Wandering Jupiter

A few weeks ago, I explored the possibilities of what might happen if Neptune's orbit should get jiggled by a rogue sun wandering too close to our system. More recently, I read an article that explains that Jupiter has already done some wandering, in order to be in the orbit it's in.

Jupiter's current orbit averages 5.2 astronomical units (AU = the average distance between the sun and Earth). But researchers now say the gas giant started to form some 18 AU away, which is about twice as far out as present-day Saturn. Furthermore, Jupiter made that journey in about 700,000 years, which is the blink of an eye in astronomical terms.

The idea of a wandering Jupiter is not new; I've heard several theories about it. But this time there is some proof that Jupiter formed a long way from the sun and then migrated inward, and that proof came from the Trojan asteroids that share Jupiter's orbit.

Jupiter has 2 groups of Trojan asteroids that share its orbit around the sun. A large group is in front of the planet, and a smaller group follow it. Researchers ran numerous computer simulations that showed the early solar system through millions of years of evolution by 50-day increments.

The simulations showed that the inward migration of the giant planet always resulted in a larger swarm of Trojans in front of Jupiter than behind it. As Jupiter traveled inwards—propelled by gravitational interactions between the fledgling gas giant and the sun's protoplanetary disk—it created a wide zone of gravitational stability in front of it, leading to more asteroids being caught before it than behind it.

Other simulations that relied on Jupiter forming in its current position resulted in both groups of asteroids being the same size.

One more step to this becoming the solar system we know today.

I can't help but wonder what was happening to Venus, Earth and Mars during the 700,000 years that Jupiter came rolling so much closer.

 

"Trojan asteroids reveal Jupiter's great migration", Astronomy, July 2019

Wandering Neptune?

I was perusing headlines the other day when I noticed one about Neptune. Normally, a headline about one of our planets grabs my attention and I read the article, but I was pressed for time that day, and decided to skip the article. Now I wish I'd read it.

The headline stated that all it would take to unravel our solar system was a star passing by and perturbing the orbit of Neptune. I have so-o-o many questions now about this possibly impending doom.

How big a star would it need to be? How big is the average rogue star? How close would the star have to get? How would that star appear to us here on Earth? Would we be able to feel any gravity or heat or radiation from that star? How much would it need to disrupt Neptune's orbit? What exactly would happen to the rest of the planets, once Neptune started to wander? How long would Earth have before it ultimately became uninhabitable?

So many questions, and no answers, because I didn't read the article. So I just now looked the article up, and read it.

Apparently, all it would take would be for the average distance between Neptune and the sun to be altered by 0.1%. Such a tiny change would increase the chance of the solar system descending into chaos 10 times higher. This 0.1% perturbation would be about 4.5 million kilometers (2.8 million miles). It would result in subtle changes to the orbits of the inner planets, reaching the Earth and Mars in about 20 million years. (Whew! I was afraid I might need to worry about it happening within my lifetime, or what's left of it.)

The team conducting the study ran 2,880 simulations with varying amounts of perturbations. 960 simulations had perturbations too small to be measured. In 4 of those, the resulting perturbation to Mercury's orbit resulted in it hitting Venus. In the remaining models, there were 26 that end in chaos; collisions between Mercury and Venus, Earth and Mars colliding, and some where Uranus, Neptune or Mercury were thrown out of the system.

They also estimated the chance of a star getting close enough to cause any of that, and concluded there were only about 20 chances over the next 100 billion years. So it doesn't seem very likely, given that our sun is only expected to last another 5 billion years.

 

https://www.iflscience.com/small-changes-to-neptunes-orbit-by-a-passing-star-could-wreck-the-entire-solar-system-64354

What Size Is It?

Astronomers have been finding more and more planets outside our home system lately. I find that extremely exciting. But when I'm reading about these discoveries, I'm sometimes left wondering, just how big is this newly-discovered planet?

First, let's understand that because of the distances involved, and the methods currently in place for discovering planets, it takes a big planet to be noticed. I don't find that disappointing, because within our own system, we have 4 big planets (Jupiter, Saturn, Neptune and Uranus), an equal number of smaller planets, and a scattering of dwarf planets. So just because they haven't found lots of Mars- or Venus-sized planets circling other stars, doesn't mean they aren't there.

So, they are finding big planets, but they've developed a short of short-hand lingo to indicate a few tidbits of information just in what they call a new discovery. I recently read an article in Astronomy magazine that briefly explained what this lingo meant.

A Super-Earth sounds exciting, doesn't it? A planet like Earth! Well, up to a point. They are rocky planets like Earth, but remember that they are mostly finding big planets. A Super-Earth can range in size up to 10 times the Earth's mass. That means a lot of gravity, and I don't think we'd be colonizing that size a planet. But they are a rocky planet! Our system is not the only place where rocky planets exist. In fact, these may be the most common type of planet in our galaxy.

Then there are Mini-Neptunes. These ice giants range in size from 14.5 to 17 times the mass of Earth. (Neptune weighs in at 17 times Earth's mass.) These are also pretty common around other stars.

Which brings us to the 'Jupiter' class of planet, which come in 2 types.

A Hot Jupiter is a gas giant that orbits their star in under 10 days. (I can't name them, but I've heard of some that circle their star in a matter of hours.) A Hot Jupiter usually orbits at around 1/10 the distance between the Earth and the sun, or less. These are not common around stars like ours, occurring in only about 1% of systems having a star similar to ours.

