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# SionR25

Members

174

1. ## Deriving Lorentz Factor

Yes, I should have put that in. I could get how to do the rest of the steps of it, just not that first bit . Sion
2. ## Deriving Lorentz Factor

Thanks for that, thought it might be something simple but just had a mental block . Sion Edit: I actually feel a bit stupid now , such a simple thing
3. ## Deriving Lorentz Factor

Hi everyone, As something to put down on my personal statement for university I have been reading why does E=mc2 by Brian Cox and Jeff Forshaw. It is a great book but the problem is they do not go into the maths very much and merely state and equation and you have to take it as it is. I usually don't have problem with it as I can see where the equation has come from and can derive it from that but I can't for the life of me derive the Lorentz factor. I will try and describe the situation. It is using a moving train and a light clock. Train moves at speed=v and time=T. So, if you imagine a right angled triangle, the base is vT. The height is classed as 1 to keep it simpler. The hypotenuse is classed cT (c=speed of light). Using Pythagoras you get (cT)2=12+(vT)2, that bit is fine, nice and simple . That bit is fine but then it just says that using complex maths you arrive at the equation T2=1/(c2-v2). I just can't see how it gets to this point so does anybody mind explaining it ? Sion
4. ## Physics at University

Thanks for that, didn't know that before hand. Will look into it. Sion
5. ## Physics at University

I am predicted A* A* A A but I think because I didn't take further maths A-level it will be seen as a disadvantage, despite the grades. Thanks again for the help , Sion Edit: The subjects I am taking are Physics, Maths, Chemistry and Geography (grades in that order).
6. ## Mass has Wavelength?

Yes, we used an example of electrons and determined their wavelength but didn't finish completely, I believe the next stage is to compare it with Muon and Tau particles. Sion
7. ## Physics at University

Thanks for the reply Chris, I do really enjoy physics and am quite a good mathematician, took maths and Advanced Maths at GCSE and taking Maths at A level. I wasn't thinking of going to Oxford or Cambridge because I think the competition would be too great and could be a wasted University choice. One of my choices is St Andrews due to the big telescopes they have and their search for exoplanets and another choice was Surrey due to the spacestation, albeit a small one , they have there. Not completely decided on other choices so will look into the Red brick ones . Sion
8. ## Mass has Wavelength?

Today in PH4 physics (A-Level) we were told that mass has a wavelength and asked to show that it does. We started from E=hc/lambda then progressed to E=mc^2 and interchanged the two to show that mass can have a wavelength. Does this then mean that mass also has a frequency at a certain speed (c=f*lambda ... f=c/lambda)? We don't really go into too much depth in class, only what is needed on syllabus. Sion
9. ## Universe

The universe isn't expanding into anything, if we believe it is infinitely big, but the space between things in the universe is getting larger, even though they are staying in the same place. The best description I heard was that it is like baking something from dough that had raisins in. Each raisin doesn't move but as it is getting baked the dough itself is expanding so the space between the raisins is increasing. If you want to believe that the universe is finitely big then we cannot say what the universe is expanding into because we are in the universe, the same way we don't know exactly how many arms the milky way has because we are part of it and cannot see 'through' it. HTH, Sion
10. ## Universe

Ok, thanks for that, it was just something I was told in a physics lesson a year or to ago: you could never reach an 'end' to our universe, no matter how fast you were travelling, so eventually you would come back to the same place so I presumed it was round . Sion
11. ## Universe

I think it is, or at least in the way if you could shoot off in one direction at enough speed and travel for long enough you will not ever get to an 'edge' of the universe but will eventually arrive back at the same place. Sion
12. ## Physics at University

Hi everyone, I am in my first year of A level, just finished my AS exams and am soon to be making my university application. From the title you may be able to guess I am going for a physics degree , I will hopefully be doing the four years masters course and then, depending on economy/job availability I may stay on to get a PhD. Just wondering has anyone else done physics at university and how did you find it? Also, which university did you go to and how did you find it? Sion P.S. Hope I put this in right section
13. ## What eyepieces to stay away from?

