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The Case of the Technical Knockout
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NASA Sci Files video containing the following nine segments. NASA Sci Files segment in which the tree house detectives have problems with their GPS device and decide to find out why it failed. NASA Sci Files segment explaining how pilots use GPS and the other uses for GPS. NASA Sci Files segment explaining how the vikings navigated the Atlantic Ocean without the use of modern technology. NASA Sci Files segment explaining how GPS receivers work with satellites to determine an exact location. This segment explains the concept of trilateration in two and three dimensions.
As a pilot for the first fighter wing, flying the most advanced fighter in the world, the
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F-A-22 Raptor, I use electronics in my work every day.
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From the heads-up display, which shows me how fast I'm going and how high I'm flying,
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to the latest stealth technology.
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The Air Force makes math, science, and technology a way of life.
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You can use math, science, and technology, along with the treehouse detectives, as they
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investigate the magnetosphere in the case of the technical knockout.
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Stay tuned and study hard, and one day you can trade your video game controls for the
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controls of one of these.
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Come on now, and learn about math, science, and technology.
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NASA ScienceFiles
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Discovering the world we're in
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Doing cool experiments
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NASA ScienceFiles
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NASA ScienceFiles
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NASA ScienceFiles
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Be sure to look for the answers to the following questions.
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What are some other uses for a GPS?
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What star can we use to find north?
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How did the Vikings navigate without a compass or the stars?
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When you see this icon, the answer is near.
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Great, keep up the good work, and keep looking.
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Hi, I'm glad you're here.
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We're close to finding our first geocache.
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You guys are quick.
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I'm still trying to figure out this whole geocaching thing.
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It's simple.
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It's like a scavenger hunt using a Global Positioning System device, or GPS.
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You create a cache, which is just a container to hold your treasure.
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Then you take it to a public park or another public area, and you hide it,
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using your GPS to note its exact location.
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Because you have to post the exact coordinates on the Internet.
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Exactly.
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So other GPS users can find the treasure in your cache.
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They take your treasure?
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They have to replace your treasure with a new treasure so others can find it.
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That makes sense.
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My mom told us all about geocaching when she gave us our geography assignment.
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What I can't figure out is how a GPS works.
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How does this thing know your exact location?
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And do I really want anyone to know my exact location?
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Well, you would if you were lost.
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That's true.
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I guess I need to do more research on how a GPS works.
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I know it uses satellites, but I'm not sure how.
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While you're up, do you think you could find the coordinates for some chocolate?
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It was a simple task.
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All you had to do was put batteries into the GPS.
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Batteries have nothing to do with the problem.
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It must be something...
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If the GPS doesn't work, or if it says we're somewhere we're not,
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then basically, we're lost.
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I can't believe it.
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Our position keeps changing, but we haven't moved.
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The GPS is giving us a lot of different coordinates.
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According to my compass, in our last coordinates...
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Let me see.
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North is over here.
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I think I'd better get in touch with the other treehouse detectives.
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Bianca, come here. Listen to me.
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I can't figure it out either.
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Just stay calm and keep taking good notes.
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We'll see what we can find out later. Over.
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That can't be good.
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No, it isn't.
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Everything was going fine,
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and then both teams reported having problems with their GPS.
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Well, from the sketchy radio communications,
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it sounds like they're receiving random coordinates.
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Yes, but they weren't even moving.
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Hmm.
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Identifying a location precisely is what geocaching is all about.
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Sounds like we need to go to the problem board.
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Good idea. So what do we know?
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We know that both teams are using GPS devices,
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and that everything was going fine until just recently.
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Now they're experiencing some kind of technical problems.
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Right.
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Both GPS devices began to give incorrect location coordinates at about the same time.
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We also know that a GPS uses information from satellites to give precise locations.
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So what do we need to know?
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We need to know how GPS, or Global Positioning Systems, work.
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What goes on under your hard plastic cover?
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What makes you tick?
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I don't know where we need to go,
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but someone needs to go outside and take a break.
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Did you say something?
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Yes. Where do we need to go?
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I'm meeting with Dr. D later this afternoon via the Internet
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to discuss my project on the history of navigation.
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Maybe he can help.
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Good. I'm meeting with Mr. Charles Cope
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to pick up some information about the NASA SHARP program for my brother.
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Mr. Cope is a pilot for NASA.
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Pilots use GPS.
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Maybe he can answer some of our questions about how GPS works.
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Pilot from NASA?
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I'm sure he'll be able to help.
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Don't forget to take a get-up-and-go sheet for some serious note-taking.
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Visit the NASA SciFiles website
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to find some cool research tools for your own investigation.
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Guys, we're making progress.
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The GPS now says we're in Virginia.
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Of course it says we're in the middle of the Chesapeake Bay.
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But we're making progress.
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Guys?
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Guys?
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I hope that helps your brother out.
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Thanks for the information on the SHARP program.
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My brother is very excited about it.
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You're welcome.
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May I ask you another question?
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It's about global positioning systems.
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Of course. What would you like to know?
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As a pilot for NASA, how do you use GPS when you're flying?
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With GPS's unique ability to provide an exact location at any second,
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pilots rely on that for accurate navigation.
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That is pretty important when you're flying.
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Yes, knowing exactly where you are helps to keep the plane clear of obstacles and mountains
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and get you to your destination safely.
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How does GPS help you navigate?
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GPS devices on aircraft are very similar to the ones you use for geocaching,
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just a little more sophisticated.
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They show great detail accurately displayed on a graphic map.
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We've learned how important accurate maps are.
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Yes, and having the capability to always know where you are,
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combined with an accurate map display,
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greatly adds to the situational awareness and to the safety of the flight.
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What would happen if the GPS device went out while you were flying?
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It might make the aircraft unable to fly and land in all types of bad weather.
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However, aircraft aren't dependent upon GPS.
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All planes and their pilots have the ability to fall back on traditional modes of navigation
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that were used prior to GPS.
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Just like we had to rely on our good old compass when our GPS went out.
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Exactly. At worst, it would be an inconvenience for the pilot.
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But he or she would be quite capable of safely flying the aircraft.
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That's good to know. Are there any other uses for GPS?
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Absolutely. There are all types of navigational uses for GPS.
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Oil companies use GPS to help them drill for oil.
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Farmers even use GPS to help them plow their fields.
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Some have even used GPS to locate a stolen vehicle.
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Most activities that benefit from knowing an exact position on Earth use GPS.
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Wow, I never realized so many people could use GPS.
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Thanks, Mr. Cope.
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Maybe we could see GPS in action by taking a quick ride on one of your research planes.
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I didn't know you and your brother were interested in flying.
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The weather wasn't cooperating for our flight, but it was great to learn more about GPS.
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I hope Jacob's meeting with Dr. D goes well.
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We still have a lot to learn about GPS and navigation.
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I'm in Oslo, Norway, for the World Year of Physics.
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But now I'm studying some of the history and culture of this great country.
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World Year of Physics
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Wow, I better get to the Viking Ship Museum for my video conference.
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I've got to hand it to the Vikings.
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How they found their way across the Atlantic Ocean without maps is amazing.
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Well, they didn't have maps like ours, but they were pretty sophisticated navigators.
