A star near the visible edge of a galaxy travels in a uniform circular orbit. It is 43,500 ly (light-years) from the galactic center and has a speed of 275 km/s. a.)Estimate the total mass of the galaxy based on the motion of the star. Gravitational constant is 6.674×10−11m3/(kg·s2) and mass of the Sun Ms=1.99 × 1030 kg. b.)The total visible mass (i.e., matter we can detect via electromagnetic radiation) of the galaxy is 1011 solar masses. What fraction of the total mass of the galaxy is visible, according to this estimate?
Stellar evolution
We may see thousands of stars in the dark sky. Our universe consists of billions of stars. Stars may appear tiny to us but they are huge balls of gasses. Sun is a star of average size. Some stars are even a thousand times larger than the sun. The stars do not exist forever they have a certain lifetime. The life span of the sun is about 10 billion years. The star undergoes various changes during its lifetime, this process is called stellar evolution. The structure of the sun-like star is shown below.
Red Shift
It is an astronomical phenomenon. In this phenomenon, increase in wavelength with corresponding decrease in photon energy and frequency of radiation of light. It is the displacement of spectrum of any kind of astronomical object to the longer wavelengths (red) side.
A star near the visible edge of a galaxy travels in a uniform circular orbit. It is 43,500 ly (light-years) from the galactic center and has a speed of 275 km/s.
a.)Estimate the total mass of the galaxy based on the motion of the star. Gravitational constant is 6.674×10−11m3/(kg·s2) and mass of the Sun Ms=1.99 × 1030 kg.
b.)The total visible mass (i.e., matter we can detect via
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