What Is Stellar Parallax? How Could We Apply It? Is There Any Other Method to Measure Distance Between Substance in the Universe?

Question：What is Stellar Parallax?  How could we apply it?  Is there any other method to measure distance between substance in the universe?

To answer this question, we first explain what Parallax is. It can simply describe by when you hold hand and point out one object away from you. First, closing your left eye, you look at it only with your right eye. Then, you try the same way by looking with left eye. Your hand then seems to move two different locations against the background. [1]

Stellar parallax refers to use the apparent motion of a close star, relative to the background of away from star as the earth orbits the sun, to calculate the distance to close star. [2]

[pic 1]

According to the diagram above, we could apply Stellar parallax by introduce the formula

d = 1/p, we use parsecs to measure d and arc seconds to measure p

This formula shows the correlation between the distance from the sun to the nearby star and the parallax angle. In other words, if the star go far way, the parallax angle will become smaller. However, Stellar Parallax is not a perfect measurement. It also has the limitation that the distance stars are so far that the parallax angle is too small to measure accurately. [1]

Beside Stellar parallax, I found three other methods could address your question about any other way to measure distance between substance in the universe.

a) Spectroscopic parallax [3]

The distance stars are so far that is hard to accurately measure the parallax angle but by applying photometry and spectroscopy an approximate distance can be determined.

b) Hubble Law [4]

This method shows the relation between galactic distance and the redshift. It can be considered as a trued method.

c) RR Lyrae and Cepheid variables [5]

This measure refers to the brightness changes in different period correlate with it absolute light intensity. So we can calculate the distance by measuring the period and the apparent light intensity.

Reference

[1] Las Cumbres Observatory Global Telescope Network. [Online] Available at http://lcogt.net/spacebook/parallax-and-distance-measurement.   [Accessed 7 Dec. 2014]

[2] Hyperphysics. [Online] Available at http://hyperphysics.phy-astr.gsu.edu/hbase/astro/para.html#c2.  [Accessed 7 Dec. 2014]

[3] CSIRO(2014).[online] Available at