Scientists stunned by ‘city-killer’ asteroid that just missed Earth

https://www.seattletimes.com/nation-world/scientists-stunned-by-city-killer-asteroid-that-just-missed-earth/

by swamp40 • 7 years ago

275 148 7 years ago

chris5745• 7 years ago

I imagine without early and widespread warning, an asteroid impact could be mistaken by nation-states for an attack. What safeguards (if any) might we have or develop to prevent an asteroid hitting country 1 from causing a “counter” strike by country 1 against country 2?

sudosteph• 7 years ago

Not sure, but that scenario does sound like a interesting plot for a book or movie.

Yetanfou• 7 years ago

Niven and Pournelle thought so as well when they wrote "Lucifer's Hammer" [1] in which "...China, anticipating the coming ice age launches a preemptive nuclear attack on Russia. The last Soviet Premier reassures the US that they are not the target, and he requests help against the unprovoked attack."

[1] https://en.wikipedia.org/wiki/Lucifer%27s_Hammer

jacobush• 7 years ago

And of course, causing a counter-counter strike from country 2 against country 1. Messy!

nvrspyx• 7 years ago

Would country 1 counter-strike without getting confirmation that it was, in fact, country 2? How would they know it wasn't country 3, 4, or 5?

tzakrajs2• 7 years ago

Similar to the cyber attack attribution problem, isn't it?

acqq• 7 years ago

If you ask what the known U.S. procedures and plans have been, the answer is a resounding YES, they would have nuclearly attacked ALL their enemies at once according to the man whose job was to evaluate these procedures and plans of the U.S. military:

https://www.bloomsbury.com/uk/the-doomsday-machine-978140888...

Just a sample quote:

"I soon discovered that in the plans of Pacific forces, from top to bottom, there was no provision at all for attacking only the Russian targets in their sphere. In every plan for war with the Soviet Union, Chinese targets (including every major city in China) were also struck."

In the whole book there are many accounts on that, on the various levels of the chain of command, even intentionally designed to act independently.

More transparency is still needed there, probably much less was changed in the following years than it ever admitted to any civilian, including the presidents, again according to the book, so the state is more than scary and when I read that insider info, I consider these involved really completely mad. Most of them Nazi-like "we just follow the orders" mad, and some simply pure evil mad.

tzakrajs2• 7 years ago

One big safeguard is that no launch would be detected?

User23• 7 years ago

Also, it really could be an attack. It's within the realm of plausibility for country 1 to launch a nudging vehicle to push a space rock into a collision course with country 2.

dandelany2• 7 years ago

Eh maybe. It strains plausibility. We can't even accurately predict where deorbiting satellites will end up... It's pretty hard to imagine a nudge with the required delta-V and accuracy to hit a specific nation. Too far away and you get too much uncertainty, too close and you don't have enough dV for the push. Even if it could be done with today's technology, the potential for error is high, and if you screw up, you've accidentally started another war or "bombed" your own country. Can't imagine that a military with the requisite technology to pull this off wouldn't be able to think of a less-risky way to obliterate their enemy.

lutorm2• 7 years ago

I think apart from the energy release there are few similarities with a nuclear explosion (no EMP, no radioactive fallout) plus I have to imagine any air defense radar system could detect the incoming asteroid in its final moments.

idlewords2• 7 years ago

Second asteroid hitting country 2

gitpusher• 7 years ago

Very unlikely that China, Russia, or US (and its allied countries) would misidentify a nuclear attack. There are massive surveillance resources dedicated toward atmospheric sampling, etc. etc. and a non-nuclear explosion would be correctly identified as such in very short order.

On top of that, even a 30-meter asteroid impact would release more energy on impact than a typical nuclear warhead. A 250-meter asteroid might release more energy than ALL nuclear weapons used in the world to date.

sanxiyn• 7 years ago

Atmospheric sampling is definitive but slow, because it necessarily propagates at wind speed. I do agree misidentification is very unlikely.

rixed• 7 years ago

Failure to automatically launch the missiles.

