Announcement: IISis2 2nd Birthday Competition!

[Dennis]

Hello,

Hmm, the meteoroid question still appears to be quite open, so I did some further research and here’s what I found:

Reference sources:
Ref A: http://neo.jpl.nasa.gov/faq/#diff
Ref B: http://en.wikipedia.org/wiki/Meteoroid
Ref C: On the Definition of the Term Meteoroid (from Ref B)

Definitions:
Ref A: NASA
A small particle from a comet or asteroid orbiting the Sun.
Ref B: IAU
A solid object moving in interplanetary space, of a size considerably smaller than an asteroid and considerably larger than an atom or molecule.
Ref C:
“…we wish to point out here that the term `meteoroid', as presently defined by the IAU, is out-dated and requires some refinement”.

"It is argued that the term `meteoroid' is best defined as being applicable to any natural solid object moving in space, and having a size between 100 µm and 10 m (10-4 ~ 10+1 m) This definition reflects modern-day instrumentation limitations and recognizes the physical constraints that dictate the production of a meteor in the Earth's atmosphere. Our argument also has implications for the definitions of the terms `asteroid' (synonym `minor planet'), `micrometeorite', and `interplanetary dust.'"

Historical Note from Ref C:
"The term `meteoroid' was first coined by H.A.Newton in 1864 (Newton 1865). Newton explained that:
It will be assumed that the phenomenon called a shooting or falling star is caused by a small body (probably solid) which originally was moving in its own orbit in the solar system, or in space; that this body coming into the atmosphere of the earth elicits light by the loss of velocity, and is usually dissipated before reaching the earth's surface. The term meteoroid will be used to designate such a body before it enters the earth's atmosphere".

"Not quite a century after Newton published the above — remarkably insightful — description, the IAU adopted the following definition for the term `meteoroid' (Millman 1961, Sadler 1962):
Meteoroid — a solid object moving in interplanetary space, of a size considerably smaller than an asteroid and considerably larger than an atom or molecule".

Ref C seems to discuss meteoroids in terms of asteroids and (arguably) comets, here is an example:

“The upper size limit of a meteoroid may reasonably be set according to the minimum detectable size of an asteroid. The lower asteroid size limit is in turn determined by the present-day observational limitations”.

“In light of the above discussion it does not seem unreasonable to adopt 10 m as the dividing line for an object to be considered to be either an asteroid or a meteoroid. We therefore propose that any natural object in space, which is solid and neither cometary in nature or planetary in size, but larger than ten metres, be defined as being an `asteroid', `minor planet' being a synonym; any object smaller than 10 m (which might indeed be cometary in nature, although volatiles are rapidly lost by such small objects), but larger than the proposed 100 µm limit discussed below, would be defined as being a `meteoroid'”.

This previous paragraph appears to discuss meteoroids in the context of asteroids and objects of a cometary nature. Perhaps this is where the folks at NASA derived their definition?

As Alice said, “Curiouser and curiouser”

Cheers

Dennis

[ving (David)]

3 entries for me... and proof that i dont read the questions properly... maybe i should do these at home so i have more time to google the answers

[AstroBug]

Interesting stats. More people got 29/30, including me, than any other amount. And I got one of the easier questions wrong. Must concentrate when answering the "obvious" ones next time. Thanks to all involved for a great comp. Once again a good excuse to do a bit of research and learn a bit along the way.

[ving (David)]

or like i saw on a t-shirt today...

grade 1 was the best 4 years of my life...

[spearo (Frank)]

great quiz thanks
frank

[astro_south (Andrew)]

30/30? How did that happen?

Thanks for a great quiz ... all of the questions were just right

p.s. can I get certificate to frame and stick on my wall .... or at least something to stick on the fridge

[[1ponders] (Paul)]

Iceinspace fridge magnets for all the finalists - all 144 of them

[h0ughy (David)]

Originally Posted by astro_south

30/30? How did that happen?

Thanks for a great quiz ... all of the questions were just right

p.s. can I get certificate to frame and stick on my wall .... or at least something to stick on the fridge

hey print this out Andrew

I IS DONE GOOD WORK!!!
I is smart too

[astro_south (Andrew)]

ta Houghy - I is done that!

[h0ughy (David)]

Originally Posted by astro_south

ta Houghy - I is done that!

and you can add

I IS A IIS MEMBA

I IS VIEWING EVRATHIN OPTIKALLI

[acropolite (Phil)]

I didn't get a single one wrong.....forgot to enter...

[RB (Andrew)]

Originally Posted by acropolite

I didn't get a single one wrong.....forgot to enter...

Phil.

I forgot too but remembered at the last moment.
I was in a department store and asked if I could use their internet access so I could enter a competition that finishes in 10 minutes......so they let me.
Just got in.

So if anyones posts get moderated it's the guys at Domayne using my account, don't blame me.

[Dennis]

I got 100% correct answers to all my questions - the one's that I submitted to Mike that is.

Dennis

[Astroman (Andrew Wall)]

When is this going to be drawn, or was this just to attract new members?

Joke guys, seriously, whens it drawn?

[Dujon]

Andrew,

Mike has already indicated that he's away 'til the 9th of the month and is trying to coerce one of the sponsors to be the one who makes the draws.

You will find his comment here:

http://www.iceinspace.com.au/forum/s...130&page=3=#60

[Astroman (Andrew Wall)]

Ahh thanks John, shows how much I listen to Mike Only jokes guys, thanks. I should stop joking around, I will go sit in the corner now.

[iceman (Mike)]

Paul Mayo will be doing the draw, sometime after next Sunday.

And Andrew, no new members cause of this competition - they wouldn't have been eligible to enter

[Astroman (Andrew Wall)]

no worries mike, thanks for the info

[jjjnettie (Jeanette)]

Paul, is that 144 entries in the draw or 144 people that entered the comp.

Geez, at least another week before we know the winners. The tension is killing me.

[iluvsaturn (Garth)]

Stupid Stupid mistakes I actually got 30 on my print out and stuffed up the transcribing, truly, honestly. Ah well 3 entries.
Happy birthday ICEINSPACE