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Ask a Professor a Question

Post your questions for Professor Mark Oreglia from The University of Chicago here.

17 DeVonta B. asks:
Show What exactly happened with the solar explosion on April 25th, 2010?

Once again, I have to catch up on answering your good questions!

First, I am very happy DeVonta asks about the recent solar flare. Did you see it on http://spaceweather.com/ ? They have good pictures, and tell you how many cosmic rays in the form of the "solar wind" are coming towards us. You might even be able to see solar spots with your telescope this week. These explosions are like volcanic eruptions on the sun, but much stronger than the ones on earth. When they happen, a lot of material (cosmic rays!) are launched from the sun, and we see their effects here on earth. They interfere with radio transmissions, so you might see an effect on your SW radio too!

Now, for the other questions:
No, the cosmic rays are not harming you -- there are not enough of them going through you to do any harm. That is why you need a very sensitive instrument to see them.

The wind does not effect them, because they go too fast for the wind to interfere with them.

What you can do to decrease the cosmic ray rate that you measure with your instruments is to go somewhere there is a lot of heavy material between you and the sky, such as in a basement. Bricks, concrete and steel can absorb some of the cosmic rays, so fewer of them make it to your counting instrument.

16 Andrew S. asks:
Show What happens during a sun explosion?
15 Nechelle V. asks:
Show Does the wind effect Cosmic Rays in any way?
14 Taiwo F. asks:
Show Can cosmic rays cause us any harm?
13 Adrienne W. asks:
Show What exactly affects the cosmic ray count and is there a way it can be altered to get a higher or lower number?

Hey guys, I have a lot of catching up to do! I'll answer a bunch of good questions now.

1) Is the sun the only place where cosmic rays come from? Does the position of Earth have any effect on how many cosmic rays we receive?
No, in fact most of the cosmic rays come from deep space. We believe they are created when stars explode, and the resulting shock waves accelerates particles. The position of the earth could in principle affect the rates, but the stars are exploding in all directions throughout the universe, so the rate really does not vary, except for the particles that come from the sun.

2) My question is that why does everybody has different cosmic ray count.
Two reasons. First, the location where you are taking the measurement might affect the count rate. Concrete absorbs a lot of the CR, soe if you are near a window you might get more counts than if you are in the basement. Second, nobody should get exactly the same number of counts; that is because of statistics and the law of probability.

3) Why is the barometric pressure on weather.com never the same as the barometric pressure read in the classroom on the mmHg?
Hmmm...could be that the weather.com barometer is not close to your school. Your school barometer might be broken or out of adjustment. See if your school barometer "tracks" weather.com...that is, when weather.com goes up, does yours too?

4) Can Meteor showers,Asteroids,and Comets effect the cosmic ray counts.Why?
Nope. These object just don't emit cosmic rays. You need something with lots of energy, like a hot or exploding star.

5) Could cosmic rays be possibly harmful to humans?
Not here at sea level. Because stuff absorbs cosmic ray, so does the atmosphere. So if you go up into thin atmosphere, say on an airplane or on top of Mt Everest, you get exposed to many more rays. Scientists are not sure if that kind of exposure is harmful or not. Probably not.

6) What exactly affects the cosmic ray count and is there a way it can be altered to get a higher or lower number?
As I said above, the rays can be absorbed, so when you repeat measurements, always do it in the same spot.
Oh, and there is another thing: there are more rays coming down from above than coming sideways. So your counter will count more when it is flat than when it is on its side.

12 Dominique S. asks:
Show Could cosmic rays be possibly harmful to humans?
11 Syrena T. asks:
Show Can Meteor showers,Asteroids,and Comets effect the cosmic ray counts.Why?
10 Mariyam S. asks:
Show Why is the barometric pressure on weather.com never the same as the barometric pressure read in the classroom on the mmHg?
9 Jamika S. asks:
Show My question is that why does everybody has different cosmic ray count.
8 Rickey R. asks:
Show Is the sun the only place where cosmic rays come from? Does the position of Earth have any effect on how many cosmic rays we receive?

Dominique, Nechelle, Anthony and Ricky all asked a similar question, which I will answer here. Cosmic rays are particles streaming throughout space, so some of them hit the earth. You have probably noticed by now that you don't count as may cosmic rays if you take your counters into the basement, or to some part of the building where a lot of material is screening them out. That tells you that stuff like metal and concrete absorbs them. Well, the atmosphere and clouds are stuff too, so they absorb some too. On a very cloudy day there is water in the air, which absorbs some of the cosmic rays...but not too much. I am not sure if you can even see the effect. I am waiting for you to tell me when you present your results. The position of the sun and earth can have a small effect too, and a type of cosmic ray comes directly from the sun and is connected to sunspots.

Now, about those radio signals. You have reported that the short-wave radio signals from far-away places like australia vary in strength and come and go. This is because of particles in the atmosphere that are reflecting the radio waves causing them to bounce from the transmitter in australia to your receiver in Chicago. When there are more charged ions in the atmosphere, the signal is stronger. The UV light from the sun affects the number of ions, so that is why there is a strong day/night difference. Also, high solar activity (associated with sunspots) causes a lot of cosmic rays to hit the atmosphere and this also changes the number of ions. In fact, sometimes these "solar storms" are so bad they cause problems with regular radio communication and even have caused power outages...but this is very rare.
- Mark