PLEASE NOTE:
*
CCNet, 20/2000 - 14 February 2000
---------------------------------
QUOTE OF THE DAY
"The alleged NASA estimate of
'background risk' is a nonsense
because it lacks a time-frame. If it
referred to a specific date
as in the first example it could be
sensible. Or if it referred
to a time period as "per
year", or even "per day", it would
convey some meaning. [...] Also, unlike
the first estimate, no
size is referred to in the reported NASA
estimate. I hope this
is not too pedantic, but I am looking
for a well-founded and
up-to-date estimate of the risk of
collision [...] There are so
many woolly estimates it is hard to get
something one can
confidently quote."
-- Colin Keay,
Australia
(1) NEAR APPROACHING ON SCHEDULE
From http://near.jhuapl.edu/news/flash/00feb13_1.html
(2) NEAR CAPTURES AN ASTEROID’S HEART
Andrew Yee <ayee@nova.astro.utoronto.ca>
(3) GUESS WHO'S COMING TO BREAKFAST?
Space Science News <express@spacescience.com>
wrote:
(4) EROS IS WAITING
The Guardian, 10 February 2000
(5) SPACECRAFT FINDS LOVE AT LAST (BBC)
http://news.bbc.co.uk/hi/english/sci/tech/newsid_642000/642052.stm
(6) ASTEROID MISSION FILLED WITH ROMANCE (MSNBC)
http://msnbc.com/news/204520.asp?cp1=1
(7) NEW CASSINI IMAGES OF ASTEROID AVAILABLE
Ron Baalke <baalke@jpl.nasa.gov>
(8) ASTEROIDS: GOLD MINE OR PILE OF RUBBLE?
Space.com, 10 February 2000
(9) ODDS OF COLLISION
Colin Keay <phcslk@cc.newcastle.edu.au>
(10) ASTEROID 2000 BF19: THE SCIENCE & THE MEDIA
Benny J Peiser <b.j.peiser@livjm.ac.uk>
=============
(1) NEAR APPROACHING ON SCHEDULE
http://near.jhuapl.edu/news/flash/00feb13_1.html
February 13, 2000
NEAR is cruising toward 433 Eros for tomorrow's historic
rendezvous
with the asteroid. The NEAR team at the Johns Hopkins University
Applied Physics Laboratory indicates all spacecraft systems are
operating as planned.
Around 2 a.m. (EST) today, NEAR began a rendezvous sequence that
includes a unique low-phase flyby of Eros. Scheduled to happen
around
midnight tonight, the flyby will put NEAR directly between the
sun
and Eros and allow it to map the minerals on the asteroid's
northern
half under optimal lighting.
NEAR team members will download data from this sequence early
tomorrow, about four hours before the spacecraft moves into
position
for orbit insertion at 10:33 a.m. Eastern time.
NEAR Science Update
http://near.jhuapl.edu/news/sci_updates/00feb13.html
February 13, 2000
On February 11, 2000 at 15:20 UT, the NEAR imager recorded a most
curious observation of Eros. It was late afternoon of that day
when I
was pulled aside and asked to 'have a look at something'. That
something turned out to be the amazing heart-shaped feature that
can
be seen in today's image-of-the-day, which was taken at a
distance of
1609 miles (2590 km). This image has undergone only our standard
processing and has not been retouched (except for the arrow drawn
on
it). The 'heart of Eros' is actually a 5 km long depression in
the
surface, and it appears as a heart because of an accidental
confluence of shadows. The same feature can be discerned in the
Eros
images from December 1998 but was not as well resolved at that
time.
It can be seen in the image-of-the-day from December 23, 1998. In
that nine-frame montage, the first frame on the left in the
bottom row shows the feature clearly, about half way to the upper
end
of Eros starting from the bright saddle-shaped depression. The
three
earlier frames and the next frame also show the feature. The
saddle-shaped depression may be the largest crater on Eros, but
the
heart-shaped depression is basically mysterious at this time. By
April we should have a much clearer idea as to what it is.
