Sun Quakes and Solar Structure

Posted February 5th, 2009 by admin

I had another really engaging lecture last year at uni – one that had me salivating for more and which has probably resulted in me alienating myself from the rest of the MRes group. The lecture was by Vincent Tong who it turns out has been at Imperial where I studied as an Undergraduate!

First off we had to think about what our goal was, what were we actually trying to acheive – to see inside the Earth of other body and see of what and how it is made. Then with lots of analogies which steadily become more rediculous as the lecture went on. We then decided we couldn’t break the Earth (or Sun) open like an egg to see its internal structure but had to view it as a presant and shake it to see whats inside.

The shaking equals eathquakes and these we record and measure. We had a quick run through of wave types which was cool as I found I had forgotten one of them! I ended up having to answer why s-waves which can’t travel through liquid are improtant along with many other things – I don’t know if they others were just being shy. I found I had remembered alot of stuff and to my suprise I am finding it far easier to infer things from information I am given than I used to.

I did find the periods of time when we were working with each other to work stuff out frustrating as everyone else just kept saying they didn’t understand (bar the guy at the front who kept asking really really techniqual questions about the software used). We ran through the standard this is how you look at the inner earth but then looked at the fact that the velocity of the earthquake waves are dependent on direction and temperature and their interactions with faults and other subsurface structures.

This was interesting as I discovered you can basically use the arrival times of the waves to work out the velcocity of the waves which is temperature dependent – meaning that you can tell if it has had to pass through realitively hot or cold areas. If you then have sequences of these you can see how they change – meaning you’ve added time and can see how things are moving or flowing – this is so useful I can not even begin to tell you.

The implications to my mind are stagering and I thought seismics where boring! We ran through (quickly) how imaging of sections works – these are generally done by man made seismic waves (big thumping lorries or air guns at sea). Now most of the siesmic sections I looked at during my undergraduate (if not all) were of reflected waves that were bouncing off of say bedding plans and the such like. But now there is this thing called Tomography which (I think) involves refracted waves – so these are waves that travel through the rock and are slowed down by different substances etc… sort of a minni version of how we use earthquake waves.

I think it is a method stolen from medical imaging but I am not sure. This again opens a whole new world and means you can see things that are not picked up by the reflective waves. There was somehting involwing time and depths and seeing flow rates again with this but I need to look that up some more. We also looked at the restrictions off all of this – basically we could really do with a global network of siesmometers and though we are getting there – most of the planet is covered in water – I suggested that they could put the detectors along the cable trunks that carry say the internet – this apparently has already been done. Plus they have detectors that onces having detected an earthquake bobb back to the surface adn tell the sattalites what they heard – I personally wondered what sort of fail rate they have for such instramentation.

I guessed correctly that time would be involved and the problems of refernce and angle etc… which I was impressed with myself for. Also another problem is that the earthquakes on the earth are not actually evenly spread out – they are concentrated along the plate boundaries and the such like giving certain biases to what we are finding out. Then the earthquakes are intermittent and we have no idea what strength they will be etc… meaning that it is quite – if not not impossible – to correlate the data.

Oh – one of things was that the waves travel faster along faults that are parralel to the direction of motion and go slower through ones that are perpendicular. And this effect is sort of amplyfied if there are say lots of parrellel fualts such as along the mid ocean ridges. Measuring flow there is quiet important as there is hydrothermal perculation and stuff through the newely formed sea floor as it is hot and stuff – this affects mineral exchange and the such like. But during the working things out time he gave us I came up with the concept of using the earthquakes to tell if you where in a back arc basin, or near an accretionary prism, ie looking at the big big structures as they have different minerals and things in them (stolen straight from Wednesdays lecture).

The girl I was sitting with said she had thought the same thing – the lecturer said we were coming up with good ideas. Later on he said I was asking the right sort of questions too – though as the lecture ended up over running what with me getting excited over the way in which the earth or spheres in general can distort with motions and the like (yes I asked more questions) I think the rest of the class where about to kill me.

