Author Topic: "Shooting Star" question  (Read 75 times)

James Gruber

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"Shooting Star" question
« on: December 24, 2017, 01:09:32 AM »
How does one tell the difference between a bona fide meteor and space debris?



Mark Deutsch

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Re: "Shooting Star" question
« Reply #1 on: December 30, 2017, 07:07:21 PM »
No sure-fire way to tell with most objects. Bigger, brighter meteoric events are probably chunks of rocket bodies. Bona fide meteors that are part of a shower will appear to have come from the shower's radiant point. Space junk can be slower and much of it will be headed in an easterly direction.

Ryan Miller

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Re: "Shooting Star" question
« Reply #2 on: January 01, 2018, 07:40:15 AM »
From my observations. meteor will streak across the sky for just a few seconds and then the light will fade away to nothing. With a satellite, the reflected light will be continuous from start until you cannot see anymore. For space debris, I cannot say for certain but one night while observing I something move across the sky. The light did not disappear like a meteor, but it blinked bright to dark over and over again like it was tumbling. My non-expert opinion is that was space debris of some sort.

Jerry Dunn

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Re: "Shooting Star" question
« Reply #3 on: January 08, 2018, 05:38:23 AM »
Debris will move much slower.

Jose Melo

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Re: "Shooting Star" question
« Reply #4 on: January 08, 2018, 07:59:20 PM »
As some of those responding have already indicated, in-falling spacecraft debris will generally move across the sky distinctly more slowly than a typical meteor will. Likewise, it will burn much longer and cross more sky (sometimes travelling horizon to horizon!) and typically burn brighter than most meteors, except perhaps bright bolides. There can also be the tendency for portions to break off into long lasting fragments that accompany the main body of the object for a considerable portion of its path.

BrooksObs.

Santosh Wolf

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Re: "Shooting Star" question
« Reply #5 on: January 09, 2018, 01:40:03 PM »
Quote
How does one tell the difference between a bona fide meteor and space debris?
I assume you mean man-made space debris that is re-entering the atmosphere, since orbiting space debris looks like satellites (moving stars, glinting or flashing irregularly if tumbling)...

<p class="citation">Quote

No sure-fire way to tell with most objects. Bigger, brighter meteoric events are probably chunks of rocket bodies. Bona fide meteors that are part of a shower will appear to have come from the shower's radiant point. Space junk can be slower and much of it will be headed in an easterly direction.
Disagree. All man-made objects will be expected as they are all tracked before re-entry by nation states....
AMS, IMO will also report on significant fireballs that were witnessed.
[/quote]
Good description of information about man-made re-entering debris:
http://www.aerospace...ry-predictions/
http://www.satobs.org/re-entry.html

Quick meteor streaks are short as stated.
Man-made objects re-entering will both be expected and will be slower moving and long lasting.
Meteors that are slow moving and longer lasting more specifically called "fireballs."
To see either of these is rare.
Re-entry man-made objects most likely will fragment,
fireballs can do the same.

A rocket body (man-made space debris) re-entering:
https://www.youtube....h?v=fFpL36n68eY
https://www.youtube....h?v=jLNsyEkelcg

A slow moving fireball:
https://www.youtube....h?v=sl_RknL9G-Q
another quicker fireball:
http://www.amsmeteor...s/?video_id=249

Other things that may be seen:
Trident submarine missile launch test:
http://www.cloudynig...pictures-11715/

fuel dumps from launches:
http://www.satobs.org/h2o_dump.html
https://www.youtube....h?v=uuAh78befA0

Sounding rockets that are doing atmospheric testing
http://www.space.com...ing-clouds.html

Nick Ellis

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Re: "Shooting Star" question
« Reply #6 on: January 09, 2018, 08:02:47 PM »
So a satellite that is blinking is actually tumbling and is not a blinking satellite?

Bob Meade

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Re: "Shooting Star" question
« Reply #7 on: January 10, 2018, 03:05:35 AM »
Quote
So a satellite that is blinking is actually tumbling and is not a blinking satellite?

All satellites (man-made or otherwise, which are not currently in the process of burning up on re-entry) are visible via reflected sunlight. They do not emit visible light of their own. Some which tumble do so in a controlled manner - I would refer to this more as 'spinning', not tumbling. Some are either 'dead' or out-of-control. In all these cases, the variation in intensity is due to different angles and surfaces of reflectivity as the body tumbles/spins. There are no satellites (at least that I am aware of) which emit visible light in pulses strong enough to be thought of as blinking.

Grant

reapriavoland

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Re: "Shooting Star" question
« Reply #8 on: January 10, 2018, 03:15:06 AM »
Quote
How does one tell the difference between a bona fide meteor and space debris?


If the question is, how can you tell *in the field of view of a telescope*, the answer is that meteorites shoot through before you can even react. Satellites (and debris) move through at a brisk walk, but even so, you're not likely to have time to offer someone else a view before it's gone.

Greg N

quetafulra

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Re: "Shooting Star" question
« Reply #9 on: January 10, 2018, 03:29:02 PM »
Quote
Quote

So a satellite that is blinking is actually tumbling and is not a blinking satellite?

All satellites (man-made or otherwise, which are not currently in the process of burning up on re-entry) are visible via reflected sunlight. They do not emit visible light of their own. Some which tumble do so in a controlled manner - I would refer to this more as 'spinning', not tumbling. Some are either 'dead' or out-of-control. In all these cases, the variation in intensity is due to different angles and surfaces of reflectivity as the body tumbles/spins. There are no satellites (at least that I am aware of) which emit visible light in pulses strong enough to be thought of as blinking.

Grant
Thanks Grant!

I guess I never really thought about it being reflected sunlight but it makes sense.

Last time I saw a blinking satellite was as kids when we were camping. Little did we know that it was actualky spinning out of control. That would have made it cooler!

Zachary Patterson

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Re: "Shooting Star" question
« Reply #10 on: January 10, 2018, 03:59:09 PM »
here's one guaranteed to "blink" because it is a spinning ball of mirrors:
http://www.heavens-a...ed&amp;alt=0&amp;tz=UCT
^put your location in, not 0lat,0long as it is
see:
http://cddis.gsfc.na...Hz SLR Data.pdf
for a discussion of it's intentions, so not really "out of control"

here's a sample video:
<iframe id="ytplayer"></iframe>Here's one guaranteed to flash irregularly because it is out of control and tumbling:
http://www.heavens-a...ed&amp;alt=0&amp;tz=UCT
^put your location in, not 0lat,0long as it is
here's a sample video:
<iframe id="ytplayer"></iframe>