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I 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
by ddahlen 2y ago
I 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 we saw it so briefly, our knowledge of its orbit is not that great, and running the clock back to 2016 for example ended up with a large chunk of sky where it could have been, and it is quite small. We will almost certainly see it again with NEO Surveyor years before its 2032 close encounter. I have not run a simulation for it, but I would not be surprised if LSST (a large ground telescope survey which is currently coming online) to catch it around the same time NEO Surveyor does.
Our knowledge of the diameter of this object is a bit fuzzy, because of surface reflectivity, small shiny things can appear as bright as dark large things. This is one of the motivations of making the NEO Surveyor an IR telescope, since IR we see black body emission off of the objects, which is mostly size dependent, and only weakly albedo dependent.
There is an even tinier chance that if it misses the Earth in 2032, it could hit the moon. I haven't run the numbers precisely for that one, but it impacted a few times in some monte-carlo simulations.
If anyone is interested in orbit dynamics, I have open sourced some of the engine we are using for observation predictions: https://github.com/Caltech-IPAC/kete https://github.com/Caltech-IPAC/kete
It is relatively high precision, though JPL Horizons has more accurate gravitational models and is far better suited for impact studies. My code is primarily for predicting when objects will be seen in telescopes.
- formerphotoj 2y agoThank you. Why I read HN!
- SubiculumCode 2y agoIf 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?
- ars 2y agoWe 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.
- rubyfan 2y ago[flagged]
- School-Cotton 2y agoHow 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.
- dylan604 2y agoDoes 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?
- School-Cotton 2y agoA lot of people do evacuate hurricane zones, even when death and destruction are not absolutely guaranteed. If we knew with certainty that a particular place was going to be hit by an asteroid, and we had time to evacuate, I am confident most people would do so.
- slackerIII 2y agoGreat 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?
- renjimen 2y agoParent mentioned Monte Carlo simulations, which allow you to simulate across a range possible scenario parameters and see what % result in some outcome (like a collision with Earth or the moon).
- VierScar 2y agoI'm sure there's a reason, but it seems like an unusual use of Monte Carlo - it's all deterministic and there is no opposing player making choices. Must have something to do with uncertainties in projected orbits or imperfect simulations maybe?
- deleted 2y ago[deleted]
- heikkilevanto 2y agoUncertain observations, I'm sure
- deleted 2y ago[deleted]
- zacharycohn 2y agoRight - we only got a short glimpse of it, not enough to get a high confidence of its trajectory.
- Projectiboga 2y agoThe guesswork is uncertainity about the object's exact paraneters. Because of this they have to use informed estimates (scientiffic guesswork).
- timewizard 2y ago> JPL Horizons A slight tangent.. but my favorite thing about Horizons is that they still maintain a telnet interface to their system. Once you learn to use it it's quite a bit of fun to play around with it.
- nonrandomstring 2y agoThat warms my heart on a winter night.
- dzdt 2y agoI wonder if we have a chance to catch it still on radar this pass. I know Arecibo used to do that and is now sadly gone, but Goldstone also has capability. Anyone know more?
- thenthenthen 2y agoFAST [0] in China maybe? [0] https://fast.bao.ac.cn/ https://fast.bao.ac.cn/
- grues-dinner 2y agoFAST also doesn't have transmitters, unlike Arecibo. So you cannot do radar observations of radio-reflective but not emitting objects with it in the same way.
- me-vs-cat 2y ago> if it misses the Earth in 2032, it could hit the moon. Oh, that's not so ba--- Wait, isn't that what happens in Seveneves?
- fnordlord 2y agoI think that was supposed to be some kind of small black hole passing through the solar system or something more exotic. Maybe I'm misremembering. Great book though and still haunts me sometimes when staring up at the night sky:)
- intrasight 2y agoI had also interpreted it as a small solo black hole. Which it itself a scary concept.
- YeGoblynQueenne 2y agoEspecially if it was a member of a band before going solo.
- zwily 2y agoHe never actually said what it was. I think some people floated theories, but the book never reveals the answer.
- dreamcompiler 2y agoAn 8 MT impact on the Moon is what the Moon calls "Tuesday." It has dealt with far, far worse. The impact probably wouldn't even be visible with the naked eye unless it hits a part of the Moon not then illuminated by the Sun -- in which case one might see a brief flash of light.
- mikeyouse 2y agoBecause I was curious and had no idea about the relative size of meteors that hit the moon, the one that hit the moon in 2013 and was captured by Spanish astronomers was traveling at 65k KPH and weighed about 400kg. That had an impact energy of 15 tons of TNT (https://www.youtube.com/watch?v=perqv4qByaI&t=1s https://www.youtube.com/watch?v=perqv4qByaI&t=1s) Safe to say, an 8 megaton impact from one that weighs 220,000,000kg would be a bit more substantial! Apparently that would be roughly the size of the Meteor Crater in Arizona (https://en.wikipedia.org/wiki/Meteor_Crater https://en.wikipedia.org/wiki/Meteor_Crater).
- tmountain 2y agoWhat are the implications of a moon impact? Would it affect life on Earth?
- euroderf 2y agoWould Earth see on-again, off-again random showers of rocks of various sizes ?
- looofooo0 2y agoDo you know people worrying about supervulcano erruptions?
- defrost 2y agohttps://www.usgs.gov/observatories/yvo https://www.usgs.gov/observatories/yvo https://en.wikipedia.org/wiki/Yellowstone_Volcano_Observatory https://en.wikipedia.org/wiki/Yellowstone_Volcano_Observator... How concerned? https://www.agiweb.org/geotimes/june05/feature_supervolcano.html https://www.agiweb.org/geotimes/june05/feature_supervolcano.... not very.
- solstice 2y agoCould we stick an rtg-powered tracking beacon on it during its next flyby so that we can better calculate its orbit?
- amluto 2y agoI would expect that a handful of retroreflectors, along the lines of lunar laser ranging, would be much less expensive and work about as well if not better. A radio beacon can give direction, at least within the precision of whatever array is used to locate it, but it does not directly give distance. And, with a reflective system, you can get extremely precise radial velocity by measuring Doppler shift, and all the fancy equipment needed is right here on Earth where it’s easy to maintain and upgrade. Doppler measurements of a remote beacon are dependent on the quality of the remote clock, which adds complexity and dependence on gravitational redshift at the beacon [0]. [0] I haven’t tried to calculate how much this would offset the apparent velocity, but it seems very likely to at least be detectable.
- AISnakeOil 2y agoVery interesting. How can we get rich from this?
- grapesodaaaaa 2y agoI’m not saying this is a good idea, but conspiracy/prepper YouTube channels seem to be thriving off ad revenue these days.
- lupusreal 2y agoThere's too many of those, you'll never stand out from the crowd. Instead, you could make a channel where you react/review to specifically asteroid impact related books and media. It could be very low effort, but topical enough to gain traction as people search and watch other asteroid videos.
- DoctorOetker 2y agoI understand that we don't know the exact trajectory of the object, but there should be relatively little play on the time of (potential) impact, and the direction it would come from, so we should already know the orientation of the earth, and the spot on the earth where it would hit if we assumed the trajectory to pass through the center of the earth. The hemisphere centered around this position on the earth surface is then effectively candidate for the future potential impact, the rest of the earth surface would be obscured by the front hemispherical earth surface from the perspective of the object. Do you know where this center is?