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  • 1.3 billion years ago,

  • two orbiting massive black holes,

  • circling each other at 250 times a second,

  • collided in a violent, universe-rippling explosion

  • that sent waves of energy

  • throughout the cosmos.

  • In its wake, a new supermassive black hole

  • formed over 60 times bigger than our Sun.

  • Fast forward to September 2015,

  • gravitational waves

  • from this ancient cosmic event

  • finally struck Earth.

  • Luckily, the gravitational waves weakened

  • over such a great distance.

  • But what if we weren't so lucky?

  • If a couple of black holes

  • in our Solar System collided,

  • could we survive?

  • This is WHAT IF,

  • and here's what would happen

  • In 1916, Albert Einstein made waves himself

  • with his groundbreaking theory of general relativity,

  • known famously by the formula E=MC*2,

  • He proved energy and mass are interchangeable,

  • and that space, or space-time,

  • curves in relation to the energy and momentum

  • of whatever matter and radiation are present.

  • With great foresight,

  • Einstein inferred the collision of black holes

  • or massive stellar objects

  • create distortions in gravity

  • which are pushed out in all directions.

  • Thanks to incredible developments

  • in atomic measurement,

  • scientists in Washington and Louisiana,

  • in the U.S.,

  • at the Laser Interferometer Gravitational-Wave Observatory,

  • were able to detect and measure

  • the first ever gravitational waves

  • here on Earth in 2015.

  • This was a historic moment in science,

  • as it was the first definitive proof

  • of Einstein's theory of relativity.

  • Using laser interferometry,

  • observatories can detect a change

  • less than ten-thousandth the diameter of a proton.

  • That's one million times smaller

  • than the width of a human hair.

  • Since then, LIGO has measured

  • 50 detections of gravitational waves.

  • There are many sources of gravitational waves,

  • including the collision of black holes,

  • the rotation of asymmetrical neutron stars,

  • supernovae or even remnants

  • of gravitational radiation

  • caused by the Big Bang.

  • These waves travel at the speed of gravity,

  • equal to the speed of light,

  • and emanate outward in all directions.

  • Like a rock being thrown in a pond,

  • the ripples it creates

  • dissipate over great distances

  • and become smaller and smaller.

  • Luckily, in our pocket of the Universe,

  • we are over 400 million light years away

  • from any orbiting black holes.

  • We're generally safe,

  • but if these black holes happened

  • to be in our Solar System,

  • the implications are much more dire.

  • When gravitational waves

  • pass through a planet,

  • one side is compressed

  • as the other expands,

  • kind of like squeezing a stress ball.

  • I could use one of those right now.

  • As a result, time and space itself

  • are stretched causing a slight wobble.

  • But if we were closer

  • to this violent event

  • and the waves were much bigger,

  • this impact could potentially

  • tear our planet apart,

  • triggering powerful

  • continent-splitting earthquakes,

  • volcanic eruptions

  • and epic storms.

  • Earth wouldn't really be a habitable place anymore,

  • except for maybe extremophiles

  • like bacteria that thrive in hydrothermal vents.

  • Let's imagine our Sun was a neutron star

  • of an imperfect, non-spherical shape,

  • sending gravitational ripples

  • outward as it spins.

  • Earth would likely look more like Io,

  • one of Jupiter's moons,

  • which is put under great gravitational pressure by Jupiter

  • and, as a result,

  • is one of the most volcanically active

  • moons in the Solar System.

  • Our landscape would be covered in lava

  • and volcanic fallout

  • with an atmosphere made up of toxic gases

  • like hydrogen sulfide.

  • This would cause massive global warming

  • and intense storms,

  • constant tsunamis,

  • tornados,

  • and well, you get the idea.

  • Climate chaos.

  • We can count our blessings

  • we are nowhere near

  • any massive objects

  • shooting out gravitational waves,

  • but thankfully, we can still measure them

  • and learn more about

  • the complexities of our Universe.

  • Even though we get hit by gravitational waves,

  • they are generally so small

  • we can't even feel any impact.

  • But on the flipside,

  • what would it be like

  • if we suddenly lost our gravity?

  • That sounds like a story for another What If.

1.3 billion years ago,

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What If a Massive Gravitational Wave Hit Earth?

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    吳子豪 posted on 2021/04/08
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