But what if we tried MORE power?

this question comes from me it's a new chapter from the 10th anniversary edition of what if which is now available online and in print at the end of the laser pointer video we constructed an array of lasers with a total power of 2 * 10 24 Watts which not only lit up the moon but violently ejected it from orbit around the Earth we decided that was enough power but why you can always make a number bigger no one can stop you there are infinitely many numbers and I want to know what if we tried even

more power a 2 * 10 the 24 W laser is powerful when we turned ours on it made the moon facing surface of the Earth significantly more luminous than the sun that's impressive but we can do better the universe contains death rays that make our moon obliterating beam look like a handheld laser pointer gamma ray bursts a gamma ray is just what we call a very high energy Photon of electromagnetic radiation when you see a chart of the electromagnetic spectrum gamma rays are basically anything more energetic than X-rays at the high end they're literally off

the chart they come from high energy events like nuclear explosions Gamay bursts are made when something very bad happens to a star when massive stars collapse their cores give into the crushing pole of their own gravity release an enormous burst of energy and tear the star apart from the inside for reasons that we don't fully understand these explosions often produce jets shooting away Along the poles of the collapsing star these Jets can travel across much of the universe and when Earth is in line with one of them we see it as a flash of gamma

rays from deep space we didn't know about gamma ray bursts until we launched a satellite to watch for gamma ray flashes from nuclear explosions on Earth and we were surprised to see flashes coming from everywhere else in the universe instead the peak power of beams from Gamay burst can be on the order of 10 to the 44 Watts which is much much more powerful than our laser array to get a 10 to the 44 watt death ray of our own we need to give each person on the moon facing side of the planet a 2

* 10 34 watt laser that is each person would need a laser 10 billion times more powerful than the final combined laser that violently ejected the moon this is an implausible scenario and it wouldn't work for reasons we'll get to in a minute but first let's think about what we could do with a beam like that we'd have to focus it carefully since laser beams spread out as they travel the minimum angle of spread depends on the size of the source of the beam for laser beams emitted by lenses 2 m wide the limit is

about .1 arcs or 3 100,000 of a degree the laser beam limit formula is weirdly similar to the formula used to determine the maximum resolution of telescopes like Hubble because in a sense a telescope is just a death ray running in Reverse Hubble has a 2.4 M mirror and its angular resolution is a little less than .1 arccs similar to the angular limit of our 2 m laser the laser array from the original chapter was pretty powerful but not particularly narrow if it had been focused into a Hubble style beam it could conceivably have fried

the surfaces of planets anywhere in our galaxy attend to the 44 watt death ray would be much worse if we tightly focused it down to the defraction Limit it could reach targets far outside our galaxy frying the surfaces of planets up to 5 or 10 billion light years away but don't rush out to buy a 10 to the 44 wat laser just yet at cosmic energy scales normal Optics breaks down for example if a beam is powerful enough it could exert a gravitational pull on itself photons carry energy and energy creates gravitational fields for normal

light beams this is negligible but for a 10 to the 44 watt laser the size of the Earth photons on the Outer Edge would experience an acceleration of over 10 G's toward the beam center line but physics has another surprise one that finally puts an upper limit on how powerful lasers can get namely if a beam of light gets too bright space itself stops being transparent if you pack enough laser energy into a small enough space quantum mechanics predicts that the strong electromagnetic fields will result in spontaneous creation of particles and antiparticles these particles mostly

electrons and positrons would intercept some of the laser energy which will result in more particles being created for laser power densities above about 10 to the 26 watt per square cm this process is expected to Cascade fully halting the Laser's progress and providing an upper limit on how much power our beam can have in the end it turns out physics is not math you can always find a bigger number but you can't always make a bigger laser