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Hi, Dr. D. I was beginning to wonder if you were going to find the museum.
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Well, it's easy to get distracted when you're doing research.
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And soon I'll be going to Andenes above the Arctic Circle to see the Northern Lights.
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Dr. D, isn't the Alomar Lidar Observatory in Andenes?
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Yes, but how do you know about the observatory in Andenes?
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Ulla and Nina, some of our fellow geocachers, live there.
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And they also happen to be members of the NASA Sci-Files Kids Club.
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That's cool. If you send me their coordinates, I can meet them.
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Speaking of coordinates, as I mentioned in my email, I have some questions about the history of navigation.
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Where do you want to start?
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Didn't the Vikings discover America about 1000 A.D., long before Columbus?
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That's right. The Vikings were excellent navigators and shipbuilders.
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This Viking ship, made of oak, is called the Oseberg.
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It is 22 meters long and was likely the burial ship of a Viking queen.
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The Gokstad was probably built around 890 A.D.
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In addition to sails, it also had 16 pairs of oars.
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In 1893, a replica of the Gokstad sailed from Norway to Canada in 28 days, without the aid of a compass.
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Wow, that's amazing!
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How do they navigate without a compass?
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The Vikings probably used stars to navigate.
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A star named Polaris, which is located above the Earth's north pole, can be used to find north.
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I know. Polaris is sometimes called the North Star.
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It's always in the same place in the sky, and you use the Big Dipper to find it.
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Very good. But when the Vikings sailed in the summer months, they would have had difficulty finding the North Star.
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Why is that?
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Because Norway is so far north, there are places where the sun never sets in the summer.
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That's why it's called the Land of the Midnight Sun.
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Even in southern Norway, it doesn't get really dark at night.
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Dr. D., how would they navigate without a compass or the use of the stars?
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Lots of ways. For example, they relied upon landmarks.
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They used ocean currents, prevailing winds and swells, and they observed the migrations of birds and whales to find their way.
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Is it possible that they used the sun?
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Yes. They apparently used the sun's shadow and the rising and setting positions of the sun to find north.
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Okay. And if there are clouds?
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Some people think they used a sunstone to locate the rising or setting sun when there were clouds on the horizon.
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I have a piece right here.
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How does it work?
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It's called Iceland's bar.
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Put a dot on top and look through it, you'll see two dots.
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You rotate it until both dots are equally dark, then the crystal points toward the sun.
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That's pretty ingenious.
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Of course they would have loved modern navigational technology like this sextant, a seagoing clot, or especially a GPS.
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Our GPS, however, is causing us some problems.
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What do you mean?
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It's giving us lots of random coordinates, even when we're not moving.
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Interesting. That makes it hard to find the cache.
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I have a friend at NASA Langley Research Center who works a lot with global positioning systems.
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I'll email you his information. I'm sure he can help you.
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Until then, I can tell you where to get a good sunstone.
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Thanks, Dr. D. But after I finish my research, I think I'll just give him a call.
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What about this one?
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If we were putting Jacob's bike in our cache, I'd say great.
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Remember, we have to hide this when we're finished.
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Plus, I'll never get that on the plane.
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Hmm. I wonder what my profit margin would be for these plastic containers in a yard sale.
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Note to self. Investigate long-term investment potential in plastics.
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Did you read Bianca and Jacob's get-up-and-go sheets?
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Yes. And we still need to learn about how satellites and GPS work if we want to complete our assignment.
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Dr. D. mentioned talking to a friend of his at NASA.
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Yes. Maybe we can meet him after we finish making our geocache.
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And finding supplies for your camping trip.
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By the way, how is it possible that you get to go on a camping trip to Colorado?
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Isn't that expensive?
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These, Catherine, are the benefits of being on the board of a high-profile financial institution.
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You're a member of the board?
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Well, no. My mom is. She's taking me camping after our meetings.
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I'll tell you all the details when you take me to the airport.
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I can't take you to the airport. I can't drive yet.
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Oh. Right. Note to self.
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Also, investigate investment opportunities in transportation companies.
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So what's up? How will the treehouse detectives find the geocache?
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What should they do if their GPS devices go out again?
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Find out in the next exciting chapter of The Case of the Technical Knockout.
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Be sure to look for the answers to the following questions.
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How do GPS receivers detect their distance from satellites?
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What is the electromagnetic spectrum?
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What is static electricity?
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When you see this icon, the answer is near.
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Dr. D's friend, Mr. Gnaud, works at NASA Langley Research Center.
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He develops new instruments for global positioning systems and has agreed to meet with us.
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If anyone can help us learn more about GPS, he can.
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GPS, or Global Positioning System, is a constellation system of 29 Earth-orbiting satellites
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that were originally designed by the U.S. military in the 1970s as a navigation system.
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Twenty-nine sounds like a lot of satellites.
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Why do you need so many?
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It takes 24 satellites to provide global coverage, leaving five spares.
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The orbits are arranged so that at any given time, anywhere on Earth, there are at least four satellites visible.
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Why do four satellites need to be visible?
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Your GPS receiver needs four satellites in order to determine its own location.
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How does our GPS locate itself?
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Using a simple mathematical principle called trilateration.
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I'm not sure simple and trilateration should be used in the same sentence.
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What is trilateration?
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It's kind of tricky to explain in three-dimensional space, so let's start with a two-dimensional example.
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Let's say you're totally lost somewhere in the U.S. and your GPS is not working.
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Like us yesterday when we couldn't find our geocache.
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As you are trying to find where you are, a friendly person tells you that you are 1,000 kilometers from Boise, Idaho.
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Do you know where you are?
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No, I could be 1,000 kilometers in any direction from Boise.
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Exactly.
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Now let's say another friendly person comes by and tells you that you're 1,110 kilometers from Minneapolis, Minnesota.
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Do you know where you are?
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Not yet, but I'm getting closer to my location.
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That's right. Now you have two choices, but you still don't know where you are.
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Finally, another friendly person informs you that you are 990 kilometers from Tucson, Arizona.
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Now do you know where you are?
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It looks like I'm in Denver, Colorado, which of course I will be soon.
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The same concept works in three-dimensional space, but instead of circles, you need to think in terms of spheres.
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And the satellites are the friendly people telling you how far you are from a place.
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That's right. If you know your distance from Satellite A, you could be anywhere on a huge imaginary sphere at that radius.
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If you know your distance from Satellite B, you can overlap the first sphere with the second sphere and they intersect in a perfect circle.
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So if you know the distance to a third satellite, you get a third sphere which intersects with the circle at two points.
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Very good. And the Earth acts as the fourth sphere, so you can eliminate the point in space because you're on Earth.
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So do you only need three satellites?
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An approximate position can be found with three satellites, but to improve accuracy and get precise altitude information, four or more are better.
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How do GPS receivers know how far they are from the satellite?
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They analyze the high-frequency, low-powered radio signals from the GPS satellites and calculate the time the signal traveled.
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Do satellites have stopwatches?
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No. The satellites need to be more accurate than a stopwatch.
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The satellites use a very accurate atomic clock which produces exact time-coded signals.
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And what happens if a satellite malfunctions?
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It's possible. Again, that's why we have 29 satellites when only 24 are needed, leaving a few spares.
