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Asteroid ZTm0038 with a >3% impact probability

newton.spacedys.com

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Re: Asteroid ZTm0038 with a >3% impact probability

#151

Post by abathur »

apatil wrote: post #136
Analemma_ wrote: post #123

Earlier quoted context omitted.

When a new potentially-hazardous asteroid is discovered, it's normal for the probability of impact to go up a couple times before abruptly plummeting to zero, as the radius of uncertainty shrinks until it shrinks past the Earth. See https://en.wikipedia.org/wiki/Torino_scale#/media/File:Apoph... . A 3% chance of impact right after discovery with the initial error ellipse isn't all that unusual; it will almost certain…

This makes sense, thanks. However, it doesn't mean that the 3% estimate of the chance of impact was wrong at the time of initial observation given data available, and that still makes it a huge deal at that time. At minimum, it would seem to justify using the best available instruments to characterize the asteroid more precisely as soon as possible. If these large numbers happen so often that asteroids with initial i…

I don't know, but I suspect this is more about the limits of the observations (which I imagine are mostly from terrestrial observatories) needed to obtain much certainty about the object's size, course, speed, density, etc.

Re: Asteroid ZTm0038 with a >3% impact probability

#152

Post by jacquesm »

version_five wrote: post #141
jacquesm wrote: post #134

Earlier quoted context omitted.

Depending on how it is aimed... straight in that would be messy.

That would be an interesting analysis to see, my guess is it wouldn't be that different than if it was a sphere of equivalent mass, and vs a 400m sphere would be 400/(4*pi*200^3/3) = .0012% the volume (and so kinetic energy), and it would not penetrate in a way that does specifically worse damage. Just guessing though. Edit: I confused radius and diameter in my calculation and revised it. I may have made other mistak…

That would highly depend on what the composition of the asteroid was and where it impacted. On a fault line? In the middle of an ocean, or a city?

For sure the depth of penetration would be different for a rod shaped object of equivalent mass compared to a spheroid, the latter would penetrate much less deep. Angle of incidence would be a factor as well as (obviously) the speed of the impacting body. But if it impacted at a higher speed than that the ejecta could get out of the way it would cause an absolutely massive crater. As though you'd exploded an absolutely enormous nuclear bomb deep underground, but not so deep that the explosion would still reach the surface. That would probably be the worst case scenario for an impact like this.

Re: Asteroid ZTm0038 with a >3% impact probability

#153

Post by JumpinJack_Cash »

jacquesm wrote: post #142
JumpinJack_Cash wrote: post #98

The public is unanimously in favor of funding asteroid protection mechanisms and research. It's even higher support than the military. Naturally what do we do with that money and goodwill instead? Yes! Let's build a massive space telescope which takes pictures that are only marginally better than the other multi-billion dollar space telescope! Protect the Earth? Fuck that, don't ya know kid? She's toast anyway becaus…

There have been many studies about what could be done to deal with asteroids that are on track to impact earth and the simple answer is 'nothing'. Frustrating, but unless you can think of something that none of the very clever people on those committees could think of it's going to stay that way.

The obvious answer to that is being able to reliably detect asteroids on a collision course, and compute where is it gonna fall in order to proceed the emergency evacuation.

But first you have to be able to detect it, second you have to do it with reasonable time to save as many people as possible

Re: Asteroid ZTm0038 with a >3% impact probability

#154

Post by cfraenkel »

apatil wrote: post #136
Analemma_ wrote: post #123

Earlier quoted context omitted.

When a new potentially-hazardous asteroid is discovered, it's normal for the probability of impact to go up a couple times before abruptly plummeting to zero, as the radius of uncertainty shrinks until it shrinks past the Earth. See https://en.wikipedia.org/wiki/Torino_scale#/media/File:Apoph... . A 3% chance of impact right after discovery with the initial error ellipse isn't all that unusual; it will almost certain…

This makes sense, thanks. However, it doesn't mean that the 3% estimate of the chance of impact was wrong at the time of initial observation given data available, and that still makes it a huge deal at that time. At minimum, it would seem to justify using the best available instruments to characterize the asteroid more precisely as soon as possible. If these large numbers happen so often that asteroids with initial i…

It's not a model that is poorly calibrated - you seem to be taking a software-centric concept far away from where it's useful. The uncertainty at initial observation is because when you first observe an object, you only have observations covering a tiny bit of the orbit, resulting in very wide error bars. The "model" (Newtonian orbital dynamics) is one of the most precise models we have. Doesn't help when the observations are noisy.

Re: Asteroid ZTm0038 with a >3% impact probability

#155

Post by pvg »

lucb1e wrote: post #119
songeater wrote: post #107

did this pass ~4000km from earth? [1] MOID given as 0.0000296 https://newton.spacedys.com/neodys2/NEOScan/risk_page/ZTm003... [2] AU to km https://www.google.com/search?q=au+to+kilomore&rlz=1C1GCEA_e...

