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Let's say that a giant space rock (10 km) is Impacting the Geographic South Pole. If humanity is at its present-day level, what would be the climatical and technological impact on Humans and the Earth?

My understanding is that a tsunami will rise from Antarctica and impact the Southern Countinents, and a mass extinction will happen. (If needed, assume that it is traveling at 40 km/h and impacts at a 45 degree angle from the surface.

Edit: I mixed up my units: the speed is 40 km/sec

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    $\begingroup$ What exactly is travelling at 40 km/h? That speed may be the right order of magnitude for a tsunami wave, but then the mention of a 45 degree angle hardly makes sense. An asteroid is going to be travelling at more like 40 Mm/h than 40 km/h. Even free-falling just toward the Earth from a large distance, an object is going to reach very close to Earth escape velocity which is over 11 km/s which is very close to 40 Mm/h. $\endgroup$ – a CVn Nov 19 '16 at 21:38
  • $\begingroup$ Have you checked the impact effects calculator impact.ese.ic.ac.uk/ImpactEffects And as noted, 40km/h is about 1000 times too slow. $\endgroup$ – James K Nov 19 '16 at 22:03
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    $\begingroup$ You obviously meant 40 km/sec. You can edit, if you like, but please make sure you make the edit plain so that comments and answers are not left dangling. $\endgroup$ – WhatRoughBeast Nov 19 '16 at 23:23
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Here are some references which I am summarizing below: here, here, and here

Impact

First off, 10km is about the estimated size of the Chixlub impactor (that killed the dinosaurs) which itself is the third largest known impact crater. So this impact would probably be a top 5 impact for the last billion years. The asteroid hits with an impact of 60 million megatons of TNT (Tsar Bomba was 50 megatons). Its energy release is equivalent to a 12.4 magnitude earthquake (~250 times more powerful than any known earthquake). Chixlub' crater is still 180km across 60 million years later, so it is going to leave a mark.

Tsunami

None! The south pole is on land, and no particularly close to water. No tsunami.

Steam

The for that 180km wide impact crator, all the snow and ice is vaporized into steam, which rapidly expands into a blast wave emanating from th south pole. Luckily very few people live near the south pole, but some unlucky folks in places like Tierra del Fuego and the Falklands get flattened and cooked by the blast wave.

Ejecta

The passage of the asteroid literall punches a hole in the atmosphere. Through this hole, molten crust/astroid bits will be thrown up nearly into space. This stuff will then land around the southern hemisphere starting fires. The sky is filled with smoke as the Amazon rainforest burns down.

Acid rain

The heat of the impact fuses nitrogen and oxygen in the atmosphere together into nitrogen dioxide, the precursor for nitric acid. The southern hemisphere is covered in nitric acid rain, dooming any plants not burned by ejecta. Fortunately, the ITCZ provides a weather barrier that limits crossing into the northern hemisphere.

Temperature

Global smoke reflects sunlight into space and causes massive cooling for several years. After that, the carbon dioxide released by massive world-fires causes massive global warming.

Doesn't sound pleasant! Hope I'm not around.

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  • $\begingroup$ no tsunami from the impact quake, plenty of tsunami from the triggered secondary earthquakes. $\endgroup$ – John Nov 20 '16 at 14:30
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massive ash clouds from the molten rock, if it hits an icesheet the ash is even worse. Every existing fault line on earth experiences severe earthquakes which also causes tsunami all over the globe. Every volcano with any pressure erupts, this plus the ash blots out the sun for days.this also cause widespread acidic rain. If it hits at the right angle you also might get a new volcano forming on the other side of the planet. honestly the asteroid is not as bad as all the earthquakes and volcanoes the shock wave triggers.

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