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It helps to have extra.
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True. Here at NASA, we use GPS to determine the position of aircraft and satellites.
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And we also are developing a system to perform remote sensing of the environment.
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All of these tasks require precision information. Spare satellites make sure we get the data we need.
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Cool. NASA is always doing amazing things.
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Mr. Ganell, what would happen if your GPS was only receiving a signal from one or two satellites? Would you get incorrect results?
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No. Usually, your GPS device will let you know that it doesn't have enough satellites to calculate an accurate position.
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Sounds like we need to do some more research.
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Thanks, Mr. Ganell.
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You're welcome. And good luck with your geocaching.
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We're about 25 meters from where we were, and when we last experienced some problems with the GPS. Over.
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Can you still hear me? The radio's coming in loud and clear, too. Keep us posted.
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We shouldn't really assume whether or not the technical problem was permanent.
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My guess is that one of the satellites was broken.
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Now, Jacob, don't jump to conclusions.
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And besides, Mr. Ganell said that 29 GPS satellites orbit the Earth.
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It's possible, but not likely that they're all good.
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I guess you're right. But what other explanation is there?
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Either way, if we want to complete our assignment, we have to make sure this works.
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It should be another 8 meters. A little to the right.
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I don't see anything.
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Another 5 meters.
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Oh, wait. I see something.
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This is so cool. I can't believe we found it.
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This is so cool. I can't believe we found it.
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RG to Headquarters. We've found the geocache. I repeat, we have found the geocache.
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At the exact coordinates listed on the website.
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Good work, guys. Are you sure the coordinates are correct?
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We're sure. We've double-checked and double-confirmed. Mission accomplished.
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We're returning to Headquarters. Over.
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It looks like you were right. I shouldn't have jumped to a conclusion.
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Clearly, the satellites and the GPS devices are working properly.
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And that's a good thing. But we still don't know what caused the problem in the first place.
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Let's go to the problem board.
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Okay. What do we know?
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We know that our GPS malfunctioned in two different locations at the same time.
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And we also know from Catherine and Tony's report that satellites communicate with GPS devices through radio waves.
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Of course. And now we know that the problem was only temporary.
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True. The satellites and GPS devices are working fine now. So what do we need to know?
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We need to know more about radio waves and how they might be affected.
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It might also help if we knew anyone else who had a similar problem.
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So where do we go?
00:20:43
Let's email Ulla and Nina in Norway and see if they had the same problem on the same day.
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Great idea. We may not have this problem solved, but we're making progress.
00:20:48
Yes. And we need to make a report for Tony. Maybe he can help us from Colorado.
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For some great ideas on creating your own reports, visit the Treehouse on the NASA SciFiles website.
00:20:57
We read about the treehouse detectives' problem with their GPS.
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But we weren't much help. We were not geocaching on the same day.
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And we haven't had any problems with our GPS.
00:21:17
We decided to ask Dr. D about it when we meet at the Alomar LiDAR Observatory.
00:21:20
I'm excited to finally be here at the observatory. I've read so much about it.
00:21:27
Dr. D, what kind of research is done here?
00:21:31
The scientists are investigating the middle atmosphere using lasers like this and radar instruments.
00:21:33
Isn't radar what the police use to bounce off cars and see how fast they're going?
00:21:38
And weathermen use it to track rain and snow storms.
00:21:41
Exactly. Radar sends out a beam of light which is reflected off the atmosphere and is then analyzed.
00:21:44
Did you just say that radar sends out a light beam? I thought that radar used radio waves.
00:21:49
It does, but radio waves are a form of light. There are many forms of light that are not visible.
00:21:53
Like what?
00:21:58
Well, for example, this observatory uses microwave light to measure water vapor,
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infrared light to detect clouds, and ultraviolet light to measure the ozone layer.
00:22:03
I've heard of ultraviolet light, but it's not visible.
00:22:08
All these different forms of light are part of what is called the electromagnetic spectrum.
00:22:10
Every form of light travels at 300 million meters per second in a vacuum and has a wavelength.
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We learned that the wavelength is the distance between the crest of two successive waves.
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That's right. Some radio light has wavelengths that are hundreds of meters long,
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where ultraviolet light wavelengths are very tiny, only about one ten-thousandth of a millimeter.
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That's a big difference.
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It is. Light also has a frequency, which is its rate of vibration.
00:22:36
Here, hold on to this spring. I'm going to make it vibrate and create what's called a standing wave.
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The faster you move your hand, the shorter the wavelength.
00:22:59
Exactly. And the shorter the wavelength, the higher the energy.
00:23:02
Which light has the most energy?
00:23:05
That would be gamma rays, followed by X-rays, ultraviolet, visible light, infrared, and radio waves.
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Wow. I still can't believe that they're all called lights.
00:23:13
Dr. D, the treehouse detectives want to know more about the radio waves the satellite uses to communicate with GPSs.
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Good question.
00:23:22
First, you need to know that there are a lot of different types of radio waves.
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GPS satellites communicate with a type of radio wave called microwave.
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I've heard of shortwave radio.
00:23:30
That's another type. There are also AM and FM radio and TV.
00:23:32
But GPS satellites communicate with microwaves because these pass easily through the atmosphere and are not absorbed.
00:23:35
Are the other forms of light absorbed by the atmosphere?
00:23:41
Not all of them. Ozone in the atmosphere is absorbed most, but not all of the ultraviolet light.
00:23:44
Fortunately, most of the X-rays and gamma rays are also absorbed.
00:23:50
But visible lights get through pretty easily.
00:23:54
Yes, the atmosphere is transparent to visible light.
00:23:56
I heard that some radio waves, like AM and shortwave radio, can bounce off the atmosphere and travel great distances.
00:23:59
That's correct. But FM radio and TV don't.
00:24:05
I also mentioned that all radio waves can be created by moving electrical charges.
00:24:08
And the Kids Club members said you might want to learn more about electricity to solve your GPS problem.
00:24:13
I agree. And if camping conditions aren't too primitive, I recommend that you look up Dr. Baganal,
00:24:18
a friend of mine who studies electricity at the University of Colorado.
00:24:25
I know that we use electricity all the time, but I'm not sure what it is exactly.
00:24:29
It's a physical phenomenon associated with static and moving electrical charges.
00:24:33
Oh, I get it.
00:24:38
I'm sorry, would you repeat that again?
00:24:40
I know. It's complex.
00:24:42
Electricity doesn't have a simple explanation, nor is it easy to understand.
00:24:44
So let's start with the basics.
00:24:48
Take this plastic stick and rub it against this cloth.
00:24:50
Okay.
00:24:53
Okay. Now take this other one, made of the same material, rub it with the cloth,
00:24:59
and see if you can try and put the ends together.
00:25:03
It looks like one is pushing the other.
00:25:06
Now rub this one, made of a different material.
00:25:08
Okay.
00:25:10
So now try and put them together.
00:25:12
The different stick pulled the first stick. Why did it do that?
00:25:21
Well, the difference between the two sticks is that they're made of the same material.
00:25:24
The different stick pulled the first stick. Why did it do that?
00:25:29
Well, let's figure it out. Do you remember the parts of the atom?
00:25:32
Yes. There is a nucleus with protons and neutrons surrounded by electrons.