We got on to the heliosiesmics and wow! I think i actually got how they are detecting the sun-quakes. Now on the earth we have seismometers on the surface but the sun is a) humungous and b) too far a way and c) uber hot. But we have images in all sorts of wave lengths and the suns surface is in continous motion. The sun is a plasma which moves as a fluid and you can see the convection cells on the surface.

You can take images and see how they change – think about it – surface that is further away from you such as that in a trough or valley (earthquakes are waves with peaks and troughs) will have a slight red shift to it as the wave gets stretched on route were as the peaks will be like mountains and nearer the earth or satallite depending were the detector is and be blue shifted compared to the base level surface colour (we are assuming constaint composition of the sun here.

This is cool as you can basically do the tomography tequnic and look at flow! We also looked at solar flares and sunspots which has me a bit disturbed – is it me or does the behavour of sunspots becoming solar flares seem to suggest that the sunspots individually are magnetic poles? But that would make them a magnetic monopole which I thought could not exist?

Am I missing something here?

Lunar Excitement!

Posted February 2nd, 2009 by admin

After my dissapointment I had what was potentially another disappointment – I was informed that it wouldn’t be ok for two students to do the same project but then she said she might be able to do something that was more along my interests.

So I sent off an email about micro-organism colonisation of impact rocks which is what I was doing last time I did this course – before I was sick – I also mentioned that I had been classifiying meteorites at the Natural History Mueseum – though this is now so long ago I doubt I can remember anything other than what sulphides verses sulphates look like under reflected light microscopy.

Then came the response that I could have a piece of Katie Joy’s lunar meteorite!!!!! Woooow!!!!

A piece of the moon!!!! It’s a NASA sample and everything – I just really can’t believe this oppurtunity!

I am very very excited about this plus nervous as I know very little about the moon – other than what I learnt whilst writting an essay on Lunar formation last term!

Cosmogenic Nuclides and Dating

Posted January 29th, 2009 by admin

Last year I had really interesting lecture on this topic – this post is an altered version of what appears over on Snell-Pym– at first I thought I was going mad as it seemed to me that I had remembered fission track stuff incorrectly from my undergraduate but no it is a similar related technic and when i asked about it Peter Vermeesh said said I was trying to jump straight to the more advance applications of the subject. I have to confess I was eeek maths, difficult panic and when he stopped for the break and asked if anyone had any questions we all said no and then me and two others dashed out to get a cup of ‘tea’ which actually involved bitting knuckles and looking at each other in dispair and asking if the other two had understood – we all shook our heads and started stressing. But…. the lecture had followed us out and had a)over heard us and b) had realised he’d lost the class – he’d said it happens to him as well – infact it had happened to him at the Tuesday Seminar the night before!

We said we thought we got the concept but it was the equations that were scaring us – then he said there was only one little bit of maths – we looked at him increduosly. But I then had a cool disgussion with him about fission tracks. I can not find wikipedia link on either of these two concepts/techniques as the pages do not exist yet – ok gosmogenic nuclids are like highly charged particals from like cosmic rays – hmmm…. ok I’ll just delve into the notes I made and hope that they make scense! There are two types of cosmic rays – GCR (Galatic Cosmic Rays) which are highly energetic and come from super novas, the others are solar rays. The GCR are 38% something I’ve written as +P which will either be protons or positrons (but I normally write these as +e) or a cation of P(but I feel this option unlickely if anyone knows let me know!), they are also 3% electrons.

Now apparently the amount of energy in these +P is alot – they travel at near the speed of light and form black wholes in our upper atmosphere all the time – I think I want to see more evidence for that particular claim personally! These cosmic rays are deflected by the earths magnetic field and due to how the feild forms there is more protection/sheilding at the equators that there is at the poles – at the poles the low energy solar cosmic rays can sneak in giving us the aurora.

