If something is 40 million light years away, it will take approximately 40 million years for the light to reach us. This is because light travels at a finite speed of about 299,792 kilometers per second (or about 186,282 miles per second) in a vacuum, which is commonly rounded to 300,000 kilometers per second for simplicity.
Since a light year is defined as the distance light travels in one year, which is approximately 9.461 trillion kilometers (or about 5.879 trillion miles), we can calculate the time it takes for light to travel a certain distance by dividing that distance by the speed of light.
Using these values, we can calculate the time it takes for light to travel 40 million light years:
Time = Distance / Speed = (40 million light years) * (9.461 trillion kilometers/light year) / (300,000 kilometers/second)
After performing the calculations, we find that it would take approximately 133,867 years for light to travel a distance of 40 million light years.