If you slowed a comet of this size to about 1m/sec and gently dropped it in a desert...

>planet's orbit or tides be affected?

Not at all. Gently dropped is the world.

What's it made of?

It might nontrivial the world but it might do a number on the economy.

That's not even a tiny pebble when compared to the planet. Earth is huge. HUGE. Also, a comets are mostly ice and dirt so they're hardly the densest objects flying around.

>orbit or tides
No, but weather would and being motherfucking weather and all could have some sort of cascading effect all over.

from what height? You say gently dropped, so short enough distance that it only accelerates to 1 m/s by the time it impacts?

Probably not much of an affect at all globally. Massive seismic activity in the local area and a small explosion of air as it landed and settled

Might affect the tectonic plates depending on how goddam heavy it is and where you drop it.

That comet is 67P/Churyumov-Gerasimenko. It's 4.3 x 4.1 km maximum length and wideness, respectively, and weights ten trillion tons.

Char go home, you're drunk

Reverse image search tells that it's a picture of a comet, 67P, compared to the Los Angeles skyline. 67P has a mass of 10^13 kg and is the size of a mountain.

The Earth accelerates at (10^13 kg/10^25 kg) * 10 m/s^2 = 10^-11 m/s^2 towards to comet, which is insignificant. The comet's effect on tides is likewise insignificant.

The impactor at 1 m/s has ≈ 10^13 J of kinetic energy. Some of the 10,000 gigajoules of energy will turn into heat glassing the desert, but the impact should also cause an ≈M5 earthquake.

The energy released (2 kt of TNT) is about 1/10th that of the Trinity test, the bombings of Hiroshima and Nagasaki, and the 2016 North Korean nuclear test, and about the same as some tactical nukes the US developed, such as the "nuclear backback" based on the W54 warhead.

So there's not a significant lasting effect?

>nuclear backpack
Why tho? Will the situation be so shit that your dudes have to deliver nukes by carrying them in backpacks?

Not really. Some local seismic events over the next few years as it settles down and the ground adjusts to the new mountain.

It is more a case of not having to break out the ICBMs. You parachute behind enemy lines and use it to hit critical targets

no missiles were detected = no counter-launch.
Israel just have similar set up in their embassies so they can hold nations to ransom 'fuck with us, we take out your capital'. Any US aircraft carrier has one in a doorless compartment for 'in event of mutiny/coup': blast should take out the carriers escort & support vessels too. I'm surprised they haven't been used in a false flag' incident yet.

>[citation needed]
I don't actually expect you to have one but it would be cool if you did.

Thanks, Dr Dan

Not that guy and have no idea as to the veracity of what he's talking about, but it wouldn't surprise me.

Look into the Samson Option.

any other effects such as possibly the collapse of the structure or maybe it sinking into the bedrock?

>If you slowed a comet of this size to about 1m/sec and gently dropped it in a desert, would the planet's orbit or tides be affected?
No, but it would still fuckcrush everything underneath it, the sheer weight would probably not allow it to continue moving at that speed and either way it would crush/deform the rock underneath it even if just placed at like .001m/s; once it was in place it would have to settle.

Take the specific shape of that one in your pic for instance: that's not a stable resting alignment for it, the overhang on the left side would press the left "resting point" down more than the right one would be on its side.

>potential damage to the tectonic plates

>1 m/s
>damage

wut
I are you just using jargon you don't know the definition of?

Even high-speed impacts on the order of 1 - 10 km second barely damage a tectonic plate
nature.com/nature/journal/v429/n6991/full/nature02577.html

On a similar topic, I'm math retarded, so figured I'd ask here: how fast would I have to fire a 10 ton projectile to destroy the moon? How about Earth itself?

Basically, how do I exterminatus without explosives?

...You just replied to Dr. Mantis Toboggan. What did you expect from his science?

Even more then that, a stone object of that size would be far too heavy to hold itself together. It would break apart and fall into a generally mound shaped object until it was resting supported on the ground, the result being something like a mountain.

You need 2.3x10^32 joules, or something like it. That treats the earth as a gravitationally bound sphere of dust in a friconless vacuum.

Using Newtonian math we get a velocity for the energy required and the mass you've offered (10,000kg) you get..

678,232,998,312 kilometers per second. The problem is that the speed of light is about 300,000 kilometers per second.

We need to bust out some special relativity on this.

Long story short, about .9997c, where c = the speed of light in a vacuum.

I'm kinda drunk and bad at math (that's why I'm a geologist) but I think you would need to launch it at 10,000,000,000 m/s

Assuming the moon is on average olivine basalt, the molecular weight is 245 g/mol. Wiki says the moon is 7.35 x 10^22 kg so 3^17 mol. Moon doesn't really have much of a mantle/core (see animation , moon's proto-core was left behind during collision with protoearth) so this is less of a problem than averaging the earth. Bouhifd et al 2006 says that the enthalpy of fusion for basalt is (averaging their values) 24.5 Kj/g. So 6000kj/mol * moon mols = 1.8 * 10^21 kj to melt the moon.

ke = mv^2 so 10000kg * (10000000000 m/s)^2 is enough kinetic energy to compeltely melt the moon. You would need less that that of course to kill everything but might as well liquefy the rocks to be sure.

