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

Mon Feb 22 18:40:16 PST 2021

I saw on TV (so it must be true!)that Sol and Proxima Centauri probably
trade extrasolar bodies. I think there have been 2 extrasolar objects (I
suppose they're asteroids) that have been seen in the past few years. The
same show claimed that the "boundary" between objects in the two solar
systems is diffuse and probably not definable. Unless you're splitting hairs
like scientists love to do. It's probably an eternal football game out there
with the occasional kick into the stands :)

Tim Fisher
Http://OreRockOn.com 
Email nospam at orerockon.com

-----Original Message-----
From: Rockhounds [mailto:rockhounds-bounces at rockhounds.drizzle.com] On
Behalf Of Axel Emmermann
Sent: Monday, February 22, 2021 3:25 PM
To: 'Rockhounds at drizzle.com: A mailing list for rock and gem collectors'
Subject: Re: [Rockhounds] Astronomers: A comet fragment, not an asteroid,
killed off the dinosaurs

More than 100.000 in the size of 100 Km ore thereabout, Bryan.
Objects ranging from tiny grains to dwarf planets such as Pluto, Haumea and
Makemake make up that belt..
Actually they are called TUO's (TransUranian Objects) or KBO (Kuyper Belt
Objects).

a 1.000 times further away lies the Oort Cloud.
There you'd find probably billions of comets. That cloud is sometimes
perturbed by passing stars and every now and then a comet is pushed to the
inner solar system. This cloud is VAST and reaches as far as somewhere
between one quarter and halfway to the nearest star (Proxima Centauri).
Needles to say that comets may be "underway" for several 100.000 or millions
of years to swing by the sun once and return, never to be seen again.
Unless they hit something... Something that has been falling towards the sun
for eons pack a mighty punch. I'd expect higher velocities than with normal
KB-comets.

Cheers
Axel 

-----Oorspronkelijk bericht-----
Van: Rockhounds <rockhounds-bounces at rockhounds.drizzle.com> Namens J Bryan
Kramer
Verzonden: maandag 22 februari 2021 19:33
Aan: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
<rockhounds at rockhounds.drizzle.com>
Onderwerp: Re: [Rockhounds] Astronomers: A comet fragment, not an asteroid,
killed off the dinosaurs

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%20c
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>
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> 20and%
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> rs%20w
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> ater%2
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> 2%20bi
>
> llion%20years%20ago%E2%80%94and%20the%20zhamanshin%20crater%20in%20kaz
> akstan
>
> %2C%20from%20an%20impact%20within%20the%20last%20million%20years.%20th
> ose%20
>
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> culati
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> ons%2C%20which%20indicate%20such%20objects%20should%20strike%20earth%2
> 0once% 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-n
> ot-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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