Pluto's Heart

If you paid attention to the data sent back by New Horizons when it zipped by Pluto and Charon, you know that Pluto has a heart-shaped region, which is known as the Tombaugh Regio. The western lobe of the heart-shaped regio was originally named Sputnik Planum but is now known as Sputnik Planitia. It lies mostly in the northern hemisphere, but does extend southward beyond the equator.

The surface of the Sputnik Planitia consists mostly of irregular polygons separated by troughs. The polygons average about 21 miles (33 km) across. The surface also has what appear to be wind streaks, with evidence of sublimation, which is the rapid change from solid to vapor form. Sublimation also appears to be the cause of pits found in the planitia. No craters were detectable by New Horizons, implying the surface is less than 10 million years old.

Most of the ice in this basin is thought to be primarily nitrogen ice, with small fractions of carbon monoxide and methane ices. At Pluto's ambient temperature of 38°K, nitrogen and carbon monoxide ices are much less rigid than water ice, making glacial-like flows possible.

This basin likely originated when something about 125 miles across hit the area. The subsequent hole would have subsequently collected volatile ices. The nature of Pluto's atmosphere means that a topographic depression becomes a cold trap.

Nitrogen ice is denser than water ice, and the accumulation of this much dense nitrogen ice has created a higher level of gravity associated with this area. This gravity anomal may have caused Pluto to reorient itself to put the planitia near the Pluto-Charon tidal axis. Currently, Pluto and Charon always keep their same faces towards each other, and Sputnik Planitia is presently close to the anti-Charon point on Pluto, which has a less than 5% probability of happening by chance.

Contrary to popular belief, Charon does not orbit Pluto. Both Charon and Pluto orbit the same point, which is located between the two of them. Some scientists believe Charon and Pluto are a binary dwarf planet. That's what I think.

I also think there is a case to call Earth and its moon a binary planet, but that's a little harder to convince people, because the point being orbited is within Earth's diameter. What do you think on the subject?

 

 

Astronomy, March 2017, Page 13, "Pluto's Slusky Heart Contains a Large Ocean.

https://en.wikipedia.org/wiki/Sputnik_Planitia

Weird Planets 12

Good morning! This is the 12th day of your tour, and it’s the last day! So tomorrow you can either rest up or start home, it’s your choice. Now, we do have a number of planets to get through today, so everybody buckle up and let’s get going!

The first one is 51 Pegasi b. Now, don’t ask about the name; they only gave us clues about one naming method, and have completely ignored any other methods that may have been used. Anyway, 51 Pegasi b is gigantic, about half the mass of Jupiter. Yet it completes its orbit in 4 days, so it’s tucked right in close, like so many seem to be. This was the first confirmed exo-planet orbiting a sun-like star, and that’s its claim to fame.

Here is system HR 8799. We aren’t here to see any one planet in this system, but the entire system. This was the first exoplanet system that was directly imaged. As you can see, the system contains a debris disk and 4 massive planets, at least.

Now this - and I keep asking for the name, but they never give it to me - was once called the Oldest Alien Planet. It is 12.7 billion years old, so it formed more than 8 billion years before Earth and only 2 billion years after the Big Bang. Its discovery made people start thinking that planets are very common in the universe and that life may have begun far sooner than anybody had ever imagined. I’m still waiting to hear from one of those civilizations that got started so much earlier than us.

Here we are, only 420 light-years away from Earth, at the Coku Tau-4 system. See the big dusty disk going around the star? Scientists think this system has the universe’s youngest star, less than 1 million years old. They haven’t actually found it yet, but if you look closely, you can see a big hole in that disk. That hole is 10 times the size of Earth’s orbit around the sun, and they surmise it’s been made by this planet cleaning up the dust as it rolls around its orbit.

This is Hat-P-1. Huge, isn’t it? It is 1.76 times bigger than Jupiter, but only has 1/2 Jupiter’s mass. It’s lighter than a ball of cork would be! What’s holding it together? I have no idea. Known as one of the Puffiest Planets known, it could float in water, if it could find a tub big enough.

