Thursday, 8 July 2010

Planck sees the microwave sky

As I promised you science-y things, I have decided to begin with the new release of data from the Planck telescope. Here's how this science stuff is going to work. I am picking a topic and going to give you the basic background of it. Sorry, unavoidable, but don't you think it makes the news much cooler? Any background that would be too tedious to go over, I will just put a link to some basic info on it. Feel free to click the link and learn even more! With that all out of the way, it is time for some learning! Here is the press release that this is about. It has appeared in the BBC, NYTimes and countless other sources, so you may have seen it by now. What is it about you may ask? Here we go!

The Planck telescope is a project launched last year by the European Space Agency (ESA). It was launched in May of last year to survey the Cosmic Microwave Background. What is this "Cosmic Microwave Background" you ask? Well, it's nickname is the CMB. You may have heard this before as it is a famous discovery that presents evidence of the Big Bang. It is, in fact, one of the more elegant discoveries of the 20th century. This is a funny story, so pay attention. The CMB was predicted when cosmologists. No, not people who put on makeup, those are cosmetologists, this means people who study the cosmos. Your confusion is acceptable. It's the same derivation: cosmos comes from Greek for 'beauty', or, the antithesis of chaos. Cool, right?

Okay, back to the funny story of the CMB. So, these cosmologists said that if there was a big explosion that started the universe, we should still be able to see it. This may sound weird to you, and it's even weirder to explain. Stick with me. Skip below if you want to remain ignorant of cool science, or you know it already. So, remember that the Big Bang says we all started at one point which rapidly expanded, like an explosion. Given how much stuff had to be in that single point, it must have been very very hot. Same concept as when you rub your hands together quickly and heat begins to build up. Now imagine hundreds of hands all practically in the same place rubbing against each other very fast. Lots of heat, right? Same thing happens when you have lots of particles in a tiny spot, they vibrate against each other and generate heat. Sexy, I know. We have all this heat and then it expands. The 'hands' are not touching each other anymore so the heat begins to cool off, but it does not disappear. Keeping numbers out of the story, it has been a long time since the universe started to expand. That heat, which remains in the universe, has cooled off a lot. It is predicted, given how big the universe is now, that that heat is only about 3 degrees above absolute zero. Early cosmologists gave predictions for what this temperature would be, but had not made an exact estimate.

So, the discovery. Two guys named Arno Penzias and Robert Wilson were working for Bell Labs in New Jersey. They had a supersensitive radio detector to detect extremely faint radio waves. They got rid of all the interference possible, including heat from the receiver itself. There was noise that did not go away; it was everywhere in the sky, at all times of the day and night. Their conclusion? Pigeon poop. In the dignified scientist way, they cleaned off all the excrement, but the noise remained. Penzias heard about research going on at Princeton to discover some radiation left over from the Big Bang that was suspiciously at the same wavelength as the noise they were fighting. Penzias suddenly realised what a big discovery this was and published their discovery jointly in Astrophysical Journals. The Nobel Prize for this discovery was given to them in 1978 for this discovery as it was the first definitive evidence of the Big Bang.

Right, so where are we now? PLANCK. Planck was a cool guy. He will feature this weekend here on this blog, so stay tuned for that. Until then, let us talk about his namesake, the Planck Telescope. The aforementioned heat is not perfectly uniform. Imagine a flat sheet of paper; if you were to zoom in on the paper, it would go from this:

to this:

Well, it is the same thing with the CMB. A non-sensitive telescope, similar to our eye, would just see the CMB as flat and unchanging. If we get a supersensitive telescope, we can measure all the differences. Why is this important you ask? Well, as it is in fact left over from the Big Bang, the tiny differences give hints to the exact structure of that tiny space when the universe began expanding. So, we need these supersensitive telescopes to see the differences. The Planck telescope was preceded by telescopes such as the WMAP and COBE.

Now, the first images have been released by Planck. Here it is, in all it's glory:

This image includes our own galaxy (the stripe across the middle) and some interstellar dust, which you can probably see yourself. They are going to remove the extra stuff, like the galaxy and the dust. The resulting image will look a little like this (courtesy of WMAP):

This image from WMAP shows extremely tiny changes in the CMB. Like looking really close at a piece of paper, this level of sensitivity gives clues towards the beginning of the universe. As science tends to work, we have predictions on how this should look as well as what that means. Bring it on!

Did you have fun? That's science! There will definitely be updates on this, so keep a wary eye out.

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