arslan

Why does the solar system oscillate up and down every 70 million years, relative to the galactic plane? Is there a scientific reason for this effect? And also, are we currently going up or down and how many years until the direction changes?

One more question. Our solar is also tilted at about 90° relative to the galactic ecliptic. Is there a reason for this also?

Hi, I have done this problem multiple times and always seem to come up with the wrong answer.

Any help is greatly appreciated!

Scientists using the Hubble Space Telescope have observed Cepheids in the galaxy M 100. Here are the actual data for three Cepheids in M 100:

Cepheid 1: luminosity = 3.9 x 10^30 watts, brightness 9.3 x 10^-19 w/m^2

Cepheid 2: luminosity = 1.2 x 10^30 watts, brightness 3.8 x 10^-19 w/m^2

Cepheid 3: luminosity = 2.5 x 10^30 watts, brightness 8.7 x 10^-19 w/m^2

Compute the distance to M 100 with data from each of the three Cepheids in light-years (d1, d2, d3)

The Tully Fisher relation can Be used to find the Distances to galaxies.

Tully Fisher relation: L= V^4

L is the luminosity

V is the rotational velocity of the galaxy in km/s

I went online and did a little research and found out that You can express the Luminosity as the Absolute magnitude. I actually found 2 equations:

M = 4.8 - 2.5 x log(L/Lsun)

or

M= -9.5 x log(Rotational velocity in km/s)+2

Where M is the Absolute magnitude

I tried to test these equations On the Andromeda Galaxy. Since I couldn't find the rotation curve Of Andromeda, I couldn't use the second equation.

Luminosity of Andromeda = 2.6 x 10^10 L_sun

M= 4.8-2.5 x log(2.6 x 10^10)

M= -21.23 <---- absolute magnitude of Andromeda.

I wanted to test If I my answer was right. So used this absolute magnitude and the apparent magnitude of Andromeda, 3.44, to find its distance, which I already know is 2,540,000 Light years.

Distance= 3.44-(-21.23)+5)/5)

Distance= 10^5.934= 859,013.522 parsecs

859,013.522 parsecs = 2,801,789.65 light years

Is that a close enough answer, or am I just using the Wrong Equation to find the Absolute Magnitude.

And since L= V^4

(2.6 x 10^10)^(1/4) = 401.55 km/s is the Rotation curve for Andromeda Right?

I just want to know the real equation and if my answers are valid.

What is the equation/Formula for finding the luminosity of a star in Solar Luminosities?

Please explain clearly and write what each letter represents

say a star was 5 time larger than the sun and it had a temperature of 8,000 kelvin, what would be the luminosity of this stars is L_sun?

Ok, I've been very confused for the last few days. my question: look at the two equations below.

1) P^2= 4pi^2 x r^3/G(M1+M2)

2) M1+M2=A^3/P^2

Ok, I have a few questions about these equations.

1) aren't these equations the same? They both look for the same thing, the orbital period( or if you rearrange the equation they can also both be looking for mas or distance), but either way they look for the same answers and they use the same factors too, semi-major axis cubed, mass of the 2 objects. The only difference is the G and the 4pi^2. So when I do the same problem using both equations, I should get the same answer, but I don't, why am I getting different answers when the equations are the same. What am I doing wrong? Or am I wrong and are these equations actually different and used for different situations? please explain?

2) When you need to find the orbital period you just do a^(3/2) right? So how come they have more complex equations like that when you can just find the orbital period or semi-major axis the short way?

3) and if these equations are used for different situations, which is for which? and if they aren't used for different situation's then does it matter what equation I use if im looking for mass, distance, or orbital period of a planet or a star?

I know these are a lot of questions, but I want to make everything clear and straightened out, because im very confused, so can You please try and answer the question and explain thoroughly

Thank You!

Ok, I have more than one question here. I tried googling these but there weren't any helpful results.

My first question: What is the equation/formula to find the orbital period of something, using ONLY its speed??

My second question: What is the formula for finding the semi-major axis of something using ONLY its speed??

my third question: What is he formula for finding the eccentricity of an orbit using ONLY the orbital period?

I appreciate all your answers, thank you.