In that case that might even be planned incompetence.

caymanjim• 7 years ago

This is a legitimate concern with the "young" nuclear powers, like India and Pakistan. Their detection technology is less mature; their command-and-control systems are less mature; there's a higher level of tension between the two. Neither country is incompetent or hungry for war, but it's worrying to me. I'd expect them to behave rationally, but if the timing happened to coincide with a particularly combative episode, things could get out of control. I'm not even going to speculate about how North Korea might react; they're a total wildcard.

vinayms• 7 years ago

This is just alarmist. The bravado shown on TV is surely not taken seriously by the authorities themselves for they know the consequences. So even if the point of impact coincides with the crescendo of tension to the T, sanity will prevail despite it seeming otherwise.

familysized• 7 years ago

That is a very naive point of view. You don't know that their systems are "less mature". And do you really think thousands of seasoned scientists on both sides are going to misclassify any such event?

walrus01• 7 years ago

Major nuclear powers all operate satellite based infrared launch detection systems. A rocket launch is a very unique thermal signature. I imagine China and Russia have satellites watching the north Dakota icbm fields, and vice versa.

lisper2• 7 years ago

If this sort of thing concerns you, you might want to consider supporting this organization:

https://b612foundation.org

lucb1e• 7 years ago

I honestly think we have bigger problems right now, like spending money on ways to reduce greenhouse gasses. We need to develop alternatives to non-renewables and, until we can use the alternatives, work on removing the gasses from the atmosphere.

Putting my money where my mouth is: I've been looking into this and as soon as I get my credit card (to be able to pay, I've never needed a CC before), I will sign up with https://climeworks.com to recapture some of my CO2. They seem to be one of the few that are actually capturing right now, so the money will be used for real capture, not just R&D that might yield results in the future. But to spread the risk, I am also going to spend money on the more traditional method of planting trees (which company is TBD, I have yet to find one that actually guarantees that they (or the locals) won't rip the tree out before it had a chance to capture its promised CO2). On the reduction side, I travel to work by public transport, work from home (it stays naturally cool) instead of using our office air conditioning unit, have a 100% renewable energy contract at home, etc.

projektfu• 7 years ago

It's called B612 Foundation and not a single reference to the Little Prince on the homepage besides the name? Weird.

lisper2• 7 years ago

Yeah, there is an explanation, but it's well hidden:

https://b612foundation.org/ever-wondered-where-the-name-b612...

Syzygies• 7 years ago

It missed Earth by 73,000 kilometers; Earth has radius 6,371 kilometers.

(79371 * 79371) / (6371 * 6371) = 155.2

This was a game of darts in a galactic pub. The dart hit the dart board, but not the bullseye (Earth). One in every 155 times we play this game, it ends badly.

rosser• 7 years ago

Assuming no other conditions change, and that the object crosses Earth's orbit as the planet is passing by, and so on.

I'd be willing to bet, however, that this object's orbit permutes a bit with every pass, especially dipping that deeply into the gravity wells of other, much more massive, objects.

pault2• 7 years ago

On galactic scales that's more like glancing off the ring of the bulls eye.

Cacti2• 7 years ago

On galactic scales it’s a meaningless analogy.

eridius• 7 years ago

How does the math change when you take into account the fact that Earth exerts a gravitational pull on the asteroid?

Skunkleton• 7 years ago

Interesting question, not sure. As the speed of the astroid is goes up, the relevance of gravity goes down. As the speed goes down, the damage it can do also goes down, and also reduces the probability of an encounter.

quickthrower2• 7 years ago

And does that make it more likely to miss? Ie it gets slung around by gravity instead of hitting?

lutorm2• 7 years ago

The degree of gravitational focusing depends on the speed of the incoming object, but I seem to recall that for typical interplanetary velocities it's of order 1, ie not huge.

dmckeon• 7 years ago

It may not change this encounter much, but it could change the orbit just enough for some future earth-orbit crossing - as could the gravitational effect of any of the other planets, their moons, and all the other asteroids change the orbits of anything out there. Solar systems can be messy places, over geologic time frames. Sometime, sooner or later, we will have a significant impact.

kryogen1c2• 7 years ago

Thinking out loud time! My favorite!

To matter for a single pass, the object must be small and/or traveling slowly. Otherwise, itll just keep on cruising.

Iteratively is a different story. Many objects repeatedly cross earths path. How that orbit changes over time i suppose is a function of the other gravity wells the objects pass when they arent near earth. I expect there are so many confounding gravities that only a certain belt\torus exists in the universe where, inside that torus, space stuff is capable of running into us.

