August 5 – Comet Chameleon

Today’s factismal: The word comet means “long-haired”.

Back in the days of the ancient Romans, when a comet would appear in the sky it was always an evil omen; they considered it to be a “bad star” or disaster. Even though the comet signaled death, destruction, and the start of the primary season, the Romans and Greeks kept their sense of humor. Because the comet had two long tails streaming out like hair in a sea breeze, they called it “long haired” or komētēs.

Comet Lovejoy as seen from the ISS (Image courtesy Dan Burbank, NASA)

The two tails of Comet Lovejoy as seen from the ISS
(Image courtesy Dan Burbank, NASA)

Nowadays we don’t think of comets as being evil omens but we are still fascinated by the tails that they trail, starting with the number of tails – two.  A comet has two tails because it is made of two types of stuff. Thanks to spectroscopy, we know that the nucleus is mainly made up of ices (water ice, ammonia ice, and even methane and carbon dioxide ice) with pieces of dust for texture; this mixture of rock and ice is why comets are often called “dirty snowballs”.

The two tails of Hale-Bopp (Image courtesy NASA)

The two tails of Hale-Bopp
(Image courtesy NASA)

As the comet gets closer to the Sun the outermost ice heats up and spews out gasses that form a globe called the coma (which means “hair” – yep, those Greeks had a thing). The gasses in the coma then become ionized and get dragged out by the solar wind forming the long glowing tail that is characteristic of comets; this gas tail always points straight away from the Sun. Little flakes of rock dust can also be lost. Because the dust is denser than the gas and isn’t ionized, it can form a second tail that curves away from the comet. (So straight tail=gas, curvy tail=dust. Now go impress your friends.) That dust is left behind in orbits that sometimes lead it to fall on Earth as fireballs.

Comet Hyakutake passes the Sun (Image from SoHo)

Comet Hyakutake passes the Sun (Image from SoHo)

The interesting thing about the tails is that they do more than expand. Thanks to all that heat from the Sun, they also glow. And scientists can use that glow to tell us what the comet is made of; things like amino acids and phosphorus – the building blocks of life. Scientists have been doing this for an amazingly long time; on August 5, 1864, Giovanni Batista Donati did the first spectroscopic analysis of a comet and discovered that they had carbon in them. The other interesting thing about comet tails is that they can help us know where the comet formed. Because different things turn solid at different temperatures, by looking for these things in a comet’s tail, we can learn how far away from the Sun it was when it was born. But in order to do that, we need more information on comets.

Comet Sealy in the Texas night sky (My camera)

Comet ISON in the Texas night sky
(My camera)

And that’s where you come in. Comet Hunters is looking for comets that have become trapped in the asteroid belt by Jupiter. If you look through the images from Hawai’is Subaru telescope on Mauna Kea, you might spot one hiding in among the rocks. To learn more (and chase some tails), head over to:

December 25 – Merry Mishmash

Today’s factismal: Christ wasn’t born on Christmas. (Nor was Isaac Newton, for that matter.)

How would you like to be the least liked person at your church’s annual Christmas pageant this morning? All you have to do is start pointing out all of the things that are wrong with the display, starting with the presence of the Christ child. You see, if you follow the Gospels (and who doesn’t?) Christ wasn’t born in December; he was born at a much different time. We know this thanks to the shepherds, who were “abiding in the field, and keeping watch by night over their flock”. Then, as now, sheep spend the winter in cotes and only start going out into the fields for the night in the late spring.

If it makes you feel better, Isaac Newton wasn’t born on Christmas Day, either. Instead, he was born on what we would call January 4th; thanks to errors in the calendar that the Protestant British didn’t want to fix because then they’d be agreeing with the Catholics, Newton’s birthday got the wrong date. (They fixed it a few years later.)

This Nativity is beautiful, but it is wrong (My camera)

This Nativity is beautiful, but it is wrong
(My camera)

So there shouldn’t be an infant in the Nativity scene. But the rest of it is OK, right? Wrong. Another common mistake is the representation of three “wise men” being at the manger with the Holy Family. The only problem with that is the Magi didn’t show up at Christ’s birth; instead, they arrived some time later, after an unfortunate stop at Herod’s palace. (This is why the Feast of Epiphany, which closes out the Christmas season {and marks the start of Mardi Gras season}, happens on January 6.) The other problem is that the Magi aren’t specifically mentioned as being kings; they could have been itinerant astrologers as was common in that period. The other, other problem is that we don’t know how many Magi there were (or what their names were). Though tradition has it that there were three, which matches the number of gifts given, it is possible that there were only two or more than a hundred and that they were named anything from Balthazar to Zebulon.

