/sci/ - Science & Math

No.

>>6291413
It wasn't a yes or no question.

yada yada lead-time yada yada mass drivers yada yada bruce willis

>>6291414
>is there actually any technology that exists right now capable of preventing it, or is that just a total pipe dream?
Yes it is

No, not really.

Lol are you guys retarded? All we'd have to do is go into space in a space shift and just push it a little to the side. You can probably fly next to it and match its speed then just get on the roof and shove it. Shouldn't be hard because ur in space so everything is massless, and since sound/heat can't travel in vacuum u r safe

Too big, too fast, too strong, too absorbent.

There is a pair of binary asteroids that are going to make a close flyby around 2021. NASA is planning to knock the smaller asteroid of the two into space to test the possibility of preventing an asteroid impact in the future.

three words: antimatter photon beams

>2014
>We still don't have a means of evacuating a minimum of 10,000 human beings from the planet to preserve humanity in the case of a catastrophe

the problem is that space is really big, and really hard to find things in, especially small dark things like asteroids. For every asteroid we track, there's dozens more we don't know about.

>>6291455
yeah, but the ones capable of destroying all civilization are pretty big, so they're easy to see.

Not yet, no. Our best possible bet would be to bunker down as deep under the Earth as we possibly could and hope for the best.

>>6291448
this

>>6291429
Nope. You're a troll.

>>6291458

I once thought that maybe we wouldnt even need to bunker. That a big problem was post impact endless winter and starvation because of it, but that a select few, outside the impact damage area, could huddle around power plants and artificially grow crops. Of course a massive cull would occur. :/

Then I saw a presentation that the dinosaurs died in a single day when reentering ejected raised atmospheric temperature to oven levels, so yeah, for certain impacts burrowing like our lucky tiny mammal forebears is the effective strategy. But maybe for others the power plant/artificial crops scenario is viable.

>>6291475
Burrowing is amazingly effective. Animals that survived as little as two feet underground were able to survive in areas where all life on the surface was wiped out.

>>6291429
>massless

gtfo

>>6291429
i went to space once. :)

>>6291408

yes, rockets with nuclear warheads can create a blast to change the asteroid's

>>6291521
>Solid mass of iron
>Not being able to take nuclear warheads like nerf darts

>Honeycombed clusters of debris
>Not absorbing it like a sponge

>>6291523
Depends on when we spot and intercept.
Early enough in the trajectory, a nuke could shift a nickel-iron asteroid out to a near-miss, or blast apart a looser agglomeration such that it's more like a shotgun blast of small particles that burn up in the atmosphere.

Of course, at our current level of tracking and prediction, we don't know if an object is definitely going to impact Earth until after it is too late to modify its track.

>>6291523
>not strip mining the fuck out of it

>>6291541
Honestly, the FUCK-THE-BUDGET solution is someone figuring out how to tow asteroids into our moon's orbit, and proceed to mine them.

A sure way to be the worlds first trillionaire.

>>6291545
I'm sure it could be done with a very large magnet

>>6291547
Hey is that free energy?

>>6291448
>he doesn't know

>>6291560
Until we're capable of manipulating the laws of physics themselves, free energy will not exist.

>>6291560
>>6291564
you could probably fire some magnetic pulses at it (if it's a ferrous metal asteroid) to slow it down enough

Depends on several things

>How far away it is
>How long we have
>How fast it's orbit is

I think in most situations, given we have an adequate amount of time to pull off a plan (At least a year), then yeah we could do it.

We'd need to create a craft and launch it into an orbit around the sun, rendezvous with it, which involves matching the asteroid's orbit, and speeding up to match the velocity of the asteroid as the asteroid passes near the space craft.

Then once you're at the asteroid, you can just push it out of harm's way. (If the asteroid is devastatingly large, you'll need a bit of fuel to do this. The entire mission itself would probably be less than a Saturn V, though). If the asteroid is far enough from earth, you'll only need to give it a little kick, and it will miss us by thousands of miles.

It's not impossible given time and money. We've landed and returned from an asteroid in the past. We'd just need to push this one out of the way.

If the asteroid was like Armageddon, and we didn't find out until weeks before it hit us, we'd be fucked.

>>6291578
>At least a year

That's funny, most scientists agree we'd need somewhere in the area of 100 - 200 years.

>>6291578
We'd need at least a good 10 years of warning to put together a mission with enough fuel to move an asteroid... Do you know how fucking heavy those things are? Imagine the mass of a small Island, like Manhattan. That's how heavy extinction event asteroids are.

>>6291585
You don't need to move it very far, just modify its orbit enough to miss Earth. Space is big and Earth is a small target; an early enough intercept doesn't need to apply much delta-v.

