Thursday17 June 20046:08pm MDT2004-06-18 UTC 0008 back top next  

The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors


Today's issue status: done
yesterdayJunetomorrowIndex

Cover: A frame from an animation posted today by the Stardust mission that “depicts Stardust’s turbulent ride through three of more than two dozen jets that blast outward from comet Wild 2. The jets pummeled the spacecraft with about a million particles per second. Twelve particles, some larger than a bullet, penetrated the top layer of the spacecraft’s protective shield.” Credit NASA/JPL. See more about today's Stardust news below.

News briefs – panel 1/2 Major News for 17 June 2004 back top next  
News briefs

Stardust news:  In a NASA Space Science Update Webcast today at 2pm EDT (1800 UTC), researchers commented on their surprise at finding "dozens" jets observed emanating from comet 81P/Wild 2 during the Stardust encounter in January. They said no jets were seen coming from the largest "sink holes," which, in a new theory of how jets work, may be collapsed geyser caverns. They also noted that the active jets were in the nucleus's equatorial, rather than polar, regions.

It was remarked that the two icy objects, 81P/Wild 2 and Saturn's moon Phoebe, "don't resemble each other at all," although 81P is believed to be from the Edgeworth-Kuiper Belt, the suspected origin of Phoebe. It was noted that 81P is a relatively recent arrival, but Phoebe was probably captured by Saturn early in Solar System history, and may have been subject to heating during Saturn's evolution.

In conjunction with the presentation, the Stardust mission today posted new images and animations, and JPL has a news release. Space.com has a report today.

New Zealand rocks:  The Otago Daily Times has a photo and more details today (and sidebar) about identification of what was first reported as a “meteorite” found during a dig for a New Zealand outhouse. The auctioneer was told by University of Otago geologists that the item is a concretion, “an object formed in iron-rich ground.” Marco Langbroek comments that “in Dutch we call this a ‘Klappersteen’ (‘rattling stone’), which is basically layers of ferro-oxide which formed around some object in the soil — a root or a mudball, etc. That's why it appears hollow. Sometimes, if the interior object is composed of material that shrinks (e.g., a clay ball), you can hear it rattle as you shake the nodule.”

The article quotes Joel Schiff of Meteorite quarterly (published in New Zealand) as saying “I have had literally dozens of inquiries about meteorites since the event in Auckland.”

The Independent of South Africa reports today from the Wellington, New Zealand Dominion Post about offers being made for the Auckland fall.

more news briefs >>

News briefs – panel 2/2 Major News for 17 June 2004 back top next  

<< continued from panel 1

NSW event:  Many news outlets worldwide have picked up a variation of today's first story from the Associated Press about a supposed large meteorite impact in New South Wales, Australia (see news yesterday). A clearer story is presented by The Australian as posted at News.com.au dated tomorrow. It notes that an impact by something “house sized” wouldn't leave any doubt about whether there had been an impact. It also reports that air traffic controllers did not see a meteor as AP had initially reported. But apparently there were other witnesses.

Marco Langbroek reports that there were no notices of re-entering space debris that would explain this event.

Risk monitoring - panel 1/1 Major News for 17 June 2004 back top next  
Risk monitoring 17 June

JPL today posted 2004 MC with one low-rated impact solution. This small object was announced today in MPEC 2004-M07 as discovered by LINEAR in New Mexico early yesterday UT, linked to LINEAR observations from the morning before, and confirmed last night by Herrenberg and Great Shefford observatories in Europe and this morning by Three Buttes, Table Mountain, Grasslands, and New Mexico Skies observatories in the U.S. southwest. JPL puts 2004 MC's diameter estimate at 80 meters/yards. It will pass Earth at 3.7 lunar distances on June 29th.

The Thursday Daily Orbit Update MPEC has observation of 2004 LV3 from LINEAR yesterday morning. Today NEODyS and JPL cut their impact solution counts again but also again raised their overall risk ratings for this object.

Summary Risk Table - sources checked at 2359 UTC, 17 Jun

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 MCJPL 6/172034-20341-4.83-4.8302.075
 2004 LV3 NEODyS 6/172012-207928-1.91-1.9404.042
JPL 6/172012-210238-1.86-1.8904.042
VI = count of "virtual impactors" (impact solutions)
See A/CC's Consolidated Risk Tables for more and maybe
  newer details, and check the monitors' links for latest info.
Note that only objects recently in view are shown here.
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