On Earth, we measure distance through steps, meters, kilometers, miles, or some other unit of measurement by which we can determine distance. The universe is so large, that sometimes measuring in kilometers or miles is pointless. In space, it is easier to measure distance with the help of light years. We can easily determine how long it takes us to cover a certain distance in kilometers if we know how fast we are going, but we never calculate how long it takes us to travel a light year. Maybe it’s time to answer that question. How long would it take to travel one light year?
To travel one light year, if we travel at the speed of light, it would take us one year. In spacecraft, time would pass differently, so one would not even have the feeling of traveling and the travel time would fly by in less than a second. Time stops for a man, as does his aging, as long as his spacecraft travels at the speed of light.
For people on Earth, however, the journey of one light year would take one year. The difference in the experience of traveling one light year occurs due to different perceptions of time on Earth and in space. On Earth, we have learned to count time in seconds, minutes, hours, days and years. For an object traveling at the speed of light, time is irrelevant. A journey lasting one light year or a billion light years for a person traveling at the speed of light will seem absolutely the same in time. Less than a second, almost zero time.
How long is a light year?
First thing you need to know: a light year is a unit of measurement for distance, not for time! It is a unit of distance that represents the total distance that the beam of light travels in one year moving in a straight line in empty space. It is assumed that there are no strong magnetic or gravitational fields at this distance. This unit of measurement is used primarily in astronomy to calculate the distance between celestial objects. It would be a bit complicated to use kilometers or miles to measure distances in space given that the distance between certain celestial bodies would require numerous zeros.
The speed of light is 299 792458 meters per second. One Julian year, the year how we measure it, has 365.25 days, or 31,500,000 seconds. The light year is equal to 9,460,730,472,580,800 meters or approximately 9,461 × 1015 meters.
How many days is a light year in human years?
A light year is used to calculate the distance that light travels in a human year. One light year is therefore the same as one human year. Fifty light years is 50 human years. There is no difference in the length of the light year and human year.
A light year is just a name used for a unit of distance, not time. When we hear the term light year, we immediately think of time, but a light year has nothing to do with calculating the year. The distances in space are becoming so great that it is impractical to express them in common units of measurement, so we turn to light years.
There is even a unit that is larger than a light year, and that is the parsec. It is used to measure the distance between celestial bodies located outside the Solar System. One parsec is equal to 3.3 light years or 31 trillion kilometers.
How fast can we travel in space?
The speed at which we will travel in space depends on the spacecraft we use.
The human speed record was set by astronauts during the Apollo 10 mission. Apollo 10 was a test mission just before sending a man to the Moon. When returning from lunar orbit, their spacecraft reached a speed of 39,897 kilometers per hour. Such speed is still not possible to reach with today’s technology. Its successor, the Apollo 11, reached tremendous speeds at times but traveled at an average speed of 5,000 km / h.
In order to stay in space orbit, the shuttle must reach a speed of 28,000 km / h. That’s 9 times faster than a bullet. However, the space shuttle doesn’t go that fast all the time. The speed at which it will fly depends on the orbital altitude, which is approximately between 304 kilometers to 528 kilometers above sea level depending on the mission.
SpaceX, a private company whose goal is to enable the colonization of Mars, is one of the most modern spacecraft companies. In 2012, it began supplying the International Space Station with supplies. In 2020, SpaceX sent its Crew Dragon spacecraft to the International Space Station for the first time. The spacecraft was transporting two astronauts traveling at an average speed of 28 163 kilometers per hour. The International Space Station is quite close to Earth, so it’s hard to reach a higher speed on such a short journey.
The fastest object that humans have made is the NASA Helios 2 rehearsal. During the mission, Helios 2 reached a speed of 252,793 km / h. This rehearsal was launched back in 1976, so it is surprising that no one has overtaken it so far.
Parker Solar Probe will soon break the record set by Helios 2. Parker solar probe is a NASA probe launched in 2018 whose mission is making observations of the outer corona of the Sun. In 2025, it should come closest to the Sun and at that time it will travel at a speed of 690,000 km / h or 0.064% of the speed of light.
When we study the speed that modern spacecraft can reach, we are still years, and perhaps centuries, far from reaching the speed of light, if we ever reach it at all.
We know, however, to what extent we can go. The first discussions about the speed of light began with the ancient Greek philosopher Aristotle who considered light travel instantaneously. Albert Einstein later in 1905 wrote a paper on special relativity. Einstein’s theory of special relativity proved that there is a limited speed of travel that we can reach: the speed of light. Nothing can travel faster than 300,000 kilometers per second which is the speed of light. The object should have an infinite amount of energy to make the object reach the speed of light.
How long would it take us right now to travel 1 light year?
With today’s technology, it would take us approximately 37,200 years to travel the distance of one light year.
For example, if we were to travel at a speed of 58,536 km / h, which is the speed at which the New Horizons rehearsal travels on its way to Pluto, it would take us just under 20,000 years to cross the path of one light year.
If the spacecraft were traveling at the speed at which Helios 2 was traveling, the spacecraft would have traveled one light-year in 4269 light-years.
If a Saturn V rocket that took the man to the moon were to travel, it would take 108,867 years to travel.
If we set out on that journey by the fastest plane, we will need 305975 human years.
If we were to set out on foot on a journey one light year long, it would take us 225 million years to cross it. At this time, the breaks that you would definitely need along the way are not even included.
A snail would cross a distance of one light-year by 83304201370000 years.
How long would it take to travel 1 light year at the speed of light?
If spacecraft traveled at the speed of a light year, it would travel the distance of one light year in one human year. If we were to travel at a speed of half a light year, it would take us 2 years. If we could travel at the speed of light, we could go around the Earth 7.5 times in one second.
However, for a man traveling in a spacecraft at the speed of light, time would not flow the same as outside the spacecraft. The man in the spacecraft would not age, and the time it took to cross one light-year would seem like a second. Even less than a second. This is not just an assumption. Numerous experiments have proven that indeed time flows differently when it travels at the speed of light.
It’s hard to explain what it would feel like to travel at the speed of light because we’re still a long way from technology that could allow us to do so at that speed. We currently need three days to the moon, but if we traveled at the speed of light, we would cross that path in just 1.3 seconds. Exploring the universe at the speed of a light year would significantly speed up the whole process, and we can only hope for that for now.
Source:
https://www.grc.nasa.gov/www/k-12/Numbers/Math/Mathematical_Thinking/how_long_is_a_light_year.htm
https://spaceplace.nasa.gov/light-year/en/
https://futurism.com/how-long-would-it-take-to-walk-a-light-year