island. This was what remained of the USS Utah and the men that are still entombed within. The Utah was a former battleship (BB) that had been redesignated as a gunnery training ship (AG). So, technically, it was not a battleship when it was lost during the attack, so the show was correct.
The Utah was moored up at the berth on the west side of Ford Island in early December, 1941. When the attack occurred, the crew responded and tried to get the ship underway, but it took several heavy hits and began to take on water. Before long, it began to list and capsized shortly thereafter. Fifty-eight men died. At least one of them was posthumously awarded the Medal of Honor.
At that time, the memorial consisted of a flag and plague. From the vantage point of the memorial, you would have been looking out across the Utah that morning towards the west, straight at the Japanese dive bombers that were coming in across the western locks of Pearl Harbor to seal the fate of the ship and crew. I asked around at my command and no one there even knew about it. Today, there is a new memorial that is more elegant, but still little known.
So, if you’re in Hawaii and are interested, ask about the USS Utah memorial on Ford Island.
All Done May 16, 2008
Posted by physics309 in Old Lyme.1 comment so far
Today was my last day at the Coast Guard Academy and I leave with mixed feelings. I could not have wished for things to come out better and am sorry to be leaving. But, I’m also looking forward to the next adventure.
The fact is, this was a great job and I have only good things to say about the academy and the people I worked with. My supervisor was an outstanding man that I really enjoyed knowing and my coworkers were all pleasant and friendly. They were professionals that knew their jobs and were dedicated. The cadets were well disciplined and intelligent. With the exception of a few bad apples, I mostly felt the cadets I worked with are going to make very good officers. What more can you ask for from a job?
But, there’s more. I was in bad shape when I got here from South Dakota and this place was very good therapy for me. I was treated very well and leave feeling like I was valued. The Superintendent’s Award for Excellence that I received a couple days ago was unexpected and greatly appreciated. My attitude and outlook are very much better today than they were this time three years ago.
So, why am I not staying? Well, it was a temporary position and I was told when I first applied that there was no chance for it to become permanent. I was filling in while some active duty Coast Guard officers went to graduate school to get their degrees. They weren’t released from their commands to go during my first year here, so I ended up getting a third year as a result. But, now they are graduating and will be here this fall, so there is no room for me. I would stay if I could (and they were clear about wanting me to stay), but they are only authorized a certain number of people.
But, my knack for finding adventures still works and I’m looking forward to moving on. I’ve known this day was coming for three years, so I’m not upset or disappointed. And, I’m sure that I will still have more than my fair share of stories to tell in my next chapter of Travels.
Gas Prices May 15, 2008
Posted by physics309 in Musings, Op-Ed.1 comment so far
My son asked me last fall when I thought gas would hit $4 a gallon. I told him that it would happen before summer. This was a bit of a stretch because gas was about $3/gallon at the time, but I was pretty confident in my prediction. Well, I paid $4/gallon for regular gas yesterday. I had more than two weeks to spare in my prediction.
Now, I understand that people in other countries and even people in California and Hawaii have been paying more than that for a long time, but this still represents how gas prices have been soaring over the last few years. I don’t like paying the extra money any more than anyone else, but I still have a different view on the matter. We have had this warning since the fall of 1973 that we are dependent on oil being supplied to us by foreign nations that are not friendly to us. And, we have been shipping out massive amounts of national wealth to those countries to pay for our habits. Yet, we have done nothing to change that. In fact, we continually make decisions to increase our dependence. Look at some of the things we have done.
We have increased the size of cars and trucks. The average size of a new vehicle in this country is 20% larger than 20 years ago. We have made great strides in increasing engine efficiency, yet the average mileage has actually dropped since 1985.
We have increased the size of the engines. Car ads promote how this car or that can go 150 mph and race down the road. Powerful engines sell, no doubt about it. Unfortunately, you can’t race down the road when the road is congested with traffic. And, unless you want to live in Montana just so you can drive at high speeds, there are speed limits everywhere else. A much smaller engine will get you to the same speed and save gas while doing it. But, its not macho to have a smaller engine. Having a bigger engine translates into having a better image. Dumber, but cool.
We increased the national speed limit. Nothing consumes gas like speed. Doubling your speed requires at least four times as much gasoline, and that’s not even including the increased wind resistance. Raising the national speed limit from 55 mph should have been called the ‘Arab Full Employment Act.’ Nothing has increased our dependence on foreign oil more than this single step.
Windfall profit taxes on oil companies. This is one of the dumbest things we can do. It is motivated only by greed, vindictiveness and stupidity. It is an prime example of how we blame someone else for our own bad decisions. The oil companies don’t even get a fair return on their investment. They average about 7.5% return, which is way below what other companies enjoy. But, they are considered the bad guys because they are selling us what we demand. Then, we turn around and demand they find new sources of oil, even though we just took away all of the profits they need to do that exploration. When we levy a windfall profits tax on the oil companies, they are then forced to go the the cheapest source of oil – foreign oil. What makes it even worse is that we can levy a windfall profit tax on U.S. companies only. So, we end up punishing U.S. oil companies and letting foreign companies off the hook.