A Cold Jupiter is a gas giant that—like our own Jupiter—lies beyond the ice line, where it's too cold for water to remain a liquid. There was no comment given about how common these might be. I assume Saturn is also a Cold Jupiter.

And then there are Brown Dwarfs, which is a type of star, not a planet. But they don't last long as a star, and then they cool off and they're just a big mass. It's not clear where the dividing line is between massive planets and dead brown dwarfs, but it seems to be somewhere around 10 times the mass of Jupiter.

Got that? Good. The next time you read about a newly-discovered planet, you can figure out a little something about it just by what they call it.

Mercury

 I’m sure we all remember Mercury from our school days. It’s the closest planet to the sun, traveling around our local star once every 88 days. Now, I learned—way back when—that Mercury was tidally locked to the sun, meaning that one side was always facing the sun, while the opposite side was forever dark. But such is not the case. It turns out that Mercury spins completely around roughly every 59 Earth days. But because it is also moving around the sun, a day/night cycle is about 176 days long. So it has long days, and short years.

It is the smallest planet of our system... except for the dwarf planets. It is slightly larger than Earth’s moon at 9,525.1 miles around its equator. By the way, Mercury has no tilt to it, so it has no seasons except whatever small differences might occur because its orbit is elliptical and not round. The gravity at its surface is roughly 3/8 that of Earth. So a person weighing 100 pounds on Earth would weigh about 37.5 pounds on Mercury.

Like all the ‘inner’ planets, Mercury is a rocky planet. It’s surface is quite cratered, much like our moon.

It is only 39 million miles from the sun. If you were standing on Mercury, the sun would look 3 times larger than it does on Earth. It would also feel 7 times hotter. The daylight temperature can climb to 800 degrees Fahrenheit. At night, that temperature would plummet to -290 degrees Fahrenheit. Therefore, it is not likely that life as we know it would be able to exist there.

That is particularly true because of the atmosphere, what there is of it. It consists of oxygen, sodium, hydrogen, helium and potassium. These are atoms that are thrown up by blasts of the solar winds as well as micrometeor strikes.

The article stated quite bluntly that Mercury has no moons. How lonely it must be. I also wonder, what if it does? In that case, it would need to be very small, or it would have been found by now. But what if there were a pea-sized moon zipping around Mercury? And let’s suppose we eventually sent a manned mission there, to land on the dark side (since the light side is so hot) to bring back Mercury samples. How many spacemen would be killed by that moon zipping through their space suit (and maybe them) before they figured out what was happening? Or would punching through their space suit slow it down enough that it would fall to Mercury’s surface, and they might never figure it out?

Well, I’d have to stop and figure out the physics. And I’m not sure where my physics book is anymore.

 

https://solarsystem.nasa.gov/planets/mercury

Hadean Eon

Unless you have a degree in geology or paleontology or something similar, you are probably as confused by the various Ages, Eons and Periods that get named when you look anything up about the History of Earth. I decided to take a look at one of them, and see if I could get it figured out as to when it happened, what major events happened during it... that sort of thing.

So, I had a list of these names, and I picked one at random: the Hadean Eon.

Turns out, I had picked the very first of Earth’s Eons; it started with the formation of Earth about 4.6 billion years ago and ended approximately 4 billion years ago. Other names for it are the Priscoan Period and the Pre-Archean Eon.

Obviously, since we are looking at the very first half billion years of the world, we won’t be talking about dinosaurs or super continents. What could there possibly be to discuss? Well, let’s dig in and see what turns up.

First, there’s the name, which gives us a clue about what was going on. ‘Hadean’ comes from Hades, the Greek god of the underworld. And that describes the conditions of what Earth was going through: The planet had just formed and it was very hot due to a number of factors, including frequent collisions with other Solar System bodies.

One important collision happened about 4.5 billion years ago, when a Mars-sized planetoid smashed into the infant Earth. The collision sent quite a lot of material into orbit around Earth, while the planetoid and the rest of Earth merged and tried to settle down. The orbiting material probably took less than a century to form the moon.

The big collision didn’t melt all of the Earth, but a fair fraction of material was vaporized, which created a rock vapor atmosphere around the young planet. But that rock vapor would have condensed out within 2,000 years, and left behind an atmosphere heavy in CO2 with some hydrogen and water vapor.

Apparently, there was a sizable quantity of water in the material that formed the Earth. After the moon was formed, the surface temperature was about 230C (446F), but even so, oceans of liquid water existed. That’s because the atmospheric pressure was over 27 times what it is today, because of the heavy CO2 atmosphere. As cooling continued, most of the CO2 was removed from the atmosphere by subduction and dissolving in ocean water, but the levels oscillated wildly.

One theory posits that between 4.4 and 4.1 billion years ago, the Earth’s climate was relatively cool, allowing for liquid water to be present at least that long. It was even suggested that the Earth may have been pretty much like it is today, except for the absence of flora and fauna.

One of the articles implied that life may have been getting started by the end of the Hadean Eon. But that was almost like a throw-away at the end of the last paragraph, so I’m thinking , one celled organisms? Maybe?

