What is the astronomical unit (AU)?
Astronomical unit (AU) is a measure of distance that is often used in astronomy, equals distances between the ground and the sun. As for more common measuring units, the astronomical unit equals about 93 million miles (150 million km), or the distance of light in just over eight minutes. The AU symbol is most often used to represent the astronomical unit, although less commonly you can see that you can see UA instead. Many Greeks have come up with measurements, often incorrectly with relatively huge edges. Greek Eusebius came up with a measurement, which is surprisingly close to the modern degree of astronomical unit. In one of his works, he estimated at 804 million stadiums. Stages, Greek specific unit, are about 605 to 625 feet (85-90 m), so its estimate somewhere between 92 and 95 million miles (149–153 million km).
At the end of the 17th century, the astronomical unit was officially estimated to be about 87 million miles (140 million km) using Mars at two different points in the Earth's orbit. At the end of the 18th century was conceived mEtode using Venus as a point of measurement during its transit through the sun. This method brought a much more accurate figure. At the beginning of the 20th century, an asteroid near the country was calculated and an even more accurate figure for the astronomical unit was calculated.
By the middle of the 20th century and further in the 21st century, it enabled to improve various measuring technologies to make much more accurate measurements, which further improves the astronomical unit. Using cosmic probes and satellites have created modern definitions with much greater accuracy than in the past. In 1976, the actual definition of the Astronomical Unit of the Updatede was to acquire more sophisticated measures. Perhaps the most accurate definition could be listed as a distance from the exact center of the Sun, in which the particles would take the Gaussian year (365,2568983 days) to complete its orbit. If it seems confusing, just consider it about the same as saying that the astronomical unit is the distance from the center of the Earth to the center of the sun.
The actual value for the astronomical unit provided by this definition and the most modern measurements is approximately 92,955 807 miles (149 597 870.691 km). This number was accepted in 1996 and is considered accurate to about 10 feet (approximately 3 m).
Astronomical unit can be useful not only for astronomers, but also for normal people who seek to get relative distances involved in our own solar systems. While the distances between planets may seem too large to ever come when they are given in kilometers or kilometers if they are listed in astronomical units is much easier to see the relationships between them. For example, while the Earth is of course 1au from the Sun, the moon is only 0.0025AA away from the ground. And while Jupiter, which we think is quite far, is just over 5au from the Sun, Pluto is an incredible 40 to 50AU. And if it seems like a long way, consider that the nearest star of our own solar system is 268 000AA.