[meteorite-list] Beautiful time-lapse movie showing the growth in discovered minor planets since 1980

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Fri, 27 Aug 2010 16:23:11 -0500
Message-ID: <E7325F7D6F7B4F7EB039F19B6792736A_at_ATARIENGINE2>

Eric, List,

> Unless of course one destroys our planet first...

The largest NEO is 1036 Ganymed. The Largest
Near-Earth Object is 32 km in diameter. The second
largest is 433 Eros (visited by NEAR); it's 33 km by
13 km.

Even the 20 mile Ganymed wouldn't destroy the
planet. Just a little dent about twice the size of
Chicxulub... Might be tough on like, you know,
living things, though...

No, if you want to "destroy" the Earth (whatever
that means to you), you need a bigger hammer.
I suggest 2060 Chiron, whose orbit between
Saturn and Uranus is not long-term stable. How
big is it?

In 1984, Larry Lebofsky derived a diameter of
180 km or 112 miles. In 1991, IRAS determined
it had to be less than 372 km. In 1994, Campins
determined 150 km. in 1996, an occultation yielded
a value of 180 km. And In 2007, the Spitzer Space
 Telescope said it was 235 km in diameter.

Personally, I'll go with Larry. If eventually, old
Saturn "persuades" Chiron to fall into the inner
solar system and it should meet up with Earth with
the 40 to 50 km/sec velocity such an elliptical orbit
implies, it would be one helluva whack.

Wouldn't destroy the Earth either. It would change
the Earth a lot. The interesting question is: what
would replace us Mammals?


Sterling K. Webb
--------------------------------------------------------------------------
----- Original Message -----
From: "Meteorites USA" <eric at meteoritesusa.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Friday, August 27, 2010 1:54 PM
Subject: Re: [meteorite-list] Beautiful time-lapse movie showing the
growth in discovered minor planets since 1980


> Wow! Wow! WOW! It really is a cosmic "soup" out there. It's so fluid,
> and reactive. All I can think is. Look at all the future meteorites!
> ;)
>
> Unless of course one destroys our planet first. The red ones are
> scary... ;)
>
> Eric
>
>
> On 8/27/2010 10:34 AM, Matson, Robert D. wrote:
>> Hi All,
>>
>> Here is a fascinating video graphically showing the exponential
>> growth
>> in
>> discovered minor planets over the last 30 years. At the beginning of
>> 1980,
>> the count stood at 8954. It's now over half a million!
>>
>> http://www.youtube.com/watch?v=S_d-gs0WoUw
>>
>> In this time-lapse video, as new minor planets are discovered, they
>> are
>> highlighted in white. You'll notice that the majority of the
>> discoveries
>> follow the earth around in its orbit (since most discoveries are made
>> at
>> opposition).
>>
>> In the 1990s, the big surveys start to come online, and the discovery
>> rates skyrocket. In 2010, a new pattern of discoveries starts to show
>> up
>> in a line perpendicular to the earth-sun line. This shows the
>> dramatic
>> increase in minor planet discoveries by WISE (the Widefield Infrared
>> Survey Explorer), which only images near 90-degree elongation.
>>
>> The final color-coding of minor planets differentiates the NEOs from
>> the
>> mainbelters. Earth-crossing NEOs are colored red; earth-approaching
>> NEOs
>> (perihelion distance less than 1.3 a.u.) are in yellow; all others
>> are
>> green.
>>
>> Cheers,
>> Rob
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Received on Fri 27 Aug 2010 05:23:11 PM PDT