So as far as stories go, what if a spaceship gets too close to a forming star system and gets clobbered by tiny planetoids until it is forced to crash land on the nearest planet, which just happens to be vaguely Earth-like, but the only life it has are some quasi-amoebas swimming in the oceans. Maybe they have plants or seeds aboard, so they can grow some food. What about the stuff they don’t realize they’re carrying? Cockroaches, mice, fungal spores... What would those things evolve into, once there was enough food on the planet for them to successfully venture off the ship? There would be a whole lot of niches in the food chain for them to fill!

https://en.wikipedia.org/wiki/Giant-impact_hypothesis

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

Martian Shelters Summation

Okay, so that was pretty much all I found for ideas about Martian shelters: tents of various shapes made of multiple layers of flexible plastic and insulation (probably foam), either buried in the sand or not; tunnels and rooms dug deep underground by robots; and a top-side shelter shaped like half a bagel with a layer of ice between the sheets of plastic.

I did see some reference to making a spun glass (fiber glass) insulation from sorting the Martian sand and melting a particular type of that sand. I’m not sure that would be available for the very first shelters, but maybe it would be a useful building material later on.

For that matter, rocks have been used to build human home for centuries, perhaps millennia. Sand could be combined with other materials to make a type of cement or even mortar. That assumes the colonists can find a supply of calcium silicate nearby, or some other binder to use. If not, they could use polymers, but that would need to be shipped to them from Earth, or they would have to make it on Mars, and I have no idea how complicated a process that might be.

One other idea, briefly mentioned, was to dig holes into a large boulder to create a small shelter, perhaps a type of emergency shelter. I kept thinking about today’s ‘tiny homes’ and thinking a sufficiently large boulder might make a nice small home for someone who really liked his/her privacy.

So, if you are going to be one of those first colonists sent to Mars, don’t expect a mansion. Of course, if you were expecting a mansion, you probably wouldn’t be one of those chosen to colonize Mars. Or anyplace else.

http://www.imagineeringezine.com/e-zine/mars-makeshelter.html

https://www.nasa.gov/feature/langley/a-new-home-on-mars-nasa-langley-s-icy-concept-for-living-on-the-red-planet

https://phys.org/news/2016-12-nasa-ice-house-mars.html

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

Weird Planets 11

Good Morning! Today we'll be visiting some of the Gliese discoveries, and then... well, we'll see if we have the time to visit anything else.

Our first visit is to Gliese 436b, which orbits that faint red dwarf you can probably see in the distance. Gliese 436b is about the size of Neptune, but has a small rocky core, surrounded by ice that makes up the majority of its size. And then 436b has a huge hydrogen cloud surrounding it, a cloud that is approximately 50 times the size of 436b proper. Like a comet, 436b exudes a 'tail' of this hydrogen as it orbits its sun. And finally, despite its icy exterior, this planet has an average temperature around 439 ⁰ C. Some people call this the 'burning ice planet'.

Here is Gliese 581c, which made headlines when its discovery was announced in 2007. This is a super-Earth, with a mass 5 times that of our own. So if you weigh 100 pounds on Earth, here you would weigh 500 pounds. Even so, this was one of the first to be announced as a potentially hospitable planet. However, further study revealed that it was 'tidally locked', meaning that one side always faces its parent star. That side would be blistering hot, and the opposite side unbelievably cold. The only possible location that might offer acceptable temperatures would be the 'twilight zone' between day and night, which I'm thinking would possibly experience a lot of wind. So, a fairly thin band of livable area with a lot of wind, and you weigh 5 times what you should. Surely we could find a better place to colonize?

Gliese 581e is in the same system. 581E used to hold the title as the smallest alien planet, but in January 2011, the announcement of Kepler 10b meant 581e lost that title.

Okay, we do have time for a couple more, so let's look at the WASP planets!

WASP 17b is the first planet discovered that orbits in the opposite direction as its host star's rotation. It also currently has the title of 'Most Puffy'. This is because it is the 2^nd largest planet currently known, but its mass is half of Jupiter's. Sounds like a big ball of gas, right?

That brings us to our final system for the day, WASP 47. This is a compact multi-planet system, the only one known to hold a 'hot Jupiter' with close companions.

Now, sit back and relax. We'll be back at the station in a jiffy.

http://www.express.co.uk/news/science/643662/The-10-weirdest-planets-to-have-been-discovered-so-far

https://www.nasa.gov/feature/jpl/20-intriguing-exoplanets

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

Weird Planets 10

Good morning! Congratulations on completing the first 9 installments of your tour. We don’t have as many worlds to visit as yesterday, so there will be ample time to relax. If you want a pillow or beverage, press the blue button on your arm rest, and either CXQ-9 or CXQ-10 will tend to you. Now, if everybody is comfortable, we’ll get started.

Excuse me. I’m sorry to disturb you, but we are entering the system of today’s first planet. If you turn your attention to your viewers, currently on their maximum magnification, you’ll see a small deep-pink blob. This is GJ-504b, the Pink Planet, 57.3 light years from Earth. The dark pink glow of GJ-504b is caused by the remaining heat of its formation. It’s about the same size as Jupiter, but it’s further from its sun than Neptune is from ours. Scientists didn’t think such a large planet could form at that distance because there wouldn’t be enough dust and debris. Your viewers will adjust their magnification as we approach and swing past, so you can get a good look.

Your attention, please. We are now 434 light-years from Earth, approaching planet J1407B, which is described as a ‘Super-Saturn’. It has a mass of 40 Jupiters and 37 rings surround it, spanning 120 million kilometres. That’s about 200 times the size of Saturn’s rings. Some scientists think these rings may be in the process of forming moons, which has them quite excited, since they’ve never seen that happen outside of our solar system. Actually, even within our system, we haven’t seen it happen.

CXQ-9 and -10 will serve brunch as we move on, complete with champagne! Enjoy!

