The ISW mystery II: Trying to see the invisible

[Note: I'm travelling at the moment and haven't had time to write as substantial a post this time around as I'd hoped. We're all new to this blogging business, so next time I'm travelling for this long I'll plan further ahead and have the post ready in advance, or something. Anyway, enough excuses from me... I'll be back in Helsinki in a few weeks and will hopefully then be able to write something more substantial...]

In my last post I introduced something known as the integrated Sachs-Wolfe (ISW) effect. You'll probably get more out of today's post if you've read that one. However, I've tried to make today's post as self-contained as possible, so don't fret if you're new to the blog or have forgotten things over the last six weeks.

Put most simply, the ISW effect is the very subtle heating and cooling of light as it travels through structures in the universe. In the standard model for the universe's history this ISW effect grows with time and is most significant when dark energy starts to dominate the universe late in its history. The effect occurs because the energy gained or lost by light as it climbs into or falls out of structures becomes smaller with time. Therefore light receives an overall change in energy when it travels through these structures.

Unfortunately, the ISW effect is tiny. It will happen to any light travelling anywhere through the universe, but it is really, really tiny. This means that, for almost every light source in the universe (galaxies, stars, supernovae, etc), we just don't know the initial light source well enough to be able to tell if it has changed by the tiny amount we expect from the ISW effect. But, there is one source for which we have a very clear, very precise prediction. This is the cosmic microwave background, or CMB (note: I introduced the CMB in this post). As regular readers of the blog might be starting to appreciate, the CMB is more or less every cosmologist's favourite data source.

Unfortunately even the CMB has tiny fluctuations in it. These arise because the source of the CMB, a plasma of hydrogen that once permeated the entire universe, was not uniform (I explained the shape of the fluctuations in the CMB in an earlier post). And, most unfortunately, even these tiny fluctuations, fluctuations so small that Nobel prizes were awarded for their detection, are bigger approximately the same size as [Edit: 16/3/2012] the predicted size of the ISW effect. I have to admit that I find this irony amusing. The ISW effect is so small that one of the most significant measurements humanity has ever made is just annoying noise in the quest to detect it.

Alas! So it seems that we can't even see the ISW effect in the CMB?

Not quite...

Cyber Espionage

[Note from Shaun: the following is a guest post from Abdo Binmadhi. James and I both met Abdo in Oxford through the Oxford University Water Polo Club. Abdo is the most mysterious person I know. I can't tell you why he is so mysterious because he made me promise not to. The topic of this post, cyber espionage, is somewhat disconnected from the primary focus of the blog. However, given how often we all use the communication tools Abdo mentions in this post, I think it is interesting to read about (and to discuss) the ways in which they are being used by those whose intentions go beyond just communication. I must admit that I was also a little worried that posting this article might bring the Eye of Sauron down on the blog. However every piece of information Abdo has written about here is freely available elsewhere on the internet. Some of it is available only because of wikileaks, but much of it is even openly available on websites owned and operated by the companies Abdo discusses below.]

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The information and telecommunication (ICT) industry has changed the way we connect and interact with each other. In this highly competitive market companies are aggressively seeking to develop new strategies to increase their revenues.

Not everyone is aware of the degree with which these communication tools are being used for privacy control, let alone what the consequences will be. Over the last decade it has stopped being a taboo (especially after 9/11) for data filtration to be used by the Government in security regulations and by corporations to help with aggressive marketing campaigns.

This segment of the IT market, defined as cyber espionage, has proved to be lucrative. Companies of this niche market are developing software that can access information flowing across the globe. Irrespective of whether the companies are start-ups or are well established in this market, their core business is making it possible for the Government, or private firms, to retrieve and analyse various types of sensitive information from individual citizens.

The information retrieved ranges from less sensitive elements such as document IDs to much more sensitive information such as clinical files.

The following are some examples of companies inhabiting this market niche:

The War of the Immune Worlds

The previous post in this series can be found here.

Another blog post, another month when the immune war wages on inside all of us; the pathogenic siege perpetually held at bay by your tireless immune soldiers and tacticians. In my previous posts I’ve talked about the organisation of the immune system and how it makes decisions about which weapons to employ in its endless fight. We may feel blessed to have such a powerful army at our backs but we have, in fact, earned it! Not on a personal level but as a species, and as the species that preceded Homo sapiens, and those that came before them stretching back long into the depths of evolutionary history. In ‘The War of the Worlds’, H.G. Wells writes of how the Martian invaders are felled by simple infection rather than by any of Man’s weapons:

“ ...the Martians--dead!--slain by the putrefactive and disease bacteria against which their systems were unprepared; slain as the red weed was being slain; slain, after all man's devices had failed, by the humblest things that God, in his wisdom, has put upon this earth.

Tripods, perhaps, but you won't get far without T cells!

For so it had come about, as indeed I and many men might have foreseen had not terror and disaster blinded our minds. These germs of disease have taken toll of humanity since the beginning of things--taken toll of our prehuman ancestors since life began here. But by virtue of this natural selection of our kind we have developed resisting power; to no germs do we succumb without a struggle, and to many--those that cause putrefaction in dead matter, for instance--our living frames are altogether immune. ... By the toll of a billion deaths Man has bought his birthright of the Earth, and it is his against all comers; it would still be his were the Martians ten times as mighty as they are. For neither do men live nor die in vain.”

We have an immune system because we need one, in the same way we have lungs because we need them. I have mentioned briefly before how individuals unfortunate enough to suffer from any of various immune deficiencies often die early in life or are severely debilitated throughout. If, as a species, we lacked this defence, we would be as the Martians in Wells’s novel and would most likely not survive a single generation. Natural selection has rewarded those individuals with more resilient defences and punished those without. From this we have evolved the elite varied military that I have previously described. The price we have paid for this is heavy : “the toll of a billion deaths” wrote Wells. However, we cannot be complacent in our immune invulnerability – to turn to H.G. Well again:

“Yet across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this Earth with envious eyes, and slowly and surely drew their plans against us.”

The invisible made visible

Last year, I uploaded a post about the Cell Picture Show, where researchers in the visualisation of molecular biology can exhibit some of their most impressive images. This month, Science has released its equivalent in the form of its visualisation challenge. This competition has been running for 9 years, with winners and honourable mentions announced in the categories of photography, illustration, informational graphics, interactive games and video. The examples this year are well worth a look - the image above is taken from the first place entry for informational graphics, entitle The Cosmic Web by Miguel. A. Aragon-Calvo et al. It depicts the overall structure of the Universe if you could see the various levels of organisation, and comes with a handy explanation for non-cosmologists like me. I really can't do it justice with this small image, so I encourage you to go and see the original for yourself! The people's choice winner for photography is entitled The Cliff of a Two-Dimensional World by Babak Anasori et al (below). There's something about this image that I love; the deep red on blue is reminiscent of the Grand Canyon, but in fact is what you see when you image ultrathin sheets of titanium compounds under an electron microscope.

The Science website also has archived records of previous years' winners, which are also well worth a look!

Image rights belong to Science and the original authors.