00:25:35
That's correct. And the protons are positively charged and the electrons are negatively charged.
00:25:39
And the neutrons are neutral.
00:25:44
Very good. And positive and negative charges are attracted to each other.
00:25:46
We call that the attractive force.
00:25:49
Aren't all atoms basically neutral?
00:25:51
Yes. But when you put different materials together, sometimes the parts of the atoms like to move.
00:25:54
However, some nuclei like to hang on to their electrons stronger than other nuclei.
00:25:59
The stronger nuclei gather electrons from the weaker nuclei.
00:26:04
Is that what happened when I rubbed the two different sticks with the cloth?
00:26:08
When you rubbed the first two sticks with the cloth, the electrons left the cloth and gathered on the sticks.
00:26:11
And then because they were both negatively charged, they repelled each other.
00:26:15
Because they were both negatively charged, they repelled each other.
00:26:19
So why did the different sticks attract one another?
00:26:22
Well, different materials cause electrons to move differently.
00:26:25
Oh, I get it. With the different stick, the electrons gathered on the cloth, leaving the stick positively charged.
00:26:28
Because once it was positively charged and the other one was negatively charged, they attract each other.
00:26:33
Yeah, I think you've got it.
00:26:37
So this kind of electricity is called static electricity because the charges are stationary and don't move.
00:26:39
Now, shuffle your feet on the carpet and then touch this metal object.
00:26:44
I have a bad feeling about this.
00:26:48
Shocking.
00:26:53
Can you explain why?
00:26:54
I'll try. When I shuffled my feet, I gathered electrons from the carpet, making me negatively charged.
00:26:55
That's correct. And what happened when you touched the metal object?
00:27:00
The extra electrons jumped over to the metal, causing pain.
00:27:03
Sorry, but you're right. It's an example of what we call current electricity.
00:27:08
Watch what happens when I connect this end of the wire to this end of the hand generator.
00:27:13
This looks like a complete circuit, where the light bulb is the load.
00:27:18
When you turn the crank, you produce current, which is electrons flowing through the circuit.
00:27:22
And the light bulb glows.
00:27:26
Exactly. Now watch what happens when I connect the generator to this circuit near these compasses.
00:27:29
Wait a minute. The compasses moved. Why'd they do that?
00:27:36
Initially, the compass was pointing towards the Earth's North Pole.
00:27:40
When we cranked the generator to make the current flow, a small magnetic field was created.
00:27:43
This field caused the compass needle to swing, because the needle is itself a small magnet with a north and south end.
00:27:48
Very interesting. The TRAILS detectives need to know about this.
00:27:55
I didn't know that electricity was so cool.
00:28:00
Dr. Bagnall said that flowing electricity creates a magnetic field.
00:28:02
If that's true, then we need to know more about magnets and magnetism.
00:28:06
So what's up? Will learning about magnets help the TREEhouse detectives?
00:28:10
What other information do they need to solve the mystery?
00:28:14
Find out in the next exciting chapter of TREEhouse!
00:28:17
Next chapter of THE CASE OF THE TECHNICAL KNOCKOUT!
00:28:29
Be sure to look for the answers to the following questions.
00:28:33
What is solar wind?
00:28:36
What does voltage measure?
00:28:38
Name the layers of the atmosphere.
00:28:40
Describe a convection cell on the sun.
00:28:42
When you see this icon, the answer is near.
00:28:44
What about a nice bag of beef jerky?
00:28:54
Don't you think after a long day of hiking and geocaching, you might want some beef jerky?
00:28:56
Or something of substance?
00:29:00
Sorry, Jacob. Nothing perishable.
00:29:02
We need to put things into our cache that are fun and interesting as treasure, not a meal.
00:29:04
Well, I'm running out of ideas.
00:29:09
What do you have so far?
00:29:11
I had lots of food items.
00:29:12
Signal flares...
00:29:16
might be hazardous in the forest.
00:29:18
Cache or a gift certificate?
00:29:21
Why don't we just put travel bugs in our caches?
00:29:24
Hi, RJ. What are travel bugs?
00:29:26
They sure don't sound like treasure.
00:29:29
My dad got me this one on the internet.
00:29:31
It doesn't look like a bug.
00:29:34
It's not a real bug.
00:29:36
Each travel bug has its own unique tracking number.
00:29:38
So when someone finds our cache, they take out the travel bug and place it into a different location.
00:29:41
Then they look up on the internet the travel bug tracking number
00:29:46
and type in the new location of the cache that they placed it in.
00:29:49
So your travel bug could travel to geocaches all around town?
00:29:52
Actually, it can travel the world.
00:29:55
How would that work?
00:29:57
Let's say we place a travel bug in our cache,
00:29:59
and then someone from New York is geocaching in our area.
00:30:01
They take the bug back to New York and place it in a cache in their city.
00:30:04
Someone from London visits New York to geocache,
00:30:07
and then they take it with them back to London.
00:30:10
What a cool idea.
00:30:12
We have to get some travel bugs.
00:30:14
We have one, but we can get some more.
00:30:16
Our travel bugs could see the world. How cool is that?
00:30:18
Wait a minute. We're getting ahead of ourselves.
00:30:21
I know working on our caches is part of the assignment,
00:30:23
but we still haven't solved our problem.
00:30:26
I was reading Tony's report on electricity,
00:30:28
and he said we need to learn more about magnetism.
00:30:30
I think Ula and Nina are meeting with Dr. D again.
00:30:33
Hopefully we should get their report soon.
00:30:36
For great ideas on creating reports,
00:30:38
visit the Treehouse and the NASA Sci-Files website.
00:30:40
I'm really looking forward to the Northern Lights Festival tonight,
00:30:46
and hopefully seeing some auroras with the kids' club members.
00:30:49
Ondinus is the perfect spot for viewing auroras
00:30:52
because it is located directly under the auroral oval.
00:30:54
Of course, Nina and Ula are also investigating magnetism
00:30:57
for the Treehouse detectives.
00:31:00
This is a good place to start.
00:31:02
We know that magnets have a north pole and a south pole.
00:31:04
And the two north poles repel,
00:31:07
and the north and the south pole attract each other.
00:31:09
Very good. Let's demonstrate that
00:31:11
by having you push light poles of these two magnets together.
00:31:13
Oy, they're really strong.
00:31:20
Let's take a look at the magnetic field of this permanent bar magnet.
00:31:22
That's impressive.
00:31:35
Notice how the south pole, or white part of this compass needle,
00:31:37
points to the north pole of the bar magnet.
00:31:40
So if a compass always points to where the Earth's north pole,
00:31:43
that must mean that the Earth is a big magnet with a magnetic pole up north.
00:31:46
You're right. The Earth's magnetic field looks very similar
00:31:49
to the field of this bar magnet.
00:31:52
I heard that the Chinese used a lodestone to produce their first compass.
00:31:54
Historians think so.
00:31:57
Here is a piece of lodestone, a naturally magnetic rock.
00:31:59
If I float it on this phone, it will point north.
00:32:02
Doesn't magnetism have something to do with electricity?
00:32:05
Yes, it does.
00:32:08
Magnetic fields are produced by moving charges.