Andy Cheng
NEAR Project Scientist
=============
(2) NEAR CAPTURES AN ASTEROID’S HEART
From Andrew Yee <ayee@nova.astro.utoronto.ca>
Johns Hopkins University
Applied Physics Laboratory
Laurel, Maryland
Media Contacts:
Mike Buckley (JHUAPL)
240-228-7536
michael.buckley@jhuapl.edu
Helen Worth (JHUAPL)
240-228-5113
helen.worth@jhuapl.edu
For Immediate Release: February 13, 2000
NEAR Captures an Asteroid's Heart
The Near Earth Asteroid Rendezvous (NEAR) spacecraft has a Feb.
14
date with a space rock named for the Greek god of love, but the
romantic robot isn't waiting until Valentine's Day to send
greetings
from asteroid 433 Eros.
NEAR has snapped about 8,000 photos of its intended since
January,
and no picture says love like the latest image showing a large
heart
carved in the asteroid. The image is available on the NEAR Web
site
at
http://near.jhuapl.edu/iod/20000213b/index.html
"It truly is a valentine from Eros," says NEAR Mission
Director Robert Farquhar.
NEAR's digital camera captured the feature Feb. 11 from 1,609
miles
(2,590 kilometers) away. The image surprised science team members
yesterday as they processed the incoming data. The narrow, 3-mile
(5-kilometer) heart-shaped depression appears just below a large
ridge on the 21-mile (33-kilometer) potato-shaped asteroid. Until
the
spacecraft sends closer images, however, NEAR team members at the
Johns Hopkins University Applied Physics Laboratory (APL) can't
say
for sure what the shadowy heart really is.
"It's a tantalizing mystery," says Dr. Joseph Veverka,
of Cornell
University, who leads the NEAR imaging team. "It makes you
wonder,
what other secrets are lurking in the heart of Eros?"
NEAR will begin unfolding such mysteries when the spacecraft
meets up
with Eros tomorrow at 10:33 a.m. (EST) and becomes the first
spacecraft to orbit an asteroid. APL designed and built NEAR and
manages the mission for NASA. For the latest mission news and
images,
visit the NEAR Web site at http://near.jhuapl.edu
.
==============
(3) GUESS WHO'S COMING TO BREAKFAST?
From Space Science News <express@spacescience.com>
wrote:
Space Science News for February 13, 2000
Guess Who's Coming to Breakfast?: The NEAR spacecraft is now less
than
1000 km from asteroid 433 Eros. It is scheduled to enter orbit
around
the space rock at 10:33 EST on Monday morning. Critical science
observations are slated to begin 11 hours earlier when the
spacecraft
passes directly between the Sun and Eros. FULL STORY at
http://www.spacescience.com/headlines/y2000/ast13feb_1.htm
===================
(4) EROS IS WAITING
From The Guardian, 10 February 2000
http://www.newsunlimited.co.uk/science/story/0,3605,134998,00.html
At last astronomers are to get their first close up view of a
near-Earth asteroid, explains Duncan Steel
Thursday February 10, 2000
This must be the satellite malfunction that Nasa engineers
planned.
Just before Christmas in 1998 a faulty rocket burn by the
Near-Earth
Asteroid Rendezvous (NEAR) space probe meant abandoning the plans
to
meet its target on February 6 last year. Of course, the world
jeered
yet another expensive failure. But the engineers may have the
last laugh, because they re-targeted Near to reach its
destination on
February 14.
Why is that amusing? Because that's Valentine's Day, and the
target is
Eros. Asteroid Eros, that is. Actually it gets better, and
sub-editors
will soon be able to have all manner of fun writing headings
about this
erotic encounter.
FULL STORY at
===================
(5) SPACECRAFT FINDS LOVE AT LAST (BBC)
FULL STORY at http://news.bbc.co.uk/hi/english/sci/tech/newsid_642000/642052.stm
===========
(6) ASTEROID MISSION FILLED WITH ROMANCE (MSNBC)
FULL STORY at http://msnbc.com/news/204520.asp?cp1=1
=============
(7) NEW CASSINI IMAGES OF ASTEROID AVAILABLE
From Ron Baalke <baalke@jpl.nasa.gov>
MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov
Contact: Jane Platt
INTERNET IMAGE ADVISORY February 11, 2000
NEW CASSINI IMAGES OF ASTEROID AVAILABLE
New images taken by the camera onboard the Saturn-bound Cassini
spacecraft are giving scientists the first size estimates on
asteroid
2685 Masursky and preliminary evidence that it may have different
material properties than previously believed.
