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  • Approaching the shores of Sicily, you're enjoying the views. The wind brings pleasant coolness,

  • and you anticipate your vacation. But suddenly, the boat shakes, and you lose balance. You

  • look up and see a huge plume of black smoke rising above the Etna volcano...

  • I'll switch from your perspective now because you won't like what happens to you in the

  • next several minutes. Let's take a look at the planet from the space. All across its

  • surface you see billowing spots of smoke - that's all the volcanoes on Earth starting to erupt

  • at once. Smoke is kind of a herald of what's to come: it rises first, warning us of the

  • danger. And then it varies for different volcanoes.

  • The active ones, like Etna in Sicily, will start spitting fire and rocks. They haven't

  • been slumbering to start with, so the magma at their core is hot and volatile. Smoking

  • boulders will fire up from the crater and fall on the ground nearby, while a fountain

  • of lava spews up and swiftly goes down the slopes. The temperature of this hot mess is

  • anywhere from 1,300 to 2,200 degrees F, which is a bit too warm for comfort. Anything this

  • stream touches will burst into flames at once, but not for long: lava is molten rock, and

  • outside the Earth's hot core it will soon cool down and become solid. What is left afterwards

  • is a greyish black mass that looks kinda wavy. Other volcanoes will have been sleeping for

  • too long, and their stock of lava wasn't that huge to begin with, so they won't really make

  • a blast. Rather, lava will slowly flow over the edge of the crater and pour down their

  • slopes. With a bit of luck, everyone in the vicinity will be safe because the hot stream

  • won't reach much further than the foothills - or shall I say, footvolcanoes?

  • Others still - and they're actually a vast majority - are underwater, so their eruptions

  • will be very different. When a submerged volcano erupts, no one on the surface will even notice

  • it if they're just a bit away. The water right above the volcano will start bubbling, and

  • its temperature will rise a lot. You'll probably also smell the stench of rotten eggs - that's

  • methane and sulfur coming from down below. If you're unfortunate enough to be in that

  • exact spot, though, you'll want it to be about a couple of hundred degrees cooler. There

  • might also be a hefty amount of pumice floating around - that's lava that cooled down in the

  • water and got filled with air bubbles. And then there are supervolcanoes. There are

  • only four of them on the planet, the most famous being the Yellowstone supervolcano.

  • If even one of these giants erupts, it will do so much damage it will change the landscape

  • of large part of the continent it's on. Now, like I said, all volcanoes on Earth start

  • erupting at once. It’s a bad day -- I’m guessing a Monday. Almost immediately they

  • bring disaster to their surrounding areas with hot lava and rockfall. As soon as that

  • stops, smoke rises into the atmosphere, and ash starts falling to the ground. It looks

  • like snow, only black. But ash is heavy and clingy, so when it falls onto roofs of the

  • buildings, it clumps together and soon makes them collapse under its weight. It's also

  • very dangerous to inhale this ash because it blocks the airways, not letting you breathe.

  • Quite soon ash covers everything. It blankets all surfaces, smothering grass, trees, and

  • bushes, and they stop producing oxygen. Smoke, on the other hand, creates a full-blown veil

  • in the skies above. This veil doesn't let the sunshine through, so the planet starts

  • to cool down by degrees. It becomes colder and colder, until a new ice age begins. If

  • there's still someone alive by this point, they'll have to deal with freezing cold and

  • huge glaciers far beyond their typical area. Closer to the equator, though, it might be

  • warmer than elsewhere, so therell still be hope.

  • But the irony is that CO2 is a greenhouse gas, and after a while its high concentration

  • in the atmosphere will warm up the planet again. The ice will draw back, and for some

  • time Earth will have a good inhabitable climate, but not nearly long enough for life to thrive.

  • Soon, the temperatures will rise to unbearable values, and itll be scalding hot until

  • CO2 goes away at least in part. Only then the planet might begin to return to normal,

  • but it may take thousands of years. Meanwhile, the oceans boil too. There are

  • hundreds of underwater volcanoes, and they erupt as well, throwing out thousands of tons

  • of gas and magma. And if magma stays mostly on the bottom of the sea, gases go up and

  • make the water hot and acidic. Much of the marine life can’t adapt to the changing

  • conditions this fast, and lots of species face mass extinction. Only the sturdiest remain,

  • and those are microscopic creatures that somehow survive boiling temperatures at the crevices

  • in the ocean’s bottom. In the next few hundred or even thousand years,

  • life on Earth is virtually nonexistent. About 95% of all living things are goneit’s

  • basically the same as what happened when a meteorite struck the planet in the era of

  • dinosaurs. Volcanoes have wiped out life, leaving only a veil of darkness in the sky,

  • plains of ash and solid magma on land, and acid instead of water in the ocean. If you

  • looked at the Earth from above, you would only hardly recognize the once blue and green

  • planet. But then, after sufficient time has passed,

  • Earth will begin recovering. At first, when carbon dioxide dissipates and the temperature

  • returns to more or less normal, plants will start appearing. Solid magma and ash might

  • make the land look desolate, but in fact theyre a rather good soil for the green. If you look

  • at Kamchatka, for example, youll see there’s grass and flowers and bushes springing from

  • the black mass around the less active volcanoes. So given enough time, the lands will become

  • lush and booming with plant lifeprobably more than ever.

  • With the return of grass and trees, oxygen will start pumping into the atmosphere. When

  • it’s rich enough, the air will once again become breathable for creatures with lungs.

  • But it will be a very long time before they appear once more. Since most life is gone,

  • the cycle will have to begin anew, from the smallest critters you can’t even see with

  • a naked eye. Thousands of years pass, and evolution kicks

  • in. New and bigger species appear. They continue evolving and growing, different animal families

  • pop up, and chances are very high they don’t resemble anything weve ever seen on our

  • planet. They might have six legs instead of four, for all we know, or even two heads!

  • Possibilities are endless. And finally, at some point in the distant

  • future, there appears the first species that learns to use tools. For us, these were primates.

  • For the Earth of the future, they could be anything. In any case, when they find sticks

  • and stones and start sharpening them to make stakes and primitive axes, it will be the

  • first step towards a new civilization. In a few more thousand years, a new intelligent

  • species will begin building their homes on the planet we used to claim for our own. Let’s

  • just hope they won’t have to deal with a massive all-out volcanic eruption same as

  • our civilization did. Well, hypothetically, of course.

  • Anyway, back to the now: what are the chances of having such a disaster? Next to none, in

  • fact. Scientists point out there has never been an eruption of this kind on Earth, and

  • there’s no indication it might happen in the future. You see, magma comes from the

  • upper layer of the Earth’s mantle. As it is, mantle is solid, but it’s so hot that

  • some part of it melts down, becoming fluid rock. When a volcano erupts, it means that

  • the pressure of this molten layer has become too much, and it needs to get out on the surface.

  • Once it does, the volcano it sprang from falls into slumber once more, only leaving traces

  • of lava down its slopes and, hopefully, no calamities nearby.

  • So, if all volcanoes on Earth were to erupt, it would take an extraordinary amount of excess

  • magma in the mantle. And since there’s not so much of it in the first place, such a collective

  • explosion is next to impossible. Ah, that’s a relief.

  • Now, about that big asteroid approaching from over thereha just kidding.

  • Hey, if you learned something new today, then give the video a like and share it with a

  • friend! And here are some other videos I think you'll enjoy. Just click to the left or right,

  • and stay on the Bright Side of life!

Approaching the shores of Sicily, you're enjoying the views. The wind brings pleasant coolness,

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