00:32:10
Let's make an electromagnet by having an electric current
00:32:12
go through this wire, which is wrapped around an iron bar.
00:32:15
This field looks just like the bar magnets.
00:32:21
Except, when I turn off the current of an electromagnet,
00:32:23
the magnetic field disappears.
00:32:26
So is the Earth like a giant electromagnet, or like a permanent magnet?
00:32:29
Well, the Earth has an outer core made of molten iron that is constantly in motion.
00:32:33
A process called the dynamo effect creates huge currents of electricity in the iron,
00:32:38
which produces a giant electromagnet.
00:32:43
In like manner, the Earth's magnetic field deflects the protons and electrons of the solar wind,
00:32:46
which the Sun is throwing at the Earth at hundreds of kilometers per second.
00:32:51
Ah, I get it.
00:32:55
Didn't a Norwegian scientist named Christian Birkland investigate the solar winds and auroras?
00:32:57
That's right. He used a magnetized sphere called a torella to represent the Earth.
00:33:01
And he fired an electron beam at it to simulate the solar wind.
00:33:05
What did he discover?
00:33:08
Well, the electron beam did cause the gases in the chamber to glow like an aurora,
00:33:10
and the magnetic field guided the electrons like beads in a string to the poles of the torella.
00:33:14
And we know that auroras occur on Earth near its poles.
00:33:18
Very good. Here is an example of how high-energy electrons can cause a gas to glow.
00:33:21
This is a tube of helium gas hooked up to a high-voltage power supply.
00:33:26
The tube is glowing pink.
00:33:31
Each gas gives off its own special color.
00:33:33
Here is neon gas, which looks orange.
00:33:36
Just like the lights I've seen at restaurants.
00:33:39
That's right. Auroras produce greens, blues, and reds
00:33:41
when electrons collide with oxygen and nitrogen atoms hundreds of kilometers above the Earth's surface.
00:33:44
Auroras certainly don't look that high.
00:33:50
Dr. D., wasn't there a problem with Birkland's theory?
00:33:52
Yes, he had the misconception that it was electrons coming directly from the Sun that caused the aurora.
00:33:55
Well, where do they come from?
00:34:00
They do come in part from the Sun.
00:34:01
The solar wind compresses the magnetic field on the day side of the Earth
00:34:03
and stretches it into a long tail called the magnetotail on the night side.
00:34:06
Electrons from the solar wind flow around the day side and into the magnetosphere at the tail.
00:34:10
Then what happens?
00:34:15
The electrons in the magnetotail are then pulled back down toward the poles
00:34:16
at increasingly high speeds by electric forces.
00:34:20
These are called Birkland currents.
00:34:22
And when they collide with the gases in the atmosphere near the poles, we have an aurora.
00:34:24
Exactly. But to really understand auroras, you must first learn more about activity on the Sun,
00:34:29
like sunspots and flares.
00:34:34
Thanks, Dr. D. Let's get a report on magnetism ready for the Trias detectives.
00:34:35
Maybe they can help us investigate the Sun.
00:34:39
Okay, let's fire up the computer.
00:34:47
I'm ready to talk magnetism with our friends at the Andenes Barn School in Norway.
00:34:49
It's not every day we have a transatlantic experiment.
00:34:53
I would love to visit Norway and see the culture close up.
00:34:56
Well, how about the next best thing?
00:34:59
We're ready to talk to the NASA Sci-Files Kids Club members in Andenes.
00:35:01
Perfect.
00:35:04
They should be ready just about now.
00:35:05
Hi, I'm Jacob here with Bianca. We understand you're doing an experiment on magnetism.
00:35:10
Hi, I'm Ingrid.
00:35:14
And I'm Alexander.
00:35:15
Hi. Dr. D. told us that you're working on an electromagnet experiment.
00:35:16
Can you tell us about it?
00:35:20
Sure. Our electromagnet is a wire wrapped around an iron nail attached to a battery.
00:35:22
We wanted to find out how the strength of the electromagnet changes when we increase the voltage.
00:35:28
And we increase the voltage by using more batteries.
00:35:35
We learned in science class that a battery is like an electrical pump that pushes electrons through a circuit.
00:35:38
The voltage measures the push.
00:35:44
And the flow of electrons through the wire is called a current.
00:35:46
We learned that too.
00:35:49
We also learned that as the voltage is increased, the current in the wire will increase.
00:35:50
So we hypothesized that if we increase the voltage and get more current, then the strength of the electromagnet will also increase.
00:35:55
Sounds like excellent reasoning.
00:36:03
We began by wrapping wire around the nail 300 times.
00:36:05
Next we placed a 1.5 volt battery in the battery pack.
00:36:09
We then connected one end of the wire to the positive battery terminal.
00:36:13
And to complete the circuit, we connected the other end to the negative terminal.
00:36:17
You won't get any current or flow of electrons unless you have a complete circuit.
00:36:23
That's right. And a current in the wire then causes the nail to become a magnet.
00:36:28
To test the strength of the magnet, we placed it in a cup of paperclips.
00:36:33
I would think that the stronger the magnet, the more paperclips it would pick up.
00:36:38
We agree. In our first trial, we picked up six paperclips.
00:36:42
We know in an experiment it is important to do multiple trials and then find the average.
00:36:46
What was your average?
00:36:50
The class average was 8 paperclips with 1.5 volt battery.
00:36:52
To continue to test our hypothesis, we added another 1.5 volt battery increasing the voltage to 3 volts.
00:36:56
The average was 14 paperclips with 2 batteries.
00:37:05
Wow! You doubled the voltage and almost doubled the number of paperclips.
00:37:08
We continue by adding a third battery.
00:37:12
With 4.5 volts, we averaged 21 paperclips.
00:37:15
And 4 batteries, or 6 volts, picked up an average of 30 paperclips.
00:37:19
Congratulations! It looks like you proved your hypothesis.
00:37:26
That's right. We graphed the results as well.
00:37:29
A graph clearly shows that the strength of the magnet increases as the voltage increases.
00:37:33
Our teacher, Ole, also told us that the Earth's magnetic field is very similar to our electromagnet,
00:37:39
except the current in the Earth is a billion times the current in our circuit.
00:37:46
That's incredible!
00:37:50
I was wondering, does the number of times you wrap the wire around the nail make a difference?
00:37:52
We think so, but that is what we are going to test next.
00:37:56
Great! Be sure to send us your results.
00:38:00
We will. Goodbye, from Andenes Børneskole, Norway.
00:38:02
Andenes!
00:38:07
I can't believe all the cool experiments we've seen.
00:38:10
Anthony, Dr. Bagnall, Dr. Dean, the Kids Club members, and now the Kids Club in Norway.
00:38:12
Clearly there is a connection between electricity and magnetism, but I'm not sure how.
00:38:17
I'm still sorting through Ulla and Nina's report on auroras.
00:38:22
Dr. D also said that before we can fully understand auroras, we need to learn more about the Sun.
00:38:25
I completely forgot about the Sun. How are we going to learn more about the Sun?
00:38:30
Don't worry. I've done some research on the Internet, and NASA does lots of research on the Sun.
00:38:34
Of course! The answer is NASA. Let's go!
00:38:39
Slow down. Ulla and Nina also reported a teleconference that they had with North Shore Christian Academy in Everett, Washington.