Got it, how big an object do I need to get it somewhere around .7 or .8 c? And what sort of time dilation shit would be going on with the projectiles?

Lol I'll tell my dad this.

But seriously, math is bullshit. I hate using it in stats (political scientist here), and still have no idea why I tutor math for my job.

Time dilation on the projectile isn't going to matter unless someone is standing on/in the thing, and even then, it'll matter a lot less once the projectile hits. You are blowing up the moon - you cannot expect the projectile to survive impact intact.

Long story short, if you are crashing into the moon in hopes of breaking it, you will have to go fast enough to void the warranty on your everything.

67P is very fluffy and only has a density of 0.5 kg/liter, half that of water. Most comets are composed of volatiles with a small percentage of rock, and are only loosely held together. It won't hold its shape.

I'd assume the immense heat released would vaporize some parts of the comet despite the low velocity of impact. If we assume 1% (10^11kg) of the comet's mass was rocky material that didn't get blown away or vaporized by the resulting explosion, and the area of the impact was around (3km)^2 = 10 km^2, it would form a pile no higher than 50m. So the result from 67P might look something like a much flatter Uluru, which is about that wide and 350m high.

Dropping an asteroid would probably be wiser if you want a prominent mountain.

...

Yes, God forbid we lose out on a slot for another primarch dick measuring thread.

EMERGENCY BUMP.

This shit is fascinating.

I'm more interested in the effect of this thing on the economy and tech of the country it landed. Nations spend billions to dig rare earth metals and even plain ol iron. Suddenly you have a whole buttload of it next to your capital. Discuss.

After reading through the thread and giving it some thought, I'm pretty sure that the biggest effect would be the comet weighing down the tectonic plate right there. It'd be like adding a new mountain. However, that's not really going to do anything. Assuming some geologists run out to it And knowing them, bust some ice off for whiskey cooling to plant some sensitive GPS sensors, within a few years they'd measure the land sinking in response to this added weight. There might be some minor effects noted with this, like very low intensity earthquakes, but that's the worst I can imagine.

What I'm wondering about is whether or not the comet melting and releasing its gases would do anything interesting. But I'm just another geologist, I've got no fucking idea on that one.

Pretty sure that if it's a comet, the biggest social results would just be a few ass-loads of scientists showing up within a couple of days to poke and prod and possibly pick up their Philae lander. Comets are mostly stuff you could find here on Earth, with the exception of fresh science.

Now a chondrite would be a different story!

Isn't that 67P/Churyumov–Gerasimenko that the Rosetta probe landed on?

would the planet's orbit or tides be affected?

No.

Orbit, not even slightly.

Tides, the closest it would get is *possibly* a very slight Spring Tide, s its being pulled in, so if there's a sea near that desert, it might have a high tide half an inch higher, if it happens to be pulled in for landing just as its at high tide.

What's more likely to result is if its a comet, the object will go "crash" into the ground causing a mild earthquake nearby, and then, over the next year or ten, the water will slowly evaporate and leech into the surrounding area - it may make the desert bloom for years after in the area - and the comet will collapse under its own weight, crumbling down into a mountain perhaps 1/2 to 1/3 its original height, rounded and spreading out in landslides as the icy water content melts and slumps into a huge gritty pile of boulders and earth. the water content may see it become green and get held together by plant life for a few decades of centuries too, softening its shape further.

Comets are mostly ice.

Could be an interesting event in a fantasy setting. A god / mega-mage cushioned the planet from the Comet's impact and instead its ice began to nourish the desert around it. It would be one of the most holy places in the land and definitely doesn't have an alien monstrosity frozen deep within.

what about the resultant flood caused by the significant amounts of water in the comet?

Depends on what percentage is water. A significant percentage would actually flash-boil.

bottle it, call its space water, claim the space has given the water health properties and sell it making more than you would from the iron and the iridium

It wouldn't change anything but, if it were the same shape, it wouldn't be stable. Something that big would collapse and crack into smaller parts after it landed, even at a slow speed.

Using the tallest skyscraper as a measure, let's guess that the comet is maybe 10 skyscrapers in diameter.
If the skyscraper is 300m or so, we'll call the comet a sphere of 3km diameter, just to simplify.
It'll have volume of (3/4)*pi*(3km/2)^3
That is 14.4 cubic kilometers.
1 km^3 is 10^15 cm^3 (I think).

Now what is the density of the comet? Is it made from Iron or dirty ice, or a mix, or just a lot of rock?

Math is wonderful, and you are a bad person.
Firstly for disliking math, but also for wanting to destroy the moon.

Anyway, you need some relativistic equations up in here, because your projectile is moving 33 times the speed of light, which means it has an inertia of several times infinity.

see

it'll do a number on the economy even if it's just made of rock. i'd say the people in the area who can sell bits of the "huge fucking rock from space" would all get pretty rich.

>comet melting and releasing its gases

Mostly CO2 and H2O and neither in sufficient volume to do much

It would be easier to just get a bigger/denser impactor

>ice has melted away, leaving the huge rocky core

>over time villages spring up in the surrounding oasis

>when that which has slept in the core awakens

Well, that's more boring than I expected. Huh.