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Solar Flares and Other Sun Activity

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Subido el 28 de mayo de 2007 por EducaMadrid

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Eighth segment of NASA Sci Files The Case of the Technical Knockout explaining the different type of solar flares and how solar activity affects the Earth.

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Be sure to look for the answers to the following questions. 00:00:00
In which layer of the atmosphere is the ionosphere? 00:00:04
What is a coronal mass ejection? 00:00:08
What is space weather? 00:00:11
Explain a solar cycle. 00:00:13
When you see this icon, the answer is near. 00:00:14
I'm still not sure about this. 00:00:30
Come on, it's easy. 00:00:39
We find a good hiding spot, note the location using our GPS, 00:00:40
put the location on the internet, and our assignment is complete. 00:00:43
I already anticipate a good grade. 00:00:46
I'm not talking about the assignment. I'm talking about our problem. 00:00:48
I've got a new hypothesis. 00:00:51
A solar flare occurred during our first attempt at geocaching. 00:00:53
Now there is no solar flare, so we aren't getting any technical interference. 00:00:56
Well, I agree we aren't receiving any interference, 00:00:59
but we still need to confirm our hypothesis. 00:01:02
No problem. 00:01:04
What do you mean, no problem? 00:01:05
GEO Eagle One to home base, come in please. 00:01:07
Hi, Jacob. We're all set. 00:01:10
We should have the results in a few minutes. 00:01:12
Jacob, what's going on? 00:01:14
I knew you wouldn't just accept my hypothesis, so I did some more research. 00:01:16
I set up an interview between R.J., Kaylee, and Dr. Sten Odenwald, 00:01:20
a NASA researcher who's also over in Norway. 00:01:24
Jacob, you're making real progress. 00:01:26
You recognize the problem, conducted solid research, 00:01:28
and you're working to verify your hypothesis. 00:01:31
I'm impressed. 00:01:33
If you think that's impressive, wait till you hear from Dr. Odenwald. 00:01:34
Home base, let me know the minute you finish talking to Dr. Odenwald. 00:01:37
Home base? 00:01:42
Home base? 00:01:44
Jacob, come in. We're getting ready to talk to Dr. Odenwald. 00:01:50
Do you have any additional questions? Over. 00:01:54
Over. 00:01:57
Well, that's funny. It was working just fine a second ago. 00:02:00
Yeah, it's really strange. 00:02:03
Maybe there's been another solar flare that's affected the radio and the GPS. 00:02:05
Poor Jacob and Bianca. 00:02:09
Oh, look. Here he is now. 00:02:12
Hi, Dr. Odenwald. 00:02:14
Hi, kids. Jacob's been telling me about his hypothesis and the research you've been doing. 00:02:16
Sounds very interesting. 00:02:20
Yes, it is. 00:02:22
Of course it will be even more exciting if the hypothesis is correct. 00:02:23
Right. We were hoping you could help us. 00:02:27
Jacob believes that a solar flare is responsible for the technical glitch with our GPS, 00:02:29
but we're not sure how. 00:02:34
Well, solar flares are one possibility, of course. 00:02:35
When we're talking about the sun and solar flares, we're talking about a huge amount of energy. 00:02:38
And that energy caused our GPS to malfunction? 00:02:42
It could have. Let's start at the beginning. 00:02:45
Solar flares happen near the surface of the sun 00:02:48
because the magnetic fields there that are all tangled up try to get untangled into simpler shapes, 00:02:50
and that releases a huge amount of energy. 00:02:55
Sometimes it can heat the surface all the way up to 100 million degrees. 00:02:57
That's incredibly hot. 00:03:01
It really is. 00:03:03
The gases near the flare are so hot that they produce X-ray light, 00:03:04
and this light travels to the Earth in about eight and a half minutes and impacts the Earth's atmosphere. 00:03:08
Wow, that's quick. 00:03:13
And when the X-rays arrive, they disrupt the ionosphere on the daytime side of the Earth. 00:03:15
We learned that the ionosphere is part of the thermosphere, 00:03:20
where there are a lot of charged particles and free electrons. 00:03:23
That's right, and these disruptions can cause shortwave radio blackouts that last for hours. 00:03:25
We also learned that GPS communicates using radio waves. 00:03:31
And because solar flares affect radio waves, Jacob's hypothesis is right. 00:03:34
Well, again, solar flares are only one possibility. 00:03:38
You could also have coronal mass ejections and super flares. 00:03:41
What are coronal mass ejections? 00:03:45
Well, during some of the largest solar flares, 00:03:47
the same magnetic changes that produce the flare can actually launch a billion-ton cloud of charged particles into space. 00:03:49
