Jupiter facts - From the core to the cloud tops!

Hello there!

I thought I'd make this one a little fun and talk about some of the facts about Jupiter, some quick facts and a lot of information on the interior. Obviously this is something you can just Wiki, but to make it better I'll be using a rather amazing book, my own knowledge and some key sites. There is a lot here which is hard to find on the web, hopefully most of this is interesting, I'm only sorry I didn't include more...

First I think some quick facts are in order just to give you an overview!

Jupiter - quick facts

Jupiter
Credit: NASA

The main properties:

• Jupiter Mass - 1898,600,000,000,000,000,000,000,000 Kilograms                            Or... 317.83 Earth masses. Or... 1.8986 x10^27 Kg
  
• Jupiter Volume - 1431,280,000,000,000 cubic kilometres
    Or... 1321.3 Earth volumes. Or... 1.43128 x10^15 km^3
  
• Jupiter Density - 1326 Kilograms per metre cubed
    Or... 24% as dense as the Earth. Or...  1.326 x10^3 Kg/m^3
  
• Jupiter Radius (equatorial) - 71,492 Kilometres
    Or... 11.2 Earth Radii. Or... 7.149 x10^4 Km

Other important facts:

• A day on Jupiter is 9 Hours, 55minutes, 33seconds
• A year on Jupiter is 11 years, 317 days, 13 hours
• Jupiter's distance from the sun is 777,909,600 kilometres (5.2A.U.)
• Jupiter has 63 Moons: The largest 4 are Io, Europa, Ganymede and Callisto 
• Jupiter's magnetosphere is the largest in the solar system, it is approx 6.4million Km in radius (90 Jupiter radii). If it were visible, it would appear several times larger than our Moon does in the night sky.
• Jupiter's composition: 89.8% Hydrogen, 10% Helium approx.

OK so that was about as concise as I could make it. There were a lot of times when I wanted to explode with additional information; having not mentioned the history of observations and various probes that have been sent... I'll endeavour to make more posts regarding those in the future. Now for the science bit:

Jupiter's Interior

I'm going to go ahead and give a brief tour of Jupiter's guts, this shows everything:

• JUPITER'S CORE
  Going against the picture for one instance, Jupiter does in fact have a core; it isn't going to be empty space now is it? The core of Jupiter is approximately 20,000 degrees C and is cooling down at a rate of 1degrees C per 1 million years. It is also contracting under gravity at a rate of ~3cm per year. Due to the relatively warm conditions within, Jupiter's core is more likely to be liquid than solid. The pressure in this region is 40million Earth atmospheres (40million bar).
  The immense heat described above comes from the fact that Jupiter was formed from an enormous gas cloud, the gravitational energy that brought it together was and continues to be converted into heat energy. In other words, gravity gives particles kinetic energy (movement), and this is transformed into heat when particles collide - analogous to friction!
  
  
• Metallic Hydrogen Layer and magnetic field production
  Moving out to the 60,000-40,000km deep region shown on the above image the temperature reduces to 8,400 degrees C. The pressure (4million bar this time) is so enormous that the hydrogen atoms are split up into their constituent parts - Protons and Electrons.
  
  If you think back to your science classes in electricity, you will see that if you have charged particles (Electrons) moving, a current is produced. Now if you recall lessons in magnetism, you will remember that a moving current gives rise to a magnetic field. It is this vast amount of moving charge that gives rise to the largest magnetosphere (planetary magnetic field) in the solar system; Jupiter's. This layer is known as a Helium-Rich region, it contains more than the next layer...
  
  
• Molecular Region and Helium rain through the transition regionAn interesting phenomenon occurs in the transition region, recent studies show that Helium falls down into the lower Metallic region, this is known as Helium rain. It isn't exactly like normal rain, it is more like pouring a heavier liquid over a light one and seeing it seep through. 
  In the molecular region where molecules aren't destroyed by the pressure on them at this point - 20,000km ish, the pressure is 0.5 million bar and the temperature is a much cooler 5000degrees C. This region is known as a Helium-Poor region for it is losing it to lower layers by 'rain' described above.
  
  
• Jupiter's surface and atmosphere???
  I think this is a question that baffles a lot of people, I will settle this once and for all... I hope. Firstly it is best to picture Jupiter as a giant ball of liquid (because that's what it is), so in that respect it must eventually have a kind of surface, just not the type you'd want to land on! Secondly, the question is where do you draw a line, the answer is simple...instead of using Jupiter's surface, we just use our own - Jupiter's surface is defined as 'the 1 bar level' or '1 Earth atmosphere'.
  
