Yarkovsky effect and 1999-RQ36 impact uncertainty

[gary]

ABC has a story today by Stuart Gary about NEO 1999-RQ36

Originally Posted by ABC Science

Reporting in the journal Icarus, scientists say the asteroid named 1999-RQ36 has a one-in-a-thousand chance of hitting the Earth in 2182.

Co-author of the study, Dr Maria Eugenia Sansaturio from Spain's Universidad de Valladolid, says the total impact probability for 1999-RQ36 is estimated to be 0.092%, and that 2182 is the most likely year for an impact to occur.

Although the orbit of 1999-RQ36 is now well determined, there remains a significant orbital uncertainty because, besides gravity, its path is influenced by the Yarkovsky effect.

Story here including more about the Yarkovsky effect -

http://www.abc.net.au/science/articl...29/2967908.htm

[wavelandscott (Scott)]

Better keep an umbrella handy just in case!

Space weather can be a bear...

[astroron (Ron)]

Thanks Gary, I had read of the Yarkovski effect but that article explaines it easy enough to understand

[gary]

Originally Posted by wavelandscott

Better keep an umbrella handy just in case!

Space weather can be a bear...

Hi Scott,

It would want to be an umbrella made of the best ripstop nylon.

According to the NASA Near Earth Object Program page, 1999-RQ36 would
deliver an estimated impact energy of 2700 Megatons (i.e. 2.7 Gigatons)

Given that the largest thermonuclear device detonated to date produced 50 Megatons,
on the slim chance 1999-RQ36 rained down, it certainly would be one bad hair
day on Earth.

[renormalised (Carl)]

Yep, it'd blow a crater about 15-20kms across and flatten everything within a 100-400km radius, depending on the terrain. The destruction would be spread out over the greater portion of the US and into parts of Canada and Mexico. Mostly fires and such caused by hot debris raining back down from the upper atmosphere and Earth orbit.

[gary]

Originally Posted by renormalised

The destruction would be spread out over the greater portion of the US and into parts of Canada and Mexico.

Hi Carl,

Sounds like you are a believer in that lightning can strike twice in the same place.

With regards the specific impact site, that would probably be news to the good folk
of the US, Canada & Mexico.

Scott, better come back to the relative safety of Sydney!

[renormalised (Carl)]

Originally Posted by gary

Hi Carl,

Sounds like you are a believer in that lightning can strike twice in the same place.

With regards the specific impact site, that would probably be news to the good folk
of the US, Canada & Mexico.

Scott, better come back to the relative safety of Sydney!

Nah....just picked a target and sent it there

Anyway, it's not quite exactly the same place...2500km apart!!

[Zaps]

Earth Impact Effects Program - courtesy Collins, Marcus and Melosh, University of Arizona.

BTW, I taught Hank Melosh darn near everything he knows about modeling cratering dynamics, which happens to be a lot less than he thinks!

[wavelandscott (Scott)]

Originally Posted by gary

Scott, better come back to the relative safety of Sydney!

That sounds like a fine idea!

But, I'll bring a very sturdy umbrella with me just in case...

[wavelandscott (Scott)]

Originally Posted by gary

According to the NASA Near Earth Object Program page, 1999-RQ36 would
deliver an estimated impact energy of 2700 Megatons (i.e. 2.7 Gigatons)

Given that the largest thermonuclear device detonated to date produced 50 Megatons,
on the slim chance 1999-RQ36 rained down, it certainly would be one bad hair
day on Earth.

That sounds like a big kaboom to me...

Remarkably that is even a bit more powerful than the New Years Fireworks in Sydney!

[renormalised (Carl)]

The umbrella's for the ejecta thrown out by the impact

[higginsdj]

Got to love these 'predictions'. Yarkovsky affects everything but there are no models to predict the extent of the effect. We are only now in a position to measure the effect on a very small number of objects that have been observed over the last decade or more. The report may as well say there is sufficient orbital ambiguity in every NEO orbit that any one of them could collide with the earth outside the next 100 years.