This Super-Neptune, called Hat-P-11b, is 4.7 times the size of Earth, but has 25 times Earth’s mass. If you weighed 100 pounds on Earth, here you’d weigh 2,500 pounds. Doesn’t sound very inviting to me. And it’s puny star is 3/4 the size of our sun, and cooler. On the other hand, 11b’s orbit is so close to that star, it only takes 4.88 days to complete an orbit, and the surface temperature is around 1100°F. Nope, still doesn’t sound inviting.

Now here’s a fun one. Most planets orbit in the same plane as their star’s equator. But XO-3b’s orbit is at a 37-degree angle to the star’s equator. How did that happen? The only other planet that’s been known to have such a tilted orbit was Pluto. But it got demoted to dwarf planet, and its eccentricities are of no interest anymore. So tilted orbits are an oddity. I’ve heard a rumor that one planet orbits backwards to its star’s rotation. But I don’t know where it is, or else we’d squeeze that in today, too.

Okay, watch carefully, or you’re going to miss this planet. SWEEPS-10 is only 740,000 miles from its parent star. It zips around so fast, a SWEEPS-10 year is only 10 hours long. This puts it in a classification called Ultra Short Period Planets. Those are the fastest planets, where their orbits last less than a day.

Take a good look, this is the last planet of the day, and of our tour. COROT-exo-3b is the densest exoplanet known to man at this time. As you can see, it’s about the same size as Jupiter, but it’s mass is 20 times Jupiter’s. That makes it about twice as dense as lead. But it might not even be a planet. Scientists are also considering the possibility that it’s a brown dwarf, or failed star.

Please watch your step as you disembark. Thank you for taking our tour, and for sticking with it for the entire 12 legs. I know the tour is called ‘Weird Planets’, but actually, this was only a sampling. If we had tried to show you all the weird planets out there, we could be at it for years. Have safe journeys home!

[At last! I don’t know what I’ll be doing next week, but it will probably have nothing to do with planets, weird or not!]

https://www.nasa/gove/feature/jpl/20-intriguing-expoplanets

www.space.com/159-strangest-alien-planets.html

Science Quiz

For 7 years, I’ve tried to ‘update my science [knowledge].’ I’ve always wanted to write science fiction, but my last science class was a quarter century ago, the one before that in 1970. I’d been busy working full time, raising kids, and so on. So when I retired and started writing science fiction, I found the vast research I did – and the results produced – shot huge holes in my time, the story background, and the plot I had picked.

Therefore, I subscribed to magazines, watched science and history documentaries, did other ‘educational’ things. I love to learn but… have I caught up? Am I ready to write science fiction?

Last week, I received the Jan/Feb 2017 issue of Discover. It includes a list of the ‘Top 100 Stories of 2016’. As I read through some of this list and the entry for each article, I realized I was not familiar with everything listed. Have I failed?

I decided to keep track of which stories I had and had not already heard about. Now, I don’t get to read a magazine in one sitting, so as of today, I’ve only gotten to #40. Don’t worry, I will finish this issue, but in the meantime, how many of these 40 items had I already learned about before this issue?

First, the ones I had no knowledge of:

#4. Oldest Human DNA Revises Our Family Tree (I’d heard of Neanderthals & Denisovans, but not this particular story)

#5. Biologists Create Organism with Smallest Genome

#9. New Particle Fizzles, Leaving Physicists to Soul Search

#10. Did Lucy Fall and Not Get Up? (I knew about Lucy, but this was a new hypothesis that she died by falling out of a tree.)

#11. Bangladesh Sits Atop Potential Major Quake Zone

#12. Big Data May Lead to Earlier Alzheimer’s Diagnosis

#18. Electrons ‘Split’ in New Form of Matter

#19. Science in a Post-Brexit World

#22. NIH Proposes Lifting ‘Chimera’ Research Ban

#23. Picky Primes (Prime numbers are not as random as believed.)

#24. Finding China’s Great Flood

#27. Battle for Access (Should scientific papers be available to all, or only those who can afford to subscribe to scientific journals?)

#28. A Bone to Pick about Philistines

#29. Go, Go AlphaGo (Computer learns game, beats human champion.)

