S defined by the International Astronomical Union<span> (IAU), a light-year is the distance that </span>light travels in vacuum<span> in one </span>Julian year<span> (365.25 days). so if a planet </span><span>15 light-years away from Earth that is inhabitable by humans like us they have developed a very powerful telescope allowing them see what is happening on Earth if they look to the telescope today, they will see 15 years ago in the earth</span>
Answer:
Viscosity is a measure of how much a liquid resists flowing freely.
The golf ball represents the solar system and the football represents the Milky Way. Our solar system is <em>a lot</em> smaller than the Milky Way, just like how a golfball is smaller than a football.
