Recent content by cp05

  1. C

    How does radius of point spread function affect reconstruction errors?

    Hi guys, I've been struggling with this concept for a few days now. I have this *good* image that I am blurring (using a gaussian blur), then adding some small percentage of gaussian white noise to it. Then from that image, I want to compute the naive solution (just assuming B=AX and solving...
  2. C

    How Can I Solve a Two-Body System Using Kepler's First Law?

    So r = GM/((1/2)v^2-W)? Why did we need to do all that work to find this? All the acceleration integration stuff makes sense...but I don't get where I am supposed to use the result :(
  3. C

    How Can I Solve a Two-Body System Using Kepler's First Law?

    eek! now I am confused again. this is kind of a question from before, when I was v, but to get rid of the cosines and sines in v1 and v2, we set the angle=0? why can we just do that without loss of generality? should I do the same for the acceleration? then with those acceleration...
  4. C

    How Can I Solve a Two-Body System Using Kepler's First Law?

    of course! haha so silly of me. yes, i got everything you got. one last question. I think I am finally getting this. I want to find a^2=a1^2+a2^2, correct? then I set a=-GM/r^2?
  5. C

    How Can I Solve a Two-Body System Using Kepler's First Law?

    Hi. I've been trying to solve the first part but I guess I am just terrible at calculus :( I have x1 = r*cos(ang) x2 = r*sin(ang) v1 = d(x1)/dt v2 = d(x2)/dt as you said. This means v1= -(dr/dt)*sin(ang)*d(ang)/dt?? And likewise v2=(dr/dt)*cos(ang)*d(ang)/dt? and...
  6. C

    How Can I Solve a Two-Body System Using Kepler's First Law?

    Hey guys! So I'm looking at this textbook that attempts to describe to me how to get kepler's first law describing a two-body system in polar coordinates, and I have no clue how to get from one step to another because I have seen NO OTHER PLACE solve this problem this way. It starts off by...
  7. C

    Alright so here is another thing I do not fully

    Alright so here is another thing I do not fully understand. Inflation is this huge, fast expansion that apparently causes the small perturbations that eventually lead into the structure we see today. But if I think about it, wouldn't a fast expansion actually eliminate perturbations...
  8. C

    Cold Dark Matter vs Hot Dark Matter

    Hey guys, I'm a bit confused about how hot/cold dark matter plays into our theory of structure formation. Hot Dark matter is relativistic then it decouples in the early universe, and these particles are light and fast and do not form small structures since there is a large mass needed to keep...
  9. C

    Number Density vs Energy Density of Radiation and Matter

    I was going through my notes preparing for finals (this is my last one hooray!), and I saw that the Number Density of radiation and matter changes at the same rate (N=Na^-3) while the energy density is different (E=Ea^-3 for matter, E=Ea^-4 for radiation). I think I get why the energy densities...
  10. C

    Effect of ratio of energy density of matter and radiation on redshift

    Homework Statement If the ratio of the energy densities of matter and radiation was much higher than it is today (by several orders of magnitude), in a few sentences describe what effect this would have on the redshift (or scale factor) when the universe switched from being...
  11. C

    Questions about Baryonic Density Perturbations

    I am completely (or mostly) lost on these two questions. For the first one, I'm supposed to describe how and why adiabatic perturbations of baryons ALONE cannot be responsible for structure formation in the expanding universe. I need two pieces of observational evidence and two facts from...
Back
Top