To be clear, Didymos and Dimorphos do not pose a threat to Earth
They don't pose a threat yet. That may change after the impact.
NASA and the Johns Hopkins Applied Physics Laboratory's (APL) Double Asteroid Redirection Test (DART) mission is under way following a successful launch atop a SpaceX Falcon 9. It was the third flight for this particular booster, and launch was from Vandenberg Space Launch Complex in California at 0620 UTC. The booster went on …
Had the Earth not been struck 50 million years ago we would probably never have evolved, back then we were just furry little balls crawling around on the surface trying to steal the dinosaurs eggs and without the impact we would never have been more than a meal. That asteroid impact lead to our evolution and lots of birds flying around so I think that it was very nice!
LOL Pascal, I don't disagree with you, certainly a huge impact could turn the world into a snowball again but a relatively small impact might fix our current climate change issues by causing a temperature drop for the next 100 years and could have the effect of making every nation start to work together to create a better and safer world for the entire human race, not just one country. The threat of an impact should be making us think that we are a world in space, not just a collection of idiots in one country that thinks that they are so much smarter than every other country (I see that criticism as applying to every country not one or another).
On the other hand, we haven't had a really bad volcanic eruption for thousands of years, one bad eruption might be worse than an average asteroid sized impact and there's a fair bit of evidence that climate change threatens a classic huge volcanic eruption.
"..and could have the effect of making every nation start to work together to create a better and safer world for the entire human race"
While the nearly dead idealistic part of me would hope that would occur, what would likely happen is the survivors would squabble over the remaining habitable zones and resources, up to and including using nuclear weapons and making the planet even less habitable. Even an event that should be survivable could easily be an extinction-level event with our current attitudes, and would at the very least likely set us back 100+ years as a species.
The next time won't matter to humans. We will have killed our species (and others) with global warming at the very least. Not to mention the forthcoming gas wars, oil wars, water wars, food wars, e.t.c.. Always assuming that a virus doesn't finish us off first.
"Not to mention the forthcoming gas wars, oil wars, water wars, food wars, e.t.c.. Always assuming that a virus doesn't finish us off first."
And yet, every time some or all of the above are predicted, we dodge the bullet. Look at the Club of Rome predictions. We're already dead according to them.
No, I'm just saying look closely at what is being predicted and how they are predicting it. A linear progression based on relatively short term trends, such what the Club Of Rome model did, can be highly misleading. Many of the wilder predictions we get about climate change are being predicted ion the same way because the people pushing them have their own agenda. Climate change is real, it's not good, we need to do stuff to mitigate it, but just be careful of who we listen to and what we do so we don't waste time on the wrong stuff.
Not the only issue. Both the eruption of the Siberian and Deccan traps triggered mass extinctions. The Siberian ones did the Late Permian, one of the biggest. That gave us the Dinosaurs etc
Though there’s a school of thought which thinks a large impactor on the other side of the globe might trigger flood basalt eruptions by cracking the crust there. A search is on to find evidence of it. Last I looked nothing. Ditto the Deccan Traps.
True - I think that it's fascinating that we discuss whether or not there might be life in the rest of the universe yet when we look at our worlds history it's clear that most of our worlds life has been almost completely removed multiple times in the distant past but it has always just sprung back again ...
"The Siberian ones did the Late Permian, one of the biggest"
The end game of the late Permian was blowouts of methane clathrate beds driving atmospheric CO2 levels past 800ppm, resulting in global acid raid that killed off most land vegetation (and massive erosion), with most land animal life folllowing shortly afterwards, whilst the acidified seas killed off most plankton and shell forming oganisms (unable to form shells) which resulted in collapses of marine food chains.
This was folllowed by "red tides on steroids" (which form most of the easy oil deposits we've been burning) and atmospheric oxygen plummeted to 11%, staying there for tens of thousands of years
When the kneepoint was hit it went "instantaneously" in geologicaly terms. The rocks show life striggling a little (declining biodiversity etc) for a few tens of thousands of years and then BAM! - it's like Nature hit an "off switch" - the final mass extinction event played out in less than a decade, possibly less than 18 months
People can move away from rising sea levels. It's harder to move away from declining oxygen levels. A decline to 17% would restrict the habitable zone down to about 1500 feet above sea level and deny us/most mammals the interior of most continents). A decline to 11% is unsurvivable and we would end up drowning in our own lungs (a most unpleasant way to die)
An asteroid strike in the wrong location could cause this - Chixulub did it to an already stressed planet 65 million years ago by hitting a shallow sea underlain by 20km of limestone. Or we could simply do what the Siberian traps did 250 millions years ago and warm up those methane clathrate deposits.
