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Congressional Candidate Brianna Wu Claims Moon-Colonizing Companies Could Destroy Cities By Dropping Rocks (washingtontimes.com)
Applehu Akbar quotes a report from Washington Times: A transgender-issues activist and Democratic candidate for Congress says the advent of the space tourism industry could give private corporations a "frightening amount of power" to destroy the Earth with rocks because of the Moon's military importance. Brianna Wu, a prominent "social justice warrior" in the "Gamergate" controversy who now is running for the House seat in Massachusetts' 8th District, suggested in a since-deleted tweet that companies could drop rocks from the Moon. "The moon is probably the most tactically valuable military ground for earth," the tweet said. "Rocks dropped from there have power of 100s of nuclear bombs." After users on social media questioned her scientific literacy, the congressional candidate clarified that the tweet was "talking about dropping [rocks] into our gravity well." Small space rocks can indeed do nuclear-weapons-scale damage if hitting the Earth at orbital speeds. But launching one from the moon, even setting aside issues of aiming, would still require escaping the satellite's gravitational field, a task that requires the power and thrust contained in a huge rocket.
Original submission: Brianna Wu Is a Harsh Mistress.
You stripped this brilliant title and wrote in your blurb that spans two lines!
a.k.a. The Moon Is a Harsh Mistress from Robert A. Heinlein
Dropping rocks from the Moon? "Dropping" them?
And who the fuck would waste so much money and energy trying to fling shit from the Moon when it's cheaper to use nukes from Earth itself and harder to intercept due to shorter distance?
I still can't believe Wu's parents wasted 500k on this idiot's education. That much money should at least have produced some basic education in physics, and some common sense, even in the stupidest person on this planet.
The head of the House Science Committee spends all of his time denying and attacking science. She'll fit right in:
http://www.slate.com/blogs/bad...
Any genetics company could unleash killer microbes on Earth.
Agricultural companies could cause mass starvation if they wanted to.
Any company running nuclear power plants could contaminate large areas.
Any company manufacturing or using explosives could build bombs.
What's the problem with dropping a few rocks?
The lunar module got off the moon with not much thrust at all, look at the size of it compared to the whacking great rocket that got them there...
Doesn't take all that much to escape the moon actually, you don't need a rocket the size of one required to get off earth...
Aiming, fair enough though.
There you have it, people! Corporations are just waiting to throw rocks at you from the moon!
Can someone please give this woman an award for being so stunning and brave?
No, you just have to roll the rock over to the edge of the moon and push it off. Simple. No need to lift it.
It's better to keep your mouth shut and have people think you're an idiot than to open your mouth and remove any doubt that might remain.
Maybe she should concentrate on social issues. Physics ain't her strong side.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Here we go again.
I am sure there are trans people out there who are actually well educated in astronomy, physics, and have common sense to not tweet shit they don't know anything about;
and they are currently covering their faces with their hands and thinking "What the fuck did we do to deserve this idiot as our representation?"
I know that the US Congress is filled with idiots, but that doesn't mean that the first trans person needs to be one as well and serve
as a stain on the community's reputation.
I am sure there are corporations out there somewhere itching to nuke their sources of income, in some parallel imaginary Universe that can only exist in books.
Rocket power? Science fiction has typically suggested that you would use magnetic accelerators to send rocks from the moon to the earth, probably with solar power. It's not trivial, but it's theoretically possible to launch stuff from here to there using these means, let alone from there to here.
I'm not suggesting that it's trivial, far from it. You have to build the track and then you have to build the projectile. But if you're going there to build heavy industry, then yes, you absolutely could throw masses at the planet relatively cheaply.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
News at 11
"Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
. . . .running against an established Congressman (Stephen Lynch) who has been in Congress for 16 years, who has routinely been winning elections by 70%+ for years.
Wu's only real "in" here, is that Lynch is considered moderate. No idea on how that particular congressional district trends. . .
"Brianna Wu references Heinlein, Dumb Puppies Don't Know Which Side To Take"
More or less any industry on the moon would need a "cheap" way of getting mass to Earth. Without that, there's no point in putting the industry on the moon.
So when the BigBadBallBearing company builds their factory on the moon, they will include the means to get their products back to Earth, and those means, like many other tools, can be used for good or bad purposes.
- The Sigless Wonder
"But launching one from the moon, even setting aside issues of aiming, would still require escaping the satellite's gravitational field, a task that requires the power and thrust contained in a huge rocket."