Good afternoon! Your viewers are currently showing KOI-314c, the lightest planet to have both its mass and physical size measured. Rather surprisingly, it has the same mass as Earth, but is 60% larger in diameter. If you weigh 100 pounds on Earth, you will still weigh 100 pounds on KOI-314c. However, the larger diameter seems to indicate a very thick atmosphere. If you look slightly to the left of the planet’s image, you’ll see the red dwarf star that it orbits. This system is about 200 light-years from Earth. Yes, we are already headed back to the tour station.

This is our final viewing for today. This is Epsilon Eridani b, which orbits an orange Sun-like star only 10.5 light years from Earth. Before long, Earth telescopes may be able to photograph it directly. Unfortunately, it is too far from its star to have liquid water or life as we know it. However, I’m going I’ll make a couple low orbits around it and set your viewers on maximum, and you can all try to spot life as we don’t know it!

Ladies and Gentlemen, we have returned to the tour station. I hope you have enjoyed your day with Star Tours. Er, I mean, Planet Tours.

http://www.popularmechanics.com/space/deep-space/g1265/space-oddities-8-of-the-strangest-exoplanets/

http://www.express.co.uk/news/science/643662/The-10-weirdest-planets-to-have-been-discovered-so-far

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

Weird Planets 9

How many are here for Leg 9 of the Weird Planets Tour? All of you? Okay, we’ll get started. Frankly, a lot of people stay in their hotel room for this day. After 8 straight days of viewing planets, they feel they’ve seen all the possibilities. I prefer to think that each planet has something that makes it unique. Everybody secured? Here we go.

Today we’re going to visit planets and systems discovered by the Kepler Telescope, which was the first unit designed and launched specifically to look for xenoplanets. Our first stop is the Kepler-11 system. Take a look; there are at least 5 planets, although sometimes I swear there’s 6. And they’re all packed in real close to their parent star. If this were the Earth system, all of them would be within Mercury’s orbit. And yet, this system is stable; they aren’t playing havoc with each other’s orbits. When this system was first discovered, a lot of scientists revisited the ideas about planet formation. And Kepler-11 also suggested that systems with multiple small planets might be common. It makes the Earth system a little less unique, but ups the possibility that other intelligent beings – or at least life of some kind – will eventually be found.

At about that same time, the Kepler Telescope discovered Kepler-10c, a mega-Earth planet that some called the “Godzilla of Earths”. 10c is 2.3 times the size of Earth, and 17 times heavier. I think that means if you weigh 100 pounds on Earth, on 10c you would weigh 1,700 pounds. You couldn’t stand up on 10c. You wouldn’t have enough muscles to do it. Now, 10c has a sibling, Kepler-10b, which is a lava world. We’ll catch a glance of that on our way out. The Kepler-10 system is 570 light years from Earth, and is located in the constellation Draco. Considering the naming practice, there should also be a planet called Kepler-10a. I keep asking about it, but they never add any notes about that planet, if it even exists.

In front of us, you can see a double star. Orbiting around both stars is a circumbinary planet, Kepler-16b, which some have nick-named “Tatooine”. You’ve already visited the other so-called “Tatooine”, haven’t you? In a trinary star system? Yes, that earlier 1 only orbits one of the 3 stars, so the chances of any occupants actually seeing 2 suns setting at the same time are pretty slim, but on Kepler-16b, that could be possible.

Our next planet is Kepler-22b. Yes, ma’am, I’m sure there were discoveries between 16 and 22, but they haven’t given me any information on them. They carefully pick which planets to have you view. I’m afraid we couldn’t possibly visit every planet that’s been discovered. At this point, there are thousands of them, and it would take years, even if we managed several in 1 day.

The next planet is Kepler-22b. This planet is in its system’s habitable zone, and could possibly be an actual water world, which we don’t have in Earth’s system.

A short hop away is the Kepler-36 system. Do you see the 2 planets? Just 2, and their orbits are extremely close to each other. At their closest, the distance between them is 1.2 million miles, which is only 5 times the distance between the Earth and her moon. That might make colonizing easier than Earth had in colonizing Mars.

And now we skip all the way to Kepler-186f. Does anything look familiar about this planet? Some people think there is, even if they can’t say what. Kepler-186f was the first rocky planet found in the habitable zone, so the temperature is right for liquid water. It’s also very close in size to Earth. It always makes me want to land and see what might live there. But we have to keep moving, or we’ll never get done.

Here we have the Kepler-444 system, the oldest known planetary system. Here we have no less than 5 terrestrial-sized planets, all in orbital resonance. This group shows that solar systems have formed and existed in our galaxy for nearly its entire life.

Kepler-452b is the first Earth-sized planet found in the habitable zone of a sun-like star. So it might look even more familiar than 186f did. 452b is only 60% larger than Earth, and 5% further from its star. Following our earlier logic, if you weigh 100 pounds on Earth, here you would weigh 160 pounds, which would be tiring, but do-able. And if a typical day on Earth got to 100°, here it might get to 95°. But there are a lot of things that have an influence on a planet’s temperature, so I’m not absolutely certain of that last statement. Still, at first glance, it certainly sounds inviting.

And now, just one last pause on our way back to the station. As you may know, the Kepler Telescope developed a technical problem, which scientists ‘fixed’, sort of, but its mission had to be modified to accommodate its somewhat limited capability. At that point, they stopped using ‘Kepler’ in the naming ritual and started using ‘K2’, to indicate these discoveries were made after its mission was modified.