#31. Pushing the Limits of Life in the Lab

#32. Disrupting Dopamine Dogma

#35. Mathematicians Find the Answers (I was unaware of this question.)

#36. T. Rex Evolution: Smarts First, Size Second

#37. The Rise and Fall of Theranos (Fake medicine exposed)

#39. Plenty of Room at the Bottom (Saving data with chlorine and copper)

#40. Pluto’s Hidden Ocean (I knew it had one, but this article is about how it’s freezing, breaking Pluto apart.)

And the ones I was familiar with:

#1. Einstein’s Ripples in Space-Time

#2. Earth’s Surprise Neighbor Hints at Exoplanet Abundance (planets of Proxima Centauri)

#3. A New Enemy Emerges (zika and mosquitoes)

#6. The Pace – and Problems – of Climate Change Accelerate

#7. Can America Avoid Another Flint?

#8. Looking for Planet Nine

#13. Persistent Heat Decimates Coral Reefs

#14. The Ozone Hole is Finally Healing (Still has a long way to go.)

#15. More Hobbitses, Prescious! (More remains of hobbit-sized hominids found.)

#16. We Are All Africans

#17. The Falcon Has Landed, Now SpaceX is Eyeing Mars

#20. Ceres Hosts an Ice Volcano

#21. Regulating the Brave New World of Human Gene Editing

#25. The End of the Periodic Table? (How many more elements can scientists make?)

#26. Drug Couriers for Brain Injuries

#30. Crowdsourced Study Pinpoints Depression Genes

#33. Planets of the Milky Way

#34. Superbug Arrives in the US (Bacteria not deterred by any known medicine.)

#38. A Sharp Find (Ancient sword found in Denmark)

How did I shape up? Hmm, 21 stories I did not know; 19 I was semi-familiar with. If I were in school, that would be less than 50%, a solid F. But, I can’t know everything, so I don’t feel bad. Besides, some of these articles have hinted at background knowledge or even a story plot. I am stoked!

What have you learned in the past 7 years? I bet it’s a lot, whether science or not.

Any More Out There?

Okay, did I manage to discover anything about more potential dwarf planets? With most (except Ceres) so far from us, scientists often have to piece together bits of information from several different sources. Even Hubble telescope doesn’t do them much good, because all it showed of Pluto (the biggest dwarf) was a fuzzy blob. So, let’s see what they’ve jigsawed together so far:

2007OR10

It doesn’t have a name yet. But those who discovered it think they are close to deciding on one.

The designation means it was discovered in 2007, but it was only recently discovered that it was much bigger than originally thought. It is the 3rd largest dwarf, right behind Pluto and Eris, at a diameter of 955 miles [1535 km]. Its surface is very dark (the better to soak up what little sunlight it gets?) and reddish, and it rotates slowly - one day there is just under 45 hours long. They think it might be covered in volatile ices of methane, carbon monoxide and nitrogen.

OR10 has an elliptical orbit, which seems to be in fashion, that brings it close to Neptune’s orbit, but it is currently twice as far from the sun as Pluto. How far out does it go? I don’t think they’ve figured that out yet. I found no indication how long it takes to complete an orbit around the sun.

But if you really want to know the weird part about OR10, NASA’s information page stated there had been a hint of vegetation on its surface. What do you think? Some kind of lichen or what? I don’t think palm trees would grow there very well.

2015 RR245

Again, no name yet. It was discovered in 2015. The animation I found about its orbit shows that it gets to Neptune’s orbit, but then skedaddles far, far away, taking 700 years to make one trip around the sun. Its size is 435 miles [700 km], so it’s not a huge dwarf. It will make its closest approach to the sun on this trip in 2096.

Sedna

What little I found on Sedna was mostly from 2004. (You’d think they would have found out more by now.) When it was discovered, Sedna was 8 billion miles [13 billion km] from Earth, 3 times as far as Pluto. It’s red, thought to be about 1,400 miles [2,250 km] in diameter, and there is some evidence it has a moon. It takes 10,000 years to travel around the sun. It’s very bashful, though - maybe that explains its blush? It will get slightly closer in the next 50 years, but still won’t be anywhere near Pluto when it starts heading back for the Inner Oort Cloud. (Strangely, the Oort Cloud was described as ‘hypothetical’, but it shows up on all my star navigation charts.)