Now you're just trolling. The Apollo moon landers managed to take off from the moon with a very small rocket. Yes, you'd need a comparatively larger one to launch a large rock, but the summary is misleading. It certainly wouldn't be a huge rocket. Now, you'd want to launch it retrograde from the moon's orbit so it would be moving slower than the moon's orbit around the Earth. That would make it take on an elliptical orbit around the Earth that picked up speed as it approached the Earth. The moon is going about 3.68 km/s in orbit and the escape velocity is 2.38 km/s so you'd only be going 1.3 km/s relative to Earth. You'd have to kill enough velocity that it would actually hit the Earth, but you're already 2/3 of the way there by escaping the Moon's gravity so it's not a "huge rocket" at all. In comparison, the delta-v required to actually get to the moon is somewhere around 15 km/s. This is basically straight from the plot of "The Moon is a Harsh Mistress." If your goal was to hit Earth with a big rock, you'd probably find it easier to do an asteroid redirect mission and nudge a large near Earth asteroid onto an impact course. Getting to the moon in the first place is about 15 km/s delta-v but getting to a near-Earth asteroid is more like 13.5 km/s, and then you can use something like a small ion thruster or solar sail to nudge it around and hit the Earth 3 passes later.
"I have never let my schooling interfere with my education." - Mark Twain
Is not entirely hinged
If people like her would keep their idiot mouths shut, the Moonie Times and right-wing zealots would stop being right about some things.
Escaping the moon's gravity is the easy part. The moon is in a really high orbit. To get something from the moon to the Earth, you need to either lose enough of your angular momentum to fall (i.e. accelerate really hard back along the orbital path) or accelerate really hard towards the Earth so that you end up in a sharply elliptical orbit that intersects the surface. Both of these require a lot of energy and would also give the ground target a few days to prepare. You'd likely evacuate the target city and then send something up with a few nuclear weapons (might less mass than big rocks!) to eliminate the threat.
TL;DR: If it were easy for things from the moon to fall to Earth, the moon would have fallen down already.
I am TheRaven on Soylent News
The Moon Escape velocity is 2.38 km/s while on Earth it is 11.186 km/s.
Since energy is proportional to the square of the speed (E=1/2*m*v^2) we can conclude that it is (11.186/ 2.38)^2 = 2 time easier to reach free space from the Moon than from Earth.
However, even if a rock is launched from the Moon at 2.38 km/s, it still inherits the inertia of the Moon. Simply speaking, the rock would not fall to Earth. It would be in an orbit similar to the Moon orbit.
The orbital speed of the Moon is about 1km/s so the rock must be given that additional acceleration to cancel its orbital speed.
At that point, the rock is immobile (from the Earth point of view) and it will start falling toward Earth because of ... gravity.
When it reaches Earth, its speed will be equal to the Earth Escape velocity (a bit less in fact since the rock did not start falling from an infinite distance) so 11.186 km/s.
The kinetic energy is given by the formula 1/2 * m * V^2 so for 1kg the kinetic energy at 11km/s is 1/2 * 1 * 11000^2 = 60 * 10^6 Joules
As a comparison, 1kg of TNT provides 4 * 10^6 Joules so each kg of moon rock would be equivalent to approximatively 15kg of TNT
The Hiroshima bomb was 15 kilotons of TNT = 15 * 10^6 Kg so a similar effect would require a 1000 tons of Moon rock and the ability to accelerate that rock to a speed of 2.38+1 = 3.38 km/s.
Look at the conservative voice being bolstered by the Slashdot conservative majority after launching into an attack on me. Just because I pointed out the Ms. Wu has approval on Slashdot roughly equal to that of the Ebola virus doesn't mean I agree with everything she says.
The double standard in effect here is also telling. The POTUS says all kinds of stupid shit on Twitter, at least weekly. Yet he is not held to everything he posts there but Slashdot readers are on a roll attacking this person who wants to run for congress over this tweet. The fact that she is even aware of the amount of damage something dropped from space could do suggests she likely has a better grasp on physics than our POTUS, even if her tweet did not show a good understanding of the matter of launching something from the surface of the Moon.
And your claim of her saying that someone would just "throw" the rock is supported by what? Yeah, nothing. But go ahead and insert whatever you want into the argument, you'll win this one by majority vote alone (as you've already seen). Slashdot will happily bash her at any opportunity while praising the GOP in the same breath regardless of which one shows a better understanding of physical reality.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
Escaping the moon's gravity is the easy part. The moon is in a really high orbit. To get something from the moon to the Earth, you need to either lose enough of your angular momentum to fall
It turns out, however, the higher an orbit is, the easier it is to kill your angular momentum and drop. So the fact that the moon is in a "really high" orbit helps here. You need about 1 km/sec to kill the moon's orbital velocity, actually less than the 2.38 km/sec escape velocity to throw the rock off the surface.
But delta-Vs don't add; energies add. Once your mass driver has gotten your rock to 2.38 km/sec, it only takes another 0.2 km/sec to kill the orbital velocity and make it drop. (Less, if you want to take an indirect trajectory via the "fuzzy boundary", but those take a lot more time).
...and, yes, actually I am a rocket scientist.
...
TL;DR: If it were easy for things from the moon to fall to Earth, the moon would have fallen down already.
In fact, rocks splashed off of the moon actually do hit the earth, of course: http://meteorites.wustl.edu/lu...
http://www.geoffreylandis.com