Sunny waves

Boulder, Colorado: Embargoed for release: 30-Aug-2007 14:00 Eastern US Time

The sun is the most familiar object in the sky - at least it was until this summer. It is also one of the best understood. But there are still some deep mysteries about what happens there.

One of the most puzzling is the fact that the outer layers of the sun's atmosphere, which is called the corona, are far hotter than the surface of the sun. This is very hard to understand. Scientists have compared it to a kettle boiling merrily on top of a block of ice.

One possible explanation is that heat is carried upwards by a special kind of wave called an Alfvén wave. Now scientists for the first time have observed Alfvén waves in the corona.

The discovery gives them an insight into the behaviour of the sun and its magnetic field. It should also lead to a better understanding of how the sun affects the earth and the rest of the solar system.

The research was led by Steve Tomczyk of the National Center for Atmospheric Research (NCAR). It is published this week in Science.

"Alfvén waves can provide us with a window into processes that are fundamental to the workings of the sun," says Tomczyk.

Alfvén waves are fast-moving disturbances that carry energy. They move out from the sun along magnetic field lines. They have been detected in space well beyond the Sun. But they have never before been seen within the corona.

Alfvén waves are hard to detect. This is partly because, unlike other types of wave, they don't create large disturbances in the corona. Also the changes in velocity they cause are small and not easily noticed.

"Our observations allowed us to unambiguously identify these oscillations as Alfvén waves," says co-author Scott McIntosh. He is at the Southwest Research Institute in Boulder.

"The waves are visible all the time and they occur all over the corona.” This was a surprise to the researchers, he added.

By tracking the speed and direction of the waves, researchers should now be able to work out basic properties of the sun's atmosphere. These include its density and the direction of its magnetic fields.

The research may also help scientists to predict solar storms. These are extremely violent events that spew thousands of tons of matter into space in the form of energetic particles.

When these particles hit earth's atmosphere they cause the aurora borealis, the northern lights. They can also have much less appealing effects, by blocking radio signals, causing electrical blackouts and damaging satellites. In March 1989 a solar storm caused a complete blackout of the city of Quebec.

Learning more about solar storms might also help to protect astronauts from dangerous levels of radiation in space.

"If we want to go to the moon and Mars, people need to know what's going to happen on the sun," Tomczyk says.

To observe the waves, Tomczyk and his colleagues used an instrument developed at the National Center for Atmospheric Research over the last few years.

The coronal multichannel polarimeter (CoMP) is attached to a telescope at the National Solar Observatory in New Mexico. It is a special instrument designed to gather light from the corona. This is much dimmer than the sun itself so is difficult to see against its glare.

The CoMP then tracks magnetic activity around the entire edge of the sun. It works fast, making a measurement as often as once every 15 seconds.

With the help of this instrument the research team were able to capture intensity and velocity measurements and polarisation images of the solar corona, all at the same time.

Those measurements and images revealed waves that were moving in paths that lined up with magnetic fields, and travelled at almost 2,500 miles per second.

So can these newly-discovered waves explain why the corona is so very hot? Well maybe. The Alfvén waves the researchers actually observed were, they say, too weak to heat the corona.

But the possibility remains that other, stronger Alfvén waves carry enough energy to do so.

The mystery of why the kettle is boiling on the block of ice has not yet been completely solved.

More help with words

atmosphere

disturbances

orbit

orbits

plane

planet

vibration

What's it all about?

1. What is the most familiar object in the sky?
2. Do we know everything there is to know about this object?
3. What word near the start of the story gave you the answer to that last question?
4. The heat of the sun is created deep beneath its surface, so this surface is not nearly as hot as its centre. That also means that it should be cooler far out from the surface. Is it?
5. What have scientists compared this to?
6. One explanation of this mystery is that Alfvén waves carry heat outwards. Have these Alfvén waves been observed before in the corona?
7. The story mentions two areas where our understanding will improve through the Alfvén wave discovery. State one of them.
8. Give one reason for Alfvén waves being hard to detect.
9. Are the scientists certain that what their instruments detected are Alfvén waves?
10. What word in the story gave you the answer to the last question?
11. By tracking the Alfvén waves, scientists will now be able to learn more about the sun's magnetic ------.
12. The work might also help scientists to predict what?
13. Give two reasons that would be very useful.
14. Why did the scientists have to use a special instrument to study the corona, instead of just looking at photographs taken through a normal telescope?
15. Apart from enabling the scientists to take images of the corona what else can the CoMP do?
16. The writer mentions three pieces of information that the CoMP was able to obtain at lots of different places in the corona. State two of these.
17. Putting all this information together allowed the scientists see that waves were travelling through the corona at almost 2,500 miles per second. In what direction?
18. Explain in one sentence why this is not the whole answer to the puzzle of the corona's high temperature.
19. If you were these scientists what would you like to study next?
20. What question would that research be trying to answer?