Quaoar

Discovered in 2002, Quaoar (pronounced kwa-whar, the name of a Native American god) lies 621,372,292 miles [1,000,000,000 km] beyond pluto in a circular orbit. Maybe it hopes to grow up to be a ‘real’ planet. It has a ways to go, with a diameter of 808 miles [1300 km]. Quaoar is also known as 2002 LM60.

I’d actually forgotten about Sedna and Quaoar, it had been so long since they had been in the news. That’s all I’ve got this week. If you still haven’t heard enough about dwarf planets, try the website http://web.gps.caltech.edu/~mbrown/dps.html , which is updated daily by Mike Brown, an astronomer who seems to be right in the midst of discovering a lot of them. Some of it may be over your head (it certainly was for me), but check it out: as of 10/16/16, he listed 10 nearly certainly, 30 highly likely, 75 likely, 147 probably, and 695 possibly dwarf planets.

Wow! What a big family!

http://www.jpl.nasa.gov/news/news.php?feature=6509

http://www.space.com/33387-dwarf-planet-discovery-2015-rr245.html

http://www.nasa.gov/vision/universe/solarsystem/planet_like_body.html

http://www.space.com/25695-sedna-dwarf-planet.html

https://science.nasa.gov/science-news/science-at-nasa/2002/07oct_newworld

Twins

I consider Pluto and Charon twins. They run around the sun, constantly together, and pretty much ignoring all their other siblings. Pluto was discovered in 1930, and was considered a planet until fairly recently, when it was demoted to dwarf planet.

Charon wasn’t discovered until 1978, and is usually considered Pluto’s closest and largest moon. However, there are scientists who (like me) think Pluto and Charon should be classified as a binary dwarf planet unit. For one thing, Charon’s diameter is slightly more than half of Pluto’s, which is very large for a moon. The relative sizes of a moon to its planet rarely approach that, from what we’ve been able to observe so far. Charon’s size is so large, compared to Pluto’s, that - strictly speaking - it doesn’t actually revolve around Pluto. Both of these twins revolve around a point somewhere between them. Kind of like 2 kids on a playground, holding each other’s hands and spinning around, laughing as they get dizzy and the world around them starts to look silly. And like those 2 kids, they don’t allow the 4 remaining ‘moons’ to join them. The tiny moons revolve around the pair, wishing they were part of the game.

Pluto’s diameter is 2,372 km[1,474 miles], making it the largest dwarf planet we know of. My quick research didn’t find Charon’s exact diameter, but it’s slightly more than 1,186 km[737 miles], which certainly makes it larger than Ceres (950 km)[590 miles].

While NASA’s probe thoroughly studied Pluto, it didn’t neglect Charon. Since it was there, why waste the opportunity? And aside from size, they do rather resemble each other.

Both Pluto and Charon are believed to have a rocky core surrounded by water ice, with other ices covering that. And at the temperatures experienced that far out, water ice is as hard as stone. I find that a little hard to fathom, but not impossible to accept.

Pluto and Charon are tidally locked, meaning each keeps the same side facing the other at all times. Rather like the 2 kids mentioned earlier. But they must have gotten so dizzy they fell over, because they travel around the sun on their sides - still revolving around each other. Maybe the twins got the idea of laying down from Uranus.

And like Uranus and Venus, Pluto rotates backwards, so that sun rises in the west and sets in the east. I found no mention of Charon doing that.

Both of the twins have some interesting features, like Pluto’s ‘heart’, which is a huge glacier made of Nitrogen ice, and Charon’s huge chasm that crosses its entire face. The ‘southern’ half of Charon is smoother and has less craters than the ‘northern’ half. The current thought is that when Charon’s internal water froze (and therefore increased in volume), the pressure forced some partially frozen water out as a type of lava. Remember Ceres’ cryovolcano?

For at least part of its year, Pluto has an atmosphere, or maybe it should be called ‘layers of haze’. And some of it is escaping into space, but not as much as scientists expected, and mostly methane, not the nitrogen they expected would be leaving. I thought I had heard that Charon also had some haze, possibly borrowed from Pluto, but I couldn’t find anything like that during my research, so I may have mis-heard or misunderstood what was said.

