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From: jdnicoll@panix.com (James Nicoll)
Newsgroups: rec.arts.sf.written
Subject: Re: "NASA to study "city-killer" asteroid as odds of hitting Earth go up"
Date: Sun, 16 Feb 2025 16:40:22 -0000 (UTC)
Organization: Public Access Networks Corp.
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In article <struqjd0up33dp7peo9h8bavv380j43efc@4ax.com>,
Paul S Person  <psperson@old.netcom.invalid> wrote:
>On Thu, 13 Feb 2025 17:19:14 -0000 (UTC), jdnicoll@panix.com (James
>Nicoll) wrote:
>
>>In article <608sqjle4440ka7d2tnb3b8n1hjam30skt@4ax.com>,
>>Paul S Person  <psperson@old.netcom.invalid> wrote:
>>>On Wed, 12 Feb 2025 22:31:04 +0100, D <nospam@example.net> wrote:
>>>
>>>>
>>>>
>>>>On Wed, 12 Feb 2025, Paul S Person wrote:
>>>>
>>>>> On Wed, 12 Feb 2025 11:28:09 +0100, D <nospam@example.net> wrote:
>>>>>
>>>>>>
>>>>>>
>>>>>> On Tue, 11 Feb 2025, Dimensional Traveler wrote:
>>>>>>
>>>>>>> On 2/11/2025 5:12 PM, Lynn McGuire wrote:
>>>>>>>> "NASA to study "city-killer" asteroid as odds of hitting Earth go up"
>>>>>>>>
>>>>>>>> https://www.msn.com/en-us/news/technology/nasa-to-study-city-killer-
>>>>>>>> asteroid-as-odds-of-hitting-earth-go-up/ar-AA1yLdde
>>>>>>>>
>>>>>>>> "Astronomers are enlisting the help of NASA's James Webb Space
>>>Telescope to
>>>>>>>> study an asteroid that has a small chance of striking Earth less
>>>than eight
>>>>>>>> years from now. Characterized as a potential "city-killer," the
>asteroid
>>>>>>>> was first detected in December and its odds of impacting our
>planet have
>>>>>>>> increased slightly since then, according to the European Space Agency."
>>>>>>>>
>>>>>>>> “The space rock is formally named 2024 YR4. Scientists say it currently
>>>>>>>> carries a 2% risk of making contact with Earth when it
>eventually reaches
>>>>>>>> this part of the solar system on Dec. 22, 2032. Although the
>>>asteroid will
>>>>>>>> most likely pass by without issue, those tasked with monitoring its
>>>>>>>> physical attributes and potential have shifted upward the
>>>probability of a
>>>>>>>> crash since 2024 YR4 was initially discovered.”
>>>>>>>>
>>>>>>>> Am I the only person who is suspicious of NASA crying wolf ?
>>>>>>>>
>>>>>>> I don't see any wolf crying.  They are refining their data to
>>>improve their
>>>>>>> accuracy.
>>>>>>
>>>>>> This would be my interpretation. Plenty of time left, they are keeping an
>>>>>> eye on it. Will it hit? If not, no problem. If yes, where will it hit? If
>>>>>> random ocean, no problem. If not random ocean, maybe little bit problem.
>>>>>
>>>>> I suggest watching /Sudden Impact/ to get an idea of what a chunk of
>>>>> space rock hitting an ocean can do.
>>>>>
>>>>
>>>>I thought you smart enough not to assume random ocean meant 10 meters 
>>>>outside new york.
>>>>
>>>>Tsunami schnunami, we've dealth with that and survived. If we have a 
>>>>couple of years advance warning we're good to go.
>>>
>>>First, as has been pointed out to me, the film I meant to cite was
>>>/Deep Impact/.
>>>
>>>Second, it is not "10 meters off New York".
>>>
>>>Third, we had a year. We were /not/ good to go.
>>>
>>>But I have also read a post with actual figures in it, so apparently
>>>the film exaggerated things a bit.
>>
>>My numbers were for a dinky 8 MT impact, whereas Deep Impact involved
>>a rock the size of Everest. Whole different game.
>
>That's the one that hit the ocean, not the much larger planet-killer
>to come, right?
>
>So, what do the formulae show for the /Deep Impact/ ocean strike?
>
wave height for an impact in deep water is roughly

h = 6.5m [y/gigaton] 0.54 [1000km/r]

h = wave height
r = range to impact
y = yield

Idealised wave run in (which is to say, not applicable to any real region):

Xmax ~ 1.0km [h/10 meters]^[4/3]

Impact energy in Deep Impact seems to be 500,000 MT.

At 1000 km, the wave would be 6.5x500x.54 or about 1800 m, which seems
kind of bad.

h/10 is 180, so Xmax is almost exactly 1000 km, which also seems bad. 
Mind you, that wave is going to have a heck of a time getting past
the Appalachians so Ontario should be fine. 


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