Thursday, May 25, 2017

Prehistoric Groundhog

Groundhog Day happens in February, when everybody - it seems - wants to know ‘Will this winter never end?’ How groundhogs ever got associated with predicting the end of winter is a mystery to me. Did any of them ever get a degree in climatology? No, not a one. They just lay in their borrow, blissfully sleeping through the cold when someone sticks his hand in, grabs one and pulls it out. Still blinking, the confused and shocked groundhog is held up high as a display, a crowd cheers and claps, and then... I don’t know, maybe they stuff the rodent with sweet treats as a reward for being a good sport. Not that the poor guy had any choice in the matter.

I started thinking, ‘Where do groundhogs come from?’ Yes, I know, from mommy and daddy groundhogs. What I mean is, millions of years ago, human ancestors were about the size and shape of a mouse, and they lived underground. Humans are a lot bigger now, and very few of us live underground. So, if we went back to that time - roughly 66 million years ago - would our ancestors be sharing burrows with ancient groundhogs? What would a groundhog from that long ago be like?

66 million years ago, all the southern hemisphere landmasses were gathered together into one supercontinent called Gondwana. Dinosaurs were still around, so I can’t blame our ancestors for seeking safety underground. Groundhogs of that day weighed 20 pounds (about twice the size of today’s groundhogs), had a skull 5 inches long and massive chewing muscles. Let’s see somebody pull one of those out of a sound sleep and hold it aloft!

A sample skull of the creature was found in a rock from Madagascar. This ancient groundhog was probably the largest mammal known for that time period, and lived on seeds, roots and nutty fruits. Its teeth included sharp incisors and wear-proof molars. Large eyes let it see in low light, and the intricate inner ear indicates it could hear higher frequencies than modern man can. A large nasal cavity means it had a keen sense of smell, and most likely it was agile. (The better to dodge large dinosaur feet?)

Alas, that particular rodent has gone extinct. So I’m not sure why it’s called a groundhog. I would assume a ‘prehistoric groundhog’ would be an ancestor of today’s groundhogs, but apparently, it’s only another branch on the family tree of groundhogs. A branch that broke, leaving other branches to fill in the hole.

Well, it did live in Madagascar, so it might have fallen prey to a blind snake, predatory frog or vegetarian crocodile, which were also Madagascar specialties.

Thursday, May 18, 2017

Planets Around Failed Stars

Stars can (but don’t necessarily) have a family of planets surrounding them. Planets can (but don’t necessarily) have moons surrounding them. What about the so-called ‘failed stars’? Do they have anything as a family?

Jupiter is sometimes called a failed star. If it had just a bit more mass, fusion could start, goes the argument. Well, not really. It would take 13 Jupiters combined to have enough mass to reach the minimum needed for a brown dwarf, AKA failed star. Also, Jupiter was created within the disk of dust that surrounded our infant sun, which is how planets are made, not stars. Not even failed stars. So we can’t take any clues from Jupiter about the possibility of planets around dwarf stars.

Okay, so exactly what is a failed star? A close apparent brown-dwarf-type object to Earth is SIMP0136. It lies 21 light-years away and is 13 times the mass of Jupiter. Theoretically, it could be a brown dwarf. Brown dwarves form like other stars, but fail to get big enough. They may have some fusion of deuterium for a relatively short time inside them, but it doesn’t last. Any light they produce tends to be in the red and infrared spectrums, so despite being called brown dwarves, they would probably appear magenta or possibly red-orange. And the older the brown dwarf is, the more it cools and contracts, until it can seem to be just another planet. Scientists have recently decided SIMP0136 is just a planet, after all. A rogue planet, big enough and close enough for them to study its weather patterns.

It could have gone the other way. The size of brown dwarves range from a minimum of 13 Jupiter masses to a maximum of 80 Jupiter masses. If it managed to gather more than 80X Jupiter’s mass, it would have made it to actual stardom.