00:38:41
Oh, I see. I think.
00:38:49
Before learning about the Sun, they talked with the students at North Shore about the layers of the Earth's atmosphere.
00:38:52
The layers of the Earth's atmosphere?
00:38:57
You know, the troposphere, closest to the Earth, and the mesosphere, which is very cold and the air is very thin.
00:39:00
And, of course, the thermosphere and ionosphere, where most of the auroras occur.
00:39:07
Jacob, I'm impressed.
00:39:11
I've been doing more than surfing the Web and reading reports. Every once in a while, you have to go old school and use books.
00:39:13
Well, I'm glad you haven't forgotten such a great resource.
00:39:18
But we still need to learn more about the Sun.
00:39:21
Well, we're in luck. Catherine and Argie are meeting with Dr. Nikki Fox to learn more about the Sun.
00:39:23
She's at the Johns Hopkins Applied Physics Laboratory and works with scientists at NASA Goddard Space Flight Center.
00:39:28
I'm sure they'll find the Sun very illuminating.
00:39:35
Very funny. But I can't wait to read their report.
00:39:39
Well, most of what we know about the Sun comes from measurements from various instruments and satellites.
00:39:42
And they observe things such as the Sun's size, mass, surface temperature, and brightness.
00:39:47
Various instruments and satellites? What kinds of satellites?
00:39:52
Well, there's SOHO, which is designed to study the internal structure of the Sun,
00:39:56
and ACE that studies the solar wind that comes from the Sun.
00:40:00
And then there's also POLAR, TIMED, and POSE,
00:40:03
that monitor how this solar wind interacts with the Earth's magnetosphere and causes auroras.
00:40:06
And, of course, we're all looking forward to the launch of STEREO,
00:40:11
which is being built here at the Applied Physics Lab.
00:40:14
And it will get the first three-dimensional images of the Sun.
00:40:16
So that's how you know so much about the Sun.
00:40:20
Well, satellites are very helpful, but there's still much more to learn.
00:40:22
Let's start with the basics. The Sun is an average star.
00:40:25
It's not the brightest star, and it's not the hottest star.
00:40:28
In fact, scientists actually classify it as a dwarf.
00:40:31
A dwarf? I thought it was really big.
00:40:34
Well, remember that size is relative.
00:40:37
Compared to the Earth, the Sun is huge.
00:40:39
The diameter of the Sun is about 110 Earths strung together.
00:40:41
If you think of the Sun as a basketball, Earth would be a tiny BB.
00:40:45
But there are stars that are much bigger.
00:40:49
Then why don't the other stars look bigger than the Sun?
00:40:52
Well, that's because they're so much farther away.
00:40:54
The Sun is 158 million kilometers away from the Earth.
00:40:57
However, the next closest star is Proxima Centauri,
00:41:00
and it's so far away that its distance has to be measured in light-years.
00:41:04
Wow, that's far.
00:41:11
And fast.
00:41:15
What is the Sun made of?
00:41:17
It's mostly made from hydrogen, with some helium and a few other elements.
00:41:19
It also has six layers.
00:41:23
The Earth has layers. Are the Sun's layers like the Earth's?
00:41:25
No.
00:41:29
Because the Sun is not solid like our Earth, they're quite different.
00:41:30
The Sun's layers consist of a core, a radiative zone, a convective zone,
00:41:33
and then there's the visible surface known as the photosphere, the chromosphere,
00:41:38
and finally the outermost layer, the corona.
00:41:42
So if the Sun is not a solid, then is it gaseous?
00:41:45
No, it's neither. It's actually a plasma.
00:41:48
Of course. I was just reading about plasma being the fourth state of matter.
00:41:51
That's correct.
00:41:55
Because this plasma is hotter in some places than others,
00:41:56
it creates convection cells in the convection zone of the Sun.
00:41:59
What are convection cells?
00:42:02
Well, they look just like rice grains, and scientists call this granulation.
00:42:03
The bright center of each cell is hot, rising material,
00:42:07
and the darker edges are cooler gas falling to be reheated, just like water boiling.
00:42:11
These granules are continuously evolving and changing.
00:42:16
But these light and dark patches should not be confused with sunspots,
00:42:19
which are dark spots higher up on the surface of the Sun.
00:42:23
I've seen pictures of sunspots before. Are they very big?
00:42:26
Well, the average size of a sunspot is about the size of the Earth.
00:42:30
I'd say that's pretty big.
00:42:33
What causes sunspots?
00:42:35
Well, just like the Earth, the Sun has poles and a magnetic field,
00:42:37
and sunspots are created when this magnetic field interacts with hot plasma at the Sun's surface.
00:42:40
The Sun has poles and a magnetic field? Cool.
00:42:45
Well, not really cool.
00:42:49
Sometimes this magnetic field causes the plasma in a sunspot to burst from the surface of the Sun
00:42:51
in what's known as a solar flare.
00:42:56
Do solar flares affect the Earth?
00:42:58
Or satellites?
00:43:00
Well, solar flares do release a tremendous amount of energy,
00:43:01
and that can affect the Earth and our satellites in lots of different ways.
00:43:04
It sounds like we need to learn more about solar flares.
00:43:08
Thanks, Dr. Fox.
00:43:11
So what's up? Could solar flares be responsible for the problem with the GPS?
00:43:13
How do the treehouse detectives figure out what happened to their GPS devices?
00:43:18
Find out in the conclusion of The Case of the Technical Knockout.
00:43:22
Be sure to look for the answers to the following questions.
00:43:26
In which layer of the atmosphere is the ionosphere?
00:43:30
What is a coronal mass ejection?
00:43:34
What is space weather?
00:43:37
Explain a solar cycle.
00:43:39
When you see this icon, the answer is near.
00:43:41
I'm still not sure about this.
00:43:48
Come on, it's easy.
00:44:04
We find a good hiding spot, note the location using our GPS,
00:44:06
put the location on the Internet, and our assignment is complete.
00:44:09
I already anticipate a good grade.
00:44:12
I'm not talking about the assignment. I'm talking about our problem.
00:44:14
I've got a new hypothesis.
00:44:17
A solar flare occurred during our first attempt at geocaching.
00:44:19
Now there is no solar flare, so we aren't getting any technical interference.
00:44:22
Well, I agree we aren't receiving any interference,
00:44:25
but we still need to confirm our hypothesis.
00:44:28
No problem.
00:44:30
What do you mean, no problem?
00:44:31
Geo Eagle One to home base, come in please.
00:44:33
Hi, Jacob. We're all set.
00:44:36
We should have the results in a few minutes.
00:44:38
Jacob, what's going on?
00:44:40
I knew you wouldn't just accept my hypothesis, so I did some more research.
00:44:42
I set up an interview between R.J. Cayley and Dr. Sten Odenwald,
00:44:46
a NASA researcher who's also over in Norway.
00:44:50
Jacob, you're making real progress.
00:44:52
You recognize the problem, conducted solid research,
00:44:54
and you're working to verify your hypothesis. I'm impressed.
00:44:57
If you think that's impressive, wait until you hear from Dr. Odenwald.
00:45:00
Home base, let me know the minute you finish talking to Dr. Odenwald.