This is the K2-3 system. We’re a bit late getting back, so we won’t stop here long. K2-3 has 3 super-Earths in orbit. If you check today’s pamphlet, the mass and radius of each is listed. The home office keeps promising to include updates on their atmosphere compositions, so if you see that information, I’d appreciate you letting me know.

And here we are. I apologize for a long day, but Leg 9 always takes longer than the home office thinks it should. Have a pleasant evening and get a good night’s sleep.

https://www.nasa.gov/feature/jpl/20-intriguing-exoplanets

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

Weird Planets 6

Some of these planets look familiar, which is how they get their nicknames. Is it a surprise that someone has imagined planets similar to actual exoplanets?

HD 188753 is sometimes called Tatooine. It is a Jupiter-sized planet located 149 light-years away from us… in a triple star system. One list explained that this meant the planet orbited a star, which orbited another star, which orbited a third star. They could be right that HD 188753 is set up this way, but it is not the only configuration available to 3 stars and 1 planet. How many other configurations can you come up with?

Whatever the configuration of this system, the gravitational fields would be complex, so scientists were surprised to find planets could be created in such a gravity maelstrom. Dr Maciej Konacki of CalTech feels the view from this planet would be spectacular, with ‘occasional’ triple sunsets. Yes, that’s possible; it depends on the distance between the triplet stars. Some ‘companion’ stars are so far apart that each appears as only a bright point to the other. But this Tatooine would definitely be hot; it completes an orbit around its star in 3.5 Earth days, so it is snuggled up real close.

CoRoT-7b was the first exoplanet to be dubbed a ‘Super Earth’. That means it’s a rocky planet, not a gaseous one. Knowing that other rocky planets exist, scientists can look for potentially habitable planets that reside in a star’s ‘Goldilocks’ zone.

However, this particular planet does not look like a pleasant place, as it is tidally locked to its star, meaning the same side always faces the star, and the temperature on that face is around 4,000° F. If you want to visit, consider that it may be the rocky core of a vaporized gas giant where it rains rocks. Be sure you take a strong umbrella with you!

Kepler-10b is the first rocky planet discovered by the Kepler equipment. It is the smallest known exoplanet; an Earth-sized world that may have a lava ocean on its surface. I love a hot tub, but that’s too hot.

OGLE-2005-BLG-390 is the first ‘cold super Earth’ exoplanet discovered, nicknamed Hoth. The thought is that it began to accumulate a Jupiter-like core of rock and ice, but didn’t stop with just a core. It is 5.5 times the mass of Earth, has a surface temperature of -364° Fahrenheit, and orbits a red dwarf star some 28,000 light-years away.

Well, on this trip, we’ve gone from Tatooine to Hoth. Have we gotten all the ‘extremes’ done? I’m not sure. But next week, we’ll start zipping through the planets that only appeared on 1 list. Bring your seat belt!

http://www.express.co.uk/news/science/643662/The-10-weirdest-planets-to-have-been-discovered-so-far

https://www.nasa.gov/feature/jpl/20-intriguing-exoplanets

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

Weird Planets 5

Now we begin exploring the exo-planets that only appeared on 2 of the 4 lists. Does it seem like this series will never end? Cheer up; the process will get faster. The fewer lists that contained a particular planet, the less information I have to pass on to you. I’d like to get through several planets today, so let’s get started.

Earth Jr is only 20 light years away. It’s official name is Gliese 581d. Actually, there may be 2 planets around the same star, but only 581d is mentioned on both lists. 581g was a ‘shiny thing’ that briefly appeared in the same paragraph on the first list.

Gliese 581 is a red dwarf star located in the Libra constellation, and 581d sits on the outer edge of the Goldilocks zone, so it would be possible for water there to be liquid. In addition, the atmosphere produces a significant greenhouse effect, making it even more hospitable for life (more or less) as we know it. It is, however, 8 times the mass of Earth, so do you think any creatures living there would be Big and Strong? Or Short and Strong? I can’t decide, myself, and I assume it would depend - at least in part - on the biochemistry of the creatures.

If it exists, Gliese 581g sits in the middle of that same habitable zone. Some research says it does exist, other research says it doesn’t. This is only 20 light years away, so let’s go find out, shall we?

WASP-18b is 325 light years away. But since we don’t yet have light-speed travel, we aren’t likely to get there before it dies. Some scientists think it should have already died, before we ever got a glimpse of it. WASP-18b races around its sun in less than 24 hours, but its orbit is apparently degrading, so it’s getting closer and closer to its sun, and in 1 million years (or less?), it will plunge into that star.

WASP-12b is 870 light-years from us. I don’t think we’ll want to settle there, for it is rather warm - 4000°F or 2250°C. It sits only 2 million miles from its sun (Earth is 93 million miles from our sun), and takes just over 1 Earth day to make a complete orbit of that star. It’s also a gaseous planet, with 1.5 times the mass of Jupiter and about twice Jupiter’s size. Obviously, it’s less dense than Jupiter, right? So, even less chance that in all that gas there would be anyplace solid to build a new home. And can you imagine the air conditioning bill?

http://www.popularmechanics.com/space/deep-space/g1265/space-oddities-8-of-the-strangest-exoplanets/

http://www.express.co.uk/news/science/643662/The-10-weirdest-planets-to-have-been-discovered-so-far

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

Weird Planets 2

I did find some exoplanets listed on more than one list. But none of them showed up on all 4 lists! So much for ‘Weird is weird.’