  So the atmosphere is then everything above 1 bar just like it is for the Earth! I will briefly summarise the atmosphere because we know an awful lot more about it than anything else - it deserves several blog posts of it's own. Jupiter's atmosphere extends from the 1 bar level to about 1000km, it has a temperature ranging from approximately -200 up to 800 deg C. The interesting thing to note at this point is, this is the part we observe from the Earth, and it is found that Jupiter is giving off twice as much heat as it is receiving, nobody knows how this is happening; although it must obviously be emanating from the hot core.
  
  
  Well thank you for your interest in Jupiter to those that have read this, I partially posted this so I could reinforce my own perspective of the planet - it is important to take a step back and look at the bigger picture.
  
  See you soon!
  
  
  
  
  - Further reading if you want it:
  For general reading: this book is handy for gas giant related things.
  I used this book to check some nice facts, I recommend it for researchers, it is pretty much the only comprehensive book on the subject, and they do a grand job!

Looking at Jupiter's hot body (emissions)

Hello there, this weekend I am struggling against a migraine, so this post will have to be short; and whilst I have a window of opportunity given to me by analgesics!

So I am now 3 months and 13 days into my new career which started on the conveniently-to-remember date; 10-10-10. 

In my present work, I have been 'cleaning' spectral images of Jupiter taken in Aug 2010 from the NASA infra-red telescope facility in Hawai'i. Note that I stated 'spectral images' and not simply 'images', the difference in this case is that a spectral image is one which shows the different amounts of light intensity at different wavelengths, e.g. Red light has an intensity of 50, blue light has an intensity of 100. With this information you can find the temperature of the body that has emitted it. So my work is to find the temperature of Jupiter's upper atmosphere by analysing the spectral data of it. I will talk more about spectral images in the future, when they are cleaned and ready. For now, below shows the difference:

Jupiter; a 'normal' image. Using it's Infra-red emissions.
Note the line in the middle is the 'spectrograph'

Jupiter; a spectral image. Using Infra-red emissions.
This is from the 'spectrograph' shown in the 'normal' image, each line from left to right in this image represents a different intensity of emission from Jupiter at different wavelengths, but all on the same one line seen on the 'normal' image. I'll go over this again in detail some day...!

So what do I mean by cleaning? Intuitively, cleaning these images means getting rid of dirt, in this case the dirt is in the form of sky emissions, cosmic rays and 'background noise'. I will talk about these below:

• Sky emission? The telescope pointed at Jupiter to record it in the infra-red (IR) region, unfortunately, the telescope is peering through the Earth's atmospheric medium, which has it's own IR emissions - so the telescope takes a picture of Jupiter, denoted A and then a picture of our own sky, denoted B and by subtracting B from A in a process called 'A B subtraction' the unwanted emissions are cleaned away.
• Cosmic Rays? These are essentially high energy particles from space, such as protons and electrons, when one of these bad boys enters the CCD lens of the camera behind the telescope, a bright flash is recorded - which looks not disimilar to a star.
• Other background noise includes IR emission by the equipment on the telescope, this is mostly removed by super-cooling  the equipment with liquid nitrogen, so that it does not radiate. The CCD lens on the camera is never 100% accurate either, some parts of the lens will record better than others, to get around this a process of flat-fielding is performed. Flat-fielding involves perfectly illuminating the CCD lens and taking an image, then it can be seen which bits aren't picking up the light as well as others. This becomes rather a complicated procedure so I won't go into it now, but it is worth mentioning that this is one of the most difficult noises to get rid of, e.g. if a pixel isn't picking up anything at all, information is permanently lost and you can never know what was there!

So maybe this wasn't as short as I thought it'd be! Thanks for reading, sorry if it is confusing - feel free to ask questions or correct me if I'm wrong ;-)

James

In the news (I)

Good evening folks.

In this post I thought I'd commentate on a couple of articles that are space-science related in the news this month. There appears to be a lot going on lately, whether this be that I am more frequently checking or that there is actually more activity I don't know - anyway here goes!


EXOPLANETS!  --planets outside our solar system--
This is big interest of mine and certainly a hot topic in astrophysics, at the time of writing, 518 planets have been discovered outside of our solar system. The significant thing about these this month is that rather a small rocky one has been found, I say small, it is still 40% more massive than the Earth. This is the first exoplanet to be discovered that is composed of a rocky material (all others being large gas giants), like our very own Solar system's inner planets, however due to it being a mere 1.8 million miles away from it's star - the rocky material that composes it is certainly in a molten liquid state.

Kepler-10b, artists impression
Credit: NASA

Most of the planets discovered so far have been far greater mass than Earth and are usually far larger than our largest neighbour Jupiter. Without getting technical, these planets are spotted because they make their parent star move due to gravity, this movement is for shorthand referred to as a star 'wobble'. The bigger the planet or the closer the planet to the star, the larger the wobble; this is why mainly huge planets are found first.