00:45:04
Home base?
00:45:09
Home base?
00:45:11
Jacob, come in. We're getting ready to talk to Dr. Odenwald.
00:45:17
Do you have any additional questions? Over.
00:45:20
Over.
00:45:23
Well, that's funny. It was working just fine a second ago.
00:45:26
Yeah, it's really strange.
00:45:29
Maybe there's been another solar flare that's affected the radio and the GPS.
00:45:31
Poor Jacob and Bianca.
00:45:35
Oh, look. Here he is now.
00:45:39
Hi, Dr. Odenwald.
00:45:41
Hi, kids. Jacob's been telling me about his hypothesis and the research you've been doing.
00:45:42
Sounds very interesting.
00:45:46
Yes, it is.
00:45:48
Of course, it'll be even more exciting if the hypothesis is correct.
00:45:49
Right. We were hoping you could help us.
00:45:53
Jacob believes that a solar flare is responsible for the technical glitch with our GPS,
00:45:55
but we're not sure how.
00:46:00
Well, solar flares are one possibility, of course.
00:46:01
When we're talking about the sun and solar flares, we're talking about a huge amount of energy.
00:46:04
And that energy caused our GPS to malfunction?
00:46:08
It could have. Let's start at the beginning.
00:46:11
Solar flares happen near the surface of the sun because the magnetic fields there that are all tangled up
00:46:14
try to get untangled into simpler shapes, and that releases a huge amount of energy.
00:46:19
Sometimes it can heat the surface all the way up to 100 million degrees.
00:46:24
That's incredibly hot.
00:46:27
It really is.
00:46:29
The gases near the flare are so hot that they produce X-ray light,
00:46:30
and this light travels to the Earth in about eight and a half minutes and impacts the Earth's atmosphere.
00:46:34
Wow, that's quick.
00:46:39
And when the X-rays arrive, they disrupt the ionosphere on the daytime side of the Earth.
00:46:41
We learned that the ionosphere is part of the thermosphere,
00:46:45
where there are a lot of charged particles and free electrons.
00:46:48
That's right, and these disruptions can cause shortwave radio blackouts that last for hours.
00:46:51
We also learned that GPS communicates using radio waves.
00:46:56
And because solar flares affect radio waves, Jacob's hypothesis is right.
00:47:00
Well, again, solar flares are only one possibility.
00:47:04
You could also have coronal mass ejections and superflares.
00:47:07
What are coronal mass ejections?
00:47:10
Well, during some of the largest solar flares,
00:47:12
the same magnetic changes that produce the flare can actually launch a billion-ton cloud of charged particles into space.
00:47:15
These are called coronal mass ejections, or CMEs.
00:47:22
Do these clouds affect radio waves?
00:47:25
Oh, yes, they can.
00:47:27
They also produce some of the most intense and widespread aurora.
00:47:29
The thing is that they travel to the Earth much slower than the X-rays do from typical solar flares.
00:47:32
It usually takes about one to four days for a CME to arrive at the Earth.
00:47:37
What is a superflare?
00:47:41
Well, fortunately for us, superflares are not very common.
00:47:43
When they happen, though, they produce an amazing amount of energy.
00:47:46
How would a superflare affect the Earth?
00:47:49
Well, if you're an astronaut in space, a superflare could produce a life-threatening dose of radiation.
00:47:51
Historical record also shows that some of the most powerful flares we've seen so far can produce satellite damage or loss of function.
00:47:56
Then our GPS really wouldn't work.
00:48:04
Well, that's right.
00:48:07
Even the CME from a modest superflare like the one in 1989 caused a blackout in Quebec.
00:48:08
Wow, radiation, power shortages.
00:48:14
These superflares sound extreme.
00:48:16
It's easy to see how something that's strong as a superflare would have an effect on our GPS.
00:48:18
But what effect would an average solar flare have?
00:48:23
Well, space weather includes all solar flares, CMEs, and superflares can disturb the ionosphere.
00:48:25
These disturbances slow down the speed of the radio signals sent to the Earth from the GPS satellite.
00:48:31
And the speed can vary from minute to minute.
00:48:37
And if the signal takes longer to get to Earth, then our GPS receiver will think that the satellite is further away and get the wrong position.
00:48:39
Because the speed changes from minute to minute, the GPS location varies as well.
00:48:46
That's exactly what happened to us.
00:48:51
What we need is some way to predict space weather.
00:48:53
And then we would know the best time to geocache.
00:48:56
And we'd be able to better protect and prepare our astronauts in space.
00:48:58
Well, that's right.
00:49:02
NASA has been working for years to understand the complex relationship between the Earth and the sun
00:49:03
using sophisticated satellite systems such as ACE and SOHO.
00:49:08
We also work with the image and time satellite systems and sounding rockets launched here in Norway
00:49:12
to study auroras and how electrons and auroral particles flow.
00:49:18
So NASA is at work all around the world.
00:49:22
That's right.
00:49:24
And we work with communities of scientists and researchers all around the world
00:49:25
to try to understand how space weather affects the Earth.
00:49:29
Thanks, Dr. Unwall.
00:49:32
You may have actually helped support Jacob's hypothesis.
00:49:33
And solved our problem with our walkie-talkies.
00:49:36
Did you say walkie-talkies?
00:49:38
Yes.
00:49:40
We lost our radio signal with Jacob just before we called you.
00:49:41
There must have been another solar flare that affected both the walkie-talkies and the GPS
00:49:44
because they both use radio waves.
00:49:49
Yeah, but walkie-talkies don't usually use radio waves to travel up to the ionosphere and then back down.
00:49:51
They usually use what's called a ground wave,
00:49:56
which is basically line of sight between the receiver and the transmitter.
00:49:58
Oh, no.
00:50:02
Our hypothesis is incorrect.
00:50:03
What do we do now?
00:50:05
Well, don't panic.
00:50:06
You did use careful reasoning after all.
00:50:07
And your basic hypothesis about the GPS problem could still be correct.
00:50:10
You just have to do more research.
00:50:13
Perhaps there's a way for us to find out if we had any solar activity on the first day of our problem and today.
00:50:15
Ah, I think you're onto something.
00:50:20
I've got a friend at NOAA who might be able to help.
00:50:22
I'll give you his email address.
00:50:25
But what about our walkie-talkie problem?
00:50:26
Well, walkie-talkies might require a completely separate hypothesis.
00:50:28
Think about a common problem that affects small electronic devices when they're in the field.
00:50:32
What would that be?
00:50:37
How about bad batteries?
00:50:38
Take care, kids.
00:50:40
Good luck.
00:50:41
Bye.
00:50:43
I'm not telling Jacob about this one.
00:50:53
Thanks, RJ, and good work.
00:50:59
I thought I lost you for a few minutes, but I understand when nature calls.
00:51:01
Over.
00:51:04
Well, I got lucky.
00:51:06
My hypothesis is correct after all.
00:51:07
I think it was more than just luck.
00:51:09
You did good research.
00:51:11
We all did good research.
00:51:12
Now all we need to do is plan our geocache and complete our assignment.
00:51:13
Let's not congratulate ourselves just yet.
00:51:17
RJ said that NOAA might be able to confirm our hypothesis.
