Yes, the level populations are determined by the temperature and density. The strength of the line is also determined by the oscillator strength of the transition.
Well, I'd say it is frequency dependent due to the relation to the radiation pressure. . .
P=\frac{ \langle S \rangle }{c}
Pressure is just the momentum flux through a surface, and photons of course carry momentum and energy.
The energy flux through an element dA from a source...
Do something outdoors, unfortunately, the sunspot activity is at a minimum right now or else tracking those could be fun if you had a telescope. Something like electrolysis with solar cells is fun, and you can make Hydrogen bubbles that make a nice pop if you light them. . .
The SDSS filter curves can be found here:
http://www.sdss.org/dr3/instruments/imager/index.html#filters
Although, each new set of filters is going to be a bit different, and the transmission curves will vary from set to set.
Also some here...
A friend of mine recently got a Basset hound who was also a rescue, and also had pretty bad separation anxiety. She called the rescue facility and they said to act like you are about to leave (as in put on your jacket, rattle your keys around, get your backpack etc), and then just sit back down...
Usually, gravitational shear is mentioned in relation to gravitational lensing, mainly weak lensing. The shear causes background galaxies in relation to a foreground cluster to become elongated, and also curved towards the center of the cluster. Look up "weak gravitational lensing". . .
Do tell why you think that "if our solar system does rotate through the milky way on an non linear plane then the doomsday scenerio could be plausible."
And yes, stars do oscillate up and down as they orbit the center of the Milky Way, which does harbor a supermassive black hole, that will not...
Well, to rule out C you can have a look at Ned Wrights Javascript cosmology calculator to determine the lookback time. Just plug in 5.37 for the redhshift. The light travel time is the "lookback time".
http://www.astro.ucla.edu/~wright/CosmoCalc.html
Consider the following:
A typical Ribeye steak is ~4"x6" and 1" thick. Said steak occupies a volume of ~393 cm^3 and has a surface area, assuming a rectangular geometry of ~440 cm^2. If we idealize our steaktips as cubic solids, 1" thick, then we can partition our original Ribeye into 24 1"...
That interaction cannot occur due to lepton and baryon number conservation. If you meant
photon -> electron + positron
This cannot happen in free space due to energy/momentum conservation. You need a heavy nucleus around for that interaction to occur to take some of the energy and momentum
First, you have to show your attempt at the solution before help can be given. However, I will say that
\vec F = F_{x}\hat x + F_{y} \hat y + F_{z} \hat z = -\vec \nabla \phi
F_{x}=-\frac{\partial \phi}{\partial x} , F_{y}=-\frac{\partial \phi}{\partial y} ,F_{z}=-\frac{\partial...
Start with the definition of a difference in apparent magnitudes. . .
m_1 - m_2 = 2.5log(I_1/I_2)
extinction, A is defined as A = m^{'} - m
Now, how are I_1, I_2, and tau related. . .