[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Dangerous Debris

Hello Bernd and all

    Wonder who edited this ASTRONOMY piece? For
example:

--- Bernd Pauli HD
<bernd.pauli@lehrer1.rz.uni-karlsruhe.de> wrote:
> ASTRONOMY, November 1999, pp. 46-51: When Disaster
> Strikes
> 
> Dangerous Debris, pp. 48-49:
>snip<

> Fortunately, the threat from asteroids can be
> predicted. 

No it can not.  While the threat "COULD" be predicted,
there are no Earth based instruments capable of
detecting asteroids around 50 meters or so in
diameter, whose impacts have caused and will cause
massive loss of life.

> Astronomers have estimated that about 2,000
asteroids > more than a kilometer in diameter cross
Earth's 
> orbit. Although only about 10 percent of these
> have been discovered, a concerted effort could
> effectively map the nearby threat, giving humanity 
> warning of any future impact. 

While here the writer got the conditional correct,
i.e. "could", the impression left is that the funding
of Earth based searches is going to be sufficient.  It
is not. More...

>snip<
> The danger from comet impacts, however, is less
> predictable. Most comets come from the Oort Cloud, 
> orbiting the sun at about half a light-year's
> distance. Directly observing these objects is
> currently impossible, so Jay A. Frogel and Andrew 
> Gould of Ohio StateUniversity recently found
> another way. The two astronomers surveyed the
> positions and motions of most nearby stars, 
> theorizing that if one had recently passed close to
> the sun it would have disturbed the Oort Cloud,
> triggering a downpour of comets earthward. 

Frogel and Gould's hypothesis is now presented as
though this mechanism was the only way in which comets
might be dislodged from the Oort cloud. More...

> Since such a deluge would take several hundred
> thousand years to reach the inner solar system,
> Frogel and Gould figured a recent close approach 
> would predict an impending cloudburst.

> Fortunately for our immediate descendants, the
> scientists discovered that in the last several 
> million years no star has passed close enough
> to disturb the Oort Cloud. 

Through this specious reasoning, we arrive at the
desired result: there is nothing we have to worry
about.  I hope that this reasoning may be by the
writer  but fear that it is that of Frogel and Gould
themselves.

> Our distant descendants, however, will have
> to contend with one star (Gliese 710) that in 1.3
> million years will pass close enough to turn the 
> present drizzle of comets into a thunderstorm.

Once again, we arrive at the desired result: while no
immediate danger exists, in the future a threat may
appear, so funding for our research should be
continued.

This kind of logic, by people who have made no effort
to survey the emerging data on historical Earth
impacts, is both misleading and dangerous.

EP

__________________________________________________
Do You Yahoo!?
Bid and sell for free at http://auctions.yahoo.com

----------
Archives located at:
http://www.meteoritecentral.com/list_best.html

For help, FAQ's and sub. info. visit:
http://www.meteoritecentral.com/mailing_list.html
----------