00:51:19
Further.
00:51:22
That's true.
00:51:23
You don't always know for certain that you're 100% correct.
00:51:24
Right, but hopefully they'll be able to help us get closer to the answer.
00:51:26
Let's plan our cache and wait for Tony's report from NOAA.
00:51:29
I'm ready for coordinates.
00:51:32
North 37.
00:51:34
I'm meeting with Mr. Joe Cunches who works with NOAA
00:51:43
and the Space Environment Center here in Boulder, Colorado.
00:51:46
He studies space weather and how to predict it.
00:51:49
Hopefully he can tell us whether there was any solar activity
00:51:51
the day we experienced the problem with our GPS.
00:51:54
Space weather refers to conditions near the Earth that affect man-made technologies
00:51:57
such as satellites and other human activities.
00:52:01
That's why it's so important to predict space weather.
00:52:04
Right.
00:52:06
Satellites were once rare and mostly government-owned,
00:52:07
but today they are more numerous and many are commercially owned,
00:52:10
so that's why it's important to know where and when they may be affected.
00:52:13
Right.
00:52:17
Satellites are very important in our lives
00:52:18
and also a nice addition to a well-balanced portfolio.
00:52:20
We heavily depend on satellites for weather information,
00:52:23
television, communication, and navigation.
00:52:26
We have learned about predicting weather here on Earth,
00:52:29
but how do you predict space weather?
00:52:31
Predictions are made primarily using data from satellites that monitor the sun.
00:52:33
For example, NOAA's GOES and POSE satellites
00:52:39
help forecasters know atmospheric conditions at low Earth orbits and higher up.
00:52:43
Do you work with NASA satellites as well?
00:52:48
Yes.
00:52:50
NASA's ACE satellite samples the solar wind,
00:52:51
and SOHO allows forecasters to see the solar eruptions that cause space weather.
00:52:54
Are there other ways to monitor space weather?
00:53:00
Yes.
00:53:02
We use data from the ground-based observatories
00:53:03
run by the United States Air Force
00:53:06
as well as the magnetometer network run by the United States Geological Survey.
00:53:08
What is a magnetometer?
00:53:13
A magnetometer is an instrument that measures the behavior of the Earth's magnetic field
00:53:15
and tells forecasters when a magnetic storm is developing.
00:53:19
Wow, you have a lot of data to monitor.
00:53:23
How do you get it all?
00:53:25
We get data through the Internet, dedicated telephone lines, and email.
00:53:26
We also have our own antennas that receive data.
00:53:31
And once you have the data, you have to analyze it.
00:53:34
Forecasters continually monitor the space environment to provide short-term, three-day predictions.
00:53:36
They don't have daily space weather predictions on the news, so who receives your forecasts?
00:53:42
The alerts go to a number of places, such as private and commercial users,
00:53:47
as well as other government agencies such as NASA.
00:53:51
Do you send out alerts often?
00:53:54
It varies depending on the time of the solar cycle,
00:53:56
but usually we average 20 to 30 alerts per week.
00:53:59
What's a solar cycle?
00:54:03
As you know, the Earth's weather changes over time with different seasons.
00:54:04
The sun's weather does, too.
00:54:08
The changes on the sun are caused by the reversal of its magnetic poles.
00:54:10
I didn't realize that the poles of the sun switched.
00:54:15
Over an 11-year period, the reversal of the sun's poles completes half of its cycle.
00:54:17
During this time, the number of sunspots seen on the surface of the sun
00:54:22
goes from high to low and then back again.
00:54:26
Sounds intense.
00:54:29
Yes. The period with lots of sunspots is intense and is called sunspot maximum.
00:54:30
The period with fewer sunspots is called sunspot minimum.
00:54:36
So during a sunspot maximum, there would be more solar flares and coronal mass ejections.
00:54:39
We would see increased auroras and more disturbances in the ionosphere,
00:54:45
causing problems with the satellite systems.
00:54:49
Good job. I think you have it.
00:54:51
But remember that even during a sunspot minimum, there can still be lots of interference.
00:54:53
If you don't mind, I have one last question.
00:54:58
Sure. What's your question?
00:55:00
We're fairly certain that our GPS devices went crazy
00:55:01
while we were geocaching due to a solar flare or space weather event that affected the ionosphere.
00:55:04
Is there any way we can be sure that was the cause?
00:55:09
We can find out if an alert was issued for that date,
00:55:11
but not if the storm affected your GPS device.
00:55:15
That makes sense.
00:55:18
Let's go over to the computer and check out the website.
00:55:19
You can find out all about space weather and geomagnetic storms
00:55:23
when you visit NOAA's Space Environment Center website.
00:55:27
NOAA confirmed that there was an alert while we were geocaching.
00:55:32
We can't be certain, but we may have solved another mystery.
00:55:35
Of course, I'm sending my report to the Trios detectives.
00:55:38
Hopefully, they will get it before they go to pick up Dr. D from the airport.
00:55:41
Look, it's Dr. D.
00:55:46
Hi, Dr. D. We solved our mystery.
00:55:51
That's great. Did it have anything to do with batteries?
00:55:53
That's funny. Dr. Udenwald mentioned the same thing.
00:55:56
We did have a small battery problem, but not with our GPS.
00:55:59
Batteries aren't the problem. Remembering to check them can be.
00:56:02
Right. To solve our GPS problem, we actually researched electricity,
00:56:06
To solve our GPS problem, we actually researched electricity,
00:56:10
magnetism, space weather, and auroras.
00:56:13
We've learned all about how GPSs work.
00:56:16
It's amazing how many new things we can learn while we're trying to find the solution to our problem.
00:56:18
I was thinking about your problem as I was watching the auroras in Norway.
00:56:22
It appears to me that the same space weather events that influenced the auroras
00:56:26
probably also affected your GPS.
00:56:30
Dr. D, why didn't you tell us earlier? We came to the same conclusion.
00:56:32
Isn't it more fun to find the solution yourself?
00:56:36
You're right. Antoni's report from Colorado finally nailed it down.
00:56:38
Dr. Udenwald told us that storms on the sun can affect the ionosphere
00:56:41
in ways that slow down the GPS signal so that the receiver reads the false distance.
00:56:45
Antoni told us that there had been a space weather advisory the day that we had the problems.
00:56:50
But don't worry, Dr. D. We know that that doesn't necessarily mean the storm caused the problem.
00:56:55
But it is a very possible solution.
00:56:59
Did you consider a multi-path signal error?
00:57:02
What's that?
00:57:05
What's an inaccuracy caused when the GPS signals bounce off of buildings or large rock surfaces?
00:57:06
Well, we weren't around any buildings and I don't remember seeing any large rocks.
00:57:12
I don't mean to alarm you. I really think your explanation is probably the best in this situation.
00:57:17
I'm just trying to keep you on your toes.
00:57:22
Thanks, Dr. D. Can you tell us about the auroras that you saw? What colors were they?
00:57:24
Did they really dance around in the sky?
00:57:29
Yes, they did. Let's take one question at a time.
00:57:31
The auroras were absolutely wonderful. Mostly kind of a pale green, a little red on the borders.
00:57:34
NASA Jet Propulsion Laboratory, California Institute of Technology
00:58:34
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