These are called coronal mass ejections, or CMEs. 00:03:56
Do these clouds affect radio waves? 00:04:00
Oh, yes, they can. 00:04:02
They also produce some of the most intense and widespread aurora. 00:04:03
The thing is that they travel to the Earth much slower than the X-rays do from typical solar flares. 00:04:07
It usually takes about one to four days for a CME to arrive at the Earth. 00:04:12
What is a super flare? 00:04:16
Well, fortunately for us, super flares are not very common. 00:04:17
When they happen, though, they produce an amazing amount of energy. 00:04:20
How would a super flare affect the Earth? 00:04:23
Well, if you're an astronaut in space, a super flare could produce a life-threatening dose of radiation. 00:04:25
Historical record also shows that some of the most powerful flares we've seen so far can produce satellite damage or loss of function. 00:04:31
Then our GPS really wouldn't work. 00:04:39
Well, that's right. 00:04:41
Even the CME from a modest super flare like the one in 1989 caused a blackout in Quebec. 00:04:42
Wow, radiation, power shortages. 00:04:48
These super flares sound extreme. 00:04:50
It's easy to see how something that's strong as a super flare would have an effect on our GPS. 00:04:53
But what effect would an average solar flare have? 00:04:57
Well, space weather includes all solar flares, CMEs, and super flares can disturb the ionosphere. 00:05:00
These disturbances slow down the speed of the radio signals sent to the Earth from the GPS satellite. 00:05:06
And the speed can vary from minute to minute. 00:05:11
And if the signal takes longer to get to Earth, then our GPS receiver will think that the satellite is further away. 00:05:13
You get the wrong position. 00:05:19
Because the speed changes from minute to minute, the GPS location varies as well. 00:05:21
That's exactly what happened to us. 00:05:26
What we need is some way to predict space weather. 00:05:28
And then we would know the best time to geocache. 00:05:31
And we'd be able to better protect and prepare our astronauts in space. 00:05:33
Well, that's right. 00:05:37
NASA's been working for years to understand the complex relationship between the Earth and the sun 00:05:38
using sophisticated satellite systems such as ACE and SOHO. 00:05:43
We also work with the image and time satellite systems and sounding rockets launched here in Norway 00:05:47
to study auroras and how electrons and auroral particles flow. 00:05:53
So NASA is at work all around the world. 00:05:56
That's right. 00:05:58
And we work with communities of scientists and researchers all around the world 00:05:59
to try to understand how space weather affects the Earth. 00:06:03
Thanks, Dr. Unwall. 00:06:06
You may have actually helped support Jacob's hypothesis. 00:06:07
And solved our problem with our walkie-talkies. 00:06:10
Did you say walkie-talkies? 00:06:12
Yes. 00:06:14
We lost our radio signal with Jacob just before we called you. 00:06:15
There must have been another solar flare that affected both the walkie-talkies and the GPS 00:06:18
because they both use radio waves. 00:06:23
Yeah, but walkie-talkies don't usually use radio waves to travel up to the ionosphere and then back down. 00:06:25
They usually use what's called a ground wave, 00:06:30
which is basically line of sight between the receiver and the transmitter. 00:06:32
Oh, no. 00:06:36
Our hypothesis is incorrect. 00:06:37
What do we do now? 00:06:39
Well, don't panic. 00:06:40
You did use careful reasoning after all. 00:06:41
And your basic hypothesis about the GPS problem could still be correct. 00:06:44
You just have to do more research. 00:06:48
Perhaps there's a way for us to find out if we had any solar activity 00:06:49
on the first day of our problem and today. 00:06:52
Ah, I think you're onto something. 00:06:54
I've got a friend at NOAA who might be able to help. 00:06:56
I'll give you his email address. 00:06:59
But what about our walkie-talkie problem? 00:07:00
Well, walkie-talkies might require a completely separate hypothesis. 00:07:02
Think about a common problem that affects small electronic devices when they're in the field. 00:07:06
What would that be? 00:07:11
How about bad batteries? 00:07:12
Take care, kids. 00:07:14
Good luck. 00:07:15
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Idioma/s:
en
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Autor/es:
NASA LaRC Office of Education
Subido por:
EducaMadrid
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
677
Fecha:
28 de mayo de 2007 - 15:34
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
07′ 17″
Relación de aspecto:
4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
Resolución:
480x360 píxeles
Tamaño:
43.76 MBytes

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