Asteroid TB145 “Spooky” or the “Great Pumpkin” is an asteroid flying by Oct 31st 17.05 UTC so 4am Nov 1st for us (basically during the early morning for us after Halloween).
A third (1.3) further out than the Moon, this is a close shave by astronomy standards (and we only spotted it 10th Oct!) At over 300m across (perhaps even more) this would be catastrophic if it hit (expected every 70,000 years or so) but we know of at least 3300 objects near Earth of similar size so a matter of time.
Moving 35km/s so 120,000 km/h this is likely a dead comet with most of the water long since heated off by close passages to the Sun so it’s almost impossible to see this coming, PanSTARRS (in Hawaii with one of the world’s largest digital cameras, 1.4 gigapixel -> 200x the latest iPhones) caught it.
It’s coming from below the Solar System to above, and since Australia stopped the asteroid search at Siding Springs, which only needed $50-100k per year, we've had a much harder time seeing these objects from that direction. Usually we’d see them with a few times further out than we are to the Sun, unusual to see it so late.
Will track it using Goldstone radar to probe features as small as 2m, critical to know what this is made of as we can hope to try and move these away if an impact is predicted. This late though, no chance can only hope to evacuate regions of impact.
Has energy of a few hundred Hiroshima nuclear bombs. If it hit the crater would be city sized (~5km across or so) and half a km deep with huge fireballs tens of kilometres further. If it hit the sea we could expect tsunamis of 10s of metres high.
It is the closest massive object since 2006 and will be until flyby in 2027 (by 800m wide object).
Check out your favourite asteroid collision with this impact simulator at https://www.purdue.edu/impactearth
Watch live at https://live.slooh.com/stadium/live/spooky-sneak-peek
Fun what if it didn’t miss piece at https://theconversation.com/now-thats-a-close-shave-secrets-of-the-halloween-asteroid-headed-for-earth-49820
Watch the orbital track at https://youtu.be/Lff8kFCDAm0
Check out ESA plan's telescope ‘fly-eye’ to search for these in future http://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness/ESA_s_bug-eyed_telescope_to_spot_risky_asteroids