scupydog said:Hi. Does the light from a lensed object take longer to reach us, than the light from an unlensed object at the same distance.
I mean because the light from a lensed object has a curved path.
Thx. Dave...
Chronos said:Correct. For discussion see
http://arxiv.org/abs/astro-ph/9606001
Lectures on Gravitational Lensing
authors: Narayan, Bartelmann
Jonathan Scott said:Yes, it takes longer to reach us but this is normally mainly because of the Shapiro delay effect rather than simply the curved path. Basically, light slows down slightly in a lower gravitational potential, closer to a massive object or system, as if it were in a medium with a refractive index slightly greater than 1. The amount of deflection relates to the gravitational field (how rapidly that potential changes with sideways displacement along the light path) but the amount of time delay mainly relates to the potential along the path.
A gravitational lens is a phenomenon where the path of light is bent due to the presence of a large mass, such as a galaxy or a black hole. This bending of light can cause the light to travel a longer distance, resulting in a longer travel time and making it appear as if the light is taking longer to reach us.
Yes, the distance between the source of light and the observer does affect the time it takes for light to reach us through a gravitational lens. The greater the distance, the longer the light will take to reach us due to the bending of light caused by the gravitational lens.
Light always travels at the same speed in a vacuum, which is approximately 299,792,458 meters per second. However, the path of light can be altered by a gravitational lens, causing it to appear as if the light is taking longer to reach us.
The mass of the object causing the gravitational lens plays a significant role in the time it takes for light to reach us. The greater the mass of the object, the stronger the gravitational lens effect will be, resulting in a longer travel time for light.
The time delay of light passing through a gravitational lens can vary depending on the strength of the lens and the distance between the source of light and the observer. In some cases, the delay can be a matter of milliseconds, while in others, it can be significant, ranging from a few minutes to even days.