Recent content by bobo1455

Ok I finally got the value I was looking for. I really was overthinking it for no reason. The final distance in Kpc worked out to be the correct one. Thanks.

I've read a bit more about this and found this page: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/hubble.html#c3 If you put in a wavelength it can give you the distance to the galaxy. I also found out that c * z = v is the velocity of the galaxy with a red-shift wavelength z. So I now I...

I have the average density of the z= 6.56 galaxy. The question says that all galaxies around the time of the red-shift = 6.56 have similar masses and number of stars to galaxies in the present universe. I'm assuming that is supposed to make the question easier and overall I'll need less...

Q: Estimate the diameter in kpc of the red-shift=6.56 galaxy at the moment when it emitted light. We're assuming that early galaxies with similar red-shifts have the same number of stars to galaxies as in the present state of the universe. I've taken a look at the small angle formula a = s / d...

Alright I calculate the average density and it is correct because I checked against the book's answer. If I were asked to express the density as the number of Hydrogen atoms per cubic meter, how would I go about it? What I've done is calculated the number of H atoms that would fit in one cubic...

Q: What was the average density of the universe at the time the light was emitted by the z = 6.56 galaxy? For the question we know the current average density of the universe and red-shift wavelength z = 6.56. It says to calculate the average density of the universe at the moment when light was...

Ok I understand. The linear size scale itself is the factor by which the size of the universe changed. I thought the question is more complex than what it really is asking. Thanks.

Question: By what factor has the linear size-scale of the Universe changed between when the light was emitted from the galaxy and now? The question gives the red shift z and I have the equation linear size scale = 1 / 1 + z and I know how to calculate the linear size scale. But I'm a little...

You can use the formula that SteamKing posted assuming you have all of the variables except for the variable you're trying to figure out. The main thing to remember is that orbital radius is the same as the distance between the object and it's star if the orbit of the object is circular...

I'm having a hard time understanding your last post. I've read it like 15 times now and still have no clue what you mean. Are you saying to to make an equation like this: F1 / F2 = L1 / L2 ?

So maybe I can somehow use the formula F = L/(4*pi*(d^2))? I read the link you gave me on wikipedia. I'll try using L ≈ 4πR^2σT^4 to calculate the star's luminosity and then substitute in for L in the other equation I have and re-arrange and solve for d. Not really sure what to do after that...

Homework Statement Calculate orbital radius of planet X using the given variables of its star: T=500 K, radius R=0.1 x Sun's radius, mass M=0.5 x Sun's mass and also its receives the same flux as the Earth receives from the Sun. I forgot to mention also that the orbit is circular, so the...

I got it. I re-arranged the doppler shift formula to solve for λshift. The known variables I need for the formula were λrest, speed of light (c) and the radial velocity of the object. I got the radial velocity for M87 in my textbook under the Appendix. Then I just plugged in the values and...

How did you get 659 nm? Are you using some form of the Doppler shift formula? I'll try using a re-arranged version of the Doppler Shift formula to solve for one of the wavelengths and maybe that will make more sense to me.

The galaxy M87, shown in Figure 15.5, was discovered by Charles Messier in 1781. Located 54 million light-years from Earth, it is one of the most massive galaxies in the Universe, including a black hole at its centre that is 4 billion times more massive than the Sun. Observing the spectrum of...