Our climate is remarkably similar to what existed back then and ironically it's off the north coast of Siberia where methane clathrate deposits have been seeping out to the surface since 2004 (Leptav sea continental shelf). What's coming out _now_ is minor, but what comes up leaves holes and destabilises what's still down there - about 20GT by most estimates. All it takes is an earthquake to rattle things and life could get interesting in the Arctic circle (there are lots of methane clathrate deposits and blowouts have happened in the past. "Storegga Slides" raised global temperatures 1-2C 9000 years ago, raised sea levels 100m in a couple of hundred years and inundated what's now the North Sea in a 1000 foot high Tsunami)
Humans tend to act when shit and fan start partying, but there's a strong possiblity we may end up acting too late this time
Hilarious to think people really believe we can solve this "problem" with guns! (_if_ we detect it in time, and _if_ it is small enough, and _if_ it is still far enough away, and _if_ we can still see it . . . etc.)
Even funnier is people thinking we can "just" blow stuff like this up.
As usual you have forgotten the troll icon but I would be very interested in any valid researched reasons why this may not have an effect.
At least NASA are doing some research and I daresay have probably modeled some likely outcomes just to see if the DART mission could end in tears.
The extended longevity of so many of NASA's missions is not down to solely blind luck, they tend to think a bit before acting.
They are not blowing anything up. They are giving one rock (which is in orbit around another, larger rock) a tiny nudge to see how it is affected. *IF* it is affected, the small rock will stay in orbit around the larger one, but just be in a slightly different orbit.
From my (admittedly limited) reading, even the "nuke it" options are usually intended to slightly alter trajectories, rather than being about turning the target into an expanding cloud of space gravel.
Why wouldn't it work? F=ma and E=1/2*mv^2 tells us that it does. All other outside influences eliminated hitting something heavy with something much lighter moving at a high relative velocity will change the velocity vector of the heavy thing. What is being demonstrated here is just how efficient such a high velocity impact will be, and that the technology required to find such a target in the vast emptiness of space, rendezvous with it and precisely target the impact works. The math on WHY it works is simple. The technology to actually do so is far from trivial.
I'd like to see you present a cost-benefit analysis for something that is unlikely to happen, but if it does, we have a 1 in 10^-12 chance that it is in the "goldilocks" speed & mass range, amongst all the other stuff.
Yeah, I know the physics.
You can't cheat Death from the Skies! It is bad psychology to expend effort pointlessly.
Understanding how to do it on something "small" and "light" (at approximately 160 to 170 meters diameter and a mass of 2170+/-350 kg, I'd prefer it not to land on my house) means we also have much better understanding on how to potentially do it on something much larger, heavier and faster.
I still don't understand why you think this is pointless. Generating understanding and data on this is a useful tool for understanding asteroids, our universe and for pushing the boundaries on what we can do to save our planet in the unhappy case we ever find something hurtling towards us. Yes, it'll have a good chance of blindsiding us like it did the dinosaurs, but I'd prefer if these boffins did their best to come up ways to give us a sliver of a chance. I won't be losing any sleep over the possibility of it happening, but it's good that the efforts are made.
"Even funnier is people thinking we can "just" blow stuff like this up."
It's generally accepted in the science community now that asteroids are mostly fluffy rubble piles which will just react like a giant feather pillow to any kind of impactor we can throw at them (either having it pass straight through, or simply puffing out slightly and reforming shortly afterwards)
The problem is that POLITICIANS need to have it demonstrated so they stop thinking it's a feasible option
In all likelihood they still wont get it until a couple of airbursting bolides seriously destroy stuff on the ground without anything actually impacting (Tunguska, Chelyabinsk)
The idea isn't to destroy the object or necessarily to move the entire rubble pile in one go. But if we can impact the asteroid early enough, even if it "blows apart" the collective trajectory of the rubble (before or after coalescing again will have moved enough to miss earth. The idea isn't to intercept and deflect an asteroid on a straight line impact course for earth just a few thousand km above our atmosphere, because that's likely beyond the realm of physics. The idea is that we can detect an asteroid that will impact earth one or two orbits later and deflect it before it passes through a "keyhole" where a minimum amount of deflection will already sent it on a widely different orbit.
or if it's just a loosely bound bunch of gravel.
I get the impression that it may be merely a huge heap of low density pumice, given that the only small asteroids explored to date (Ryugu and Bennu) turned out to be loosely assembled rock piles. Even the boulders on Bennu's surface were light and fragile, judging by the way they were moved about by the low velocity impact and airblast of Osiris-Rex's sampling touch and go maneuver.