Side note: this article is clickbaity because it implies no one knew asteroids almost crash into us without us knowing, but thats not true. People know. There are hard reset buttons floating around in space and we might just press one without warning.

https://en.m.wikipedia.org/wiki/Potentially_hazardous_object

gamedori• 7 years ago

It probably has no effect: objects that are not in stable orbits around the earth are going to be in hyperbolic orbits relative to the Earth's gravitational field. A dangerous asteroid would need a periapsis lower than the Earth's radius by a certain amount to hit the Earth, so the risk of collision is still roughly proportional to Area. If gravity is a factor I would expect it to be a high order term. Atmospheric effects are probably more significant.

ls6122• 7 years ago

Even if it hit the earth the odds of it landing anywhere near a city are slim. 3/4 of the time it hits the ocean, Siberia, the Canadian north, or the Antarctic.

StavrosK• 7 years ago

Serendipitously cooling the surface of the earth down by exactly 2.2 C.

ChuckMcM• 7 years ago

Although an asteroid of that size, depending on its makeup, can have other damaging effects. For example, by area, the pacific ocean covers a lot of the planet. An asteroid hitting the pacific can cause a tsunami that could seriously damage any coastal city in range.

vkou2• 7 years ago

One thing to note: the Tunguska meteor was ~50-200m in diameter, and was equivalent to a 3-30 mega-tonne explosion.

mrb• 7 years ago

You massively underestimate the destruction caused by a 1km asteroid. Remember some scientists estimate the asteroid that killed dinosaurs was as small as 11km. In other words a 1km one may be 1/10th the diameter needed to cause an extinction-level event.

A 1km asteroid will cause massive casualties no matter where it impacts. If it hits the ocean it will cause a tsunami. If it hits a remote land it will eject so much debris in the atmosphere that they will block sunlight around the globe and reduce temperatures by multiple degrees, thus reducing food crop yields and causing worldwide food shortages and famine.

vkou2• 7 years ago

How often do we play this game?

How often would it hit something we care about on the dartboard?

idlewords2• 7 years ago

Your math is off because the bullseye gravitationally attracts the dart

sideshowb• 7 years ago

Only significantly so if the dart is going very slow

jarfil• 7 years ago

How often do we play this same game, though? If a 1Km size asteroid seems to hit the Earth about once every 500,000 years, it would seem like they would pass this close to the Earth only once every 32,000 years or so.

So either the 500Ky figure is wrong, or we've been extremely lucky to witness a once-in-30Ky event, or we're missing something.

mikeash• 7 years ago

This was only 100m. Those probably hit semi-regularly and would have usually gone unnoticed or at least unrecorded before modern times.

whamlastxmas• 7 years ago

It was described as "astronomically small" that something like this would hit us so I imagine there's factors not being considered here

mr_toad• 7 years ago

One in every 155 times we play this game, it ends badly.

That assumes only one degree of freedom. If you consider the area of the dart-board vs the area of the bullseye, the odds are much lower.

Sharlin• 7 years ago

No, the GP specifically talked about area.

dv_dt3• 7 years ago

It's too bad the "space force" isn't setup just for this.

hdfbdtbcdg4• 7 years ago

Scientists are already searching for and tracking such objects. More funding would be nice but we definitely don't need the US to break more treaties in order for the world to track NEOs.

antepodius• 7 years ago

Who really cares about the space treaty?

It'd be nice to have a well-funded group that has 'making sure no asteroids hit us' as part of its motto

dv_dt3• 7 years ago

I meant just as in exclusively for this. And what is the point of tracking them if we don't plan to do anything about them?

mturmon• 7 years ago

You can browse recent approaches at:

https://cneos.jpl.nasa.gov/ca/

To isolate to really near stuff, choose +/- 30 days, and Nominal distance <= 1LD (lunar distance).

The asteroid in OP is linked to here: https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2019%20OK -- there's an orbit diagram.

ratsmack• 7 years ago

The interactive 3D orbital graphic is great for visualizing the orbits and how they cross the Earth's path.

tunesmith• 7 years ago

"More than 90 percent of those (extinction-level) asteroids, which are 1 kilometer, 0.62 miles, or larger, have already been identified by NASA and its partners."

How do they know it's 90%? I mean, if the denominator is unknown? If the denominator is known, then doesn't that mean they've identified them?

Cacti2• 7 years ago

It’s a statistical argument based on the observed distribution of asteroids. It’s not precisely true, and could even be widely incorrect, but they think it’s likely to be in the correct neighborhood.

Also, after a certain size things become significantly easier to detect with your existing instruments, so there is some confidence from that.

parcec• 7 years ago

Related to this (though maybe not directly applicable), in certain scenarios there is a difference between what can be reliably detected vs tracked. For example, in the context of debris orbiting the earth, our radars can take LEO census measurements down to 3-4mm, even though we can only reliably track things on the ~10cm size range.

