– Light travels at a speed of 186,000 miles per second — it circles the earth 7 times in one second. Explains thunder following lightening by a few seconds. A light year is 6 trillion miles (6,000,000,000,000), the distance light travels in one year.
– Because light does not travel instantaneously but st a precise constant we can ascertain how old a star or galaxy is or was when we are looking at it based on how far away it is. Allowing us to look far back into the past. We see the crab nebula as it was 6500 years ago. The galactic core of our own milky way galaxy 26,000 years ago. The Andromeda Galaxy our closest neighbor 2.5 million years ago. In other words we have no idea what these objects look like NOW. Only what they looked like back then. Because of how long it takes light to travel. Its a catch 22. Though it’s fast, the speed of light still limits our ability to see things in the universe as they actually appear now.
– Moving at the light speed time slows down time compared to regular earth speed. So a person ages much slower if traveling at rhe speed lf light. And what may seem like four days to a light speed traveler may indeed be 40 years to someone on earth. But the closer to light speed we travel the more mass is needed to get to that energy till the mass reached is infinite– making it impossible.
– Two alternatives have been posed. One would be creating a worm hole by zapping a large amount of energy using lasers into an exact point in space to break a hole in it and then going to a diff place in the universe. Also we may be able to travel at warp drive– using the warping of space-time, space expanded behind the ship and contracted in front of it, creating a bubble around the ship propelling it faster than the speed of light in order to get to remote places in far away space.
– Communication between earth and Neil Armstrong on the moon took 2.6 seconds between each transmission because it takes the radio signals traveling at the speed of light 1.3 seconds between earth and the moon. – Light from the sun takes more than 8 minutes to reach earth. – 44 minutes for the probes that are exploring Mars. -2 hours to talk to the Cassini probe at Saturn. -Over 29 hours to talk to voyager 1 now heading out of the solar system which is 10 billion miles away.
– We’ve recently learned that Light is not in fact the fastest thing in the universe. Space now is. Because we know that space itself is expanding, space in the outermost reaches of the universe is expanding faster than the speed of light. Mind boggling.
– Our light horizon or limit — the farthest
we can see light in the universe due to how far things r that we can not see the light of is 13.5 billion light years. So that’s the farthest we can see in the universe though it might be bigger than that. Way bigger.
– In fact some theorize that the universe may be ten to one hundred times larger than current estimates; other theories postulate that there may be more than one universe, that the current model that we now believe we live in may be just one out of many. The simple truth of the matter is that due to our current technological limitations in seeing beyond light that is too far away from the earth for us to ever see, no matter how old it may be, at present we can never know how large the universe really is nor have a definitive knowledge of how many other stars or galaxies may exist in the universe besides the ones we are already aware of.