This news obviously shows progress is being made in finding smaller planets, but as for a planet that really is  Earth-like, I.e. being far enough from it's parent star to be fairly cool, I doubt this will occur this year. My reasoning for this is simply that it took 8 months to detect this one, and it had the advantage (in terms of being detectable) of being 20 times closer to it's star then Mercury is to our Sun! Still, it is still fantastic to hear about the various combinations of planets that are out there.



The problem with Astrology
I must admit, this next piece of news made me laugh. I will post the video below first for your perusal.


Credit: BBC

So, Astrology has been around since ancient times in various forms. Generally it is the belief that the bodies of our solar system and galaxy that we can see, can be used to obtain information about ourselves. Lately this is in the form of star signs, telling you how your day will be and maybe even your future.

Astrology, along with palm reading, Scientology and Go Compare adverts, make up a high percentage of my pet hates. The position of Saturn in relation to the Sun has about as much effect on your day as the position of  the clothes in your wardrobe, in fact; the latter has significantly more to do with your day. [Rant over].

The funny thing about this video is that the only science that this pseudo-science is based upon has turned out to be wrong, for thousands of years - it was formerly based around a different North star. Now the genuine followers of Astrology are panicking because they have been living in the wrong star sign, due to using two different North Stars. Guess they didn't see that coming...



European Space Agency (ESA) - Rivalling NASA
So finally I quickly wanted to show people this image:

ESA's space sport in French Guiana

Whilst I'm a scientist in the field of space physics, I was blissfully unaware that Europe was such a big contender, above shows the European space-port in French Guiana (N.E. of S.America). This seems almost science-fiction, it is a shame to see this kind of place doesn't make the news quite as much as NASA.

If you live in the UK, in 2009 the government paid  ESA approx. €254 million. So it would interest people to see how their money is spent. Since it's creation in 1975, it has sent over 200 rockets into space. ESA has dubbed 2011 'The year of rockets' for Europe, with as many as one per month going up (that's almost as many as Heathrow in a cold December!). So it is exciting times ahead.


I'm going to leave it at that tonight, see you soon!
James

The first three months (PhD life I)

Hello there! This post will talk a little about the first three months of my PhD, this could prove useful for people thinking about starting a PhD.

Towards the end of my degree in "Physics with planetary and space science" at Aberystwyth University, I applied to Leicester University to do a PhD. When I heard that a place was awarded to me, a sudden sense of worry appeared, worry that I hadn't felt since the first year of degree level physics.

You find in asking ex-supervisors and current/past PhD students, that this is a perfectly normal state of mind; they all say you feel very stupid for the first year. It is my pleasure to confirm that this (at least so far) is true.

The stupid-feeling, is derived not just from having to learn incredible amounts more or learning complex new techniques. The main reason is that you've just come from being in the comforting state of mind where you feel you know your subject well, only to suddenly find that every tiny piece of your subject is a subject in itself. The analogy 'big fish in a small sea' to 'small fish in a huge sea' has never applied so well!



Below is a list of some of the things I've got up to, with a brief description. (You will find that I like to write lists in my blog, they are often a much better way to disseminate information than a sentence - when there is a lot to say).

1. Seminars! This has been an eye opener, roughly once every three weeks we have a visiting researcher from another university to give a talk, they specialise in similar work to ours. It has been great to hear what they have to say in their seminars, although I only understand a small amount of their talk, I feel much is learnt each time. Plus every time one comes, our whole group has a curry and a beer with them...
   
2. Conferences! I've been to two conferences which have both been held at the Royal Astronomical Society (RAS), London. Essentially these appear to be similar to seminars, but with about fifteen speakers and chances to mingle in-between talks. These are great for seeing the latest research in your field, being on the frontier of science is a humbling experience. This has also been a good chance to meet people that do similar work to myself, I endeavour to get them following my blog!
   
3. Work!? I suppose I'd better say something about the work I've done, less my supervisor reads this and thinks my time is spent waiting for curries, beer and packing for trips to London. The main challenge in my PhD thus far has been programming, it has also simultaneously been the most rewarding.
   My first task was to arrange image files taken at the NASA Infra-Red Telescope Facility (IRTF) in Hawai'i. These were images of Jupiter taken in the Infra-Red band, it was my job to arrange these in order of their longitude, by which I mean; if you had images of Earth rotating - you would want it to rotate in the order the Earth does and not be centered on France in one frame and then suddenly India in the next. Below is a movie of this:
   
   

Jupiter through the IRTF, Hawai'i. 

A mini-conclusion to this PhD life post would be to say, I am really enjoying it, there isn't anything else I'd rather be doing. It is rewarding, interesting and let's face it - cool!


Thanks for reading, my next blog will appear within the next 10 days.
James