And now, I’m going to give a self-satisfied raspberry to those who decided Pluto was ‘just’ a dwarf planet. It (and Charon) were full of surprises and brain-twisting facts for the entire New Horizons team that studied the incoming data. Way to go, Twins!

To Do or Not To Do?

Yeah, I know I’m late getting this posted. Again. But only by a week. Or maybe two.

I find myself of 2 minds about continuing this blog.

     A.   Do I declare a hiatus at least until the new year (2017), and remove it from my to do list (and stress level) until that time? I am experiencing a lot of stress, caught in the tedium of trying to get moved, but – at this point - with nothing more I can do to get moved.

a.    It’s not that I have a lot to do, it’s that my choices of what to do are so limited. All my hobbies, like leatherwork and needlework, are in storage.

                                                i.    Without that relaxing time with a hobby, doing fairly repetitious stuff that doesn’t take much brain power, my subconscious doesn’t roam through various possibilities for my Work In Progress, so I don’t make any progress with my writing. Even a short blog once a week is difficult to accomplish.

b.    Also, with Hubby retired - and we immediately started preparing to move – we haven’t really adjusted to having all this time together. I wind up doing whatever he wants to do, and things on my To Do list get pushed aside.

     B.   Or do I tell myself to grow a pair, and keep doing my blog, hoping to work my way back to once a week? I am supposed to be writing regularly, if not every day.

a.    I don’t want to keep complaining about not being moved yet, so I’d have to do some research, find things to talk about.

                                               i.    Research would be more productive than games. (Somehow, playing games does not let my subconscious roam free.)

                                             ii.    There’s plenty of things to research, like discoveries made about Pluto or Ceres, or even the actual diet eaten by Paleo man.

b.    When the house does sell, I expect we’ll take a couple days to tie up things here in Omaha, put the rest of our stuff in storage and then head for Florida, which will take 2-3 days. That might make it tough to get a blog posted that week.

                                               i.    I could write a ‘spare’ blog ahead of time. Then I could upload it and schedule it to post at the right time.

                                             ii.    Repeat for the week that we come back, get our stuff out of storage and take it down to Florida.

Hmm. When I started writing this, I was strongly leaning towards a hiatus. Now I’m leaning toward ‘growing a pair’. J And that tells me that I’ve enjoyed writing this post, that I miss writing, which is much more interesting than ‘the usual’ games have become.

I also just finished an editing job, which took lots of my ‘spare’ time. The subject of the book, however, made me depressed, so it’s a relief to have it done.

I’ll try for #B. The next time I feel like doing a tough Sudoku, or order my Tribez to get to work, I’ll open one of my incomplete manuscripts instead. Or see what’s new about Ceres. Cross your fingers that I’ll post something next Wednesday.

More on Pluto & Charon

Last week, I made a prediction to a friend that, alas, has come true. My prediction was that by this week, NASA’s look at Pluto and Charon would have fallen out of the news as being too old, and the ‘news’ programs will have returned to dissecting and analyzing some politician’s speech or statement made last week... or even earlier. As exciting as the Pluto/Charon photos and info are, the people analyzing that information are scientists who want to be sure they understand what they have before making any big announcements like “Life found on Pluto!” or “Charon a huge alien generation ship!”

I find Pluto and Charon far more interesting than all this way-too-early political jibber-jabber we’ve been getting for what seems like the past decade. So I’ll take this opportunity to go through my reasons why I feel Pluto (& Charon) should go through yet another reclassification.

In my research reading the past couple of days, it seems there is no upper size limit to ‘dwarf planet’. One article actually said that if an object larger than Mercury were found in the Keiper Belt, it would be classified as a dwarf planet, because it has not substantially cleared out its neighborhood of debris. Can you imagine? If Earth were located in the asteroid belt, it would be a ‘dwarf planet’! 

The lower size limit of ‘dwarf planet’ is pretty fuzzy, too, but from what I gathered, the lower size for a rocky planet is about a radius of 372 miles.

