Hey, Space Placers!
In 1927 Nobel Prize Winner Albert Michelson determined the speed of light was 299,796 Kilometers per second, just 3.542 Kilometers per second off from the modern figure. He did this during experiments at Mount Wilson Observatory.
The speed of light is fast but finite. The following gives you an excellent feel for how vast our solar system really is. Once we leave the Earth-Moon system we start to add up the minutes and hours it takes for light to reach us from the other planets.
Oh, and don't forget to multiply the time "x2" to account for round trip time!
It staggers the mind to contemplate the time necessary for light to reach us from even the closest star beyond our Sun - Proxima Centauri - 4.2 YEARS. Light travel time becomes even more incomprehensible when we look at the Milky Way - 27,000 years to the galaxy's center to BILLIONS of years for distant galaxies.
Space is big and gets bigger by the second due to the expansion of the Universe.....
Sky Guy in VA