We can therefore semi-confidently say we know how many 1cm objects there are out there, even if we can’t predict the trajectory of any single one. (Similar to atoms, really)

mattkrause• 7 years ago

Abundance estimation is a big problem in ecology (and other fields), and they’ve developed some clever ways to estimate population sizes without doing an exhaustive census.

One popular approach is a capture-recapture experiment. On your first trip, you find as many of your targets as possible and mark each one. With turtles, you might paint something on the shell; here, it might be something like determining its orbit and other characteristics. You wait a bit, and search again (starting from scratch), but this time you separately record the number of “new” specimens and the number recaptured. A tiny bit of algebra from these three numbers gives you an estimate of the population size.

joemag• 7 years ago

It comes with a bias though, since your searches will bias towards finding asteroids that are easiest to find using your search method.

raymondh• 7 years ago

IIRC, the 90% estimate is based on how often searches encounter previously cataloged objects.

goodcanadian• 7 years ago

The mark-recapture method has been mentioned. Additionally, you can create fake data and run it through your search algorithm to get an estimate of your detection efficiency.

ghostDancer• 7 years ago

Planetary defense from Planetary Society if you want to help or participate http://www.planetary.org/explore/projects/planetary-defense/

shoo• 7 years ago

on another hand, if you see a gamma-ray-burst heading this way, duck and cover... https://www.youtube.com/watch?v=8HvwNOSnveE

thatswrong0• 7 years ago

I mean that’d be near instant vaporization wouldn’t it? For some reason that makes me less scared about it since you wouldn’t really know what’s happening before it’s all over

omegaworks• 7 years ago

No, according to the video gamma ray burst means increase in UV potentially damaging DNA of phytoplankton, global cooling due to NO2 solar energy reflection.

It'll be pretty slow, but at a large scale.

GarrisonPrime2• 7 years ago

I have no reason to doubt this story - that it caught everyone by surprise. But if such an asteroid was discovered in advance and it was determined we were at high risk of being hit, I'm not so sure the public at large would be notified in every circumstance. If the impact would be large enough and/or the warning short enough, getting people panicky might do more harm than good.

dandelany2• 7 years ago

The problem with this idea is that it rests on two incorrect assumptions - that there is some governing body that would be able to prevent the release of such information, and that we would immediately know upon detection that the asteroid was on a collision course.

In fact, in this case, the asteroid was detected independently by the SONEAR survey in Brazil and the ASAS-SN telescope network run by Ohio State University. Neither of these would fall under the "jurisdiction" of NASA or any governmental organization that would effectively be able to prevent them from talking about it. ASAS-SN tweeted the discovery, and I'm quite sure they didn't have to ask anyone permission to do so.

Secondly, the first few observations of a newly-discovered near-Earth object are generally not enough information to calculate the object's orbit accurately enough to know if it will hit Earth or not. So what do scientists do when they discover one? They immediately report it to the IAU and get the word out to as many other astronomers as possible, in order to obtain more observations & accurately determine the orbit.

As a result, it's hard to imagine how such a discovery could be kept secret.

GarrisonPrime2• 7 years ago

The problem with this idea is that it rests on two incorrect assumptions - that there is some governing body that would be able to prevent the release of such information, and that we would immediately know upon detection that the asteroid was on a collision course.

Not necessarily. Only a couple people knew about this one before it had whizzed by. While I agree it'd be impossible to keep an upcoming impact secret, if the timeframe is short enough it would only take a few select people to keep it contained long enough to no longer matter.

And choosing to keep it secret wouldn't only be done if collision was known to be certain. Just having a moderate chance of impact might be enough.

jmkappz• 7 years ago

JPL Horizons is awesome for this. You can easily obtain the information on your own using the ephemerides at https://ssd.jpl.nasa.gov/horizons.cgi#top :

- minimum distance of 71350 km (44,334 miles vs 45,360 in article)

- Speed around 24.5 km/s (15.2 miles/sec vs 15 in article)

- Closest on july 25 at 01:21 UTC

Here's a rendering of the trajectory of the asteroid and the moon in july to get an idea of how close it came (moon orbits around 384,000 km from earth): https://imgur.com/a/3JaakFJ

phkahler2• 7 years ago

An asteroid on collision course will not be seen. I just realized an old concept applies here. When two objects are on a collision course with each traveling in a straight line, the apparent heading toward one as viewed from the other does not change. In other words, when a deer runs in front of a car, the angle to the deer doesn't change - it just gets bigger as you close in, but position in your field of view doesn't change.