The first one we’ll look at is 55 Cancri e, which somebody has nicknamed ‘The Diamond Planet. It is only 40 light-years from us, and one list says it is worth about $26.9 nonillion ($26.9 followed by 29 zeroes). None of the other planets on these lists come with a price tag, so why does this one? Because they figure about 1/3 of its surface is made of diamonds. It is only twice the size of Earth, but it is almost 8 times denser than Earth. There must be something there that is denser than Earth’s rocky core. There is speculation that it has a ‘weird’ chemistry from what we know on Earth, and that it might consist of graphite and other forms of carbon.

So why would so much of it be made of diamond? Diamonds are carbon that is exposed to high temperatures and intense pressure over time. And 55 Cancri e has plenty of both! Despite its size, it orbits its sun closely, about 1/25th the distance from our sun to Mercury. At that distance, its ‘year’ is 18 hours long, and it is tidally locked, meaning the same face of the planet is always pointed at its sun. On that sunny side of the planet, the temperature could be about 3900 degrees F. Plenty hot, I would think. And as dense as it is, anything that is not actually laying on the surface would soon find itself squeezed so hard, its molecules get really up close and personal. If that item was mostly carbon, that pressure and heat would produce a diamond.

So far, 3 of the lists agree about it, but the NASA list included some thoughts about it that the others didn’t. It has been proposed that 55 Cancri e has a rocky core surrounded by a layer of water in a ‘supercritical’ state where it is both liquid and gas. It is also thought this planet is topped by a blanket of steam.

Does that negate the idea of a big chunk of it being diamond? I don’t know. NASA didn’t mention graphite, carbon or diamonds. Yes, the name on each list is 55 Cancri e; I double and triple checked. I suppose all 3 lists could be right, but those who compiled the lists only mentioned the tidbits of information that they found fascinating. What do you think?

Weird Planets

A couple years ago, one of the panels I ‘moderated’ at mid-west sf conventions was about some of the definitely-odd exo-planets that had been found. Since astronomers are scientists and are never happy with what they know, they keep looking out into space. And they keep finding things, a certain percentage of which can be called ‘weird’. So I thought I’d take a fresh look at their current list of odd-balls. This could take more than one post, because I’ve found 3 different lists; one of 8 planets, one of 10 planets, and another of 20 planets.

Wait.

Yes, this is definitely going to take more than 1 posting, because I scrolled down the google page of search results, and found more lists. I decided I would not bother with other lists of 8 or 10, because they were probably just repeats or rewrites of one of the lists I already had. But I did decide to look at the list of 25 planets, because... well, I didn’t yet have a list that large.

That gives me - potentially - 63 planets to look at. Of course, I am hoping that there are some that are on more than 1 list, just to whittle that number down a bit. I mean, weird is weird, right? So each of the planets on the list of 8 should also be on the larger lists. Right?

Maybe. NASA’s list of 20 planets calls them ‘intriguing exoplanets’, and ‘intriguing’ does not necessarily equal ‘weird.’

Well, Jumping Jupiters. I spent so much time researching these planets that it’s time to post a blog, and all I’ve gotten written is this intro. Which is rather long for an intro to a blog post.

But, being an intro to a series of blog posts, maybe it isn’t too long. Okay, consider this the intro to the entire series of blog posts on ‘weird planets’. Next week, we’ll look at 1 - or maybe 2 - of the exoplanets that show up on the most lists that I’m working with. Exactly what will make them ‘weird’?

I can hardly wait!

http://www.popularmechanics.com/space/deep-space/g1265/space-oddities-8-of-the-strangest-exoplanets/

http://www.express.co.uk/news/science/643662/The-10-weirdest-planets-to-have-been-discovered-so-far

https://www.nasa.gov/feature/jpl/20-intriguing-exoplanets

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

Rings

I’ve talked before about our solar system as if it were a family, with the sun as the parent, and the planets as the children. The moons, asteroids and other bits would be the grandchildren, I suppose.

I am quite fascinated with our solar system. Until scientists find facts about other solar systems, this is the only one I’ve got to study; these are the only planets I can use as a springboard when my imagination wants to design one for a story. So I keep looking for new things about them that I didn’t know before. Luckily, NASA and scientists keep looking at them, too.

Today’s subject is Saturn and its rings.

You’d think the solar system was a big family, with 9 8 planets and several dwarf planets. But for Saturn, 8 or 9 was not enough. Saturn has 62 moons that have names, and another 9 that have not yet been named. Wow! Can you imagine 71 kids? I’d have lots of trouble remembering half their names, not just 9 of them. I had a couple batches of cousins who had 8 siblings in each family. Gram gave up trying to remember our names; all the girls became ‘Pigtails’ and the boys were ‘Junior’.

I didn’t realize just how many moons Saturn has. One day I will have to start looking more closely at them, but today, I’m looking at the rings.

There are 7 rings. They don’t exactly have names, but each is designated by a letter. I suspect the letters were assigned as the individual rings were discovered, because otherwise, there doesn’t appear to be any rhyme or reason for the assignments.

If you start at Saturn and move away from the planet, you arrive at Ring D, then Ring C, Ring B and Ring A. Continue outward, and you will find Ring F, Ring G and Ring E. Between each pair of rings is a gap, a space that is not absolutely empty, but is relatively empty compared to the rings. (I haven’t figured out if any of the gaps is home to a moon, but I do know that some of the moons are somewhere in the ‘rings’. Some day, I have to figure that out.) Each ring and gap is its own width, meaning the distance between the side closest to Saturn and the side furthest from Saturn.