"The Masursky images represent the first time that Cassini
has gathered
information on a body not extensively studied from Earth,"
said Carolyn C.
Porco, Cassini imaging team leader and associate professor at the
Lunar and
Planetary Laboratory of the University of Arizona, Tucson.
The images, taken on Jan. 23, also marked the first use of
Cassini's
automated object-targeting capabilities, and they functioned as
expected,
Porco said. The two new images are available at the
following websites:
http://www.jpl.nasa.gov/pictures/cassini
and http://ciclops.lpl.arizona.edu
Launched October 15, 1997, Cassini flew by Venus and Mars before
heading
toward a flyby of Jupiter next December. It entered the asteroid
belt
between Mars and Jupiter, a region populated by asteroids, in
mid-November
of 1999.
Cassini's camera took pictures of the asteroid when the
spacecraft was 7
hours and 5-1/2 hours before closest approach, at a distance of
1.6 million
kilometers (960,000 miles). Since Masursky is too small to
be measured
from Earth, scientists hoped Cassini could help them determine
its size, as
well as its reflectivity, asteroid category, and possibly its
rotation period.
"So far, the images reveal that the side of Masursky imaged
by Cassini is
roughly 15 to 20 kilometers (9 to 12 miles) across," Porco
said.
The Cassini spacecraft is scheduled to arrive at Saturn in July
2004 to
begin a four-year exploration of the ringed planet and its moons.
The
Cassini mission is managed by NASA's Jet Propulsion Laboratory in
Pasadena,
Calif., for NASA's Office of Space Science, Washington, D.C. JPL
is a
division of the California Institute of Technology in Pasadena.
===================
(8) ASTEROIDS: GOLD MINE OR PILE OF RUBBLE?
From Space.com, 10 February 2000
http://www.space.com/space/business/asteroid_mining_000210.html
By Mary Motta
Senior Business Correspondent
WASHINGTON – Mention the word "asteroid" to most
people and
thoughts of Armageddon and doomsday come to mind.
But to entrepreneur Jim Benson, these space rocks are this
millennium’s Holy Grail.
Benson is chief executive of SpaceDev, a Colorado-based
commercial
space exploration and development company that plans to one day
launch a robot craft, or a Near Earth Asteroid Prospector (NEAP),
to an asteroid. Once there, it would land instruments to take
photographs and scientific readings to detect the presence of
such
precious commodities as platinum, gold, cobalt and water.
FULL STORY at
http://www.space.com/space/business/asteroid_mining_000210.html
=============================
* LETTERS TO THE MODERATOR *
==============================
(9) ODDS OF COLLISION
From Colin Keay <phcslk@cc.newcastle.edu.au>
Dear Benny:
I believe a great number of meaningless estimates are quoted
about
the the chances of asteroid impacts. In a recent CCNet
message
(8/2/00) there is a perfect example of both a meaningful estimate
and
one that is quite meaningless. Here it is....
>Feb. 7 — Another potential asteroid threat has
been added to the list
>of astronomers’ worries — and although it’s
likely to be eliminated
>from the list eventually, this one is tricky. Asteroid 2000
BF19 is so
>small and faint that it can’t be seen by most amateur
telescopes.
>
>THIS ASTEROID, discovered Jan. 28 by the University of
Arizona’s
>Spacewatch Project, is no “Armageddon”: It’s
thought to be much less
>than 0.6 miles (1 kilometer) wide. That takes it out of
the category
>that scientists say could cause a global catastrophe on
Earth.
>
>What’s more, the possibility of a collision in the year
2022 is rated
>at roughly one chance in a million. In comparison, NASA
estimates the
>“background risk” of an asteroid impact — that
is, the chance that an
>undetected kilometer-wide space rock might collide with Earth
— at
>between 1 in 100,000 and 1 in a million.
