A quick update. Due to some horrible time constraints caused by work; I have had to ditch S383 and just study S382 until October.
It's one of those risks that you tend to run, as a full time employee and a part-time student. It is a transient situation, which I hope will be sorted out before October comes, as I am planning in two modules then.
I decided to stick with the Astrophysics over the Cosmology, simply because it appears to me, to hold the best hope of obtaining a grade 1 pass overall. Also, it looks so damn interesting!
The only way that I could have held on to two modules this summer, would have been for me to find a way to make the rest of the world move at a velocity that was near to the speed of light, relative to my house. I might then have stood a chance of finding the time.
If anyone reading this, doesn't understand the last paragraph; I now have a book for sale, that will bring you right up to speed.
Wednesday, 6 February 2013
Friday, 1 February 2013
Checking with the OU
In the interests of good scholarship, I will remove the previous post and ask an ou tutor to check through the points made, before re-posting it with any updates.
I think that as Duncan and I have begun to debate this subject, that we may have strayed from the original premise of 'why the sun is hot' and entered into a broader discussion of how that heat is sustained over a long period.
A discussion that has opened up complexities that depend on many different factors such as mass, temperature, luminosity, etc... and one in which I am not yet qualified to argue successfully.
Anyway, I will post any update, as soon as I have approached one of the course academics.
I think that as Duncan and I have begun to debate this subject, that we may have strayed from the original premise of 'why the sun is hot' and entered into a broader discussion of how that heat is sustained over a long period.
A discussion that has opened up complexities that depend on many different factors such as mass, temperature, luminosity, etc... and one in which I am not yet qualified to argue successfully.
Anyway, I will post any update, as soon as I have approached one of the course academics.
Thursday, 31 January 2013
Wednesday, 30 January 2013
Why the Sun is Hot (spoiler alert!)
Well, I never!
I have been left slightly flabbergasted this morning, since I have just had a lifelong belief, overturned by the course notes from my course S382, Astrophysics.
What do I mean?
Well, I had always assumed, nay, believed; that the reason why the sun and other stars, are so god-damn hot, was because of all that fusion energy going on within the star. I mean, just get too close to a 1 megaton H-bomb as it detonates, and you would feel the effects of why that assumption might seem correct.
However, If one explores the equations that govern luminosity, and work out, from the proton-proton chain fusion reactions that occur at the core of the sun; you would see that for each square meter of nuclear material that is available to 'burn', it only produces approximately 300W of power per cubic metre.
The course notes use the example of imagining three 100W light bulbs in a cupboard, as an equivalent amount of energy release per unit volume.
So then, why is the sun so damn hot?
Well, it turns out that the fusion energy only really prevents the sun from collapsing in on itself uncontrollably, due to the energy released from this reaction which counters the gravitational energy from the mass of all that material.
The Sun is hot, simply because, it is so massive, that it has a mindbending amount of gravitational potential energy. As all of this mass attracts itself and causes a contraction, the gravitational potential energy, is converted to kinetic energy. And, fast moving particles, are very hot.
So, the main source of heat for all stars is caused by this conversion of energy from gravitational to kinetic. The fusion reaction energy just seems to retard the gravitational collapse.
Well, it impressed me anyway....
I have been left slightly flabbergasted this morning, since I have just had a lifelong belief, overturned by the course notes from my course S382, Astrophysics.
What do I mean?
Well, I had always assumed, nay, believed; that the reason why the sun and other stars, are so god-damn hot, was because of all that fusion energy going on within the star. I mean, just get too close to a 1 megaton H-bomb as it detonates, and you would feel the effects of why that assumption might seem correct.
However, If one explores the equations that govern luminosity, and work out, from the proton-proton chain fusion reactions that occur at the core of the sun; you would see that for each square meter of nuclear material that is available to 'burn', it only produces approximately 300W of power per cubic metre.
The course notes use the example of imagining three 100W light bulbs in a cupboard, as an equivalent amount of energy release per unit volume.
So then, why is the sun so damn hot?
Well, it turns out that the fusion energy only really prevents the sun from collapsing in on itself uncontrollably, due to the energy released from this reaction which counters the gravitational energy from the mass of all that material.
The Sun is hot, simply because, it is so massive, that it has a mindbending amount of gravitational potential energy. As all of this mass attracts itself and causes a contraction, the gravitational potential energy, is converted to kinetic energy. And, fast moving particles, are very hot.
So, the main source of heat for all stars is caused by this conversion of energy from gravitational to kinetic. The fusion reaction energy just seems to retard the gravitational collapse.
Well, it impressed me anyway....
Subscribe to:
Posts (Atom)