Breakdown:

1. Quick Trips within Our Solar System
   If we could travel at the speed of light, interplanetary journeys would be incredibly short. For example, it would take:
   • 1 second to reach the Moon.
   • 3 minutes to get to Mars.
   • 8 minutes to reach the Sun.
     These short distances highlight the sheer speed of light (about 300,000 kilometers per second), making nearby travel within our solar system almost instantaneous.
2. Leaving the Milky Way
   Traveling beyond our solar system introduces a different scale. To exit our galaxy, the Milky Way, at the speed of light, it would take about 100,000 years. This emphasizes the immense size of just our galaxy and the limits of speed-of-light travel when considering astronomical distances.
3. Journey to Andromeda
   The nearest galaxy to the Milky Way is Andromeda, which is approximately 2.5 million light-years away. Even at the speed of light, it would take 2.5 million years to reach Andromeda. This shows that intergalactic travel, even at light speed, is a daunting challenge due to the vast distances between galaxies.
4. Traveling to the Edge of the Universe
   If you’re more ambitious and plan to travel to the edge of the observable universe, light-speed travel falls short. The universe is about 93 billion light-years in diameter, and it’s constantly expanding at a rate faster than the speed of light. This means it would be impossible to reach the edge of the universe, no matter how fast you travel.
5. The Expansion of the Universe
   The reason you can’t reach the edge of the universe at light speed is that the universe itself is expanding faster than light. This cosmic expansion creates a boundary that you cannot cross, even with the ability to travel at light speed. To surpass this limit, you would need to defy the current laws of physics as we know them.
6. The Limits of Light-Speed Travel
   While light-speed travel would revolutionize short-range space travel, such as trips within the solar system, the scale of the universe makes it insufficient for larger cosmic voyages. The immense distances between galaxies and the expansion of space itself make it clear that light-speed travel is far from a universal solution.
7. Defying Physics for Faster Travel
   To travel beyond the limitations imposed by light speed, a technology or phenomenon that allows faster-than-light travel would be necessary — a concept that, as of now, defies all known laws of physics. Speculative ideas like wormholes or warp drives have been suggested in theory but remain far from practical application.

In summary, while traveling at the speed of light would enable quick trips within our solar system, it would take hundreds of thousands to millions of years to travel to other galaxies. Reaching the edge of the universe would be impossible due to the ongoing expansion of space itself.