Even with the high energy particles there is a defernce in how many of the rays/particles can crash into the ground giving us somehting to count – this gives us geomagnetic latitudes with the effects. Just help make things more complicated there are secondary particles produced when a +P enters our atmosphere ie it hits/collids with oxygen, nitrogen molecules and the atom they hit sort of explodes into a host of secondary particles – this is called spillation (sigh there is no wikipedia article on this either ūüôĀ ) So from these collisions in the atmosphere we now have nuetrons,protons, alpha particles and many more – these are secondary cosmic rays and you get a comic ray cascade – sort of the priamid selling of the sub-atomic particle world.

There is a big increase in the number of nuetrons as they are the most abundent secondary particle. Of cource the secopndary particles hit other molecules and atoms in the atmosphere and so the cascade propogates through the atmosphere but the energy of the origonal cosmic ray is being spread out and there is a corrasponding – and basically exponential decrease in the energy.

This means that not many of the cosmogenic nuclids actually hit the ground – those that hit the ground are called in-situ and until recently (the 1980’s) these could not be measured! Anyway new elements are made in this way – now 99% of those will be useless for dating rocks as there will be so much of that element around on the earth you can not detect the new from old! This means we need the rarer elements and then there is all complexiaty with the expected amounts of that element in a sample and the actual amount then there is weather they are radio active etc… Then there is the fact that the cosmic rays only penitrate the very surface rocks – this is actually cool as it gives you burial and erosion rates. We ploted a graph which looks at the rates of burial and exposure – when done on a log scale it is known as the Banana Plot! (no wikipedia again :'( ) this is becuase it looks like a banana!

Anyway I got very excited about the applications of this and asked about the nuclear disastor/test factor and think I might have agreed to look for a cesium spike in one of my milk teeth – though I did get a bit too excited and started on about brizil nuts affecting the results – not sure what I was going on about there! Still I also asked about extraterrestrial material and therefore made the class late leaving yet again! But this was sooooo interesting – becuase in space there is no or little shielding the rate of rays hitting the surface is higher and you can therefore get a ‘burial’ age for say a meteorite which has landed on the earth due to the atmophere stopping most of the cosmic rays! – now this is info I can use!

Oh and I got told off for trying to solve an equation – I didn’t initially know what I was doing with the ploting of the graph – as always I thought he was asking for somehting much harder than what he actually wanted – I am awear that this is a really really bad explanation of this subject but I’m still sorting it out in my own head :/

A Lunar Disappointment

Posted January 26th, 2009 by admin

I had been umming and ahing about which project to choose for my MRes minni project. There was only one planetary option which involves re-calibrated data from Clementine and one of the other students is planetary and not even geology so it really is the only project she can do.

I checked that you were allowed more than one person on each project but was in two minds anyway – there was a microprobe project that sounded fun – the technique was the sort of thing I want to learn were as the clementine stuff seemed to just be being a data monkey, but the microprobe one was on volcanic rocks and I felt I should really be doing something planetary based.

Anyway the other girl went to see the lecture first and then I went along – we were told to sort out our projects after christmas and this was our first lecture back. So I was not expected to be told off for not having sorted it out weeks back and to be told no I couldn’t do it.

Ashamdely I was actually fighting tears when I returned to the classroom for our lecture. I told the others what had happened and the other girl said he’d told her off too and she was really worried she’d destroyed my chances of doing a descent project.

I then explained that I had another project I could do – one of the other students then came in and said that he couldn’t do his first choice and so was going for the one I had as my back up – eeek!

Again we checked that two people could do the project so now we are awaiting the return of the lecturer who’s project it is.

UFO

Posted January 22nd, 2009 by admin

On the 9th of Febuary 2008 at approximatly 6:30 pm I spotted a strange fast and smooth moving star heading from approximatly west to east does anybody know what this was?

