The life of a star is just a perpetual acrobatic act at the precipice of gravitational collapse and runaway electromagnetic explosion. This delicate balance determines the mass, size (radius) as well as luminosity (how bright or how dull the star can be). However, since astrophysics is exclusively an observational science (distant and remotely detached) instead of experimental (up close and personal), the allowable data are all limited to three specific information: (1) the distance – how far the star is (2) its apparent brightness (3) its color from spectral analysis. With just these three, scientists can basically chart the future course of every star found within the range of observational instruments (optical and radio telescopes). This range is called the visible universe. What lies deeper your guess is as good as mine.

Distances are usually measured by either of two methods (1) parallax (2) relative brightness of same type objects at different distances. In addition, these are correlated by spectral analyses with detected Doppler effects (red or blue shift) as motion-velocity correction. Moreover, the stellar spectra can also be used to determine stellar mass, temperature as well as composition. Furthermore, size or temperature classification relates to color using the Hertzsprung-Russell empirical diagram. Spectral types are classified into various major divisions of color index: O, B, A, F, G, K, and M. For memory retention, the mnemonic is given as ‘oh, be a fine girl, kiss me.

If the opposite end of the universe suffers a cataclysmic demise at this very moment, the limit of lightspeed won’t allow us to see it before another 15 billions years. The deeper we look into outer space, the farther we see into the past. It is a privilege point our consciousness is poised where the future is the past and the past is the future depending whether we are looking into outer space or inner space of the mind. Similar to the stars, where they are balanced at the edge of space between gravity and electromagnetism, we are living at the edge of time where there is no distinction between past and future. But together, we and the stars live at the edge of spacetime where its mean curvature is always zero caused by the dynamic equilibrium between positive principal curvature and negative principal curvature.