More science teaching resources for this story

Sunny waves UK US

Topic for discussion, research or pupil presentations

Stanford University has an excellent collection of sun science investigations, activities and discussion topics.

These include retrieving solar images, understanding the solar scale and an interview with Mr Sol:

"Have you ever wondered what our star thinks about his (or her?) role up there in the sky? Have you considered what an awesome responsibility it must be, generating all that heat and light from fusion and having so many living beings depending upon you?

Sol really does light up our life. Imagine what he might say if you could interview him. Why don't you do a little research (this web site is a good place to start) and then you and a friend create your own interview with Mr. Sol!

If you come up with a good interview, send it to us and we'll publish it here on the web!"

Tips for science class discussions and groupwork

No 60

Your students may not have the reasoning skills, or may not have the requisite prior knowledge to solve the problem you have given them. In either case you need to develop interventions which will chunk the ideas smaller while still giving them space to learn for themselves.

Our inclination in this case, based on our own learning experiences as students, is to tell the students things they need to know to solve the problem. In so doing you take away, as you have pointed out, opportunities for them to learn. Perhaps you are telling too much and not instead developing a set of questions for the students to work on and discuss that will lead them to where you when you want them to be.

....

Sometimes it seems to me that my students have a little mental switch in their heads, and I have to ask the right question to get them to turn it on.

Often the question is "Explain your reasoning."

Extract from a contribution to an NSTA teachers' forum by Joseph J. Bellina, Professor of Physics at Saint Mary's College, Notre Dame, Indiana

Out of body in the lab

University College London: 23-Aug-2007

Scientists can now give healthy people an out-of-body experience. In a paper published today in Science, Henrik Ehrsson tells how it is done. The neuroscientist from University College London also talks about the implications of the new discovery.

An out-of-body experience is just what it says - the feeling that you have left your body. It is usually described as feeling very real, not like a dream. People often report looking down on their actual bodies. The experience is taken by some people to be evidence that we have souls.

Out-of-body experiences are often linked to some kind of damage to the brain. This includes stroke and epilepsy, as well as drug abuse. They have also been reported by some people following traumatic events such as car accidents.

Around one in ten people claim to have had an out-of-body experience at some time in their lives.

What happens during one of these is that a person seems to be seeing his or her own body from outside of it.

Out-of-body experiences have fascinated mankind for thousands of years, Ehrsson says. “Their existence has raised fundamental questions about the relationship between human consciousness and the body.”

The experiences have been talked about in articles on religion, philosophy and psychology, he goes on. “Although out-of-body experiences have been reported in a number of clinical conditions, the neuroscientific basis of this phenomenon remains unclear.”

Being able to produce the illusion in the lab is important, Ehrsson says. One reason is that this tells us a little about how we normally get the feeling of being inside our bodies. Scientists don’t know much about that.

“This represents a significant advance, because the experience of one’s own body as the centre of awareness is a fundamental aspect of self-consciousness,” Ehrsson says.

Discovering how to create an out-of-body experience could also have real applications, Ehrsson says. “This is essentially a means of projecting yourself, a form of teleportation.”

One possible application is computer games, Ehrsson suggests. We should now be able to put people into a virtual character. That would mean they would feel and respond just as if they were that character.

“The experience of playing video games could reach a whole new level. But it could go much beyond that. For example a surgeon could perform remote surgery, by controlling their virtual self from a different location.”

The way the scientists create the experience in the lab is like this. A person sits in a chair wearing a small screen over each eye. These are connected to two cameras behind the participant’s head.

The image from the left camera is sent to the left eye screen. The image from the right camera is sent to the right eye screen. The participant’s brains sees these separate images as one 3-D image. This is what happens normally when we use two eyes to look at something.

In this case, though, the participants see their own back as it would look to someone sitting behind them.

The researcher then stands beside the participant. He touches the participant’s actual chest with a rod. At the same time he seems to touch the chest of the image’s body. He does this by moving a second rod towards where that body would be, just below the camera’s view.

When this is done the participants feel they are sitting behind their own body and looking at it. “This was a bizarre, fascinating experience for the participants,” Ehrsson says.

“It felt absolutely real for them and was not scary. Many of them giggled and said ‘Wow, this is so weird!’”.

To test the illusion some more, Ehrsson did another experiment. He measured the response of the participant’s body. In particular he measured the amount of sweat on the skin. He did this when it looked like the imaginary body was being threatened.

The response showed strongly that the participant thought the threat was real.

This whole experiment came from an idea Ehrsson had as a medical student. He wondered what would happen to our feeling of self if we could move our eyes a few metres away. This would let us see ourselves from the outside.

Would the self follow the eyes or stay in the body, Ehrsson wondered. This experiment seems to have answered that question.