Because brown dwarves are a type of star, at least some of them do have a family of planets, such as 2M1207b and MOA-2007-BLG-192Lb. This makes sense, because brown dwarves form the same way as other stars, just in the middle of a smaller dust cloud. Once the center of the cloud collapses into a proto-brown-dwarf, the remainder of the cloud thins into a rotating disk of dust, which would normally form planets. It is thought that this disk would not extend far, since the entire cloud was small to begin with, so any resulting planets would be fairly close to the brown dwarf. It is also believed that these planets would be rocky, like Earth and Mars, rather than gas giants like Jupiter, because most of the gas would be taken by the brown dwarf. So, let's look at some known brown dwarf systems:

170 light years from Earth, planet 2M1207b orbits a brown dwarf. Its mass is somewhere between 3X and 10X that of Jupiter, and it orbits its primary at approximately the same distance as Pluto from our sun. Although there is some indication of water, it is not likely to be habitable.

Occasionally shortened to MOA-192 b, MOA-2007-BLG-192Lb is about 3,000 light-years away. This small planet is 3.3X Earth’s mass, and circles a small brown dwarf in an orbit approximately 2/3 the size of Earth’s orbit around the sun. It is believed to have lots of ice and gases, more like Neptune than Earth.

And then there’s the quadruplets: a small brown dwarf (2MASS J04414489+2301513, with a mass 20X that of Jupiter) has a companion (5X to 10X the mass of Jupiter) that could be either a planet or a sub-brown dwarf. There are also two other brown dwarves in close association. All four objects together only have 26% the mass of our sun, making it the quad system with the least mass. It is 470 light years away.

So yes, it is entirely possible - almost probable - that ‘failed stars’ will have planets. Or possibly siblings, as in the quad system.

Friday, May 12, 2017

Enigmatic Sounds

I hear things.

I’m not talking about rumors, or all the usual sounds most people hear during the course of their daily lives. I’m not even talking about those creaks in the middle of the night as the house relaxes after a long day, though the sounds I am talking about come to me after the dark of night settles in and mostly after everybody else in the house has gone to bed.

The thing is, I’m don’t think these sounds are coming through my ears.

Ghosts? If it is, they have followed me from our old house in Nebraska to our new house in Florida.

What I hear is - frequently - music. I’ll be sitting here, playing games working on my computer, and I’ll become aware of music. Specifically, a radio playing Elvis tunes, or 50s hits, or once in a while, swing. But it’s not a strong signal; it reminds me of when I briefly lived in Cheyenne, and while I did my homework, I would try to tune in a specific radio station from Oklahoma. I frequently couldn’t find it, but if the clouds between us were in the correct positions, I could. Kind of. As I remember it, the static threatened to overtake the music, and that’s what this ‘night serenade’ sounds like. And there isn’t any DJ.

I’ve heard - now, this is a rumor - that some people pick up radio signals because of fillings in their teeth. But for me, this only started a couple years ago, and all my old-type fillings are much older than that. This past decade, my dentists have used ‘composite’ fillings, which don’t have the same minerals in them.

But static-laced music isn’t the only thing I hear. Last night, I listened to a phone ring for about an hour. We don’t have a land line in our house, and neither cell phone sounds like an actual phone ringing. In any case, this was the kind of ringing when you have ‘dialed’ and are waiting for someone to answer. Nobody ever did, nor did it go to voice mail or an answering machine. It just kept ringing.

I’m not the only one who ‘hears’ this kind of stuff. A couple friends have admitted having similar experiences, and all of us are diabetic. I don’t know if that last part has any bearing on it, but I would like to know why my mind does this. Is it so bored, it’s entertaining itself? How does it pick what it’s going to listen to? I’ve enjoyed Elvis as an entertainer, but I never bought any of his records. The 50s songs would have been popular when I was a child, but I don’t remember listening to a radio at that age. Swing music from WWII was definitely before my time. And a ringing phone? Who was it trying to call?

Now, here’s another way to think about it: When I’m all alone, I hear things that aren’t there. Things that aren’t creepy or scary. So I’m wondering if, when space travel becomes ‘fairly normal’, and some people are traveling by space ship but don’t have constant contact with ‘base’, will they hear things that aren’t there? Would it creep them out? Would they inform base of it at their next contact? Will science have an explanation for this strange brain activity by then?

How long has the ‘human’ brain been doing this? Did the brain of an ancient person entertain itself with birdsongs or the chattering of small animals (think squirrels)?

Okay, confess. What does your brain do when you’re all alone and not paying it much attention?

Thursday, May 4, 2017


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.