Estimating Time of Day & Year of KT "Chicxulub" Impactor

[Widdekind]

According to the National Geographic Channel documentary 24 Hours After Impact (DVD), the KT Impactor hit the ground, at an angle, of 30° above the horizon, from the south-east.

 

It seems most likely, that the impactor moved towards the Earth, through the Ecliptic Plane of our Solar System. Thus, working out the angles, this seems much more consistent, with either (1) a (pre-)midnight strike during the Northern Hemisphere summer; (2) a (pre-)noonday strike during the Northern Hemisphere winter.

 

Is there a scientific consensus, on what time of day & year, the impact happened ?

 

 

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If massive (metallic) impactors penetrate planetary Crust, and sink through the Mantle into the Core, how much (more) energy do they dump in the interior ??

 

(1) Estimation of Gravitational Potential Energy (GPE) of planet core vs. surface

 

From the definition equation for GPE:

 

[math]g \equiv - \frac{dU}{dr}[/math]

 

[math]g = -\frac{G M_{<r}}{r^{2}}[/math]

 

If the density is constant, then:

 

[math]M_{<r} = \int_{0}^{r} 4 \; \pi \; x^{2} \; \rho \; dx = M_{tot} \left( \frac{r}{R} \right)^{3}[/math]

 

Thus,

 

[math]g = g_{surf} \left( \frac{r}{R} \right)[/math]

 

and

 

[math]\frac{dU}{dr} = g_{surf} \left( \frac{r}{R} \right)[/math]

 

so

 

[math]\Delta U = \int_{0}^{R} g_{surf} \left( \frac{r}{R} \right) \; dr = g_{surf} \; R \int_{0}^{1} x \; dx = \frac{1}{2} g_{surf} \; R = \frac{G \; M}{2 \; R}[/math]

 

Since the surface GPE is already U_surf = -G M / R, which is half again that amount more than the core, we therefore have:

 

[math]U_{core} = - \frac{3}{2} \frac{G \; M}{R}[/math]

 

Since Earth's mass is actually more centrally concentrated than that, the central potential will be deeper. Thus, in round numbers, material sinking into the core, from the surface, releases roughly as much GPE as that same amount of mass, infalling from infinity, onto said surface.

 

 

(2) Could sinking metallic impactors help heat the Earth's interior ??

 

Earth's interior heat is escaping, through its surface, into space, at the rate of roughly 10 kilotons-TNT per second (1 ton-TNT = 4e9 J = 4e16 erg):

Heat is known to be escaping into space, through the surface of the Earth, at a rate of 4 x 10²⁰ ergs s^-1. If the only source of energy, in the interior, were the heat left over from the formation of the planet 4.5 billion years ago, plate tectonic activity would have long since ceased. Other sources of heat augment the Energy Budget of Earth, including the tidal dissipation of its rotational kinetic energy, possible ongoing gravitational separation (releasing GPE as heavier constituents sink toward the center of the planet), and the continual radioactive decay of unstable isotopes (believed to be the primary source of the heat). This allows much of the interior to remain somewhat plastic, supporting the large, sluggish convection cells that drive the motions of the crustal plates.

 

Carroll & Ostlie. Intro. to Mod. Astro.Phys., pg. 797.

 

Now, according to Wikipedia, the KT Impactor "released the same energy as 100 trillion tonnes of TNT".

 

If this amount of energy were released again, as the metals sank into the interior, then that energy (100 billion kilo-tons TNT) could have powered the whole planet's Geothermal Energy Budget (10 kilo-tons TNT per second) for roughly 300 years.

 

Could this conceivably explain the presence of "Hot Spots" & "Mantle Plumes" ? Could Mantle Plumes be the "fiery trails" of ancient impactors, which cracked the Crust, penetrated into the planet, and sank (are still sinking???) into the interior ???

 

[swansont]

Now, according to Wikipedia, the KT Impactor "released the same energy as 100 trillion tonnes of TNT".

 

If this amount of energy were released again, as the metals sank into the interior, then that energy (100 billion kilo-tons TNT) could have powered the whole planet's Geothermal Energy Budget (10 kilo-tons TNT per second) for roughly 300 years.

 

Could this conceivably explain the presence of "Hot Spots" & "Mantle Plumes" ? Could Mantle Plumes be the "fiery trails" of ancient impactors, which cracked the Crust, penetrated into the planet, and sank (are still sinking???) into the interior ???

 

 

Why would it not just radiate the energy off into space?

[Widdekind]

If dense metallic materials, from the Chicxulub impactor, sank down deep into the interior, then the Yucatan region should have showed intense Hot-Spot-like geothermal & volcanic activity, long after the event, due to the released heat energy rising back towards the surface. That does not appear to be common consensus for what occurred.

[JCP]

Could this conceivably explain the presence of "Hot Spots" & "Mantle Plumes" ? Could Mantle Plumes be the "fiery trails" of ancient impactors, which cracked the Crust, penetrated into the planet, and sank (are still sinking???) into the interior ???

 

 

I would think that highly improbable. Most of these impacts occurred millions of years ago, and the energy from them has long since dissipated.

[Ophiolite]

If dense metallic materials, from the Chicxulub impactor, sank down deep into the interior, then the Yucatan region should have showed intense Hot-Spot-like geothermal & volcanic activity, long after the event, due to the released heat energy rising back towards the surface. That does not appear to be common consensus for what occurred.

1. The metallic content of the impactor was not necessarily large. The precise nature of the bolide is still disputed, but the smart money is on a stone, or a comet, not an iron.

2. As swansont has pointed out the majority of the energy was employed in ways other than sinking material into the mantle. This includes crater excavation, crustal compaction, generation of tsunamis, melting and vapourising country rock, ejecting material into orbital and sub-orbital trajectories, heating the atmosphere, evaporating part of the ocean, etc.

3. Therefore no singificant activity of the type you suggest was to expected and - guess what - we don't see any.

4. Mantle plumes are thought to be very long lived and very deep seated. Your proposal seems incapable of initiating such an entity.

5. Although the total energy released by the impact is large and worthy of the adjective catastrophic, it is very small compared with the total thermal energy of the Earth, by several orders of magnitude and would not therefore be expected to influence long term, deep seated processes.

[DrRocket]

This question is easily addressed. The impact occurred at five o'clock (somewhere).

[Ophiolite]

This question is easily addressed. The impact occurred at five o'clock (somewhere).

Is that D.S.T.? Dinosaur Saving Time?

[DrRocket]

Is that D.S.T.? Dinosaur Saving Time?

 

 

dunno for sure. Ask Alan Jackson. Or Jimmy Buffet.

 

But it apparently failed to save the dinosaurs.

Edited June 13, 2011 by DrRocket

[Widdekind]

This question is easily addressed. The impact occurred at five o'clock (somewhere).

 

How many hours in the day were there, 65 Mya ?

 

 

Ophiolite's points seem sensical. 'Anti-podal focusing' may not be particularly plausible, for a planet-sized system, which is by no means a 'single ceramic crystal', but rather a rough & fractured & disparate 'clump' of plastic & thermally deformable semi-molten rocks.

Edited June 24, 2011 by Widdekind