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/sci/ - Science & Math

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4854833 No.4854833 [Reply] [Original]

Hey /sci/, what would it take to send the moon on a crash course to Earth? What kind of devastation would the moon bring, and what about the tides?

>> No.4854841

pretty sure the moon smashing into the earth would be an extinction event.

>> No.4854842

>>4854841
Well, don't just sit there, tell me more or give me a link to a document about this stuff.

>> No.4854851

It would take approximately one fuck-ton of energy to deorbit the moon. Specifically, you'd have to subtract 3.837 X 10^28 joules of kinetic energy from its orbit to get it to come down.

If it would crash, we'd be utterly fucked. I don't have the ability to calculate just how much it would fuck us over, because gravity changes with distance and I don't care enough to work this out at one-thirty in the morning. Just trust me, it'd be XK-class extinction-level event.

As for tides, assuming we had any liquid water left, they'd pretty much stop except for the much smaller solar tides.

>> No.4854854
File: 147 KB, 325x324, 1302989021038.png [View same] [iqdb] [saucenao] [google]
4854854

I just wish for mercury and the moon to switch places. I want something new to look at. And the moon is still bigger than mercury.

>> No.4854859

>>4854851
What about the moon leaving its orbit? How much energy would be needed for that? What kind of doomsday are we looking at there?

>> No.4854870
File: 117 KB, 600x250, earthmoon.png [View same] [iqdb] [saucenao] [google]
4854870

>>4854859
A question like yours was asked in Astronomy magazine--

First it would take an object about 25% of the moons size-- hitting it head on in its orbit-- to slow it down enough so that it would crash onto the Earth. (or about the size of Ceres)

The moon would gradually spiral into the Earth over about a 1 week period, and extinguish all life on Earth.

>> No.4854883

I have returned, bearing more numbers- this time, for impact!

According to this: [google URL shortener]/bcVRA and some really rough back-of-the envelope numbers, the impact would release about 3.61 * 10^27 joules; According to the Boom Table, this is not much less than the energy required to vaporize all of our oceans, and more than ten times the energy needed to strip off our atmosphere. In short, we are utterly fucked.

Furthermore, even /all the way on the other side of the planet/, we'd be subjected to a magnitude 12.6 earthquake, worse than anything in recorded history. Furthermore, the boom would reach 103 deciBels even all the way on the other side of the planet, winds and shockwaves would be so severe that huge damage would be caused, which would be followed shortly by the shockwave blowing our atmosphere into space and a cloud of boiling-hot an entire ocean. In short, utterly fucked.

Also, depending on where it hit, we'd probably spit out enough random planet bits to make a temporary ring and a new, smaller moon- the calculator says no ejecta, but I call bullshit. It's probably just because I guessed it'd land in the ocean.

>> No.4854886

Here's the Boom Table, by the way: [Google URL shortener]/f4Rqr

Damned useful.

>> No.4854887

>>4854883
daaammmnnnn

>> No.4854900

Oh, whoops! I accidentally mucked up the calculations.

In the wussy direction. The moon's actually a /thousand times heavier/ than I plugged in.

Actual energy released? 3.61 x 10^30 Joules. Consulting the boom table, that's !!TWICE THE ENERGY REQUIRED TO BLOW OFF EARTH'S CRUST INTO SPACE!!

I think this needs repeating.

!!IT WOULD BLOW. OUR FUCKING CRUST. INTO SPACE. ALL OF IT. AND STILL HAVE ENOUGH BOOM LEFT TO DO IT AGAIN.!!

It will take about an hour before the shockwave reaches the other side of the planet from the impact. They will die. Instantly.

>> No.4854906

>>4854859
The moon is actually slipping out of Earth's orbit.

>> No.4854908

Just for kicks, the crater size, even though I'm sure the calculator breaks down at this scale:

Transient Crater Diameter: 4710 km ( = 2920 miles )
Transient Crater Depth: 1660 km ( = 1030 miles )

Final Crater Diameter: 14200 km ( = 8820 miles )
Final Crater Depth: 5.26 km ( = 3.27 miles )

So, final crater diameter is 14,200 km. For reference, that's /larger than Earth's diameter/. Yeah... something tells me that the calculator breaks down at this scale.

So yeah. This is definitely apocalyptic shit.

>> No.4854916

>>4854859

I already mentioned that- a bit of quick Googling brought me the figure of 3.837 X 10^28 joules, delivered towards slowing the moon down so it starts falling in a less "orbity" way and in a more "fally" way.

This is a pretty ridiculous amount of power in its own right, so don't worry, this isn't going to happen soon.

>> No.4854919

>>4854908
Not if we pray hard enough!