Posts Tagged‘radiation’

Seeing the Invisible, Radiation Peppered World We Live in.

There’s a lot more to the world we live in that what we can see with our eyes. The colours of the world that we see are merely a subset of the wide spectrum of available light, one that extends out in both directions in an infinite expanse of wavelengths. Beyond that there are countless other things happening around us which eyes simply can’t perceive, that is until we construct something that allows us to see the world that’s invisible to us. One such device is called a Cloud Chamber which allows us to see the streams of ionizing radiation that permeate throughout our world. The video below is probably the best example I’ve seen of one and it makes for some extremely soothing viewing:

It’s striking to see the chamber light up constantly with just the background radiation that’s ever present here on earth. Even if you’re familiar with the idea of the  world having a constant source of radioactivity it’s still another thing to see it in action, the ionizing particles whizzing through the space at an incredibly rapid pace. Adding in a radioactive source is a great way to visualize what radioactive decay is and how various materials decay at different rates and in different ways.

Cloud Chambers played an important role in the early days of particle physics with the discovery of the positron (the anti-electron) and the muon. There have been numerous improvements to the devices in the time since they were first used with the modern day equivalents being solid state devices, typically cooled to cryogenic temperatures. Unfortunately the modern versions don’t provide as good of a show as their historic counterparts did but we’re able to do much better science with them than we ever were with a cloud chamber.

Solar Flares, Northern Lights and the Luck of Apollo.

Solar flares are one of those well understood phenomena that still manage to inspire all sorts of crazy ideas in people. Whilst many of them never make it past most people’s bullshit detectors there are still those out there that believe that at the end of 2012 a massive solar flare will cause all sorts of trouble on Earth. Of course we know that’s not the case as Earth has been bombarded by these flares for millennia with no such effect being observed. Still whilst solar flares might not be the death of us all they’re still quite interesting and can have quite an impact with our life here on earth.

The most known solar flare related phenomena would be the Aurora Borealis(and the less known but identical Aurora Australis). These are those ghostly lights than can be seen within a certain range in the Arctic and Antarctic regions of our world and come in a wide variety of colours. The lights are caused by charged particles from the sun slamming into the various components of our upper atmosphere causing them to become highly energetic. In order to release this energy they emit photons of light and depending on what the charged particles hit the colors produced will change.

Solar flares are also responsible for wrecking havok with satellites and sometimes even directly with devices here on earth. The events are quite rare however and designing systems with protection against them is usually not cost effective. Most satellites are built with enough shielding and redundancy that they’re only temporarily blinded and similarly earth based systems are usually only affected whilst the flare passes.

Earth is actually quite well protected from these energetic particles by our large magnetic field. However the field is distorted by the constant bombardment of solar particles, stretching it out into an elongated tear drop shape around the earth. Solar flares stretch the magnetic field even further and eventually the magnetic loop breaks, snapping back and draging the energetic solar particles with it. This protective barrier doesn’t extend very far past earth however and that poses risks not only to our satellites out in space, but also to our brave space explorers.

Space is a dangerous place at the best of times but there some areas that are safer than others. For nearly all of space history all our astronauts have been sent into Low Earth Orbit (LEO). There are two distinct advantages to this, the first being that it requires quite a lot less energy to achieve LEO than any other orbit. The second is that this orbit sits them comfortably within earth’s magnetosphere significantly reducing the amount of shielding required on the spacecraft, although most modern craft are quite well shielded despite this. Back in the heydays of the Apollo program however the vehicles that took our astronauts to the moon and back weren’t so quite well guarded and this could have led to disaster.

You see beyond the protection of Earth’s magnetosphere any craft and it’s occupying astronauts would be laid bare to the full fury of the sun’s wrath. This poses a significant risk as the sun is quite capable of delivering a fatal dose of radiation in some of its more extreme moments. Luckily for the the only astronauts to ever leave earth’s protective sphere no events ever occurred during their missions to and from our celestial sister. Had any of them been on a moonwalk or EVA during such an event the consequences would have been quite dire as whilst the spacesuits might protect astronauts from the hard vacuum of space they do little to stop the radiation. Fortunately the space craft that brought them there would’ve been sufficient shields to reduce the lethal dose to something more manageable, but it wouldn’t be a pleasant experience.

Solar flares are one of those things that are both beautiful in sight yet terrifying in their magnitude. They are something that we will have to consider if we want to make any long journeys into our solar system or establish a permanent presence outside our earth’s protective shell. Realistically they’re just another engineering challenge that I’m sure we’ll overcome but until then I’m sure we can all enjoy a few pictures of what a flare looks in space when it strikes our atmosphere: