Cosmic rays that arrive here on Earth are important to understand because they may teach us quite a bit about their sources in outer space. Depending on what we learn, these discoveries may lead to technological applications someday. However, cosmic rays here and now on Earth are used for a few useful or interesting purposes. For example, the carbon-14 whose concentration is measured to carbon-14 date ancient artifacts? The carbon-14 wouldn't be there if it weren't for cosmic rays.

To understand this you have to remember that you are made of the same things that the cosmic rays are -- atoms, or more accurately pieces of atoms called nuclei. A single atom can be roughly imagined as like the solar system. An atom has a small center called a nucleus with parts called electrons going around the nucleus a bit like planets going around the Sun.

We refer to it as "cosmic" because the only known source of this radiation is the early universe. It can now be firmly concluded that the CMB is the cooled remnant of the hot Big Bang itself. Light comes in a range of wavelengths, from the shortest wavelength gamma-rays to the longest wavelength radio waves, with common-or-garden visible light in the middle.

Stardust" is a word that people have been using in stories, poems, and songs for a lot longer than the modern study of stars. We have to remember that the wonder and excitement of the stories is what came first, getting people interested in knowing what the stars were actually made of. The "stardust" we collect is a dusting of microscopic particles that come streaming off the surface of a star. Scientists usually refer to these as cosmic rays.

The cosmic ray particles we are looking for are microscopic. The actual size of one of them would be about 1 billion times smaller than the width of one of your hairs. Back to Cosmic Ray Science Questions Back to Categories

The cosmic ray particles are individually very light. That's part of why you don't notice when one goes through you! How light are they? Each one is about 1,000,000,000,000,000,000,000 times lighter than a paperclip! But it is lots and lots of tiny particles like these that make up the paperclip, or your body, or the electricity flowing to your house. Back to Cosmic Ray Science Questions Back to Categories

Not this kind. A telescope lets you get a better view of things that are far away. A microscope is what you would have to use to view things that are small. BUT the cosmic ray stardust is too tiny for ordinary microscopes as well. That's why we detect the particles instead of actually seeing them. Back to Cosmic Ray Science Questions Back to Categories

Cosmic rays are not rays like sunbeams but streams of very small bits of material that come from the centers of atoms. A single atom can be roughly imagined like the solar system. An atom has a small center called a nucleus with parts called electrons going around the nucleus a bit like planets going around the Sun. When we talk about a mixture of atoms the atoms' centers are referred to in the plural and are called nuclei.

The nuclei that make up cosmic rays travel just about as fast as something can travel in nature. This is called the speed of light. This is about 186,000 miles or 300,000 kilometers in a single second. That is like traveling around the Earth seven times in about the time it takes you to blink! Back to Cosmic Ray Science Questions Back to Categories

This is a very good and deep question. One simple answer is that stars through the normal course of their life blow off nuclei through winds or by exploding. Since these nuclei are sprayed off at random in all directions some of them will, of course, fall on the Earth were we see them as stardust so the stardust has to exist.

We cannot tell if they have fallen on us because they are so small and most of the particles go right through our bodies with out us feeling a thing. That is why we need a detector to know about them. Back to Cosmic Ray Science Questions Back to Categories

No, the cosmic rays are stardust. (See Question 1 in this category.) Back to Cosmic Ray Science Questions Back to Categories

No, they won't! The Sun will eventually collapse (in several billion years), but that won't be caused by cosmic rays. The Sun's light and heat come from a nuclear fusion reaction going on in its core. Eventually the Sun will use up all its fuel for this nuclear reactor, and without the power source at its center the Sun will ultimately collapse under its own weight. But we have more pressing worries here on Earth! Back to Cosmic Ray Science Questions Back to Categories

The cosmic rays that reach us here on Earth are not harmful to our health. They have always been around throughout the history of life on Earth. However, the reason they are harmless is that we have the atmosphere above us, shielding us by taking high-energy cosmic rays and dissipating their energy in cosmic ray "showers" like the ones we study. Getting hit by many low-energy cosmic rays is harmless, while getting hit by one high-energy cosmic ray might not be.