I was wondering if it was some satallite or the International Space Station etc… It looked very much like when we saw the space shuttle catching up with it last year

I origonally posted this on Snell-Pym¬†but no one ever responded and it’s still bugging me!

Showing the Stars to a 3 yr Old

Posted January 21st, 2009 by admin

Me and my husband run a scout and cub group respectivily and this means we are coming home around 9 o’clock on Wednesdays, we live in the middle of no were and have nice dark clear skies.

Tonight was a buetifully clear night and I took the oppertunity to show my little girl some constellations. We only did this for about ten minutes and only covered five constellations before she said she was cold and we went in for hot chocolate and bed – but I feel it is a beginning.

She is already really interested in the moon and the first scout camp she went on was our space camp though that was when she could bearly walk!

I myself am not really an astronomer and as such find myself learning lots of fun things the more I do with the kids.

Launch Conference

Posted January 15th, 2009 by admin

Today see’s the opening event of the International Year of Astronomy – the Launch Conference in France. ¬†It is unfortunatly invite only – I wish I was there basically – I haven’t been to any confernces since the EANA 04 at the OU.

The talks look interesting but I couldn’t find anything about media coverage.

But what I did find was a whole array of web resources such as Arena, which stands for¬†Antarctic Research, a European Network for Astrophysics. ¬†I shall be adding these to the blog roll ūüôā

Structure of Posts

Posted January 8th, 2009 by admin

Ok the plan with this blog is that I am going to write little ‘articles’ on things I find interesting – they may be lectures I’ve been to in the past and may be present in some form on my personal blog. ¬†Or I may just be bringing your attention to some space orientated craft project I have taken part in. ¬†Or it may just be something interesting I find out!

I hope to post whats coming up event wise both here on Earth and in the vualt of heaven and also my experiences of actual observations etc… but these will be posted when they happen and so will not be so periodic. ¬†This means I hope to produce one post at least a week!

The other issue is that I am dyslexic and though I shall be making an effort I am positive that some errors will slip in – please feel free to let me know.

Happy New Year of Astronomy!

Posted January 1st, 2009 by admin

2009 is the International Year of Astronomy, so I thought it was time to start getting into this old interest РI did try last year but we were having our house re-done after the floods the previous year, plus there has been some major domestic reshuffling due to the older members of our family becoming sick and the like.  If your interested in that sort of mundane thing then it can all be read at Snell-Pym, a blog I share with my husband.

Last year I attempted to see lunar eclipse and stayed up half the night making a hook rug but it annoyingly clouded over about an half an hour before hand.  That and doing the astronomy badge and astronautics badge withmy Scout group was as far as I got.

This year has to be different, not only becuase it is a big year for the subject itself but becuase I have returned part time to my studies. ¬†I’m nornamlly a web-consultant¬†but am doing a MRes (Masters of Research) at Birkbeck College. ¬†This were I have to appologise for calling the blog Astronomy – you may have noticed the Geology-Rocks part after it?

Well I AM A GEOLOGIST and all this space stuff why its all just another branch of geology and so I will probably have a slightly different take on things compared to other star gazers. ¬†My life ambitions lerk somewhere in the hazy zone that is Astrobiology and that is what I want to be when I grow up – I also wish to share the wonders of science with everybody but I probably shouldn’t start writing about that here.

I am looking forward to writing this blog – even if it descends into planetary science rather than pure star-gazing – face it thats what is going to happen!

I shall go and find some interesting things to write about and hopefully an astronomy society to join!  So see you soon!

The Dawn of 2009 is being started with an observation of the sun – this afternoon! ¬†Hopefully there will be people with telescopes outside in public areas so that anyone can have a go! ¬†I’m hoping to pop along to the South Kensington in the hope that Imperial College still has an Astro-soc. ¬†One thing I will say about this though is that veiwing the sun can be dangerous so I wouldn’t attempt it on my own – find someone who knows what they are doing – alternatively just look stuff up on the SOHO¬†website.