If it is determined years ahead that it will hit, will there be a months to years ahead period where we will know the exact target/landing spot, eg so we can have evacuations of the impacted area and surrounding areas?
Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy
171–180 of 374 posts
Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy
#172It needs a pictogram to help understand how destructive 8Mt of energy is. Is this a cool light show? Worldwide extinction?
Medium scale nuclear test. Largest was 50Mt
Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy
#173Any idea which hemisphere is going to be exposed to the (low) risk of impact?
Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy
#174Earlier quoted context omitted.
If in 2032 an impact did occur, how much time before that impact would be able to ascertain over 50% probability of impact? hypothetically. That is, does the certainty increase steadily or non-linearly over time? Does near certainty of an impact occur from measurements taken just minutes before the impact, or hours, days, years?
We would see it years before, and we would know with certainty years before. If the object really looked like it might impact I'm sure someone would get time on a powerful telescope to lock in the orbit.
How far in advance would we know exactly _where_ on the Earth it will hit? If, say, New York is going to be destroyed, it makes a big difference if we know that a year in advance vs. a day.
Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy
#175Earlier quoted context omitted.
Why crisis? People should simply not look up.
> Why crisis? People should simply not look up. I don't understand why this apt pun on that movie is being downvoted. Would anyone of the downvoters of parent care to explain?
A lot of people think off-topic puns and jokes are annoying, and HN has a much higher concentration of such people than most of the internet.
That's part of why discussion on HN tends to be much higher-signal than Facebook or Reddit.
Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy
#176I work on the Near Earth Object Surveyor space telescope (NEO Surveyor) writing simulation code which predicts which objects we will see. This one has drummed up a bit of interest due to its (relatively) high chance of impact. I actually spent quite a bit of time yesterday digging through archive images trying trying to see if it was spotted on some previous times it came by the Earth (no luck unfortunately). Since w…
Great post, thank you! Where does the uncertainty (1%) come from? For example, is it more from our ability to precisely determine the orbit based on limited observations, or is it because orbits for objects like this just aren't predictable years out, or something else?
It's a bit of both, observing has uncertainty in a lot of places, if you are on the ground you get atmospheric effects, imprecision of timing, imprecision of optics, etc etc. You are also observing an object where you dont know how far away it is. That distance has to be solved by basically doing a sort of triangulation, which requires either the observer or the object to move enough.
So if you observe over a short time (hours for example), you can see it is moving, but it is hard to tell distance.
Once you have an estimated orbit, if it has any interactions with planets (IE: flyby of Earth), small differences in positions during the close encounter make LARGE differences decades later. Add to this the effects of photons from the sun pushing on the smaller asteroids or dust, or out-gassing /dust from comets cause these objects to slightly drift from just the basic gravitational forces. Generally inner solar system asteroids (inside mars) are very chaotic over hundreds of years, though typically predictable less than a century.
Note that I am not an expert on impact calculations, I just know a bit about and and can do back of the envelope ones. There are a number of ways to get to the ~1%, the orbit fits have uncertainties on them and those can be propagated forward in time. However there are all sorts of complexities with doing that, and often the easiest method is to sample the uncertainty region a few hundred thousand times (Monte-carlo), and propagate those and see what hits.
Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy
#177Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy
#178Is there a "sweet spot" for asteroids where they don't impact the earth, but come within like 20 meters of it?
Like is it possible for an asteroid to give a city a "buzz cut" and then continue on into outer space?
Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy
#179With the cheap kg to orbit heavy lift systems coming online, these near misses are becoming opportunities for vast riches if they can be captured and mined. Less massive making the orbit easier to change.
Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy
#180Earlier quoted context omitted.
We would see it years before, and we would know with certainty years before. If the object really looked like it might impact I'm sure someone would get time on a powerful telescope to lock in the orbit.
How far in advance would we know exactly _where_ on the Earth it will hit? If, say, New York is going to be destroyed, it makes a big difference if we know that a year in advance vs. a day.
Does it though? People don't leave hurricane zones. People don't heed tornado warnings. I just have very little faith in humanity, and fell like "Don't Look Up" would be not too far off.
Also, if you evacuate New York a year in advance, who's to say that the prediction isn't just a skosh off so that New York is left untouched but the real impact location was hit unprepared?