Galaxy collisions in an expanding universe are a fascinating topic that delves into the mysteries of the cosmos. In a recent column, a reader posed an intriguing question about the possibility of aliens observing dinosaurs from a staggering distance of 66 million light-years away. The thought experiment led to a whimsical exploration of the size of telescopes needed to witness such a spectacle.
To begin with, the distance of 66 million light-years is significant because it corresponds to the time when the Chicxulub asteroid impact wiped out the dinosaurs on Earth. Light travels at a rate of one light-year per year, so the light from this cataclysmic event would just now be reaching a galaxy 66 million light-years away. If extraterrestrial observers in that distant galaxy were inclined to build a colossal telescope, they could potentially catch a glimpse of the last remaining dinosaurs.
Calculating the apparent size of a dinosaur from such a vast distance involves intricate mathematical equations based on the object’s physical size and its distance from the observer. Using the small-angle approximation formula, it was determined that a Tyrannosaurus rex viewed from 66 million light-years away would appear incredibly minuscule, measuring just one sextillionth of a degree.
The real challenge lies in the construction of a telescope capable of resolving such a tiny object. The resolution of a telescope depends on the size of its mirror, with Dawes’s limit formula indicating that a telescope with a mirror diameter of 32 quadrillion meters would be needed to observe the dinosaur in detail. This translates to a mirror spanning about 3.4 light-years, a monumental task beyond our current technological capabilities.
Even if aliens managed to build such a colossal telescope, maintaining its alignment and tracking a distant, faint object like a dinosaur would pose significant challenges. The motion of celestial bodies and the need for precise targeting over immense distances would require sophisticated engineering and computational techniques.
While the concept of aliens observing dinosaurs from afar is a playful exercise, it underscores the potential for future advancements in astronomy. Building telescopes powerful enough to detect surface features on distant exoplanets is a goal within reach, albeit with substantial technological and logistical hurdles to overcome. Visualizing continents on exoplanets orbiting distant stars may one day become a reality, pushing the boundaries of our understanding of the universe.
The whimsical scenario of aliens observing dinosaurs serves as a reminder of the boundless possibilities in the field of astronomy. As we continue to push the limits of our technological capabilities, the prospect of unraveling the mysteries of the cosmos grows ever closer. The journey towards exploring distant worlds and uncovering the secrets of the universe is a thrilling adventure that awaits us, fueled by curiosity and innovation.
