Question

What is really the speed of light?

It looks so easy but it is very hard question!!! Because of the direction of moving object.​

Answer 1

Answer:

The speed of light in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. Its exact value is defined as 299792458 metres per second (approximately 300000 km/s, or 186000 mi/s).[Note 3] It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time interval of 1⁄299792458 second.[Note 4][3] According to special relativity, c is the upper limit for the speed at which conventional matter, energy or any information can travel through coordinate space.