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

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

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.

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

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'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?

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.

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.

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.

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.

In that case that might even be planned incompetence.

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?

> 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.”

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.

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...