How many kilometers is a light year (how far is a light year?)
On September 5, 1977, the United States launched Voyager 1 detector. This probe has been flying in the vast universe for nearly 44 years. Data show that as of October 23, 2019, Voyager 1 is 21.1 billion kilometers away from the sun.
Light blue dot
On February 14, 1990, the Voyager 1 probe had flown 6.4 billion kilometers away from the earth. It was instructed by scientists to point its lens at the earth and take this famous photo of the earth – the faint blue dot.
1.1 billion kilometers. how far is it How far is 6.4 billion kilometers? These distance figures are truly astronomical. They are too big for us to imagine. In life, the distance we touch is only a few kilometers, tens of kilometers or hundreds of kilometers. The flight distance of Voyager 1 is 2,110,000,000 kilometers, and there are 8 zeros after 2,11. This number is so large that it looks dazzling. Can you express this distance in larger units? Like light years.
Earth and Moon
The distance between celestial bodies in the universe is very large. The closest celestial body to the earth is the moon, and its average distance from the earth is 384,400 kilometers. The average distance between the earth and the sun is about 150 million kilometers. Pluto is about 5.9 billion kilometers from the sun. In the solar system, the distance between celestial bodies is often tens of millions or even billions of kilometers. There is no doubt that the distance between these numbers is very large. However, it is equally inconvenient if we convert them into light-years. Because the unit of length of a light year is too large.
Celestial bodies in the solar system
What is a light year? How far is a light year? A light year is the distance that light travels in a straight line in the universe. true The speed of light in the air is 299792.458 kilometers per second (about 300,000 kilometers), so 1 light year is 9460730472580.8 kilometers. Does the distance of 1 light year make you more dazzling? The ID number is much easier to remember than this. For convenience, we only take an approximate value. 1 light-year has a resource network of about 9460.7 billion kilometers.
How long will it take us to travel a light year with the existing means of transportation? And slow transportation such as cars and high-speed rails can be skipped directly, and we can go directly to the plane. The speed of a passenger plane is generally 900 kilometers per hour. It takes 1.2 million years to travel one light-year at this speed. However, it would take a probe like Voyager 1 more than 18,800 years to travel a light-year distance.
The speed of light
Do you understand how far 1 light year is? Let’s use it to measure the solar system and see what we get.
The average distance from the moon to the earth is 384,400 kilometers. Light can travel from the Moon to Earth in a little over a second. The distance between the earth and the moon expressed in light years is 4/100,000,000 (4/100 million) light years.
The average distance to the earth is 150 million kilometers, and it takes more than 8 minutes for light to reach the earth from the sun. Therefore, the average distance between the sun and the earth is about 8 light minutes, which is 0.0000159 light years in light years.
We know that there are eight planets in our solar system. Among the eight planets, the planet farthest from the sun is Neptune. The average distance from Neptune to the sun is 4.5 billion kilometers, which is 0.00048 light years in light years.
Neptune and the Sun
How many light years and 21.1 billion kilometers did Voyager 1 fly? Converted to 0.0022 light years. Discovered in 2003, Sedna is one of the most distant objects from the Sun ever discovered. Its aphelion is about 140.6 billion kilometers, which translates to about 0.015 light-years.
Scientists believe that Sedna is one of the discovered Oort Cloud objects. The Oort cloud is a spherical cloud surrounding the solar system, where hundreds of billions of comets are distributed. The outer edge of the Oort cloud is considered the edge of the solar system, about 1 light-year from the sun. In other words, the radius of the solar system is 1 light-year.
The radius of the solar system is about 1 light-year, and the distance between Neptune and the sun is only 0.00048 light-year. From a macro perspective, the sun and the eight planets occupy most of the mass of the solar system, but only occupy such a “small” empty space. Does this strike you as incredible?
Oort cloud and the solar system
The solar system is measured in light years, and the radius of the entire solar system is only 1 light year. Therefore, measuring the solar system by light years is really killing the chicken and taking the eggs, making a big fuss.
However, the distance between the sun and its nearest stellar neighbor, Proxima Centauri, is 40 trillion kilometers, and the distance between the sun and the brightest star in the sky, Sirius, is 81 trillion kilometers. These distances are even greater than we thought. At this point, it’s a lot easier for us to express these distances in light years. Proxima Centauri is 40 trillion kilometers away from the sun, 4.22 light-years away, and Sirius is 8.6 light-years away from the sun.
The Milky Way system
Expressed in light years, Proxima Centauri and Sirius, which feel far away, suddenly become the back garden of the sun, which is extremely close . Make us look bigger. Orion Betelgeuse is about 640 light-years away from the sun, the Milky Way is 180,000 light-years away, and the Andromeda Galaxy is 2.54 million light-years away from Earth. The current Hubble volume has a radius of 46 billion light-years. It seems too much to measure the universe with the huge ruler of light years.
The vast universe
The solar system is very large. It will take about 30,000 years for Voyager 1 to fly out of the solar system. The solar system is too big for us to ever fly out of. At the same time, the solar system is very small, with a radius of only 1 light-year, which is only 460 of the radius of the visible universe.one billionth.
In the final analysis, human beings are too small and the universe is too vast. Isn’t that so? Let’s chat!