
Earth had a near-miss with 'city-killer' asteroid this morning - pseudolus
https://www.smh.com.au/national/earth-had-a-near-miss-with-city-killer-asteroid-this-morning-20190725-p52apn.html
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o_nate
Whenever I read articles like this, a couple of questions come to mind.
Cumulative probability of being struck by one of these things within next 10,
20, etc. years? What would we do if we did see one coming that was going to
strike earth given 1 day, 1 week, 1 month, etc. lead time?

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wrycoder
A little over 10 Earth radii. That is very close for something this size,
compared to other near misses trumpeted as “close”.

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Someone
Scaringly close. 70,000 km is only 11 times the radius of the earth.

That means a rock that size thrown at random that does get that close or
closer to earth has a probability of a collision course with earth of about 1
in 11² ~= 0.8%.

Being on collision course doesn’t imply it will impact, as it may explode in
the atmosphere (probability? I wouldn’t know) or bounce of it (probability
effectively zero, I would say/guess)

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DoreenMichele
TIL: Meteors don't just _burn up_ in Earth's atmosphere. Some explode.

[https://physics.stackexchange.com/questions/76045/why-do-
met...](https://physics.stackexchange.com/questions/76045/why-do-meteors-
explode)

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qserasera
I find this report raises my hopes for Giant Meteor 2020. For this asteroid we
had a couple days notice, perhaps it would be nicer if we get can get early
confirmation for a 2020 run.