The illusion is different from anything published before, Ehrsson says. “It is the first to involve a change in the perceived location of the self, relative to the physical body.”

It is also different from any virtual reality set-up, he says. “There has been no way of inducing an out-of-body experience in healthy people before, apart from unsubstantiated reports in occult literature.”

This is a very exciting development, Ehrsson says. “It has implications for a range of disciplines from neuroscience to theology.”

More help with words

evidence

convulsions

seizure

More science teaching resources for this story

Out-of-body in the lab UK US

What's it all about?

1. Scientists can now give ------- people an out-of-body experience.
2. People who get out-of-body experiences usually have some kind of damage to their brain. The article lists three ways this can happen. State two of them.
3. It also mentions events like car accidents that create shock and fear that last, but not actual brain damage. What word does the writer use for this type of event?
4. What percentage of people say they have had an out-of-body experience at some time in their lives?
5. Out-of-body experiences make people wonder about the connection between themselves and their ------.
6. The writer says out-of-body experiences are talked about in articles about three different areas of study. Name two of them.
7. What does “clinical conditions” mean?
8. When Ehrsson says “the neuroscientific basis of this phenomenon remains unclear” he means that scientists don’t understand yet what makes out-of-body ----------- happen.
9. What else about our relationship to our bodies do scientists not yet know much about?
10. Apart from making a start on the science of people’s feelings of themselves and their bodies, state two other ways this research could be useful.
11. What equipment did the scientists use to do the experiment?
12. What did it feel like to the participants be outside their own body and looking at it?
13. Can you think why the scientists pointed the cameras at the back of the participant rather than the front?
14. In one sentence what was the point of the sweat test the scientists did?
15. What were the two possibilities Ehrsson thought of when he wondered, as a medical student, what it would feel like if your eyes could move away from your body?
16. Which one actually happens according to the results of this experiment?
17. Imagine you are a scientist in Ehrsson’s team. Think up one question about all this that you would like to find the answer to.
18. Try to outline in one sentence an experiment that might help to answer that question.

Topic for discussion, research or pupil presentations

There are countless stories about out-of-body experiences all over the Web. Actually that's not quite true - with the help of modern technology they can now be counted.

A search on "out of body experience" in Google yields no fewer than 145 millions hits, while Yahoo finds an even more whopping 195 million.

Here's a small sample of them:

Alice: The first thing I experienced was the reality of consciousness ....everywhere! On every level I saw it. I felt it and experienced the reality of a caterpillar, and I was shown that life on any and all levels is equal and the level of awareness in every creature is the same. ... and it was as though I poked my head through some layer of some kind and I could see that there were not just a few dimensions, but that the dimensions went on and on... that there was nothing but creation continuing, never ending.

Dorothy: I couldn't believe it, but I knew, that I was dying. I was on the NE corner of the ceiling and adjacent to me on the NW corner of the ceiling, was a male presence who was "pulling" me with some kind of rope or cord that was connected to me, and he was telling me, "It's time to go, it's time to leave this world" and I told him "No! I can't leave my Mom, my Dad, Melvin Calvin Pete Marylou and Dolores.

Michael: She was holding a bowl of fruit in one arm. ... Oya showed herself as a black woman who had the most amazing brilliant white, deep, "old" eyes that I have ever seen. She was absolutely HUGE and very, very tall. I could tell just by looking into her eyes that this was a very wise collection of not just one spirit, but many, many spirits, probably hundreds, who are fiercely powerful. She had on an orange robe and a white turban-type headdress.

So the questions for discussion today are these:

What is the difference between this type of account and the research reported in the news story?

What is it exactly that makes Ehrsson's work science while most of the hundreds of millions of out-of-body experiences that people have recorded on the web are .... Well what are they exactly?

Some are pure fantasy, but others are no doubt genuine attempts to recount exactly what one person experienced.

Can this kind of subjective experience be part of science? If so how do we separate it from fiction, illusion, delusion or just plain lies?

Is Ehrsson's work science because it was done in a lab using scientific equipment?

Is it science because it was done by people who call themselves scientists?

Is it science because the story appears on a website called Real Science?

What is it that makes something science?

Tips for science class discussions and groupwork

No 59

Teachers often do not appreciate how the process of argumentation can help pupils engage with and understand the conceptual basis of what is under discussion. By thinking about alternative theories and the nature of evidence that supports them, pupils can be helped to appreciate not only the reasons for established scientific views but also why alternative views are not accepted. Commitment to these epistemological aims is necessary for teachers to implement ‘ideas and evidence’ lessons successfully.

Simon, S. and Maloney, J. (2006) Learning to teach ‘ideas and evidence’ in science: a study of school mentors and trainee teachers. School Science Review, 87(321), pp 75-82