4 ms·

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.

by mrb 3y 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.

onlyrealcuzzo 3y ago
Probability without confidence interval is not very useful. If there's <1% confidence - this is not exactly news.
- Enginerrrd 3y ago
  The probability takes into account the error on the measurements so I'm not sure what you're getting at
- hollerith 3y ago
  I don't know what you mean.
Karellen 3y ago
TDB: https://en.wikipedia.org/wiki/Barycentric_Dynamical_Time 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 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!
- mabbo 3y ago
  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.

by mrb 3y ago

onlyrealcuzzo 3y ago

Probability without confidence interval is not very useful. If there's <1% confidence - this is not exactly news.

Enginerrrd 3y ago
The probability takes into account the error on the measurements so I'm not sure what you're getting at
hollerith 3y ago
I don't know what you mean.

Karellen 3y ago

TDB: https://en.wikipedia.org/wiki/Barycentric_Dynamical_Time 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 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!

mabbo 3y ago
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.