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by mrb 1045 days ago
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 words the asteroid already passed Earth, and is currently no longer a risk.
2 comments

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!

It seems pedantic, but I'll bet the differences matter when you're talking about objects that have relative speeds in the tens of km per second.

2ms at 10km/s is off by 20m.

Probability without confidence interval is not very useful.

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

The probability takes into account the error on the measurements so I'm not sure what you're getting at
I don't know what you mean.