[Rockhounds] Astronomers: A comet fragment, not an asteroid, killed off the dinosaurs

[J Bryan Kramer]

All based on statistical guesses not actual proof. I wish these people
would put some uncertainty in their announcements. We don't have any idea
of how many ice balls aka comets exist in the Kuiper belt do we?

BK

““There exists a law…inborn of our hearts…by natural intuition. … If our
lives are endangered by plots or violence or armed robbers or enemies, any
and every method of protecting ourselves is morally right.””
Cicero

J Bryan Krämer       North Florida, USA
photos at: http://pbase.com/photoburner


On Mon, Feb 22, 2021 at 1:22 PM Tim Fisher <nospam at orerockon.com> wrote:

> I saw this theory on some science TV show or another, it was probably a
> way-out-there proposition back then. Good to see someone backed it up :)
>
> Tim Fisher
> Http://OreRockOn.com
> Email nospam at orerockon.com
>
> -----Original Message-----
> From: Rockhounds [mailto:rockhounds-bounces at rockhounds.drizzle.com] On
> Behalf Of Kreigh Tomaszewski
> Sent: Monday, February 15, 2021 5:50 PM
> To: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
> Subject: [Rockhounds] Astronomers: A comet fragment, not an asteroid,
> killed
> off the dinosaurs
>
> Jupiter's gravity pushed comet toward Sun; comet was ripped apart by tidal
> forces.
> Some 66 million years ago, a catastrophic event occurred that wiped out
> three-quarters of all plant and animal species on Earth, most notably
> taking
> down the dinosaurs. An errant asteroid from the asteroid belt
> <https://en.wikipedia.org/wiki/Asteroid_belt> has been deemed the most
> likely culprit. However, in a new paper
> <https://www.nature.com/articles/s41598-021-82320-2> published in
> Scientific
> Reports, Harvard astronomers offer an alternative: a special kind of comet—
> originating from a field of debris at the edge of our solar system known as
> the Oort cloud
> <http://their
> %20findings%20also%20offer%20evidence%20that%20the%20unusual%20
>
> composition%20of%20the%20chicxulub%20impactor%E2%80%94carbonaceous%20chondri
>
> te%E2%80%94indicates%20it%20originated%20from%20the%20oort%20cloud%2C%20and%
>
> 20not%20from%20the%20main%20asteroid%20belt%2C%20as%20suggested%20by%20one%2
>
> 0of%20the%20more%20popular%20origin%20theories.%20it%27s%20a%20rare%20compos
>
> ition%20for%20main-belt%20asteroids%2C%20but%20common%20among%20long-period%
>
> 20comets.%20the%20authors%20also%20point%20to%20other%20impact%20craters%20w
>
> ith%20similar%20composition%2C%20most%20notably%20the%20vredefort%20crater%2
>
> 0in%20south%20africa%E2%80%94the%20result%20of%20an%20impact%20some%202%20bi
>
> llion%20years%20ago%E2%80%94and%20the%20zhamanshin%20crater%20in%20kazakstan
>
> %2C%20from%20an%20impact%20within%20the%20last%20million%20years.%20those%20
>
> times%20frames%20are%20in%20line%20with%20siraj%20and%20loeb%27s%20calculati
>
> ons%2C%20which%20indicate%20such%20objects%20should%20strike%20earth%20once%
> 20every%20250%2C000%20to%20730%2C000%20years./>—that
> was thrown off course by Jupiter's gravity toward the Sun. The Sun's
> powerful tidal forces then ripped pieces off the comet, and one of the
> larger fragments of this "cometary shrapnel" eventually collided with
> Earth.
>
> https://arstechnica.com/science/2021/02/astronomers-a-comet-fragment-not-an-
> asteroid-killed-off-the-dinosaurs/
> <https://arstechnica.com/science/2021/02/astronomers-a-comet-fragment-not-an-asteroid-killed-off-the-dinosaurs/>
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