Pluto’s radius is 1,430 miles, about half the size of Mercury, and definitely bigger than that lower limit. NASA’s new photos show it as round and rocky/icy. But look at this; Charon’s radius is 751 miles (about half Pluto’s size), also bigger than that lower limit, and it is also round and rocky/icy. So, why is it still considered by most to be a moon and not a dwarf planet?

Technically, Charon does not revolve around Pluto. Both Charon and Pluto revolve around a common point that is located outside Pluto’s body. If Earth and Mars were in the same orbit and both revolving around a common point, they would be a binary planet. Why not just jump in and classify Pluto/Charon a binary dwarf planet?

I have to imagine that Pluto’s ‘other’ 4 moons probably revolve around that same point, or run the risk of slamming into Charon. If they’re small enough, they could zip around Pluto inside Charon’s ‘orbit’, but from what I understand, Pluto and Charon are pretty close.

The European Space Agency referred to Earth/Moon as a binary planet, and the moon is 1/4 the size of Earth. Another website said that unequivocally, Earth/Moon is not a binary planet, because the moon does not orbit the sun, as set forth in the current definition of planet. Really? How does the moon orbit Earth and not go around the sun at the same time? By that reasoning, binary planets are impossible, because their primary orbit would not be around their star. So, what would they be?

To be fair, I did glimpse some websites that indicate there are others who - like me - think Pluto and Charon are a binary dwarf planet. I hope the idea spreads. Pluto deserves to be somewhat special, in my mind.

What do you think?

Names for Pluto

If you’ve kept track of the various space trips we’ve sent machines on, you are aware that New Horizons is approaching Pluto. Of course, that was launched some 9 years ago, and some of us have trouble remembering what we had for breakfast. But I saw an article in January of this year that the New Horizons was ‘waking up,’ getting ready for the closest fly-by of Pluto ever. So I’ve kept my eyes open for updates on that.

In the meantime, I’ve discovered that Pluto has not just 1, but 5 moons! I’ve known about Charon for a long time, and it’s almost as large as Pluto. But the others are mere specks in comparison, and are named Nix, Hydra, Kerberos and Styx. I think I see a pattern in these names.

Recently, I saw an article asking people to submit and vote on names for when they start creating maps of Pluto’s and Charon’s surfaces, once New Horizons sends back photos taken close enough to show geological features. I hope they pick some good ones. I don’t want Pluto and Charon saddled with names like ‘Tom’s Mountain Range’ and ‘Smith’s Canyon’.

Again, they are looking for names for geological features. They don’t expect to find cities, villages or roads. Nor are they likely to find rivers, lakes or oceans... although I suppose there is some possibility that something may have frozen into long strings or blobs that might bear some resemblance to waterways. Mars has its ‘canals’, and now the bed of an ancient ocean. Even the moon has areas called oceans and seas, though it’s not likely any water ever sat in them.

So, do start coming up with names to propose for mountains, crevices, plateaus, craters and so on. The naming campaign is being promoted by SETI. You can propose names - and vote - at http://ourpluto.seti.org through April 7, which is only a few days away. The International Astronomical Union will decide which names will actually be used.

I wonder why there’s such a hurry to get a list generated? New Horizons’ closest approach won’t be until July of this year, the pictures won’t arrive here until after that, and then the maps will be begun. So, what would be your guess? A year from now, will that map be done and all the features named?

Here There Be Dwarves

I’ve been looking into this ‘Dwarf Planet’ issue. I was not happy to have Pluto no longer be a ‘real planet’, but decided maybe it made sense to have another classification for those items in our system that did not quite fit the definition of ‘planet’. Of course, they devised that definition so that it would exclude Pluto, because another body they did not want to consider as a planet was roughly the same size as Pluto. Or so it seems.

Still, it works, as long as they use the definition of ‘dwarf planet’ consistently, right? But, are they?

Mercury is a planet (now called a Classic Planet). It’s about twice the size of Pluto, so... They had to put the dividing line somewhere, right?

Eris is further out than Pluto, and may or may not be as large. The diameters for these two said Pluto was slightly larger, but each had a margin of error. So, if Eris is larger than they think, and Pluto is smaller than they think, then they could be the same size, or Pluto could be slightly smaller. Ergo, if one is a dwarf planet, it makes sense that the other is also.

