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...

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.

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.

[Yes]

Ironically, requesting the desktop site uses more bandwidth, defeating the purpose of a rate limit.

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

2019 OK :

- "2019" => discovered in 2019

- O => discovered in 2nd half of july

- K => 10th object discovered in this period

https://github.com/tomtaylor/lowflyingrocks

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.

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?

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.

I mean, asteroids don't deliberately hide.

Sure, some are darker and/or have a less visible radar profile or whatever, but the variations seem manageable.

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

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)

(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.

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.

http://www.aboriginalastronomy.com.au/content/topics/craters...

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.

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

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.

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

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.

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.

https://b612foundation.org

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.

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

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.

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.

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

In that case that might even be planned incompetence.

Are you just commenting for the sake of commenting?

Is this satire?

It's was not entirely clueless as I actually know a little about this, but still. Sorry all.

You can read it without js, when you disable css

I think that’s because they are so small. The impact of earth’s atmosphere on a 100m solid rock will be negligible in comparison.

Their speed perpendicular to earth also is very low, meaning they spend more time in the athmosphere. I guess they may even bounce of it a couple of times. If so, computing impact location requires calculating how many times a skipping stone will skip.

(But no, I don’t think we have the technology to make this an effective weapon. I would go for that rail gun on the moon instead. Still not quite within reach, but it would be a lot easier to get targeting accuracy)

- 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

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?

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.

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

> 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.”

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?

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.

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.

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

https://arxiv.org/abs/1403.7303

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...

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

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?

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.