Originally Posted by Stupid Doog
No point in them returning to Earth. Everyone is dead.

Man, there was a lot to wade through at that link.

But in a nutshell...

Quote
Ok, let’s step even more firmly outside the realm of plausibility.

The most powerful laser on Earth is the confinement beam at the National Ignition Facility, a fusion research laboratory. It’s an ultraviolet laser with an output of 500 terawatts. However, it only fires in single pulses lasting a few nanoseconds, so the total energy delivered is about equivalent to a quarter-cup of gasoline.

Let’s imagine we somehow found a way to power and fire it continuously, gave one to everyone, and pointed them all at the Moon. Unfortunately, the laser energy flow would turn the atmosphere to plasma, instantly igniting the Earth’s surface and killing us all.

But let’s assume that the lasers somehow pass through the atmosphere without interacting.

Under those circumstances, it turns out Earth still catches fire. The reflected light from the Moon would be four thousand times brighter than the noonday sun. Moonlight would become bright enough to boil away Earth’s oceans in less than a year.

But forget the Earth—what would happen to the Moon?

The laser itself would exert enough radiation pressure to accelerate the Moon at about one ten millionth of a gee. This acceleration wouldn’t be noticeable in the short term, but over the years, it adds up to enough to push it free from Earth orbit.

… If radiation pressure were the only force involved. [ etc., etc. ...]

So basically, a laser powerful enough to even be seen on the moon, let alone be viewed in a rocket ship flown by Batman and Robin in space flying near the moon, a laser light that strong would burn away the Earth's atmosphere and kill everyone on the planet.

And maybe push the moon out of its orbit as well.

Definitely stuff that could not have been even imagined at the time that cover was drawn in 1950.
A Bat-signal visible on the moon is still a no-way scenario even in our era, but we at least have lasers now approaching that level of power, and can at least conceive what that level of power could do to the Earth's atmosphere, and to the moon.
Which definitely ups the WTF-factor.