What is the light aberration?
In astronomy, the aberration of light is a shift in the apparent position of the object caused by the relative movement of the object and the observer. Light aberration is only significant on very large scales and affects the perceived positions of stars and planets for observers on Earth. The obvious shift of the stars is the result of the movement of the Earth around the Sun and from its rotation. The idea was that the apparent position of the star should change throughout the year because the Earth orbits the sun. If the exact position of the star in the sky was checked at the given date, then re -checked six months later, when the Earth was opposite its position since the first measurement was carried out, two measuring measures separated by the Earth's orbit diameter - a distance of approximately 186,000,000 miles (300,000 km). This was sufficient to get the value of the parallax, so it calculated the distance of the star by means of trigonometry.
several measurements were made but the results were fromáhadné. The greatest apparent shift in the star's observed should be found between observation six months apart, when the location of observation was the farthest apart. However, real shifts followed a completely different formula and were obviously not caused by parallax. For example, star star stars, Polaris, have been found to watch roughly a circular path with a diameter of about 40 arc seconds (40 ”), the second of the arch is 1/3 600 degrees.
The secret was solved by James Bradley, the British astronomer Royal, in 1729. He found that the observed shifts in the star position were caused by the Earth's speed, not on its position, given the star. Star light takes time to reach the ground, and because the ground moves, it seems that stellar light seems to come from a point that is slightly moved from the real position of the star in the direction of movement. The largest shifts are observed when movement isThe land perpendicular to the direction of star light. The same phenomenon can be seen with rain vertical; On a moving observer - for example on a train or bus - the rain seems to diagonally fall from the point of origin in front of the observer in the direction of movement.
Bradley's calculation using the speed of light and the speed of the Earth's movement around the sun indicated a maximum shift of about 20 "to the Eithhuer side of the actual position for Polaris. This gave a total change of about 40” per year, in accordance with observation. When calculating light aberration, modern astronomers must take into account the effects of relativity, but in most cases the classic calculation is adequate.
seasonal shifts in stars positions are known as annual aberrations or star aberrations and the real position of the star is called its geometric position. Smaller shifts are the result of the country's rotation; This is known as daily aberration. Secular aberration is a term used to describe astronomical aberration caused by the movement of the solar system in the galaxy; Although affects the apparent positions of very distant stars andOther galaxies, are very small and usually do not take into account. When calculating a stellar aberration, only the movement of the Earth should be considered; Planetary aberrations - which, however, affect the apparent position of the planets - the results of the movement of Earth and the planets, so both should be included to calculate the correct value.