The equation is given by:

$s = vt$

To calculate the time taken, we can use the formula:

$s = vt$

Where:

• Distance, $s = 1.5 imes 10^{11}$ m
• Speed, $v = 3.0 imes 10^{8}$ m/s

Rearranging the formula to find time ($t$):

$t = \frac{s}{v} = \frac{1.5 \times 10^{11}}{3.0 \times 10^{8}} = 500 \text{ seconds}$

Life Cycle of Massive Stars

1. Formation: The life cycle begins with a cloud of gas and dust (predominantly hydrogen) collapsing under its own gravity, forming a protostar.

2. Main Sequence: Once the protostar's core temperature becomes high enough, nuclear fusion starts, allowing the star to enter the main sequence phase where it fuses hydrogen into helium.

3. Red Supergiant Stage: After exhausting hydrogen, the star's core contracts, leading to increased temperatures where helium fuses into heavier elements like carbon and oxygen. This stage culminates in the formation of a red supergiant.

4. Supernova Explosion: Once the core produces iron, fusion cannot continue, leading to instability. The outer layers are expelled in a supernova explosion, dispersing heavy elements throughout the universe.

5. Neutron Star or Black Hole: Depending on the mass remaining, the core may collapse into a neutron star or, if sufficiently massive, a black hole.

This process enriches the universe with new elements, contributing to the formation of future stars and planets.

The range of wavelengths emitted by a star depends on its temperature.