Lots and lots! We'll get back to you if we have an estimate on this number!! Back to Cosmic Ray Science Questions Back to Categories

The study of cosmic rays involves primarily nuclear science and astronomy. In that way, it is generally considered a field of physics; in recent years, it lives within a subfield called "particle astrophysics." However, cosmic rays, their effects, and their uses also show up in other fields as varied as archaeology and medicine! Back to Cosmic Ray Science Questions Back to Categories

Cosmic rays can cause mutation. Their likelihood of doing so depends on how much energy per particle they have. The constant background "rain" of low-energy cosmic rays on Earth's surface is thought to contribute significantly to the normal rate of mutation for life on Earth. Exposure to higher-energy cosmic rays, for example, through spending time at very high altitudes or in space, can cause higher rates of mutation and potentially lead to health complications such as cancers.

There are several ways to detect cosmic rays (besides the "solid scintillator" detection method used in CHICOS). To learn the basics of several different detection methods, visit a web page provided by the cosmic ray group at the University of Leeds. Back to Detector Questions Back to Categories

The exact value can vary and depends on the energy of the cosmic rays but a typical value is a few hundred per second. You can even see this if you look at the screen of CHICOS. The detector A and B gauges show the number of hits per second. Back to Detector Questions Back to Categories

Well, we can't see the particles themselves because they are too tiny. Scientists think the particles are protons (basically round) or clumps of protons and neutrons stuck together (called atomic nuclei). We can see the blue glow in special scintillator plastic when the cosmic rays have hit. Actually near the north and south poles of the Earth, cosmic rays make colored flashes just passing through the atmosphere and the Earth's magnetic field.

Wow, about two hundred particles per second on each square meter of the Earth's surface. Now, there are 60 seconds in a minute and 60 minutes in an hour, so that would be 200x60x60=720,000 particles per hour on each square meter of the surface. Earth's surface area is about 500 trillion square meters.

A Cosmic Wimpout is an unusually fun roll that ends with a player wimping out and losing a lot of points. It usually happens after the player is forced to keep rolling by the Futtless Rule, Re-Roll Rule, or the You May Not Want To But You Must Rule. You will know when it happens by all the laughter and twisted expression on the face of the victim-player.

The short answer is no. The amount of cosmic rays is very, very, very small in comparison the with the amount of atoms in the air we inhale every day. Further, the cosmic rays are mostly made up of non-toxic nuclei so again the interference to our health is very small. The great speeds that the cosmic rays travel at can potentially interfere with our health just a little as they break apart molecules in our bodies but this does not happen by breathing it.

Each cosmic ray is an individual subatomic particle (piece of an atom). Some cosmic rays are electrons and protons. Back to Cosmic Ray Science Questions Back to Categories

Almost certainly. There will be improvements in the reliability of cosmic ray detectors, and in our ability to calibrate them. That means our ability to understand the data we take -- determining exactly how much energy a cosmic ray had, for instance, instead of being able to roughly estimate it. However, it's not clear if or when there will be any revolutionary change in the basic methods used for cosmic ray detection. Back to Cosmic Ray Science Questions Back to Categories

We think you are asking if there are any devices to use cosmic rays to drive humanly or technologically useful "energy sources," in the way that solar cells can convert the Sun's light energy into stored chemical energy useful for electricity needs. If this is the question, then... so far, no uses of this kind are in place.

Professor McKeown became interested in detecting cosmic rays because he attended talks and read journal articles in which people talked about the puzzle of ultra-high energy cosmic rays. Other members of the CHICOS collaboration, particularly at UC Irvine, have been involved in related areas of cosmic ray research for many years.

First, how far do these cosmic rays really travel? The stars themselves are very, very far away so cosmic rays must be travelling a long ways just because of that. But, they also float between the stars just like a bottle in the ocean, and can sort of surf magnetic waves between stars. If they surf enough of these waves they can pick up a lot of speed. But this may take a long time and during that time they can travel a distance even greater then the between the stars.

By looking at the CHICOS data screen at your school, you can see how many cosmic rays your detectors have measured in the last second (and at any time during the last week). We don't get the data at Caltech that quickly, though. Each CHICOS computer sends us its previous day's data in the middle of the night, so if your detectors do something strange today, we won't know about it until tomorrow morning. Back to Detector Questions Back to Categories

Since the earth is protected from cosmic rays by geomagnetism and the geomagnetism surrounding the earth has shielding power equivalent to a water wall 10 m thick, the intensity of the cosmic rays that reach the ground is very low and they do not affect human health. The living organisms on the earth have been exposed to low-level cosmic rays etc. and have evolved from a primitive unicellular organism.