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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.
Would someone please inform Ms. Wu that while there may be many people who are interested in what she has to say, that does not give her license to go speculating far outside her field of speciality (which I'm fairly certain consists solely of electronic entertainments). ...Actually on second thought, that's probably exactly why she'd fit right in with Congress. Get her on the House Science committee with Lamar Smith; I'm sure they'd get along famously.
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.'"
The physics might work, but even assuming the technology is developed I doubt earth governments would allow the construction. And they'd have a lot more power at their disposal - 1 nuke would be the end of it.
News at 11
"Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
That's brilliant, but what if it hits a turtle?
Homeopathic WMDs! OMG!
So, let me see if I have the summary right:
1. Take a large rock in space
2. Dilute that rock with space, yielding a large space rock tincture
3. Repeat the process until you have a small space rock tincture
4. Drop the small space rocks on Earth, from the height of the moon (works because the moon is "up" and the Earth is "down")
5. Kaboom!
6. ???
7. Profit!
My god! What if she thinks to use space dust, instead! The more you dilute a homeopathic tincture like that, the more effective it becomes! We're all doomed!
. . . .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"
All you'll hit is the moon and not that hard.
Wanna buy a shirt?
https://www.redbubble.com/people/stealthfinger/shop?asc=u
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
The turtles are 100% covered by the elephants, so the turtles will be perfectly safe.
Is not entirely hinged
Look at the idiot trying to defend an idiot. How cute.
And Hank Johnson was just "joking" when he talked about Guam capsizing too, right? A "kinetic weapon" on the moon is tech far over Brianna Wu's head. Besides, why put it on the moon when you could just have it in orbit for several orders of magnitude less cost? No. She literally said "dropping rocks". ROCKS. All the bit about lunar gravity (which is slight but nonzero), orbital mechanics, trajectories, and having to survive re-entry through our atmosphere are merely incidental. She thinks if you throw a ROCK hard enough from the moon, you could hit the Earth. And of course because the moon is so "high" in the sky, I'm sure she thinks that the rock will be approaching light speed by the time it lands...
Seven puppies were harmed during the making of this post.
By comparison the LEM weights 2 tons dry and 15 tons total, with 8 tons fuel.
Uh, but that's to land and then take off again. The LM Ascent Stage is what you need to compare to:
Dry mass: 2,150 kg
Propellant mass: 2,353 kg
--but, as noted above many times, nobody's suggesting a rocket to do this. Heinlein proposed this decades ago. You'd use a mass driver.
http://www.geoffreylandis.com
If people like her would keep their idiot mouths shut, the Moonie Times and right-wing zealots would stop being right about some things.
I remember a day when slashdotters would instead ponder the point at hand, then enjoy themselves as they work out the maths and engineering details to accomplish it.
I'm god, but it's a bit of a drag really...
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 Earth will take it in the same way that it took the moon - it will enter Earth orbit. Starting from a lunar orbit, you need quite a lot of energy to move it into an orbit that intersects the Earth (or even intersects the atmosphere enough that eventually friction will decay the orbit into one that hits the Earth).
I am TheRaven on Soylent News
I've been noticing the same thing, I used to be considered "OMG he's a fucking Fascist" around here and now I'm just a smidgen right of center. Before posting anything in a AGW thread was instant karma death, now I even get modded up more often than down. The group-think here seems to have done a 180!
Apocalypse Cancelled, Sorry, No Ticket Refunds
She's read The Moon is a Harsh Mistress. (Which most of the commenters apparently haven't.)
The bigger point she's bringing up (clumsily or not) is that the Moon is uniquely valuable real estate and we really ought to keep that in mind as we address its impending exploration, explotation, and colonization.
Rule 35 of the internet: "If it can be hacked, it will be". - Charles Stross
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
Fondness for the organs, contempt for the person. It really isn't that complicated.
My comments were on the technical part-- this site is news for nerds, you know. Whether you should be "afraid" is a completely different question.
I do point out that this is, so far, 480 posts (on slashdot alone) discussing details of a 140-character tweet. That's 3.4 posts for each character of the tweet, including the blank spaces at the end.
It's possible that you're overthinking it.
http://www.geoffreylandis.com
your attempt to defend the indefensible
I encourage you to go back and try reading what I wrote, before you make such sweeping assumptions about its content. I never defended any position of hers in my comments. I merely pointed out that she is a very popular target of the Slashdot conservative majority. Being as you likely didn't read any of the actual text involved - one would have to go far beyond the slashdot summary and even beyond the shitty Washington Times article that said summary links to in order to do so - it doesn't surprise me that you also didn't read what I wrote before you hit the submit button to reply to it.
In other words, your bias is showing. Try putting some thought into your comments next time.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
Republicans tend to have a hard time with jokes that don't end in "Clinton" - especially the republicans that run this joint.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.