But they are also thin, meaning the distance from the ‘top’ of the ring to the ‘bottom’. Thickness for all the rings is less than 1 km.

If there is one thing Saturn’s rings are, it’s not consistent. The various rings are made up of water ice particles (with a trace of rock for flavoring), but those particles range from the size of a grain of sugar to the size of a house.

The rings are a very busy place. With 71 moons of various sizes orbiting around this big ol’ gas giant, the gravity and magnetic fields are forever fluctuating. The latest probe documented ‘lines’ in some rings, which are called spokes. The spokes come and go, and they aren’t sure what causes them, but they suspect they are a temporary ‘pile-up’ (traffic jam) of particles caused by the gravity or magnetic fields. Or maybe by electricity leaking from storms in Saturn’s upper atmosphere.

And spokes are not the only oddity in the rings. Ring F seems to be ‘braided’. Who taught those particles how to do that?

But don’t worry about Saturn’s rings. Some of the moons (bigger siblings) act as shepherds for the rings, using their gravity/magnetic fields to keep the ring particles where they belong. More or less.

I’ve just barely touched on Saturn, but that’s all for today. After all, it is a gas giant, with a huge family; too big a subject for me to explore the entire thing in one sitting.

  

http://nineplanets.org/saturn.html

Dione

I thought we’d talk about Dione today. That was before I found out there were 4 ‘Dione’s’ in Greek mythology and one in the Phoenician mythology of Sanchuniathon. Rather than try to sort through all those, I changed my mind and decided to discuss Dione, a moon of Saturn. (What or who is Sanchuniathon? I may have to come back to that one sometime.)

This moon was discovered by Giovanni Domenico Cassini in 1684. It is also sometimes called Saturn IV.

Dione’s orbit around Saturn is an ellipse, and at its closest approach, it is slightly closer to Saturn’s center than our own moon is to the Earth’s center. Because Saturn is a lot bigger than Earth, Dione races around it, taking 2.74 days to complete an orbit, as well as a Dione ‘day’. It never turns its face away from Saturn. It’s interesting that every time Dione completes one orbit, Enceladus (another Saturn moon) completes two. Each time they pass each other, the gravimetric tugging generates internal heat in both moons.

Also interesting is that Dione is one of a set of triplets. Two other moons of Saturn, Helene and Polydeuces, share the same orbit as Dione. They run around Saturn in single file, one 60° ahead of Dione, and the other 60° behind.

Who knew this kind of stuff could actually happen ‘naturally’? May I should have stuck with mythology after all.

It is believed that Dione is about 2/3 water in various forms, and the remainder is a dense core of silicate rock. The top of the ‘water’ is an ice crust, probably as thick as 99 kilometers ( 62 miles). The temperature at Dione’s surface is about -121°F, which would make the ice so hard, it would act like rock. Between the rock core and the ice crust is about 65 km ( 41 miles) of liquid ocean. The crust does have various features, such as chasms, ridges, long narrow depressions, craters and crater chains.

Dione is pretty well covered in craters, as large as 100 km (62 miles) across. However, most of the craters are on the opposite side as scientists expect them to be. The theory is that on something the size and mass of Dione, anything big enough to make a 35 km (22 mile) crater would be able to spin the moon about. There are enough large craters to indicate Dione did a lot of spinning in the past. So maybe she keeps her back to Saturn, trying to see the next spin-inducing attacker before it hits?

Oh, and let’s not forget the ice cliffs (formerly known as ‘wispy terrain’ when it was discovered by the Voyager space probe). At the time, they were called ‘wispy’ because whatever they were, they didn’t hide the countryside in their vicinity. But more recent photos by Cassini show that these ‘wispy’ lines were, in fact, ice cliffs, fractures created by chasms. We now know that some of them are several hundreds of meters tall.

In 2010, the Cassini probe detected oxygen ions around Dione, but there were so few of them, scientists prefer to call it an exosphere rather than a tenuous atmosphere.

en.wikipedia.org/wiki/Dione_(moon)

https://solarsystem.nasa.gov/planets/dione

Gone Fishing on Ganymede

In the past, fishing was a skill used to provide food for the table. Whether or not ancient man enjoyed the process, they needed to be good at it – or at hunting – in order to thrive. Today, fishing on a personal level has become a pleasurable activity for some. They don’t need to do it to put fish on the dinner table, but they find the experience rewarding. Some go so far as to try for ‘a big fish’ out in the middle of the ocean.

What do you suppose will happen when humans find their way to other planets?

Water has been found on our moon, Mars, Ceres, even Pluto, as well as various other places. On Ganymede, a moon of Jupiter, salty water is hidden under a thick (about 95 miles) crust of ice. There is probably more water on Ganymede than all of the Earth’s surface water combined. Scientists believe that ocean is 60 miles deep, about 10 times the deepest part of any Earth ocean.

I can envision future tours being organized to take die-hard fishers to Ganymede to drill a big hole in the exterior ice to facilitate fishing. I doubt if they’ll dangle a 100-mile-long fishing line into that hole – think how long it would take to reel it back in! So maybe their spacesuit for leaving the space boat would also be a diving suit, and they would ‘hunt’ for ‘fish’ with a spear gun.