I had never heard of Makemake or Haumea until I started this research, but they have both been named dwarf planets. Their diameters are each a bit more than half of Pluto’s.

One rule of the definition of a dwarf planet is that it must have enough mass to pull itself into a roughly spheroid shape. It has been postulated that these bodies would need a diameter of at least 400 km before that was likely. I was surprised to read, then, that Haumea was not a sphere - its diameter through the equator is much longer than its diameter through the poles. The explanation (excuse?) was that Haumea rotates so fast, it has warped into a flattened shape.

So far, Ceres is the only asteroid to be named a dwarf planet. Its diameter is less than 1,000 km, but it is the largest asteroid. There are at least 3 other asteroids that are over that minimum diameter of 400 km, and so far as I have been able to discover, they are at least roughly spherical.

There are also 10 or more heavily bodies beyond the orbit of Pluto that are currently under consideration for being Dwarf Planets.

And that brings us to Charon. Long known as - and even now considered - Pluto’s moon, I suggest it be named a Dwarf Planet. Charon’s diameter is slightly less than half of Pluto’s, considerably larger than Ceres’. Yes, there are plenty of big moons in our system, but none of them are so large in relation to the planet they circle. And, technically, Charon does NOT revolve around Pluto. With this division of mass between them, both Charon and Pluto revolve around a point that is between them.

At least one astronomer has suggested that Pluto and Charon be considered a double Dwarf Planet. I definitely agree.

Name	Diameter (km)	# Moons
Mercury	4,879	0
Pluto	2,368	5
Eris	2,326	1
Makemake	1,430	0
Haumea*	1,300	2
2007 OR10	1,280
Charon	1,207
Sedna	1,000
Orcus	946
Ceres	942	0
2002 MS4	934
2005 UQ513	920
2007 UK126	880
Salacia	854
Quaoar	844
Ixion	804
Varuna	700
Pallas	544
Vesta	525
Hygiea	431

* NOT spherical

Pluto & Company

Sometimes, reading science fills my imagination.

Remember when Pluto was declared NOT a planet? Mercury is also tiny, I objected. Turns out, Pluto’s diameter is half of Mercury’s. They are both small, but that is a significant difference. Still, they have decided Pluto IS a planet, although they stuck ‘dwarf’ in front. I didn’t realize that until today.

Pluto has a moon. Charon is big enough, compared to Pluto, that it doesn’t revolve around Pluto; they both revolve around a point between them. Weird. I don’t know of any other planet & moon that does that. Today, I discovered Pluto has 4 additional moons. Way to go, Pluto!

There are other dwarf planets in our system, way out in the nether regions, so Pluto is not alone. At least 3 have names. Our system has more planets than the 9 I grew up learning about.

Pluto has an atmosphere. What? How can it? It’s so tiny, so little gravity, so cold- Some times. When Pluto gets closer to the sun (it comes within Neptune’s orbit), some of the surface thaws into a thin atmosphere, mostly nitrogen with methane and carbon monoxide for flavor. When it’s not that close, that atmosphere freezes and falls to the ground.

In 2006, NASA launched a probe for Pluto. It woke up in December 2014, and is seeing if it needs to correct its trajectory. In July 2015, it will reach a point 6,000 miles from Pluto, and it will snap pictures and take readings as fast as it can. At some point after that, it will send its observations to Earth. Just think, if you had snuck onto that spacecraft just before it launched, you’d... Well, you’d be dead, because it wasn’t built for passengers, but your body would almost be there to not see it for yourself!

The most interesting bit of today’s research was that frozen dwarf planets may be the most numerous type of planet in the universe. Really? I figure we should set up bases on/in ours. Why would we want to? Once we figure out how to colonize Pluto and its cohorts, we would know how to colonize frozen dwarf planets in other systems; to study, to serve as a base, a stepping stone.

Yeah, when I dream, I can dream big. I got that from the science fiction I read as a kid.

What do you think? If you were designing a colony for Pluto, would you build on the surface or dig inside?