>
.... In the last para the first estimate has meaning
because it
refers to a *specific* date. The alleged NASA estimate of
"background
risk" is a nonsense because it lacks a time-frame. If it
referred to
a specific date as in the first example it could be sensible. Or
if
it referred to a time period as "per year", or even
"per day", it
would convey some meaning. Perhaps the original NASA source
quoted a
time scale, in which case it is a pity that it was not given.
Also, unlike the first estimate, no size is referred to in the
reported
NASA estimate.
I hope this is not too pedantic, but I am looking for a
well-founded
and up-to-date estimate of the risk of collision per year with
objects
capable of (1) destroying a city - say 50 kt equiv. (2)
destroying a
country the size of, say, Denmark, or the State of Tasmania in
Australia (with obvious effects beyond its borders), and (3)
global
consequences leading to major extinctions like the dinosaur
scenario 65
MBP. There are so many woolly estimates it is hard to get
something one
can confidently quote.
Keep up the good work.
Cheers ..... Colin Keay, Physics, University of Newcastle, NSW.
===========
(10) ASTEROID 2000 BF19: THE SCIENCE & THE MEDIA
From Benny J Peiser <b.j.peiser@livjm.ac.uk>
Dear Colin,
I think you are absolutely right to point out the problems and
pitfalls of impact probability estimates. I regret to say that
this
perplexity is not limited to science journalists. Sometimes, it
is
actually the direct result of ambiguous or unclear statements
made by
members of the scientific community themselves. The case of
asteroid
2000 BF19 is a good example.
It was indeed unfortunate that the MSNBC story you refer to did
not
include a time scale. The problem was that the press release by
NASA’s NEO Office, on which the MSNBC report was based, did
not
include a time frame either (see below). Regrettably, the NEO
Office’s press release of 7 February, which informed the
wider media
about Andrea Milani’s impact probability calculations, was
rather
vague, stating, "It should be noted that the quoted impact
probability of one in a million is well below the 'background
level'
of the Earth being hit by a comparably sized asteroid that has
not
yet been discovered."
While this statement was ment to reassure the public, I would
agree
that it does not make any scientific sense. However, I
believe it
was important in the context of 2000 BF19 to point out that there
was
no reason for concern. In addition, it was reasonable to suggest,
as
I made clear on CCNet as well, that Milani’s hypothetical
impact
scenario would most likely be eliminated by further observations.
From a scientific point of view, however, it would appear that at
least three important details were missing in the NASA statement
on
asteroid 2000 BF19:
1) a time scale related to the “background” impact rate
for such
objects;
2) an estimate of the size of asteroid 2000 BF19 (~500m) and,
3) the actual impact probability for objects this size
(somdwhere in the region of 1:20,000 -50,000).
I do believe that everyone involved in the calculation,
discussion
and dissemination of impact estimates needs to be as clear,
accurate
and thruthful as possible. This is particularly important if we
want
to safeguard our credibility in the eyes of the public. We do
neither
want to exaggerate nor underestimate any potential problem. And
the
question as to whether or not asteroid 2000 BF19 was handled
better
than the four cases we experienced durong the last two years,
will
have to be carefully assessed.
I am currently working on a rewview of the 2000 BF19 event and
how it
unfolded during the 7th and 8th of February and hope to report
back in
the next three or four days or so. I expect this review not only
to
focus on the handling of the public announcements by members of
the
scientific community, but also how the science media reacted to
the
story.
Benny J Peiser
------------------
From NASA NEO Progam Office
http://neo.jpl.nasa.gov/news/news084.html
Asteroid 2000 BF19 Has Small Earth Impact Probability In 2022
Don Yeomans
NASA's Near-Earth Object Program Manager
February 7, 2000
Italian scientist Andrea Milani has announced that the recently
discovered close Earth approaching asteroid 2000 BF19 has a very
small
Earth impact probability in the year 2022. Because there is only
6 days
of observations for this object, the most likely scenario will be
that,
with additional observations, this impact possibility will go
away.
However, a call for additional observations has been made to
verify
this likely result. It should be noted that the quoted impact
probability of one in a million is well below the
"background level" of
the Earth being hit by a comparably sized asteroid that has not
yet
been discovered.
[...]
----------------------------------------
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