OK, so there shouldn’t be an infant and there shouldn’t be any Magi. Now can we go on? Nope. You see those animals? They probably shouldn’t be there, either. You see, though there was “no room at the inn”, people wouldn’t have been asked to bed down with animals as that would have been ritually unclean; having animals sleep in the same place as people would have required the men to undergo a purification ritual at the temple. So the animals would have been turned out in corrals for the night and wouldn’t have been permitted to put so much as a hair inside while Joseph and Mary spent the night in the stable.

Cute? Definitely. Accurate? Definitely not. (My camera)

Cute? Definitely. Accurate? Definitely not.
(My camera)

Fine. We’ve gotten rid of the infant, the Magi, and the animals. Now can we go on? Nope – there’s just one last thing that needs to be fixed. You see that star? It shouldn’t be there either. Even though the Gospels do mention a star leading the Magi, that star doesn’t show up over the house where the Holy Family is living until the Magi arrive much later in the story. And there is also the question of if the star was really a star. Given the rather limited knowledge that people in 4 BCE had about astronomical phenomena, the word “star” could have meant a nova, a conjunction, a comet, or even an aurora.

So what would a true Nativity scene look like in December? It would look like a young couple struggling to put together enough money to make the trip to Bethlehem. The young man would be nervous and excited and a little proud. And the young bride-to-be would be just showing evidence of the child she bears as she glows with the serene majesty of impending motherhood. And far off in the distance would be all of the surprises that will make their life fully and truly blessed – not the least of which is the child that they will raise together.

And that is the true meaning of Christmas – people coming together in love to care for the future.  So I wish you the Merriest Christmas of all, full of love and joy and a bright future for you and yours!

December 18 – Search The GLOBE

Today’s factismal: The “Big Dippper” is not a constellation.

If you ask anyone other than a Trekkie what a constellation is, they’ll tell you that it is a grouping of stars in the sky.  And if you ask them to name a constellation, odds are that they’ll tell you about the Big Dipper. While they would be mostly right about what a constellation is, they would be mostly wrong about the Big Dipper being one. Instead, the Big Dipper is what astronomers refer to as an “asterism”. So what’s the difference and why does it matter?

Since time immemorial, people have looked up into the night sky and grouped together the stars that they see. They typically pulled names from their mythology to assign to the groups of stars, and the groups changed from people to people. For example, the Chinese know of a constellation called the Supreme Palace Right Wall, the Vedic astrologers called part of it Purvaphalguni and part of it Chitra, and it makes up part of the Leo and Virgo constellations of the ancient Greeks. Given all of the confusion over naming the groups of stars, in 1922 the IAU defined a set of constellations with specific names and groups of stars. Naturally, since most of the IAU members at the time were European and American, they followed the Greek names for the most part.

The asterism of the Big Dipper (Image courtesy NASA, taken by MMM MMM on the ISS)

The asterism of the Big Dipper
(Image courtesy NASA, taken by Donald R. Pettit on the ISS)

As a result, there is a constellation known as Ursa Major (“The Big Bear”) that includes both faint, hard to see stars and bright, easily recognizable stars. The most easily seen set of stars in Ursa Major form a shape like a plow or a dipper, which is why they are sometimes referred to as “the Plow” or “the Big Dipper”.  But that asterism is only part of the whole; where the Big Dipper includes just seven stars, there are at least twenty in Ursa Major.  (As an amusing sidelight, the Big Dipper is actually the tail of the bear; you can make up your own joke about what end most people see.)


The sad thing about the Big Dipper and many other asterisms is that they are becoming the only part of constellations that most people can see today. Thanks to light pollution, the fainter stars are being washed out of the night sky and only the brighter stars, which form most of the asterisms, are left visible. This is more than a loss of beauty; light pollution also causes problems for sea turtles (who rely on the light of the Moon for navigation), whales, and many other creatures. If you’d like to learn more about light pollution and maybe even help measure it, why not join GLOBE at Night? This long-running citizen science project has been measuring light pollution for nearly a decade now and has made over 100,000 measurements of the night sky.  To learn more, scope out:

November 13 – Frightfully Fun

Today’s Factismal: Fear of Friday the 13th is known as paraskevidekatriaphobia or friggatriskaidekaphobia .

One of the more interesting things about humans is that if something exists, there’s someone out there who is unreasonably afraid of it; in layman’s terms. they have a phobia. (Phobia is one of those words that started out being used with precision and grace by scientists before it was stolen by the popular press and used in every situation, appropriate or not. See “-gate” and “green” for more examples.) And in honor of Friday the 13th, here is a list of twenty-five phobias. Enjoy – unless you have pinaciphobia (a fear of lists)!

