(To redirect Chixculub would require a MUCH larger capability, probably on the order of 10 million tons in orbit, but that's possible with a fleet of large reusable rockets capable of getting the cost to orbit down to around $10/kg, or equivalent development of in-space resource utilization capacity.)
For greatest success I think there would need to be two but probably not many more than two major efforts going on simulatneously, in much the same way that CMS and ATLAS experiments at CERN were independently looking for the Higgs. If one fails for some unforseen technical reason, the other might not if they took a different approach.
Well, yes. It's not fair to the dinosaurs, I admit. They hardly had a chance to develop language and mathematics. They were still too busy ripping each other's faces off. And not having opposable thumbs, of course, really put a damper on technological development. Maybe in a another million years things would have been different, but the asteroid had a different idea.
We, on the other hand, are at least on the precipice of the capability to divert asteroids. Hopefully we don't get an asteroid visit too soon.
Diverting an asteroid, however, is not evolution.
If they got further than us, tried to capture an asteroid and mine it, could they have wiped themselves out without leaving behind technosignatures that would still be visible?
Film-makers would use stop-motion techniques to depict battles between Fordusprefectops and Chevroletcamaro-Rex whilst their own early ancestors look on, clad in loincloths and bras made from footwell mats.
To make things worse for a hypothetical advanced dinosaur species, if they were at the point they could capture an asteroid, they would be roughly equivalent or better with us but we could survive an asteroid extinction event just fine. Society as we know it perhaps wouldn't survive but an event that could genuinely end us as a species would need to be exceedingly destructive or long term. Otherwise the remnants will rebuild, give or take a couple 10s of thousands of years, which is basically nothing on the timescales we're thinking about here.
Some real geologists explored the idea (someone could find the paper and subsequent news articles) and I think the conclusion was that on geological time periods, there might not be much left for us to find.
I doubt the dinosaurs shuttled away or buried all their geo-engineering marks.
There's no good way to read just those strips, but it starts here:
The rate at which we're accumulating change compared to geological record is also a strong argument against, although they argue limitations in current dating methods reducing how much can be said with certainty about prior epochs.
While there is precious little reason and evidence to believe a priori in a previous advanced dino civ, there are studies that could be done on sediment data that'd lend more certainty (such as looking for unusually rapid metal production).
> Anthropocene layer in ocean sediment will be abrupt and multi-variate, consisting of seemingly concurrent-specific peaks in multiple geochemical proxies, biomarkers, elemental composition and mineralogy. It will likely demarcate a clear transition of faunal taxa prior to the event compared with afterwards. Most of the individual markers will not be unique in the context of Earth history as we demonstrate below, but the combination of tracers may be. However, we speculate that some specific tracers that would be unique, specifically persistent synthetic molecules, plastics and (potentially) very long-lived radioactive fallout in the event of nuclear catastrophe. Absent those markers, the uniqueness of the event may well be seen in the multitude of relatively independent fingerprints as opposed to a coherent set of changes associated with a single geophysical cause.
My opinion is this ultimately boils down to how hard human level intelligence is to evolve, which is why the hypothesis is interesting in the context of the Fermi Paradox. Intelligence might be extremely difficult to evolve, it might require an unusual background environment set of condition or just might not be that useful in general.