ARCHIMEDES: Eeeeh. Ocenuju konkretni cisla, akorat ze to co rikam xchaosovi porad plati: ignorujes pusobeni dalsich teles (vcetne Zeme), coz asi za deset let neco udela a pocitat uhnuti na presne nebo skoro presne polomer zeme znamena, ze mas extremne optimistej nazor na presnost mereni polohy a drahy deset let a vice dopredu.
Co to tom rika JPL?
99942 Apophis (2004 MN4)
https://cneos.jpl.nasa.gov/doc/apophis/
a close approach that is not dangerous (like Apophis in 2029) nonetheless close enough to obscure the proximity and the danger of a later approach (like Apophis in 2036) by amplifying trajectory prediction uncertainties caused by difficult-to-observe physical characteristics interacting with solar radiation as well as other factors.
the effect [of solar energy] on Apophis’ predicted position can grow to between 520,000 and 30 million km (323,000 and 18.6 million miles; 0.0035-0.2 AU)
It was found that small uncertainties in the masses and positions of the planets and Sun can cause up to 23 Earth radii of prediction error for Apophis by 2036.
Dokonce i velmi prekvapive
The standard model of the Earth as a point mass can introduce up to 2.9 Earth radii of prediction error by 2036; at least the Earth’s oblateness must be considered to predict an impact.
Vyse uvedene nepisu proto, ze se chci bavit konkretne o Apophisu, ale proto, abych ukazal, jaky vsechny faktory hrajou roli.
Tenhle trivialni vypocet proste sice dava "dolni mez", ale zhruba na stejny urovni, jako "dolni mez jak rychle se dostanu s desatyho patra do prizemi" je vydelit vejsku baraku rychlosti svetla. Rychlejc to nepujde, to je pravda, ale ignoruje to tolik podstatnejch faktoru, ze to proste neni uzitecny cislo.
Kazdopadne, muzes prosim nejakej pointer na vzorce, podle kterejch jsi to pocital? Diky.
A tresnicka na dortu na zaver:
Changing the amount of energy Apophis absorbs by half a percent as late as 2018 - for example by covering a 40 x 40 meter (130 x 130 foot) patch with lightweight reflective materials (an 8 kg payload) - can change its position in 2036 by a minimum of one Earth radius. - takze, pokud chceme za patnact let soupnout asteroid stranou o polomer Zeme, mame dve moznosti: bud tam podle xchaose poslat spousu robotu, ktery ten sutr postupne rozeberou na kousky a odhazej stranou. Nebo na nej proste nechame americany nastrikat velkej bilej napis Coca Cola. Vysledek bude stejnej 8)))