Its also noticeable that the only bigger asteroids visited so far (Eros, Vesta and Ceres) seemed to be rather more solid, with NEAR's landing on Eros showing what looks like a rather more compacted surface.
This all makes me wonder if DART may simply fly through the moonlet, with the shock of the collision turning the latter into a rapidly dispersing cloud of disintegrating pieces of low density pumice.
At least we won't have all that long to wait before we see what happens when DART scores 50.
A large piece fell off NZ’s highest snow capped alp Aoraki/Mt Cook once. The geologists were interested to get a look inside. “it looks just like weetbix” was the conclusion. IOW this sharp pointy alp is just a gravel pile.
Some guys were recently rescued from high up it in a piece of rescue derring do for the history books.
this could be solved far more elegantly by resurrecting Project Orion.
What is the elegant solution for burning out all the electronics in the hemisphere that Orion launches from?
[Note: launching from the other hemisphere is liable to cause "get your retaliation in first" style problems with those living there.]
"What is the elegant solution for burning out all the electronics in the hemisphere that Orion launches from?"
Not using megaton-class devices is a good starting point (Starfish Prime was 1.45MT, the Soviet equivalent was larger and fried most of central asia's electrical grid) ). Orion was built around 50kT devices - one of the reasons large parts of it are still classified - the bombs are SMALL and would be of use to terrorists because they're highly portable
It does make sense. A fraction of 1% change in speed/direction a few million km out can have a big effect by the time Earth orbit is reached - the difference between taking out the ISS and taking out New York.
But it will need preparation.
Presumably if DART proves the principle, it will be wise to shift some large masses into orbit on stand-by to be shoved in the right direction when needed?
Presumably the main trick is to transfer momentum to the target; and to get an impactor with a defined momentum doesn't require a large mass, but merely some mass, going fast enough. Since p=mv, you could get the same momentum from something with half the mass but twice the speed.
A small mass going fast might presumably get there sooner, which sounds helpful; but I suppose it is possible that a larger mass might have some advantages in whatever horribly nonlinear collision process it is that takes place on impact.
There are two basic opposing effects in play when changing a given impulse between mass & speed. Smaller but faster has more of a chance for some of the impulse to be wasted, if it's so small and fast that some of it just keeps right on going through the target. Bigger but slower is more likely to transfer 100% of its own momentum, but will get less potential amplification from the impact throwing debris out from the crater, giving a little extra impulse for your buck. I don't know which effect would dominate over the other, though.
inelastic collisions will have a bigger effectl than a glancing elastic collision. If you are lucky enough to hit it straight on (so that all momentum transfers) like a billiard ball, then sure, why not. But the more likely scenario is a glancing blow that sends both objects off in predictable directions. So an inelastic collision (i.e. buries itself a few feet into the dirt on impact) would guarantee momentum is entirely transferred to the asteroid's moon.
In billiards only one of the objects is moving upon impact. I have no idea of the science involved in the collision part of DART's mission, but i'm thinking it's velocity will need to be significantly higher than the asteroid to produce the impact required?
Otherwise DART will just ricochet away or obliterate on impact won't it?
I wonder what the actual numbers are
A small diameter spacecraft is likely to crash into the soft surface of an asteroid and impart its momentum and no more. The same spacecraft in a zorb type protection would bounce of possibly imparting twice as much momentum. The impact point can be chosen to maximise the effect as the spacecraft approaches.
I have it on good authority that the target for the probe is not a space rock, but an alien space craft due to land here in dec 2022, hence hitting it with a large mass going at 6 km/sec
The source is also the one that revealed the godzilla attack of 2005, and that Elvis is running a diner in Dayton Ohio
Not that it's particularly pertinent to this article, but "Armageddon" was the only move I've seen in a theater that I've ever walked out on before the ending. I was annoyed by the banal cliches throughout it, it lost me at the utterly improbable (and likely impossible) simultaneous dual shuttle launch, and finally I couldn't take it anymore during Bruce's character's hammy "I did it for God and country" speech when he knew he would die. Just utter dreck. YMMV.
Sounds like Planetary Pool to me...
RIMMER: What the smeg is going on?
LISTER: She rides!
RIMMER: You jammy goit!
LISTER: Played for, and got!
KRYTEN: Surely not, Sir!
CAT: Are you trying to say that was a trick shot?
LISTER: (Doing the touch-up shuffle) Intended! Pool God! King of the Cues! Prince of the Planet-Potters!
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