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> In Oumuamua defense, it hasn't seen this much of Sun to be impressed or inflicted by its thermal power. 25. kilometers. per. second. It went in and out before Sun could do its damage.

…it was (and still will be) in the solar system for quite a while. The Solar System is big.

> it would be disintegrated by having its surface polished with cosmic energy long before it could reach 25km/s

…no? Relative to cosmic energy, it might as well be at rest.

> Upon impact, it would either penetrate Earth surface exploding inside the core, like any hollow bullet does, or it would cut Earth in half like a high power laser and deform itself on way out.

I suggest you read up on high velocity impacts: https://en.wikipedia.org/wiki/Impact_depth

I read it. It doesn't make a difference that majority of meteors burn in atmosphere and barely hit Earth surface. Oumuamua may have traveled through earth atmosphere and hit Earth undamaged. The difference is obviously like day and night.

This does not meaningfully change the result; as far as I'm aware you can just change the A/B ratio to account for the density of the atmosphere and treat it as any another layer. Even accounting for this, speed does not have a meaningful effect.

> It doesn't make a difference that majority of meteors burn in atmosphere and barely hit Earth surface. Oumuamua may have traveled through earth atmosphere and hit Earth undamaged. The difference is obviously like day and night.

https://en.m.wikipedia.org/wiki/Impact_event

Contains some tables with actual numbers (based on a 17km/s impact), including how big of a airburst a non-impacting object makes and how much of a crater an impacting object makes.

You aren't splitting the Earth with something the size we are talking about with any of the estimates of it's size, even at 25km/s, which basically a little over doubles impact energy, the same as a 29% increase in diameter does.

Leaving aside everything else...

> and some form of human life looking nothing like we do today would argue 250,000 years from now what caused the first human near-extinction.

Well, they might, but they would probably be talking about the Toba supervolcano 320,000 years in their past.

> You're talking about razor-sharp thin and lightweight object traveling with insane speed.

Shape is not all that important (though I think that a long tumbling object is more likely to break up break up at altitude), the speed is high, sure, but not so far out of line with typical meteors as to make that big of a difference, and the low density offsets the effects of speed (also makes it more likely to break up at altitude). And the later estimates of it's size are not enormous. It would perhaps be a bag meteor impact, but quite possibly not the worst to hit during the existence of humans.

> Upon impact, it would either penetrate Earth surface exploding inside the core, like any hollow bullet does, or it would cut Earth in half like a high power laser and deform itself on way out.

No, it would do neither of those things: it would either explode in the atmosphere or make a crater on the surface.

You seem to think it is a superstrong heat-resistant stabilized penetrator dart coming point first, rather than a tumbling body of (probably) rock and ice.

This is all predicated on 25 km/s being very fast, which in this case it really isn't. Man made objects like the ISS travel at 7 km/s, so these are relatively achievable speeds, even for humanity.

We can look at meteor impacts, too. The first source I found on the topic said meteors commonly impact with 11- 72 km/s. [1] This happens every day with small objects and we're fine. With bigger objects you'll get extinction events and features like the Chicxulub crater, but no way you'd see anything "penetrate Earth surface ... like any hollow bullet does, or ... cut Earth in half like a high power laser."

The speed of light is 300,000 km/s, more than 10,000 times faster than Oumuamua. An object at 0.1c or even 0.01c would be very threatening, but those are still orders of magnitude faster than Oumuamua.

In short - 25 km/s isn't that fast, don't worry about it. There are plenty of asteroids that could hit us faster than that that we also don't always see!

[1] - https://www.amsmeteors.org/meteor-showers/meteor-faq/

> This is all predicated on 25 km/s being very fast, which in this case it really isn't. Man made objects like the ISS travel at 7 km/s, so these are relatively achievable speeds, even for humanity.

Quite a few spacecraft have reached this speed. Off the top of my head, I think Juno reached something like 70 km/s when approaching Jupiter.

That's pretty meaningless though, the speed of interest is the heliocentric velocity. Juno was accelerating toward the largest planet in the solar system and orbiting it, not doing a gravitational slingshot.

The current record is Voyager 1, which got its speed from a flyby tour of the outer solar system. It is going 17 km/s.

https://en.wikipedia.org/wiki/List_of_artificial_objects_lea...

We still don't know what Oumuamua is made off of. I think we can agree anyone would rather be hurt by a baseball flying 10km/hour, than being hurt by a knife that travels 1km/h.

Your intuition of how impacts work falls apart at high speeds.

> We still don't know what Oumuamua is made off of.

The fact that it is tumbling and not coming on like a dart along it's long axis means it pretty much doesn't matter what it's made of, aside from it's total mass, it's not going to do some kind of radical penetration or anything else that unusual of it were to hit the Earth.

(Even if it was a stabilized penetrator dart of some kind, AFAIK, that doesn't really change much about surface impact unless you make radically implausible assumptions of composition, but I think it might effect the probability of it making a ground impact rather than an airburst.)

> cosmic energy

Huh? What's "cosmic energy? Do you mean cosmic rays? Those are actually atoms or electrons moving at an exceedingly high speed. Matter, albeit highly energized matter, but not energy itself.

If that is what you meant, the fact that this object was moving at 25 k/s is a fart in a whirlwind compared to the overall velocity of those atoms/electrons. It would have a virtually identical effect to something moving at 25 kph. Not to mention those particles are too small to really "disintegrate" anything. At best, they would knock a few particles off some of the atoms that comprise the object, perhaps changing a few into another element/isotope. There just isn't enough mass there to do any damage on a macro scale.

this is all nonsense - why are you proclaiming this fantasy as if you were some authority?