We have cut government research into alternative energy sources. Are there sufficient words to express how bad of a decision this was?
We have cut funding to mass transit systems. See my comments above.
We saw in 1973 Arab oil embargo how dependent we are on foreign countries for our oil. We saw it again in 1979 when the Shah of Iran fell and we had to implement gas rationing. We went to war in 1990 when we felt Iraq had threatened our oil supplies and we certainly are in Iraq today because of oil. And what has been the result of all of this? We are more dependent on foreign oil today than we have ever been. The management of this problem has been distressingly incompetent.
But, things may be changing. Not because we are any less incompentent in the way we are handling this issue, but because the dynamics are demanding a change.
I know someone that works in Washington, D.C. and she tells me about how she ’slugs.’ This is a system where people park their cars and wait in designated areas for someone to pick them up that is going towards the same destination. The person parking their car (sluggers) obviously don’t have to pay for gas or do any driving. The advantage to the drivers is that they can now use the carpool lanes, which is a major advantage in D.C. Well, she has been telling me about how more and more people are slugging. This has led me to an observation about what is happening to mass transit in the U.S.
Mass transit in the U.S. is generally terrible. Some places like New York City have good mass transit and the the Washington Metro is very good, but they are more exceptions than rule in this country. We Americans just don’t like to use mass transit. Growing up overseas, I learned to use the mass transit systems and fell in love with them. I would much rather leave my car behind and pay someone else to get me there. But, it just doesn’t work here. I remember the system in Norfolk, Virginia. It would get you anywhere in the city, but only if you had a couple of hours to spare. Then it was the same on the return trip. So, whenever we introduce mass transit systems people will use them up to the point that they are convenient. Once traffic congestion eases to the point that it is bearable, people will opt to drive instead.
But, not anymore. It is now becoming so expensive to drive that people are parking their cars and taking mass transit. Not because its convenient, but because they can’t afford to do otherwise. Even as traffic congestion is improving, the number of people taking mass transit continues to increase. And, we haven’t seen the end of higher gas prices. I think we will see prices continue to rise over the summer and this will become a major issue in the presidential election. People will vote in November based on their feelings about higher gas prices. The fact that the president has nothing to do with the higher prices is irrelevant. I’m sure you won’t hear a lot of people saying that its our own fault. Instead, the voters will demand that the new president provide them with relief and will vote accordingly. It will be the number one issue this fall.
So, while I’m not thrilled with the hit to my pocket book by the higher gas prices I also realize that it is what must happen in order for us to do something about this very bad problem we are in. Hopefully, we will finally be motivated to act because the only thing that will force us to change our habits is cost. Logical arguments won’t work, but personal costs will.
Keeping the Tradition Alive May 9, 2008
Posted by physics309 in Musings, Old Lyme.add a comment
Well, the Yankees were playing an afternoon game yesterday at home. So, my son and I enjoyed an old tradition and played hookey yesterday to take the train down to New York to go to the game. Believe me, we weren’t the only ones. We were standing in line to catch the subway train at the end of the game and my son asked me how many people I thought had played hookey. I said just about everyone there was supposed to be either at work or school. I noticed all the people around us nodding their heads when I said this. But, it was a great day and we had a blast. The Yankees beat Cleveland, 6-3, with four home runs. It was certainly a good mental health day for both of us.
When I bought the tickets online I got the best available. These happened to be in the VERY top row of Yankee Stadium. We were closer to the International Space Station than the playing field. The vendors were yelling, ‘Popcorn! Peanuts! Oxygen! Popcorn! Peanuts! Oxygen!’ Actually, they weren’t bad seats and we could see all of the action very clearly. There was also a bonus. It rained on and off all afternoon. But, we were so high that we were under the roof supporting the stadium lights and were out of the rain.
Right in front of us was the new Yankee Stadium and it is looking very good. Its supposed to be ready for the season next year and, based on what we could see, they should make it pretty easily. It will be sad to see the old stadium, the House that Ruth Built, go away. But I think the new stadium is just a modernized version of the old one. And, let’s face it, the old one really is getting pretty decrepit. Still, there is so much history and tradition there. Just think of all of the great moments of baseball that occurred in that stadium.
One last note, I have to say that the price of going to a game is getting ridiculous. Even with the top row seats, it cost nearly $200 to take my son to the game, including roundtrip train fare. As we were leaving, I saw a game day ticket booth. The top tickets had a list price of $400. That means it would cost nearly $1000 dollars for the two of us. How can anyone afford those prices? As it is, I would go to more games, but they are just too expensive. Of course, in a city the size of New York, there are a hundred people waiting for every seat in the stadium. They can pretty much charge as much as they want.
So, while I can’t go to as many games as I would like, we really enjoyed the one we got to go to. I wonder. Was I being irresponsible by playing hookey and taking my son out of school for the day? Or, was I being responsible by spending some time with him and having a good time?
Actually, I don’t really wonder about that question at all.