>>6291584
>100 years

That's fucking retarded. Designing and testing the rocket would take a few years. Other than that, all you need is the time it takes to get into the sun's orbit, which is a few months.

>>6291585
I'm assuming the rocket is already mostly built and tested. Yes, that's the hard part is designing a rocket that can carry that much fuel that far out. If the asteroid is far enough away, you won't need a terrible amount of fuel. Just enough to kick it a little out of a collision course with us.

>>6291441

i don't really trust beams

i think we need to make an antimatter copy of the asteroid and to send it to intercept the asteroid

what I hate is movies such as Armageddon or whatever that think spaceships burn fuel all the time

>>6291584
lolwhat

we have the technology to change an asteroid's orbit since like 60s

>>6291598

To be fair, if you made no attempt to establish any orbit, then yeah, you would be burning fuel the entire time.

>>6291598
Hollywood will never get space travel right until the majority of the audience need to understand orbital mechanics in their daily lives. Not much point in sperging over it; just watch 2001 and enjoy the one film that looks remotely plausible.

also what fuel, it will be a few tactical nuclear bombs

>>6291591
Try moving a rock with a mass of 10^14 kg to 10^16 kg with less than a few thousand tons of fuel.

>>6291606

It annoys me when they're orbitting the moon and they feel gravity in 2001.

Even the best of movies has its flaws

>>6291596
>>6291601
>>6291605

Is this namefag some sort of notable /sci/ troll? I don't browse this board often enough to know.

>>6291618
No, he's just an ephemeral newfag. Is probably here for the second time and soon we're never gonna see him and his ignorance again.

>>6291615
The lunar shuttle in 2001 had no gravity, just seat belts and velcro shoes.

>>6291613
http://www.flightglobal.com/news/articles/nasa-plans-39armageddon39-spacecraft-to-blast-215924/

At that point we would have to use nukes or kinetic impactors, and would need several years of advance warning.

>>6291632

Not the shuttle, when they're orbiting the planet to get to the monolith, they're clearly under the effects of gravity.

>>6291646
Oh, when they're having lunch?
I thought that was a rover. Haven't seen it in a while.

>>6291615
You mean when they are on the space station with simulated gravity? Because that's simulated gravity, which was proven possible with NASA's Gemini 11 mission.

>>6291615
they might have a rotating ship
considering the level of most people on this board i suppose you might never heard of artificial gravity though

>>6291618
where did you see trolling

we had the technical ability to deliver something to a hypothetical asteroid located relatively close to the earth since 60s. it shouldn't be a manned flight. btw the first lunar impact was even earlier, in 59 i.e. in 50s

nuclear charge is definitely a better way to make a thrust than delivering fuel and engines (sic! honestly it was a funny idea, at least it made me smile) since we don't really care where it would fly afterwards as far its would miss the earth

the real problem would be to detect the asteroid though

>>6291654

lol, proved the school course of physics

>>6291654
It's pretty sad that we stopped seriously considering cool space ideas after Apollo when we realized Congress would have to pay for them.

>>6291665
>i think we need to make an antimatter copy of the asteroid and to send it to intercept the asteroid
This is something a retarded child would say. It seems like you're trying to show off by making a joke that shows us that you understand what antimatter is.

>we have the technology to change an asteroid's orbit since like 60s
>also what fuel, it will be a few tactical nuclear bombs
A nuclear detonation would have almost no effect on an extinction level size asteroid. Nukes can't even cause a damaging earthquake, let alone move an object with the mass of mount Everest.

Now stop being a childish fool or get out.

>>6291672
But anon don't you know that nuclear bombs are so powerful that they could blow up the entire planet

>>6291676
woa realy? thats so coooool

>>6291669
People say privatizing the space industry is the best way just to cope.

>>6291672
http://en.wikipedia.org/wiki/Asteroid_impact_avoidance#Nuclear_explosive_device

may be you will stop saying bullshit

>>6291684
>NASA has concluded that 1 mission utilizing nuclear stand off, can deflect NEOs of 100–500-metre (330–1,600 ft) diameters two years before the estimated earth impact

Extinction event asteroids are several kilometres across and several magnitudes more massive retard. Unless you've got a few 10 gigaton yield warheads up your ass that NASA could use, we couldn't do anything with less than a 10 year warning.

>>6291681
SpaceX, Orbital Sciences, Blue Origin, Bigelow, and Sierra Nevada are promising so far, but NASA still needs to provide contracts for development and then continue to maintain a manned space presence to provide a market.

If left entirely to private industry all we'll ever get is more communication satellites. Hopefully that asteroid capture mission goes through as a proof of concept so that Planetary Resources has something to do in the near future.

