How do they measure distance in space ??
One night i was surfing on my mobile and i came to know that nearest galaxy to us is Andromeda Galaxy which is about 2.5 million light years away from us. After reading it i was amazed and one question pooped up in my mind that How do scientists measure distance between objects in space ?? First of all let us understand that distance in space is measured with reference to light i.e. in light years. One light year is the distance which light travels in one year which is approx 10 trillion km (9,500,000,000,000 km) which is so huge. 1.How do we measure distance with light ?? We measure distance by using time taken by light to reach at an object and multiplied that time with speed of light.For example Suppose light takes 2 hours to reach from one object to another. So the distance= speed*time = 1,080,000,000km/hr * 2hr = 2,160,000,000 km 2.But nearest galaxy is 2.3 million light years away, so do we need to wait 2.3