Both eyepieces have arrived today, excellent service as usual from FLO and Alan at Skys the limit. Hopefully will post a first light report/review soon . Sion
14. ## GCSE Astronomy

Just found this http://www.edexcel.com/migrationdocuments/GCSE%20New%20GCSE/GCSE_Astronomy_Spec_2012.pdf from page 11 it details what will be taught. Thought it might be useful so you know roughly the level and content of GCSE courses. Sion
15. ## Improving My Scope

The sticky pad would hold the baseplate on permanently but the Telrad itself can then be removed. You can buy other baseplates to but the Telrad on different scopes. Sion
16. ## Improving My Scope

It attaches via a baseplate which you can stick onto your scope with sticky pads, which I think are included, or some people use cable ties. You can put it next to the finder included and use both, or, remove the finder included and stick the Telrad where the finder was, whichever you find easier to use. Just a note though, the Telrads have quite a long waiting list due to demand so it could be best getting in an order early . Sion
17. ## Improving My Scope

I have just started getting eyepieces for my 200p and I am getting a 6mm to give 200x, a 12mm to give 100x (don't rally like using a barlow, brings eyepiece to high for comfortable sitting viewing ). I also want to get an 18mm. The best value for money seem to be the BST explorers from Skys the limit on ebay, £47 each, but they don't do a 6mm so I got the TMB 6mm, £37, from same shop as they are also recommended. I will keep my 25mm to give me some nice low power view because I think it works quite well. Sion
18. ## Improving My Scope

If you are getting the 200p, the first thing I would recommend is a Telrad finder. Haven't received mine yet but am looking forward to because of the ease people say things can be found with it. You should also look at getting a dew shield, either buying one or making one out of some foam or neoprene. Other then that I would just say save up some and invest in some more and better eyepieces to enhance your views. If you don't have Turn Left at Orion I would recommend that as well, really useful book and each object has a sketch on what you should see on a dob of about that size. Sion
19. ## Help! Registax6!

Yes, the images need to be of the same area as registax places alignment points on the image which it looks for in the other images to align up the details. If you want different images put together you need to create a mosaic, lots of images stitched next to each other to create one bigger image with more detail. Sion
20. ## Stacking

Noise is just a random discolouration or brightening of pixels. Happens most at high ISO settings and is more noticable in darker photos. Because the noise is random, by taking multiple shots you can get rid of the affected pixels. Signal, I think, is the actual detail that you want in the image, E.G. the features you are trying to capture. A bit unsure on this though as I haven't heard it being called that before. Sion
21. ## Help! Registax6!

Things like this can be done, but I don't think with Registax (correct me if I am wrong). I think it would have to be done in photoshop or similar program through layers, placing the crater over the spot on the moon in a new layer and then making that part visible over the top. There may be simpler ways but that is how I would do it. Sion
22. ## 12" Revelation Dob

http://www.ebay.co.u...3#ht_500wt_1413 Just seen this on ebay. Don't know the quality of these telescopes but thought I should post it. Sion
23. ## Skymax 127: Good allrounder?

They can be quite heavy to move as one unit but you can easily unscrew the scope from the base and move each separately. I recently bought the 200p dob and its fine to move short distances with scope and base together or take them apart to move further. Sion
24. ## What eyepieces to stay away from?

Sorted now . Ordered the TMB 6mm from Skys the limit to give me a nice 200x, and got a 12mm Celestron X-cel from FLO, heard they slightly out preform the BSTs and Orange and Black are my 2 favourite colours . Thanks for the help . Sion
25. ## Dark Matter and Dark Energy

They think there is missing mass because the results from their gravitational field strength and the mass of what they are made from (E.G. stars being Hydrogen and Helium) does not match up. By creating this 'Dark Matter', which is about 84% of the mass of these bodies, the values make sense. Sion
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