>>6291695
>can deflect NEOs of 100–500-metre (330–1,600 ft) diameters two years before the estimated earth impact, and larger NEOs with a five year warning.

Post the whole thing, faggot.

Extinction event asteroids are also easier to spot and considerably more rare in the vicinity of Earth orbit. There is a good chance we would have that warning.

>>6291701
>and larger NEOs with a five year warning.
They mean NEOs just over a kilometre or two in diameter. You'd still need AT LEAST 10 - 20 years and a nuclear yield of several gigatons to deflect a several kilometre wide asteroid. I'd like to remind you that an asteroid 10 times the diameter will generally weigh in at over 10,000 times the mass. Using modern nuclear weapons against such asteroids would be utterly pointless and accomplish nothing.

If you want to deflect an asteroid that size, a manned mission or the most complex robotic mission in history would be required, with something so large, and less then a century to prepare, you'd need to turn the asteroid into a rocket.

Depends on the size. If it's going to be the size of Texas, then well, we're fucked.

>>6291710
Thankfully, such asteroids don't exist. At that point, we just call them dwarf planets, and they're all in stable orbits far from Earth.

>>6291681
>not including DARPA

>>6291709
I suspect neither of us are willing to do the math on how much delta-v needs to be imparted to nudge an object from an Earth impact 10-20 years in the future vs. how much delta-v is imparted by an impactor-nuclear mission as outlined by NASA, so this can't really go anywhere.

>>6291721
A ten gigaton warhead is equivalent to 10,000,000,000 tons of TNT.

The asteroid would weigh about 100,000,000,000,000,000 tons.

That's 1 ton of TNT per 10,000,000 tons of rock.

I highly doubt 1 ton of TNT would push 10,000,000 tons of rock very far.

There's the extremely rough math.

>>6291726
>The asteroid would weigh about 100,000,000,000,000,000 tons.

how big an asteroid is that?

>>6291736
I took the biggest asteroid who's mass is known, and divided it's mass by 10,000 to get that number. That should be about the mass of an extinction event asteroid, maybe a bit bigger than the one that fucked the dinosaurs.

I'd just like to remind you
>rough math.

>>6291736
if we're using a big ball of iron
>1,152,712,833,545,108,005,082 M3

I'm surprised nobody has yet mentioned gravitational attraction methods. Basically you just fly out some mass far enough ahead of time in a ship, lock orbits, and let the gravity of the ship gently pull the asteroid into a new orbit over the course of a few years. No explosives necessary. Just letting a small amount of gravitational attraction build up over time.

>>6291665
>>6291654

I'm not talking about when they're on the ship.

I'm talking about this
>>6291646
>>6291651

>>6291756
100,000,000,000,000,000 kilograms
Mixed up kilograms with tons because I was measuring the explosive power in tons of TNT.

That comes out to a cube of iron about 887 metres on a side.

>>6291776
For everyone not doing the math, my previous asteroid measured in tons came out to be a cube of iron 10485.127 kilometres on a side. That was a wee bit too much.

>>6291776
242,874 metres on a side.

I multiplied density by mass when I should have divided mass by density to get the volume.

Whoops.

how big is the chance that even if it's on trajectory for earth it gets past Jupiter?

>>6291669
time for a kickstarter

>>6291726
>>6291776

It depends on how far out the asteroid is. If we launch all of our nukes to collide with the asteroid when it's about 1 year out, I think it could make a difference.

A ton of TNT is 4.2x10^9 Nm. So that warhead would be 4.2x10^19 Nm, if I'm correct. So detonating the warhead 1m away would unleash 4.2x10^19N on the asteroid. An asteroid 1x10^17kg hit by the nuke would be accelerated 4.2x10^2m/s2 for, say, 1 second(?), giving 420m/s change in velocity(?). I'm obviously talking out my ass, but if 6000+ nukes were fired and exploded 1 second apart from each other, I'm guessing the asteroid is either dust or had a significant enough change in velocity for it to not hit earth.

>>6291792

First off, asteroids are in orbit. They have a chance to run into Jupiter any time the two orbits intersect (Which is incredibly rare). Second off, Jupiter is fucking tiny compared to the entire solar system. The odds of an asteroid in the direct trajectory with Jupiter and Earth are nearly impossible.

>>6291721
Well, here's an extremely rough calculation. This is very, very handwavy, though.

Let's assume the asteroid is headed smack-dab for Earth. In order to be sure it doesn't hit, we're going to want to deflect it such that its orbit no longer intercepts our Hill sphere - the region in which Earth gravitationally dominates the surrounding space.

Earth's Hill sphere is about 1 million km in radius, so we're going to need to make sure the rock ends up at least 1 million km off from its current destination.