Astronomers look for things moving against the background sky, but over a short enough time span (maybe a few days) the earth and an asteroid are moving almost in straight lines. That means all you'd see is a speck of light that gets brighter as it gets closer, but does not appear to move against the distant background stars.

Has anyone quantified this phenomenon with respect to asteroid hunting?

Smithalicious• 7 years ago

This would be true if the asteroid and the earth are both points. Obviously, they aren't. An observing scientist would not see it this way unless it were heading directly for them.

phkahler2• 7 years ago

> An observing scientist would not see it this way unless it were heading directly for them.

That was my point exactly. An asteroid heading directly towards us will not appear to be moving against the background. If that movement is required in their detection methods, it will fail for the most dangerous ones.

hdfbdtbcdg4• 7 years ago

I suspect that astronomers are using exactly this principal to search for NEOs.

krzat• 7 years ago

I'm not an expert, but I imagine that astronomers are pretty good at determining brightness of objects. And space stuff moves in orbits anyway.

partiallypro• 7 years ago

The likelihood it would hit a highly populated area is still incredibly slim even if it did strike earth. I wonder if there are some smaller asteroids on rare occasions just landing in the ocean that we don't really know about.

mikhailfranco3• 7 years ago

The distribution of orbits, and hence strikes, is an interesting problem.

Here is a plot of population against latitude:

https://www.themarysue.com/world-population-latitude-longitu...

I assume a bias to the ecliptic, hence the area within the tropics is more likely to get hit. Big spikes for Jakarta, Dhaka, Shanghai/PRD, Delhi/Mumbai/Karachi/Lahore, Kinshasa, Lagos ...

I also suppose you could attack the problem in two ways: historical strikes (confounded by erosion, tectonics and subduction), and orbital statistics, perhaps weighted by asteroid size.

Anyone have refs for this?

mkl• 7 years ago

This is actually really common for smaller ones:

2015: https://en.wikipedia.org/wiki/List_of_asteroid_close_approac...

2016: https://en.wikipedia.org/wiki/List_of_asteroid_close_approac...

2017: https://en.wikipedia.org/wiki/List_of_asteroid_close_approac...

2018: https://en.wikipedia.org/wiki/List_of_asteroid_close_approac...

All the ones coloured red in the tables (the majority) weren't discovered until after their closest approach.

m0zg• 7 years ago

So here's what I was wondering for quite some time: if, let's say, hypothetically, there were an object approaching Earth at nearly the speed of light, is there any way in our frame of reference to even detect it?

And is it possible for such an object to exist in our universe, and if not, why?

The math seems to work out such that the object the size of a US quarter (5.67g) at 0.999 C will have a relativistic kinetic energy around 2.6MT of TNT.

Ididntdothis• 7 years ago

If something travels nearly the speed of light we couldn’t detect it. Any kind of information from this object would at maximum travel at the speed of light so this information would arrive only a little sooner.

simonebrunozzi• 7 years ago

I might be wrong, but in a previous comment [0] a few days ago I noted that the asteroid composition is mostly ice, which means it should be much less dangerous than a "rock".

[0] https://news.ycombinator.com/item?id=20508618

xenonite• 7 years ago

Similary, the Seattle Post writes:

Lakdawalla said that while the asteroid’s close brush with Earth may have sparked some concern, “it is zero percent danger to us. It’s the kind of thing where you learn about something that you didn’t know about, like things flying close by us, and your inclination is to be scared,” she said. “But just like sharks in the ocean, they’re really not going to hurt you and they’re really fascinating to look at.”

ycombonator• 7 years ago

Asking for a friend, is it not possible to park phased array satellites out at 43,000 KM orbit looking for faint smaller asteroids with current technology?

rishav_sharan• 7 years ago

Technically, yes. Politically? We don't use the word sense with politics.

torgian• 7 years ago

I still think someone tried to redirect its path and made a minor mistake in their calculations ;)

pulkitsh1234• 7 years ago

For those interested, you can watch Joe Rogan's podcast with Randall Carlson on this topic: https://www.youtube.com/watch?v=R31SXuFeX0A

scraplab2• 7 years ago

I made a Twitter bot @lowflyingrocks, that tweets whenever something passes close enough to note. If you find Twitter doesn’t offer you enough existential dread already you might like it.

