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Planet discussion

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GrimsbyPacer

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Hi everyone.
I'm creating this thread for discussing all types of planets, including Exoplanets, Rogue Planets, Major, Dwarf* & Minor Planets, and Moons.
*This IAU term is total nonsense.

Today from 12:12 to 17:42, the Transit of Mercury is visible from the UK, a solar filter is needed on all binocular and telescope viewings to be safe for the eyes. Magnification is needed to view the event which won't occur again for 3 years. An alternative way of viewing uses cardboard, but I've always disliked that method.
Mercury Facts:
1, it's smaller than Ganymede, Jupiter's biggest moon.
2, it's typically varies from +400 to -170 degrees Celsius.
3, there's a outward dent on one side of the planet caused by an impact crater on the opposite side.
4, it was once thought there was a planet Vulcan even closer to the Sun than Mercury, this has no current evidence.

Also in the news, a small red dwarf star, Trappist-1 which is just 40 light years away, has 3 potentially habitable M-Class planets, the first such discovery from such a dim star.

Anyone else has planet info or news they'd like to talk about?
 
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90sWereBetter

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Well, I demand that Pluto be reinstated as a planet, and that the scientists who led the campaign for it to be demoted to dwarf planet status be rounded up and pelted with rotten fruit in the stocks. They must not be allowed to continue their campaign of bullying and belittling innocent planets just because they're smaller than the other planets.

#JusticeForPluto

Continue as you were. :lol:
 

DaleCooper

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Well, I demand that Pluto be reinstated as a planet, and that the scientists who led the campaign for it to be demoted to dwarf planet status be rounded up and pelted with rotten fruit in the stocks. They must not be allowed to continue their campaign of bullying and belittling innocent planets just because they're smaller than the other planets.

#JusticeForPluto

Continue as you were. :lol:

I agree, I was always very fond of Pluto, it was no way to treat man's (or mouse's) best friend.
 

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GrimsbyPacer

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What basis do you have for calling an official IAU term 'nonsense'?

Well starters:
1, the term Dwarf Planet has no relation to the planet's size, Belt Planet might be more accurate.
2, Pluto (and others), are declassified as planets as the IAU claim their orbits aren't cleared. This is solely because 2,000 known objects exist in the 40au wide Kuiper Belt in which Pluto isn't always in. More known objects exist in all other planetary otbits.
3, the criteria for what counts as a cleared orbit (or not) doesn't exist in the IAU books.
4, under the IAU own rules (assuming the case for Pluto and Ceres exists) Charon and Pallas should also count as Dwarf Planets but don't as the IAU pick and choose things in a non-scientific way.
5, the guy who invented the Dwarf Planet term didn't want it to declassify planets.
6, a huge Jupiter size planet in the Oort Cloud would probably be a Dwarf too, thanks to an extremely long orbit.
7, Alan Stern from New Horizons is the biggest expert on the planet and also thinks the new rule is stupid.
8, what about those three planets close together in Trappist-1? Are they Dwarve's or not, we can't look at an entire orbit.
9, again how to we know if Mars isn't a Dwarf? Pluto was very far away from Eris (the discovery that lead to demotion), a planet incorrectly believed bigger than Pluto..
10, The IAU made their ruling before the spaceprobes could investigate, yet again not scientific.

11, the vote was taken at a time when only 4% of members could attend.
12, a petition for a revote was ignored.
13, planetary scientists are a minority in the IAU.
14, what was the result of the vote? You'll never know as no count of votes ever took place. It's all political to keep the numbers down like in 1850s with Ceres.

Anyway.
Did anyone see Mercury's Transit?
 

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TheKnightWho

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Pluto hasn't cleared its orbit because the barycentre of its orbit with its moon Charon is outside of it! It has nothing to do with the Kuiper belt. Charon does also count as a dwarf planet.
 

GrimsbyPacer

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Well in that case Jupiter isn't a planet as it orbits a barycentre in space too. Orbiting the Sun is another IAU rule.
Anyway they still call Charon a moon at the IAU last time I checked. And satelites are the only objects specifically excluded.
If it's nothing to do with the belt, why is Eris not a planet according to the IAU?
 
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TheKnightWho

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Well in that case Jupiter isn't a planet as it orbits a barycentre in space too. Orbiting the Sun is another IAU rule.
Anyway they still call Charon a moon at the IAU last time I checked. And satelites are the only objects specifically excluded.
If it's nothing to do with the belt, why is Eris not a planet according to the IAU?

You've completely missed the point. The barycentre between the orbits of Pluto and its "moon" (actually co-dwarf planet) Charon.
 

GrimsbyPacer

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You've completely missed the point. The barycentre between the orbits of Pluto and its "moon" (actually co-dwarf planet) Charon.

I know, it's the same for the five little asteroids/satelites which orbit that same barycentre, it's a double planetary system.
The Moon is getting further from Earth each year, in several hundred million years the Earth-Luna barycentre will also move beyond the surface, should that make Earth a Dwarf Planet aswell though?
 

TheKnightWho

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I know, it's the same for the five little asteroids/satelites which orbit that same barycentre, it's a double planetary system.
The Moon is getting further from Earth each year, in several hundred million years the Earth-Luna barycentre will also move beyond the surface, should that make Earth a Dwarf Planet aswell though?

As far as I know the Moon will escape the gravitational pull of Earth before then.
 

Harbornite

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I got back just in time to see it, had a good look at it through our solar scope.
 

Busaholic

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Not much chance of seeing Mercury crossing the sun from Penzance. We did see the sun for about an hour this morning, the same yesterday, otherwise not at all since Thursday. As for heatwave, do us a favour - had the fire on for half an hour yesterday evening.
 

Xenophon PCDGS

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I agree, I was always very fond of Pluto, it was no way to treat man's (or mouse's) best friend.

As a former scholar of Classical education up to my time at university some 50 years ago, I have to call upon the Greek part of that education in my response to your posting above.

Pluto, in Greek mythology, was known in the religious ceremonies performed as being the god of the Underworld, referred to as Hades. He was the son of Kronos and Rhea. In the belief of that time, when the fall of the Titans occurred, the universe was divided amongst the three brothers, Pluto, Zeus and Poseidon, It was decreed that everything underground was awarded to Pluto and together with his wife, Persephone, as his queen, they ruled over Hades.
 

GrimsbyPacer

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A new study of the huge light dips in Tabby's Star (the one with the Dyson Sphere), has suggested the effects are probably natural and not alien activity.
And the Keplar space-telescope has now found over 2,500 planets itself alone.
 
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