A light-year is the distance light travels in one Earth year. One light-year is about 6 trillion miles (9 trillion km). That is a 6 with 12 zeros behind it!
Light-year is the distance light travels in one year. Light zips through interstellar space at 186,000 miles (300,000 kilometers) per second and 5.88 trillion miles (9.46 trillion kilometers) per year.
The more commonly used light-year is also currently defined to be equal to precisely 31557600 light-seconds, since the definition of a year is based on a Julian year (not the Gregorian year) of exactly 365.25 days, each of exactly 86400 SI seconds.
One of the most distant exoplanets is 3,000 light-years (17.6 quadrillion miles) away from us in the Milky Way. If you were to travel at 60 miles an hour, you would not reach this exoplanet for 28 billion years.
Travel Time
At the rate of 17.3 km/sec (the rate Voyager is traveling away from the Sun), it would take around 225,000,000,000,000 years to reach this distance.
Save this answer. Show activity on this post. We don't see stars and galaxies at a proper distance of 46 Gly, because this distance corresponds to a light travel time of 13.7 billion years, or very shortly after the big bang.
Nothing can travel faster than 300,000 kilometers per second (186,000 miles per second). Only massless particles, including photons, which make up light, can travel at that speed. It's impossible to accelerate any material object up to the speed of light because it would take an infinite amount of energy to do so.
Complete step-by-step solution: The light travels at the speed of 1 light year. Therefore, if we assume light to be travelling, then it will travel 500 light years in 500 years.
Constant Speed
So what does this sentence really mean? Surprisingly, the answer has nothing to do with the actual speed of light, which is 300,000 kilometers per second (186,000 miles per second) through the "vacuum" of empty space.
For most space objects, we use light-years to describe their distance. A light-year is the distance light travels in one Earth year. One light-year is about 6 trillion miles (9 trillion km). That is a 6 with 12 zeros behind it!
Light can travel at a speed of 300,000 km (186,000 miles) a second. That means that in one second, light travels the distance you would cover if you traveled around Earth 7.5 times!
Light travels at a constant, finite speed of 186,000 mi/sec. A traveler, moving at the speed of light, would circum-navigate the equator approximately 7.5 times in one second.
So the furthest out we can see is about 46.5 billion light years away, which is crazy, but it also means you can look back into the past and try to figure out how the universe formed, which again, is what cosmologists do.
1 Light Year in Days
As defined by the International Astronomical units (IAU), A light year is the distance traveled by light in a vacuum in one Julian year is equal to 365.25 days. Therefore, one light - year = 365.25 days.
And so 92 billion light years might seem like a large number for a 13.8 billion year old Universe, but it's the right number for the Universe we have today, full of matter, radiation, dark energy, and obeying the laws of General Relativity.
So will it ever be possible for us to travel at light speed? Based on our current understanding of physics and the limits of the natural world, the answer, sadly, is no.
If an object ever did reach the speed of light, its mass would become infinite. And as a result, the energy required to move the object would also become infinite: an impossibility.
The fastest spaceship journey to date took around three years and two months to travel from Earth to Saturn. In addition to the speed of the spaceship, the travel time to Saturn also depends on the path taken.
This is a little hard to wrap your head around, but shadows can move faster than the speed of light, even though nothing can move faster than the speed of light.
In special relativity, the speed of light is the ultimate speed limit to the universe. Nothing can travel faster than it. Every single moving object in the universe is constrained by that fundamental limit.
Darkness travels at the speed of light. More accurately, darkness does not exist by itself as a unique physical entity, but is simply the absence of light. Any time you block out most of the light – for instance, by cupping your hands together – you get darkness.
The trite answer is that both space and time were created at the big bang about 14 billion years ago, so there is nothing beyond the universe. However, much of the universe exists beyond the observable universe, which is maybe about 90 billion light years across.
And since the universe is only about 13.8 billion years old and light takes time to travel through space, then regardless of what direction we look, we see light that's been traveling, at most, 13.8 billion years.