It scrapes the JPL data hourly, and it’s satisfying when it picks up these close passes discovered at short notice:

https://twitter.com/lowflyingrocks/status/115420008580852531...

fabiandesimone• 7 years ago

This is fantastic, thank you!

codeulike• 7 years ago

what does '2019 OK' mean, is that the rock name?

It would be good if your bot attached some sort of 'oh shit' scale, based on size and closest approach

Rexxar• 7 years ago

It seems to be a naming convention for provisional names (https://www.quora.com/How-are-asteroids-named)

2019 OK :

- "2019" => discovered in 2019

- O => discovered in 2nd half of july

- K => 10th object discovered in this period

radisb• 7 years ago

'2019' = present year, 'OK' = we didn't get wiped out

number6• 7 years ago

Ok little pet peeve of mine:

Every other time I hit some arbitrary Twitter limits of a post and 5 minutes later I can access it.

At this point I believe it is to bully me into an account or using the app or something.

I have a bunch of profanities in reply to this.

hansjorg• 7 years ago

Are you using Firefox on Android? Using that I almost always get the rate limit error. Never seen it otherwise.

hag• 7 years ago

I have the same issue on Chrome on Android and I always reload the page (not the Twitter reload button), which always seem to work for me. I don't know if they do this on purpose, but it does make you wonder. I do not want the Twitter-app on my phone.

jdnenej• 7 years ago

Yeah I get the rate limited error every time. I think Twitter just marks anyone not using the app as a bot

napsterbr• 7 years ago

Twitter for mobile (web) is filled with dark patterns like these. They do everything in their power to make you download their app, including limiting and/or sabotaging features that would obviously work on any web browser.

For example, you can see someone's tweets but you can't click on the mentions or media tabs. Search is downright unusable. Try searching for something and scrolling to the top to get the latest results.

I know I make no difference at all for the folks at Twitter, but they certainly lost me as a loyal user after witnessing such shady practices.

esquire_900• 7 years ago

That is awesome, thank you!

fyfy18• 7 years ago

Does it handle the case when something doesn't miss?

lostlogin• 7 years ago

How would it bypass the fail whale?

scraplab2• 7 years ago

No, but it's open source, so maybe future surviving generations can pick up that issue?

https://github.com/tomtaylor/lowflyingrocks

flancian• 7 years ago

This is great, thanks! Unsolicited advice: perhaps consider making the bot pin the tweet about the most interesting encounter of the last N days, for some definition. Likely something like the nearest miss.

Asmod4n• 7 years ago

There is no API for pins.

aasasd• 7 years ago

So it was set to stun, not to kill?

mikhailfranco3• 7 years ago

I am surprised with the talk about optical visibility. Are there no radars deployed for scanning the skies?

scarhill• 7 years ago

Because these objects are moving fast, you would need to look a long way out. Long range radar is hard because the inverse square law applies in both directions, so you need 16x the power to double the range.

mikhailfranco3• 7 years ago

Maybe a solar powered array on the dark side of the Moon, to restrict any interference from Earth systems, and you get a nice sweep of the ecliptic for free.

known• 7 years ago

Doesn't it vindicate the we need to weaponize space?

skyfaller• 7 years ago

Not really, because space weapons inevitably lead to at the very least space weapons testing, and most likely space combat. Space combat creates space junk, which prevents us from going to space in the future, which prevents us from detecting and deflecting asteroids.

You might think "well, we just need to find ways to destroy space junk" but unfortunately (almost?) all tools useful for destroying space junk can also be used to destroy perfectly functional objects in space, and therefore count as space weapons, which lead to space junk...

jmiskovic• 7 years ago

Sir Arthur Clarke describes the impact itself nicely in Rama intro: https://youtu.be/yMPA25SGlpA?t=88

As I understand, the mayor threat is the dust which doesn't settle for many months. This could starve world's population and pose a major existential risk. Maybe we can use our spy satellite network and just turn all sensors outwards?

AtomicOrbital• 7 years ago

duplicate thread see https://news.ycombinator.com/item?id=20537941

ralphm• 7 years ago

The original article (https://www.washingtonpost.com/nation/2019/07/26/it-snuck-up...) includes links to some interesting background information, including the event leveling a huge forest area. And it correctly uses square km/miles instead of "square acres".

Scientists stunned by ‘city-killer’ asteroid that just missed Earth

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