* Light-year: A light-year is the distance that light travels in one year, which is about 9.461 trillion kilometers (5.879 trillion miles). So, if a galaxy is one light-year away, it means that light from that galaxy takes one year to reach us here on Earth.
* Parsec: A parsec (pc) is a slightly larger unit of distance used in astronomy. One parsec is defined as the distance from the Earth to an object that has an annual parallax angle of one arcsecond (1/3600 of a degree). This is approximately equivalent to 3.26 light-years or 206,265 astronomical units (AU). An astronomical unit is the average distance from the Earth to the Sun, which is about 149,597,871 kilometers (92,955,807 miles).
So, when astronomers talk about "far, far away" galaxies, they might mean distances that are millions, billions, or even tens of billions of light-years away. The most distant galaxies that have been observed are billions of light-years away, which means that the light from those galaxies took billions of years to reach us.
It's important to note that these distances are based on our current understanding of the universe, which is constantly evolving as we make new discoveries and gather more data. As our telescopes and instruments become more powerful and advanced, we may be able to probe even deeper into the vastness of space and observe even more distant galaxies in the future.