MOID being minimum orbit intersection distance, for anyone else wondering. Sounded like someID (identifier) to me, was wondering why that value was given in AU

MOID is an id that is just that big. You wanted more id, you got MOID.

Re: Asteroid ZTm0038 with a >3% impact probability

#156

Post by tophi »

Leary wrote: post #132
killthebuddha wrote: post #100

I'm having a weirdly difficult time finding some basic ELI5 answers. - What is the probability that this asteroid will hit us? - What is the time interval where that probability applies? - Do we have a probability distribution for where it might hit? I don't know anything about anything, but I assume we know what *general direction* it's coming from? - Do we have a probability distribution for the potential blast rad…

Found this tweet with an impact probability map that is around northern US/Asia/Europe : https://twitter.com/JoelSercel/status/1691549821629526219 "If it is real this IS the worst asteroid threat ever discovered and the impact location and times are ugly (will post pics shortly). Note that the impact is in the next couple days! However, an Italian colleague of one of our astronomers suspects there is an error in the…

There is a disclaimer from the data source: “Scout data are about unconfirmed objects and all information should therefore be treated as potentially unreliable”

I’m hoping this ztm0038 is an error or hoax.

Re: Asteroid ZTm0038 with a >3% impact probability

#157

Post by almostnormal »

jacquesm wrote: post #134
dougmwne wrote: post #113

Earlier quoted context omitted.

That would sound like a kinetic bombardment weapon and that we were about to get rodded. My level of concern would be sky high!

Depending on how it is aimed... straight in that would be messy.

If it has the same density than earth, it wont pierce deeper than its length. If it is made of uranium a bit over twice that (assuming earth is made of iron).

Re: Asteroid ZTm0038 with a >3% impact probability

#158

Post by onlyrealcuzzo »

Leary wrote: post #132
killthebuddha wrote: post #100

I'm having a weirdly difficult time finding some basic ELI5 answers. - What is the probability that this asteroid will hit us? - What is the time interval where that probability applies? - Do we have a probability distribution for where it might hit? I don't know anything about anything, but I assume we know what *general direction* it's coming from? - Do we have a probability distribution for the potential blast rad…

Found this tweet with an impact probability map that is around northern US/Asia/Europe : https://twitter.com/JoelSercel/status/1691549821629526219 "If it is real this IS the worst asteroid threat ever discovered and the impact location and times are ugly (will post pics shortly). Note that the impact is in the next couple days! However, an Italian colleague of one of our astronomers suspects there is an error in the…

If it hits the ocean, how big will the tidal wave be?

Re: Asteroid ZTm0038 with a >3% impact probability

#159

Post by jacquesm »

JumpinJack_Cash wrote: post #153
jacquesm wrote: post #142

Earlier quoted context omitted.

There have been many studies about what could be done to deal with asteroids that are on track to impact earth and the simple answer is 'nothing'. Frustrating, but unless you can think of something that none of the very clever people on those committees could think of it's going to stay that way.

The obvious answer to that is being able to reliably detect asteroids on a collision course, and compute where is it gonna fall in order to proceed the emergency evacuation. But first you have to be able to detect it, second you have to do it with reasonable time to save as many people as possible

Again, these people aren't stupid. You will have a very large amount of uncertainty based on a series of observations which essentially project a circle of probability on the planet that shrinks as more information from newer observations comes in and then just before impact that probability will either drop to zero because it is deemed to be a near miss (sorry, George) or it will then become a certainty. By that time it will be too late to evacuate. I can dig up the report from one of these committees if you want (I should be able to find it), they make for very interesting reading, it is a really nice example of science at work, even if the result is a negative. Anything more advanced makes for great special effects in movies and science fiction but isn't going to work. You'd have a very short time to move the entire population of a circle with a radius of a few hundred kilometers to outside of that circle starting from the center. The longer you waited the fewer people you'd have to move but the bigger the chance you'd be too late.

Re: Asteroid ZTm0038 with a >3% impact probability

#160

Post by onlyrealcuzzo »

mrb wrote: post #130
killthebuddha wrote: post #100

I'm having a weirdly difficult time finding some basic ELI5 answers. - What is the probability that this asteroid will hit us? - What is the time interval where that probability applies? - Do we have a probability distribution for where it might hit? I don't know anything about anything, but I assume we know what *general direction* it's coming from? - Do we have a probability distribution for the potential blast rad…

I can answer 2 of your questions: - What is the probability that this asteroid will hit us? It's listed in the article: Impact probability 0.034, meaning 3.4% chance of impact. - What is the time interval where that probability applies? It's also listed: impact was estimated to potentially occur between 2023/08/14 04:48 TDB and 2023/08/15 12:22 TDB. (TDB seems to be UTC time without leap seconds? not sure). In other…

Probability without confidence interval is not very useful.

If there's <1% confidence - this is not exactly news.

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