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Comment by tommoor | Hacker News Reader

> This is only the ninth time that humankind has discovered an asteroid before it impacts Earth

TIL. It seems like it's basically luck if someone is looking through a telescope in the right place at the right time?

Luck has a lot to do with it, sure, but we're (thankfully) a bit more advanced than just hoping someone is looking through a telescope at the right place/time.

NASA's Center for Near Earth Object Studies does a lot of neat work related to this. For example, Sentry [1], the NEOWISE mission [2], etc.

[1] https://cneos.jpl.nasa.gov/sentry/

[2] https://www.jpl.nasa.gov/missions/neowise

Thank you for your useful comment. It sent me down a brief rabbit hole of looking for a grid of amateur telescope owners cooperating for NEO object detection. I found eSTAR for the big boy telescopes [1] [2], but nothing for enthusiasts. I ran across NEO Surveyor that launches in September 2027, will run for 5 years, and is aiming for 90% coverage [3], so I suppose a grid of amateurs contributing telescope time into a software-driven grid and detection system won't be helpful?

[1] https://indico.cern.ch/event/423169/contributions/1890157/at...

[2] https://ui.adsabs.harvard.edu/abs/2002SPIE.4845...13S/abstra...

[3] https://www.jpl.nasa.gov/missions/near-earth-object-surveyor

You might be interested in the work of Robert Holmes.

https://www.techbriefs.com/component/content/article/33153-q...

https://en.wikipedia.org/wiki/Robert_Holmes_(astronomer)

https://www.youtube.com/watch?v=MWLDvuK_4qU

Although there's always luck involved, it was discovered by the Catalina Sky Survey, a survey specifically designed to spot near-earth objects.

Their main telescope has a very large field of view (20 square degrees), and takes only 30 seconds per exposure, giving it many chances to get "lucky".

Does anyone know how the 10,000 Starlink satellites and the other 30,000 LEO competitors by the end of the decade are going to affect spotting near-earth objects?

I would have a hard time believing "not at all".

Vaguely related this is my favorite amateur astronomer spotting accident ever, capturing supernova an hour before it happened which hasn't been done before:

https://www.popsci.com/amateur-astronomer-photographs-birth-...

makes me wonder when the sky becomes so difficult to see through if we are going to lose all that enthusiastic effort

In sailing and shipping, another vessel is set for a collision course for you if and only if its direction from you doesn't change (assuming both keep constant speed).

Is this roughly the same for orbiting bodies? If so, it would seem that things on a collision course would be harder to detect, as they're indistinguishable from bodies far away that don't move. Possibly orbital mechanics change this significantly, but over the course of a few days the earth's trajectory is pretty much straight.

Objects in orbit are by definition constantly changing direction.

Yes, up until recently. The Vera Rubin observatory will change that quite a bit, and soon. Most observatories and telescopes are currently aimed at deep field (very long exposures of tiny portions of the sky). There are a few surveys meant for transients (supernovae, variables etc) and those are also well suited for near earth objects: look at the Catalina sky survey and the zwicky transient facility. When I was (very mildly) involved, the Vera Rubin observatory expected its first 25% of the mission to be overtaken by observing new near earth objects, even as its mission was to catalog variable stars and spot supernovae and other transients.

Some interesting stories about how these surveys work today and how they will work in ~10 years. Right now, it’s so rare to spot a weird thing in the sky that the alarms are all verified by grad students in graveyard shifts. When the new observatories come online, there won’t be enough grad students in the world :) so it’ll all be ML.

Well yes, but these are only spotted so late because they're so small, which also makes them harmless. Anything that would be large enough to do damage would be also easier to detect sooner.

There are a number of projects dedicated to looking for near earth objects that could impact the earth. Pan-Starrs and Atlas are the ones that come immediately to mind for me, but there are others.

And it seems to have just barely made it in the asteroid class being >1m if less it would be a meteoroid.

Not really. What the article fails to tell you is that there have been many, many, many more than nine times that asteroids have been spotted, often years in advance, where the initial data had wide enough error bars to make an Earth impact possible, but continued observation quickly ruled that out and predicted, correctly, that the asteroid would pass near the Earth but miss it. True, those asteroids were quite a bit larger than 1 meter wide, but as the article's description of the "impact" shows, a 1 meter wide asteroid isn't a real threat anyway.

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