We perceive time as a passage of events, a marker of change
The daily cycles of Sun rise and set, the monthly phases of the Moon, and the annual repeating seasons are natural "clocks", standards that are references for other changes
Study of astronomical phenomena on very short timescales
High time-resolution astrophysics (HTRA) is a section of astronomy/astrophysics involved in measuring and studying astronomical phenomena in time scales of 1 second and smaller (t.b.c.).This breed of astronomy has developed with higher efficiency detectors and larger telescopes to get more photons per second along with better computers to store and analyse the vast amounts of data acquired in one night.
Calculation of elapsed time by the apparent position of the sun
Solar time is a calculation of the passage of time based on the position of the Sun in the sky.The fundamental unit of solar time is the day
Based on the synodic rotation period.Traditionally
There are three types of time reckoning based on astronomical observations:
Apparent solar time and mean solar time
And sidereal timeWhich is based on the apparent motions of stars other than the Sun.
Stellar astronomy - time scale
The thermal time scale or Kelvin–Helmholtz time scale is the approximate time it takes for a star to radiate away its total kinetic energy content at its current luminosity rate.Along with the nuclear and free-fall time scales
It is used to estimate the length of time a particular star will remain in a certain phase of its life and its lifespan if hypothetical conditions are met.In reality
The lifespan of a star is greater than what is estimated by the thermal time scale because as one fuel becomes scarce
Another will generally take its place – hydrogen burning gives way to helium burning
Which is replaced by carbon burning.
