Universal Parallax?

Question

I found out that using the Universal Parallax, you can calculate the distances to other Universal Objects, such as Stars and Galaxies, calculation based on luminance,size and the escape velocity from an object going away from another object!
But, stars have different luminosity, the one star can be yellow brightness +10, while the other star is brightness +5. Also they are variable in colour, from yellow, red and blue, etc...
They also have different sizes, like the Sun is 1 and the i.e. Antares is +- 300!
The speed of an object such as a Star is influenced by i.e. another star. So the parallax speed varies from one to another!

So, my guess is that the Universal Parallax is not that all accurate, taking the above factors into consideration!

In the Universe there are variable speeds, various sizes and luminosities!

So, I believe we don't know the acual distances, but using the Parallax is more theoretical

Answer 1

The original method for determining distances to galaxies was by means of Cepheid Variables, and that's fairly accurate, regardless of your comments on this "Universal Parallax". See link to learn about Cepheid Variables.

Answer 2

Looks like you might have confused 'spectroscopic parallax' with just plain old parallax. What you've sort of described best fits spectrsoscopic parallax, but velocities have nothing to do with that. Here's a summary of how spectroscopic parallax works --

1. measure the apparent brightness of a star
2. collect the absorption spectrum of a star
3. compare it to standard spectra to determine the class of the star
4. knowing the class of the star gives you the temperature of the star
5. use the H-R diagram to determine the luminosity of a main sequence star at the given temperature
6. knowing apparent brightness and luminosity, calculate distance using the inverse square law

Answer 3

Parallax, for Astronomers to use efficiently, is merely measuring the position of the stars in the sky relative to the position of other stars. The stars may seem to be fixed in the sky, but the subtle differences between them as the earth travels around the sun is visible with measurements taken with instruments we have on earth, as well as in orbit around us.

The simple matter is taking a picture of the sky during one season (let's say summer), and then taking a picture of the same section of the sky as the earth is on the other side of the sun, 2 Astronomical units away from it's previous position (let's say winter). This allows us a different vantage point to observe the stars and, if we're right, the closer a star is to us, the further it will have moved in the night sky relative to further away stars and galaxies (which honestly are impossible to measure the distance of using Parallax.)

The luminosity of stars and their sizes, as well as any objects that may be orbiting them or they might be orbiting, is definitely something to take into consideration. There are many means of trying to see through all of these variables, however. The light shift, red or blue, between one side or the other of a star when observed through the proper means can show us it's rotation rate, while the different colors of the stars can show us how brightly they are burning compared to other stars in the sky, as well as their spectra showing what they are composed of.

Of course no ONE means of measuring distance or size or any other factor in the night sky is going to give us all the information we need; It takes multiple measurements repeated again and again, as well as other factors to observe before any true facts begin to emerge.

Parallax, of course, can only show us so much of course. Science, albeit a tried and true method, isn't without its errors and miscalculations; but as long as we keep on looking to find new ways to interpret what we see, we can keep learning more and more about the facts of the cosmos (and the world) around us.

Oh, and if you get a chance, I highly recommend downloading Celestia. It's a program that allows you to see many of the objects in our night sky, all tied together to a rather nice database of information. I, personally, think it's a great program.

http://www.shatters.net/celestia/