This is why numbers should always be bounded. Is this 3.3-3.5%?
Or 0-3.4%?
Or 0-6.8%?
Etc
Asteroid ZTm0038 with a >3% impact probability
161–170 of 252 posts
Re: Asteroid ZTm0038 with a >3% impact probability
#162I'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…
TDB: https://en.wikipedia.org/wiki/Barycentric_Dynamical_Time
> [TDB] is a relativistic coordinate time scale, intended for astronomical use as a time standard to take account of time dilation when calculating orbits and astronomical ephemerides of planets, asteroids, comets and interplanetary spacecraft in the Solar System. TDB is now (since 2006) defined as a linear scaling of Barycentric Coordinate Time (TCB). A feature that distinguishes TDB from TCB is that TDB, when observed from the Earth's surface, has a difference from Terrestrial Time (TT) that is about as small as can be practically arranged with consistent definition: the differences are mainly periodic, and overall will remain at less than 2 milliseconds for several millennia.
https://en.wikipedia.org/wiki/Terrestrial_Time
> TT is distinct from the time scale often used as a basis for civil purposes, Coordinated Universal Time (UTC). TT is indirectly the basis of UTC, via International Atomic Time (TAI). Because of the historical difference between TAI and [Ephemeris Time] ET when TT was introduced, TT is approximately 32.184s ahead of TAI.
Phew!
Re: Asteroid ZTm0038 with a >3% impact probability
#163Earlier quoted context omitted.
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.
Do NEOscan and CNEOS share data? They have slightly different details:
Re: Asteroid ZTm0038 with a >3% impact probability
#164Earlier quoted context omitted.
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 I'm looking at the time chart correctly, that basically corresponds to "daylight hours", when you're facing the sun, tomorrow within the northern hemisphere...
We should look for secondary evidence, did the gov start continuity of gov operations etc. If it is real and if nothing can be done about it, we cannot expect official confirmation.
Re: Asteroid ZTm0038 with a >3% impact probability
#165Earlier quoted context omitted.
Can you elaborate on the question you're asking?
Put differently: am I missing something if I say this website is similar in function to https://hasthelargehadroncolliderdestroyedtheworldyet.com ? At least in terms of a public service announcement; I understand it's interesting for science but not so much for linking "hey look there's an X% chance of impact....yesterday!" on news websites
When I was taking physics at the University 20 years ago, one of my professors said that the closest we have ever come to predicting an asteroid impact was "whoa that was close" as it zipped by.
Sounds like that's still state of the art.
Re: Asteroid ZTm0038 with a >3% impact probability
#166Earlier quoted context omitted.
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 observa…
Unless one in every 33 asteroids that have 3% impact probability at some point in time actually impacts earth, there is clearly some unwarranted assumption in the error bar/distribution calculation.
"The measurement data has noise" does not explain why the noise has a bias towards "the asteroid will hit earth" whereas reality so far has been biased towards "the asteroid will not hit earth".
(This assumes that significantly more than 33 asteroids have had >= 3% impact probability predicted at some point. The opposite would not be less concerning.)
Re: Asteroid ZTm0038 with a >3% impact probability
#167Earlier quoted context omitted.
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 observa…
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Re: Asteroid ZTm0038 with a >3% impact probability
#168Earlier quoted context omitted.
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).
I wonder if there have been any simulations of such an impact and what the worst case would look like for equivalent mass but different shapes and asteroid compositions.
Re: Asteroid ZTm0038 with a >3% impact probability
#169I'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…
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…
What percent of the times when the initial probability is 3% will it later be revised to zero? Is it more than 97%?
Re: Asteroid ZTm0038 with a >3% impact probability
#170Looks like it is about the same size as 25143 Itokawa that the Hayabusa probe visited. That has a mass of 35 billion kg. The Burj Khalifa is 0.45 billion kg so that is about 80 Burj Khalifa's.
Yes, but how many ant-sized swimming pools deep is it?