Asteroid 2024 YR4 now has a 1.94% chance to hit the Moon (according to my own calculations) angielski

Potatisen, 2 dni temu

Wooow, this is super cool!

As someone who doesn’t know or understand any of this math/physics. Would you mind doing a super simple explanation of how the calculation works and why you chose certain factors?

Might be a dumb thing to ask but just curious and want to understand more.

LostXOR, wczoraj (edited wczoraj)

Sure thing!

D_nominal, D_min, and D_max represent the most likely, minimum, and maximum (well technically not maximum, just 3 standard deviations from most likely, of which 99.7% of trajectories will fall within) distance 2024 YR4 will pass from the center of the Moon (NOT the surface). They're taken from the linked NASA website. R_moon is the radius of the Moon.

L_impact is length of the impact corridor (the line where 2024 YR4 could impact the Moon). Since it doesn't pass through the center of the Moon, it's not simply 2*R_moon and so we need a simple formula to calculate it from R_moon and D_min.

P(x) is a probability density function; it's the black curve you can see. It shows, for a given trajectory along the line of possible trajectories, how likely 2024 YR4 is to follow that trajectory. It's shifted a bit from the center since the most likely trajectories are not exactly centered on the Moon. P_impact is the area of P(x) that falls within +/- L_impact, AKA the probability that the trajectory will intersect the Moon, AKA the impact probability.

The rest is just some graphing stuff that doesn't matter to the calculation.

keepthepace, wczoraj

AKA the probability that the trajectory will intersect the Moon, AKA the impact probability.

(Disclaimer, I know close to nothing about these) Am I pedantic about a useless detail or does it significantly change the probability if we consider that an object may still impact the moon after “missing it” if it comes close enough to be captured and come back after a semi orbit? Or do the relative speeds makes this extremely unlikely?

LostXOR, wczoraj

It's going far too fast to be gravitationally captured.

Potatisen, 11 godzin temu

Cool! Thanks for the explanation.

conditional_soup, 2 dni temu

This is super cool! I was kinda hoping it would hit soonish. 2032 feels like it might as well be 3032 with how things are going. Hopefully this doesn’t mess up any of the world’s plans for lunar bases.

edgemaster72, 2 dni temu

Nooo not the moon, it didn’t do nothing to no one. Come back YR4, we still have some lovely cities you could obliterate.

threelonmusketeers, 14 godzin temu

Do we know if the Moon will be in the correct phase in it’s orbit when 2024 YR4 comes by? I didn’t notice a term to account for that, but I’m not too familiar with Desmos.

LostXOR, 13 godzin temu

The calculations for the close approach data I'm using to calculate the probability already take the Moon's orbit into account.

crapwittyname, 10 godzin temu

Nice work! Does the uncertainty come from error bars in the observed trajectory? I would’ve thought an asteroid’s path is pretty easy to pinpoint with enough information.

LostXOR, 4 godziny temu

Yep, even the best telescopes have a bit of inaccuracy in their measurements, and we haven't been tracking it for long enough to determine its orbit with enough precision to know its exact trajectory.