Hmm. There’s problems with that vision, according to some of what I read. The Ganymede’s ocean is not only covered with ice, it also rests on ice, pressurized into a crystalized form. On other moons, the ocean bed is rock, which apparently keeps the water warmer, and provides various minerals as it is eroded by the salty ocean. The theory is that those warmer, rock-bedded oceans are far more likely to produce some kind of ‘life.’

Still, we keep getting surprised, the more we look around our neighborhood, don’t we? And science fiction writers like to take the science we know now and extrapolate possibilities we don’t – yet - have any proof for.

So, how about this? There’s a lot of different salts, besides table salt, which could be helping Ganymede’s ocean remain liquid. Nobody definitively stated the only salt in Ganymede’s ocean was NaCl (table salt), so these other salts could provide minerals for building ‘life’. I’m not sure the temperature of the ocean is that big a deal, but the salty ocean of Ganymede reacts to the magnetic field of Jupiter, and I’m thinking that reaction might produce some heat, although probably not much.

Sounds good to me. So good, I anticipate someone will make some money someday, selling signs that say, “Gone Fishing on Ganymede.”

http://www.space.com/28807-jupiter-moon-ganymede-salty-ocean.html

http://earthsky.org/space/underground-ocean-on-jupiters-largest-moon

http://www.planetary.org/blogs/emily-lakdawalla/2015/03121716-ganymede-ocean.html

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

3 Blind Dwarfs

Okay, I’ve talked about Ceres and Pluto. That leaves the blind dwarves. I call them blind not because they can’t see (although they probably can’t), but because humans have not - yet - sent out a probe to get a good look at any of them. Our information on them is relatively skimpy, so this probably won’t take long.

Eris

Eris was originally (2003) thought to be larger than Pluto, and was submitted as our system’s 10th planet. Designated 2003UB313 (and nicknamed Xena), it is now named for the Greek goddess of discord and strife, which seems rather fitting, since it caused Pluto’s demotion.

Eris’ diameter is 1,445 miles [2,326 km], which makes it pretty close to the same size as Pluto. The motions of its moon, Dysnomia, shows that Eris is about 27% heavier than Pluto, which means it is denser - probably a large rocky body with a thin mantle of nitrogen-rich ice mixed with frozen methane. This surface may be a frozen atmosphere, which only becomes an atmosphere for a small portion of its 557 year trip around the sun. And unlike most of its siblings, Eris’ orbit sits far outside the plane the other planets inhabit.

One website stated that an Eris day lasts for 25 hours. Another stated that Dysnomia’s circular orbit around Eris takes 16 days.

Makemake

First discovered in March 2005, its first ‘name’ was 2005 FY9, its codename was Easterbunny. I can pronounce Easterbunny, but what’s the proper pronunciation of Makemake? Is it Make-make? Mak-ee-mak-ee? Ma-kee-ma-kee? Well, never mind, let’s move on. Oh, wait, here it is. It’s pronounced mah-kee-mah-kee, which is the name of the god of fertility of the Rapanui, the native people of Easter Island.

Makemake’s diameter is 870 miles [1,400 km], which is about 2/3 the size of Pluto, and takes about 310 years to circle the sun. Its orbit is quite lop-sided, as it goes as far out as 53 Å* from the sun and gets as close as 38 Å, not quite far enough in to say hello to Neptune. Its day is 22.5 hours. It has no atmosphere, is reddish in color, and has been determined to have frozen methane, ethane and nitrogen on its surface.

Makemake has a moon. S/2015(136472)1 (nicknamed MK2) is approximately 100 miles [160 km] in diameter and lives about 13,000 miles [20,900 km] from Makemake. It’s the color of charcoal. It’s been suggested that MK2’s gravity is too weak to hold onto any ices that might have been on the surface, so they sublimated into space. Scientists are still watching MK2, trying to discern the shape of its orbit; if it’s circular, the moon was probably produced by an impact, but if it’s elliptical, MK2 was probably captured by Makemake’s gravity as they passed.

Haumea

Even though Haumea was discovered in 2003, it wasn’t announced until 2005, about the time its 2 moons were discovered. It was designated 2003EL61 (and nicknamed Santa), then named after the Hawaiian goddess of childbirth and fertility. Its moons - Hi’aka and Namaka - are named for her daughters.

Despite being found before the other two dwarves, every website I visited had about 10 sentences on Haumea, most of it repeating what every other website said. So, here some sketchy details:

At its equator, Haumea’s diameter is about 1,200 miles (1,931 km), making it almost as wide as Pluto. But its mass is only 1/3 of Pluto, at least partially because the diameter from pole to pole is much less. Now, even dwarf planets are supposed to be spherical, so why is this called a dwarf planet? Well, they’ve cut it some slack because its ‘day’ is less than 4 hours. That speed has deformed it into something resembling a half-flat beach ball. There is speculation that an impact set it spinning so fast, as well as created its moons.

Haumea is believed to be a big rock with a coating of ices that takes 285 Earth years to make a trip around our sun.

Those are all the juicy tidbits I could find about the 3 ‘blind’ dwarves. However, as I was doing this research, I caught tantalizing hints of other discoveries that may be on their way to being named dwarf planets. If I can find enough information to make a blog, I’ll let you know about those, too.

There’s also been some speculation of a Planet 10 or Planet X, also located in the Kuiper Belt. I’ll look into that, too, but I’m not promising I’ll find much. I heard some hype about the possibility for a little while, and then it just seemed to fizzle out.

So, be sure to come back next week, kids! Same time, same channel. See you then!

*Å = Astronomical unit, the distance between the sun and Earth.