I want to practice the Inverse square law. Can you give me a few practice problems. I tried googling it, but there weren't any results.

Please give a few Inverse square law practice problems.

Mostly for light and gravity.

(im in the 8th grade, so don0t give me too hard problems, but not too easy either)

I appreciate your answers, thank you.

what is the formula for finding the center of mass of two celestial objects orbiting each other.

Please explain what each letter means and step-by-step explanation.

A practice problem would be nice too (without telling me the answer)

thank you

Suppose you are in a "Relativity Lab" You send a muon at 99% speed of light through a source to a detector that will detect the muon. The total distance the muon has to travel is 3 km. But here's the catch, Muon particles are unstable and decay in .22 milliseconds, so the muon at 99% speed of light will only reach .65 km before it decay's. So you predict that the detector will not be able to detect the muon because it will decay before it gets there. But the detector does detect the muon, how? Time dilation. Time for the muon slowed down by a factor of 7.1. So you multiply .65 km by 7.1 and get about 4.5 km. So the muon could have traveled 4.5 km before it decayed so it easily reached the detector which was only 3 km away.

So I have a question, If time dilates by a factor of 7.1 at 99% the speed of light, then by how much does time dilate at 100% or exactly the speed of light?

Just curious, thank you.

Name top four bodies in our Solar System that have the Best Chance of Sustaining Life?

It could be a planet, moon, dwarf, asteroid....

These are my top three

1) Mars

2) Enceladus

3) Titan

4) Europa

Please explain this equation. Newton derived this equation from Keplers third law.

p^2=4 pi^2/G(M1+M2)r^3

Please be specific in explaining what each letter represents and how the equation is calculated.

What is this equation use to find?

please explain, thank you

Sometimes an electron get pushed of its obit by a strong enough photon or from another electron that kicks it off. When this process, Ionization, the electron gets pushed away from its proton and freely wanders around but then immediately latches on to another lone proton, recombination, and now everything is back to normal.

I was wondering, is it possible for an electron to get Ionized and not recombinate for a long time? In other words, what if an electron gets Ionized and it keeps getting pushed around by photons and other electrons before it can latch on to a proton? is this possible, can an electron roam freely for a long time, say an hour or more? And what would happen to the atom if this is possible?

Please explain and thank you.

This may be a little hard to understand, you might need to have a decent knowledge of spectroscopy and physics to understand this question because im not good at explaining it (not cause your stupid or anything)

A hydrogen atom, which consists of a single electron jumps from one energy level to the next depending on the photon it absorbs.

if the electron is on the first energy level, it can go to 2,3,4,5,6.., this is in the ultraviolet section in the spectra called Lyman; alpha, beta, gamma, delta, epsilon.

If the electron is on the 2nd energy level it can transfer to 3, 4, 5, 6..., This part of the spectra is in the visible section and its called Balmer; aplha, beta, gamma, delta.

If the electron is on the third energy level it can go to 4, 5, 6..., this causes absorption lines in the infrared part of the spectra and its known as Pachen; alpha, beta, gamma.

my question is, is that it? does it end at Pachen or is there more?

please explain.

thank you.

I've been pondering this for a while.

Is it possible for a gamma ray to undergo Inverse Compton Scattering causing it to decrease in wavelength (increase in energy) and this causes it to change its direction to earth with even more energy than it started with?

I just bought the DVD for alex filippenko's Understanding the Universe 96 lectures, 2nd edition.

I want to know whats the difference between 2nd edition and first edition.

Am I missing anything by watching the 2nd edition first?

please explain?

What exactly is a neutrino?

How are they formed?

what is there mass and their speed?

please answer all those questions and any other information you have about neutrinos, im curious and it will be of much help.

Thank You.

I want to fully understand newtons equation GM2/r

This is the equation to find the gravitational energy of a celestial objects, right?

Please explain this theory, and what each letter represents.

in detail.

thnx.

Ive been watching astronomy documentaries for years now, and i have run out sources.

can you give me any good astronomy documentaries like this one

http://www.youtube.com/watch?v=dK4gxEBQrPs

that one abpve was really good, can you give some that are like that.

thnx