Yeah, I remember the big flap about Pluto.
In fact the local uni has one astro-prof prominent enough to get regularly interviewed, who's still pretty pissed-off.
"It's illogical to maintain that a 'dwarf planet' is NOT a planet!"<sic>

Most of the rancor seems to revolve around the sneaky way that it was done.
Reportedly, only a minority, not even close to 1/2, of international org actually voted on the resolution, &, also, reportedly, the scheme was kept under wraps to avoid alerting those in opposition. 

It's all just nitpicking semantics to me.

As far as the TU is concerned, those sysgen rules were never, at least in my ,mind anyway, really intended to do much more than produce 'cool' systems w/ earthlike planets orbiting gas giants,etc. And it all could easily be explained by all the 'meddling' that G'father & his clones did.

--------------------------------------------------------------------------------------------------------------------------------------------------------------

On Tuesday, January 22, 2019, 5:36:26 PM MST, Bruce Johnson <xxxxxx@Pharmacy.Arizona.EDU> wrote:


The demotion of Pluto was a bitter pill for many. https://news.nationalgeographic.com/news/2006/08/dwarf-planet-pluto-astronomy/

 

But yeah it’s just another dwarf planet (not planetesimal, which I think is still a term for ‘asteroid’) among many; actually given how large Charon is, it’s closer to a binary dwarf planet system; they orbit each other. Now that we actually have sent a probe by it we know a ton more. (there’s also some agitation in the astronomical community to revisit the ‘Pluto is/is not a planet’ thing but a greater mystery is where is Planet X? The whole reason Clyde Tombaugh went looking for Pluto in the first place is because we know there’s something big out there disrupting the orbit of Neptune and other objects farther out. As it turns out, Pluto isn’t big enough to do that. https://solarsystem.nasa.gov/planets/hypothetical-planet-x/in-depth/

 

Astronomers always knew that the Oort cloud, and hence the solar system extend far beyond what was conventionally considered the ‘Solar system’; but now we finally have documented evidence of where that boundary (the heliopause) exists: https://www.space.com/42040-voyager-2-approaching-solar-system-edge.html

 

What we didn’t know was just how many objects there were out there.

 

As for the sun capturing extrasolar objects, I don’t know of any definitive proof one way or the other.

 

Galaxies do ‘collide’, or rather pass through each other and get disrupted: https://apod.nasa.gov/apod/ap130514.html and accretion of smaller ones is one theory of how ours came to be https://apod.nasa.gov/apod/ap080619.html

 

Planetary formation theory  is currently undergoing an explosion of revisions because we finally have more than N=1 examples to observe...

 

-- 
Bruce Johnson
University of Arizona
College of Pharmacy
Information Technology Group

Institutions do not have opinions, merely customs

 

 

On 1/22/19, 4:42 PM, "xxxxxx@simplelists.com on behalf of Peter L. Berghold" <xxxxxx@simplelists.com on behalf of xxxxxx@berghold.net> wrote:

 

I've been watching a series on Science Channel "Secrets of the

Universe" and besides them repeating themselves over and over again on

a few topics (the Universe is dangerous it's going to kill us all!) I

am amazed at how much of our knowledge of the universe and especially

our solar system has changed.

 

Some of these:

 

* Pluto is no longer a planet but a planetesimal  -- curious as to how

they came to that conclusion...

 

 

My gosh... when I went to school it was in all the science text books

that our solar system consisted of a sun and nine planets!  Only eight

planets? Horrors! 

 

* Our solar system extends out to approximately one light year if you

include the OORT cloud and things beyond that!

 

* Magnetic bubbles at the furthest extremes of our solar system

 

* our solar system doesn't really have a boundary, it just merges with

the influence of the next solar system.

 

 

I also have noted some of theory of how planets formed has slowly

changed over the years. Especially the tidbits about the gas giants

influences on how the inner planets were formed and more importantly

survived. 

 

Our sun a thief?  One episode they discussed (briefly) how some of the

objects in our solar system may have formed around other stars and our

sun stole those objects from its sibling stars.  I wonder how much got

stolen from our solar system in return? 

 

Our galaxy is eating matter from mini galaxies that are in an ongoing

collision with our galaxy?

 

 

Any sciency folks on the list want to comment on some of these random

bits I've picked up from this program...  If I really worked at it I

could come up with more choice bits from that show.

 

 

--

 

 

Peter L. Berghold                                 <xxxxxx@berghold.net>

Professonally: IT Professional (DevOps, Puppet, Perl...)

Advocations: Dog Training, Beer Brewing, BBQ, Cooking 

 

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