Cosmic Laser Debate | New Insights on Odds of Hitting in Space

A growing conversation online is examining the likelihood of a laser hitting something in the universe. Participants are diving into practical implications of light speed and space vastness, which adds a new twist to the ongoing debate.

Examining the Odds of a Hit

Discussion revolves around whether a randomly aimed laser could strike anything. Many people believe the odds are low. A commenter succinctly noted, "In practical terms, you very likely wouldn’t hit anything."

However, some inject optimism into the debate. One participant confidently stated, "If I point in a random direction, the answer is probably around 100%." This view hinges on the sheer expanse of the universe, even though probabilities might be slim.

Beam Dynamics and Their Limitations

The dynamics of laser beams are critical in this discussion. A new comment suggests that, due to its properties, a laser beam spreads out as it travels. Given a typical 650 nm laser pointer with a 1 milliwatt output, the beam width can expand significantly; at the distance to the nearest star, it can reach a diameter of 175 times greater than the Earth-sun distance.

"If you accidentally point it in the plane of the Galaxy, there’s a lot of dust, leading to significant extinction."

The commenter calculated that at 35 magnitudes of extinction, only one out of every trillion photons would make it through. Notably, even if a laser is pointed incorrectly, it could release around 330 photons per second into intergalactic space, albeit with very slim odds of hitting something.

Olbers' Paradox and Cosmic Expansion

The conversation is also tackling Olbers' paradox. As some stars exist beyond any potential laser paths, people pointed out that "in an infinite forest where distant trees recede faster than light, the laser will not hit them ever!"

Key Insights from the Ongoing Debate

• ⚫ Practicalities vs. Optimism: Real-world challenges temper expectations of hitting cosmic objects.

• ⚪ Beam Distribution: Lasers face significant obstacles like atmospheric conditions and distance-related beam spread.

• ※ Visible Stars: A rough estimate suggests a chance of 1 in 1500 for hitting a visible star.

Curiosity about cosmic inquiries continues to spark interest, blending practical physics and theoretical limits, as this topic fuels conversations on various forums.