No, it is not possible to go back in time by simply observing past starlight. While starlight does travel across vast distances before reaching our eyes, allowing us to see objects as they were in the past, it does not provide a means for physical time travel.
When we observe distant objects in space, we are essentially seeing them as they were when the light left those objects and began its journey toward us. For example, if we observe a star that is located 100 light-years away, the light we see today actually left that star 100 years ago. We are observing the star as it was 100 years in the past, but we are still in the present.
Although observing distant starlight can give us insight into the history of the universe and the objects within it, it does not provide us with the ability to physically travel back in time or interact with the past. The light we see has already traveled to us at the speed of light, adhering to the laws of physics and causality.
Time travel, as currently understood, involves complex concepts and hypothetical scenarios that go beyond the observation of starlight. It typically involves exploring concepts from theoretical physics, such as wormholes, time dilation, and the manipulation of spacetime. While these ideas are the subject of scientific study and speculation, they remain purely theoretical at this point, and no practical method for time travel has been discovered or validated.