1 million km / 10 years = 3.2 m/s, or in other words, over 10 years a kick of 3.2 meters per second will result in 1 million km of divergence.

So, for 10 year's warning, we're looking at a delta-V in the order of a few meters per second.

As long as Bruce Willis is alive, we don't have to fear anything.

>>6291903
But delta-V isn't just enough - we're on a time limit here, remember! We need to make sure our asteroid gets accelerated fast enough to actually miss us, and that means we also care about thrust.

The Chicxulub (or Dinosaur Killer) asteroid was about 1.5e15 kg, so let's go with that as our mass.

So how much thrust do we need?

F=MA, and d = (1/2)At2 , so for a time of 10 years and a displacement of 1.5 million km (let's be generous, throw in a little wiggle room), we're going to need about 3e-8 m/s2 of acceleration. At this mass, that's about 45 MegaNewtons of thrust. (Although as you pack on fuel for your engine, that's going to increase the mass still further, and thus further increasing the thrust required - but this at least tells us we're looking at the tens/hundreds of meganewtons range)

So what kind of things can produce that much thrust?

The most powerful rocket ever built, the Saturn V, produced that kind of thrust - about 37 MN. However, chemical rockets have awful efficiency - if we just strapped a continuously-firing Saturn V to our asteroid, we'd use up an insane quantity of kerosense - someone else will have to do the math, because I can't be assed, but I suspect it would be a sizable fraction of the world's fossil fuel reserves. So just strapping on a chemical rocket engine is out. (Maybe - if it's an ice-based or carbonaceous asteroid, it might be possible to refine your fuel and oxidizer out of the material of the asteroid itself, which would make things easier.)

Ion and plasma rockets - which have very high specific impulse, and so would need nowhere near as much fuel - have another problem: They have inherently low thrust and high energy usage. Managing that kind of thrust with the most efficient plasma engines today would take more energy than our entire civilization produces.

>>6291903
hill sphere isn't some magical sphere where the earth will capture any object no matter what, if that asteroid has a sufficient speed (and it probably has since asteroids usually move way faster than 11 km/s i.e. than the earth's escape velocity at its surface) it will probably just pass this sphere and even if not you should just force it to move may be 7000-10000 km (the earth's radius + its atmosphere). also there is another option of making the asteroid yet another satellit of the earth (if it's speed is too small)

>>6291963
the inefficiency of chemical rockets it's the reason why nuclear propulsion was suggested

>>6291408
The best idea I ever read for diverting an asteroid involved binding it to a large counter-weight that would basically shift its center of mass and cause its trajectory to gradually drift many thousands of miles before it could hit us.

I think comets are probably more of a concern since they can gain such huge velocities as they are approaching the Sun from much larger, elliptical orbits.

And no, firing nukes at a significantly sized mass like an asteroid won't do a whole lot.

>>6291963
So what about nuclear, then?

The DUMBO nuclear rocket design would have actually managed thrust on the order of 3.5 meganewtons - an order of magnitude short compared to what we want, but hey, we'll just send up twenty.

One of the benefits of NTR* is that you can run them off of a whole range of working fluids. So again, if we have the luck for this asteroid to be a carbonaceous chondrite or big old comet, then we can just keep shoveling ice (methane, H2, whatever) into the fuel tanks, flaring off the asteroid to make reaction mass.

So hey, we've saved the earth! But let's keep looking.

On the other side of nuclear, what about Project Orion? (AKA - bomb the shit out of it to make it move backwards.)

Does this have the thrust? Hell fucking yes, it does. NASA's 1959 design for a 1st-gen Orion spacecraft had 80 meganewtons of thrust - and the 2nd-gen design called for 400. (Although that number seems a bit sketchy to me, so let's go with the less-silly 80 number.)

Orion's bombs are basically nuclear charges that are optimized for propulsion - shaped charges, directing their blast in all one direction.

Unfortunately, estimating the yield of the bomb we'd need is very difficult - because much of the important detail about Orion is classified! (Anyway, we probably wouldn't want to use one big bomb - too much risk of blasting the asteroid into pieces - too many to divert, but each still big enough to cause damage.)

The effective exhaust velocity of the first-gen, less-optimistic Orion design would be about 39,000 m/s. Plug that into the rocket equation, and that tells us that - for a delta-V of around five to ten meters per second - we're going to need about 200 million tons (that's tons MASS, not tons yield, as in a pile of Orion charges weighing 200 million metric tons) of specialized nuclear bombs.

For asteroids this world-killingly big, then, it's clear that nuclear bombs won't work. (It's just fine for smaller asteroids, though.)

Okay, this rock is iron?

Why don't we just make a super magnet and thrust away from the asteroid to pull it slightly askew?

>he hasn't see Armageddon