Cosmic Rays

The effects of cosmic rays on computer chips has been known for quite some time now. Back in the 60s when we were sending up sounding rockets to study the solar wind and the Aurora Borealis, we had to add lead shielding for some parts of the payload controllers to ward off cosmic rays. Lead shielding stops many, but not all the effects. As computer memories got denser in the 80s, it became necessary to design in error detection and correction circuitry in computers and disk drives to prevent crashes and recover from these effects.

How can distant supernovae, black holes and other cosmic events cause a desktop computer to crash? The answer is that these co-inhabitants of the universe produce cosmic rays, which produce high energy particles in the Earth's atmosphere that can occasionally hit RAM chips. The moving particles trail electrons, which can upset chips' circuits and cause errors.

By the 1990s computer density was escalating, chips' circuit features were decreasing in size, and the problem was getting serious. Computer giant IBM thoroughly investigated the problem in the mid 90s, testing nearly 1,000 memory devices at sea level, in mountains and in caves. They showed that at higher altitude, more soft errors occurred, while in the caves there were nearly none. That proved cosmic rays were to blame. In 1996 IBM estimated you would see one error a month for every 256MB of RAM.

Now comes Intel, who in December received a patent for on-chip cosmic ray detection. Intel thinks we may still be living on borrowed time:

"Cosmic ray induced computer crashes have occurred and are expected to increase with frequency as devices (for example, transistors) decrease in size in chips. This problem is projected to become a major limiter of computer reliability in the next decade. "

Their patent has chips with built-in cosmic ray detectors, which they conclude may be the best option. The detector would detect cosmic ray hits on nearby circuits, or directly on the detector itself.

When triggered, it could activate error-checking circuits that refresh the nearby memory, repeat the most recent actions, or ask for the last message from outside circuits to be sent again. Similar to what we did with our primitive electronics we flew on cheap college sounding rocket experiments. You detect a probable error, just drop the acknowledge(ACK) and ask for a repeat. Things moved much slower then so the time taken was not a big deal.

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Not only can cosmic rays upset chips in computers, there is the issue of cosmic rays upsetting the Earth's climate. The German team, from the Max Planck Institute of Nuclear Physics in Heidelberg, used a large ion mass spectrometer mounted on an aircraft.

German scientists have found a significant piece of evidence linking cosmic rays to climate change.

They have detected charged particle clusters in the lower atmosphere that were probably caused by the space radiation.

They say the clusters can lead to the condensed nuclei which form into dense clouds.

Clouds play a major, but as yet not fully understood, role in the dynamics of the climate, with some types acting to cool the planet and others warming it up.

The amount of cosmic rays reaching Earth is largely controlled by the Sun, and many solar scientists believe the star's indirect influence on Earth's global climate has been underestimated.

Some think a significant part of the global warming recorded in 20th Century may in fact have its origin in changes in solar activity - not just in the increase in fossil-fuel-produced greenhouse gases.

Just when you thought it was safe to blame CO2, some scientists upset the apple cart.

Missing link

Research published last August(2002) suggested the rays might cause changes in cloud cover which could explain the temperature conundrum.

The discrepancy in temperatures has led some scientists to argue that the case for human-induced climate change is weak, because our influence should presumably show a uniform temperature rise from the surface up through the atmosphere.

Although researchers have proposed that changes in cloud cover could help to explain the discrepancy, none had been able to account for the varying heat profiles.

But the study suggested that cosmic rays, tiny charged particles which bombard all planets with varying frequency depending on solar wind intensity, could be the missing link.

It appears to work like this, the solar wind is normally strong enough to essentially "blow away" the cosmic rays before they impact the Earth's atmosphere. One theory has it, that periods of low solar activity, primarily gauged by sunspot numbers, allows larger numbers of cloud forming cosmic rays to impact the Earth's atmosphere, forming clouds. Clouds reflect light, so this lowers the amount of heat from the sun that eventually warms Earth. The solar wind acts as sort of an umbrella, shielding Earth from the cosmic rays. When the shield is down, the cosmic rays come and the Earth cools. Like what is happening today. Not yet conclusion, but there is as much if not more evidence that this effect has more to do with Earth's climate, hot and cold, than does CO2. An interesting theory ... I doubt funding will be fourth coming to study the effect in more detail.

Cosmic rays, born of exploding stars, you will be hearing more about them in the near future -- The Great Observatories were there watching, observing, increasing man's knowledge of the universe at rates never seen before. First there was the Hubble Space Telescope, then there was the Compton Gamma Ray Observatory, and lastly there was the Chandra X-Ray Observatory. In 2000 Compton was de-orbited and burned up in the atmosphere, it was replaced by the SWIFT Observatory in 2004, which has similar observation characteristics.

The Earth's cliamte has changed before, repeatedly, long before man, something caused the Earth's climate to alternately switch between ice age snowball and temperate warm. I wonder what caused it.