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The Sun follows the solar circle (eccentricity e < 0.1) at a speed of about 255 km/s in a clockwise direction when viewed from the galactic north pole at a radius of ≈ 8.34 kpc [4] about the center of the galaxy near Sgr A*, and has only a slight motion, towards the solar apex, relative to the LSR. [5] [6]
The speed at which light propagates through transparent materials, such as glass or air, is less than c; similarly, the speed of electromagnetic waves in wire cables is slower than c. The ratio between c and the speed v at which light travels in a material is called the refractive index n of the material (n = c / v ).
The Sun, taking along the whole Solar System, orbits the galaxy's center of mass at an average speed of 230 km/s (828,000 km/h) or 143 mi/s (514,000 mph), [167] taking about 220–250 million Earth years to complete a revolution (a Galactic year), [168] having done so about 20 times since the Sun's formation.
In galactic astronomy, peculiar motion refers to the motion of an object (usually a star) relative to a Galactic rest frame. Local objects are commonly examined as to their vectors of position angle and radial velocity. These can be combined through vector addition to state the object's motion relative to the Sun.
The Parker Solar Probe passed within just 3.8 million miles of the sun's surface — seven times closer to the burning ball of gas than any other mission has gotten.
The Sun is part of one of the Milky Way's outer spiral arms, known as the Orion–Cygnus Arm or Local Spur. [272] [273] It is a member of the thin disk population of stars orbiting close to the galactic plane. [274] Its speed around the center of the Milky Way is about 220 km/s, so that it completes one revolution every 240 million years. [271]
This motion is caused by the movement of the stars relative to the Sun and Solar System. The Sun travels in a nearly circular orbit (the solar circle ) about the center of the galaxy at a speed of about 220 km/s at a radius of 8,000 parsecs (26,000 ly) from Sagittarius A* [ 5 ] [ 6 ] which can be taken as the rate of rotation of the Milky Way ...
The Andromeda Galaxy is a barred spiral galaxy and is the nearest major galaxy to the Milky Way. It was originally named the Andromeda Nebula and is cataloged as Messier 31 , M31 , and NGC 224 . Andromeda has a D 25 isophotal diameter of about 46.56 kiloparsecs (152,000 light-years ) [ 8 ] and is approximately 765 kpc (2.5 million light-years ...