If you have Then you fear
Anthophobia Flowers
Barophobia Gravity
Chiroptophobia Bats

It's Bat-Banyan! (My camera)

It’s Bat-Banyan!
(My camera)

Decidophobia Choosing
Ergophobia Work or functioning
Frigophobia Becoming too cold

Definitely NOT the place for a frigiphobic! (My camera)

Definitely NOT the place for a frigophobic!
(My camera)

Gephyrophobia Bridges
Hierophobia Priests
Ichthyophobia Fish
Koumpounophobia Buttons
Lipophobia Fats in food
Melissophobia Bees

Who could be afraid of such a cute little - OUCH! (My camera)

Who could be afraid of such a cute little – OUCH!
(My camera)

Nyctophobia Darkness
Ombrophobia Rain
Pogonophobia Beards
Radiophobia Radioactivity or X-rays
Selenophobia The Moon

I'm only afraid that we might never make it back! (My camera)

I’m only afraid that we might never make it back!
(My camera)

Uranophobia Outer space
Workplace phobia The workplace
Xerophobia Dryness
Ylophobia Trees, forests or woods
Zoophobia Animals

November 6 – No Bull

Today’s factismal: The Taurid meteor shower looks like it is coming from Taurus the bull.

One of the cool things about the Earth is how often it gets hit by a meteorite. On average, 42,000 meteorites hit the Earth every year. That works out to be about 150 strikes each day! But some days are more average than others, and we are having a few of those days right now because we are in the middle of the Taurid meteor shower.

Named for Taurus the bull, which is the constellation just to the right of Orion as you look at it in the sky, this meteor shower happens when the Earth’s orbit takes it through the debris of comet Encke. As comets move closer to the Sun, they heat up and begin to outgas (which means just what it sounds like: they start to give off gas in noxious clouds {like Uncle Joe} and in large jets {like Aunt Sally}). The outgassing also breaks off small chunks of the comet which form a giant debris trail in the sky. Most of these chunks are about the size of a grain of sand, but some can be much larger. When the debris from the comet meets the Earth’s atmosphere, they create the meteor.

These eight images show how much gas is jetted off of a comet in just half an hour! (Image courtesy NASA)

These eight images show how much gas is jetted off of a comet in just half an hour!
(Image courtesy NASA)

Encke is pretty famous in astronomical circles; it was the second periodic comet every discovered (after Halley’s comet). A large reason for it being discovered was the fact that it has a very short period – just 3.3 years! Thanks to that short period, Encke has been shedding tons of dust and rocks into space. And thanks to that shrot period, we are fairly sure that Encke itself is the remains of a larger comet that broke apart some 20,000 years ago. Because it is so new, Encke has created one of the largest and broadest swaths of cosmic debris in the Solar system. Instead of lasting for a few days, the Taurid meteor shower typically lasts for a month!

The best place to watch a meteor shower, ever! (Image courtesy NASA)

The best place to watch a meteor shower, ever!
(Image courtesy NASA)

And if you’d like to do more than just ooh and aah at the pretty meteor as they burn up, why not download NASA’s Meteor Counter App (available for iPad, iPhone, and iWannaMeteor)? You’ll be able to send NASA scientists valuable information on the number of meteors that hit during the shower. To get the app, go to the iTunes store:

October 30 – The Unparalleled Adventure of One Hans Pfaall

Today’s factismal: Earth had at least 27 close encounters with an asteroid in this month alone!

It is, no fooling, a dangerous universe out there. There are gamma ray bursts and black holes and even some strange life forms out there. But perhaps the most amazing thing about the universe is how many close encounters the Earth has considering that space is mostly empty space. In the last month alone, NASA has recorded some 27 things that passed near enough to our orbit to be interesting (without the “Oh God, Oh God, we’re all going to die” part). NASA prefers to call these things “objects” because while most of them are just hunks of space rock heading for a fatal collision, some of them are actually bits of space junk headed back home.

A meteor enters the Earth's atmosphere, as seen from the ISS (Image courtesy NASA)

A meteor enters the Earth’s atmosphere, as seen from the ISS
(Image courtesy NASA)

And, of course, if we expand our definition of “asteroid” to include the bits of rock and dust and ice left in a comet’s wake, then there have been literally millions of “close encounters of the worst kind” in the past month. That’s because every day, more than 80,000 pounds of space debris hit the Earth’s atmosphere! If you look up at night, you’ll see those bits of rock and ice and dust; we call them meteors or shooting stars; if they are very big and very bright, then we call them “fireballs”.

The Great Daylight Fireball of 1972 (Image courtesy and copyright James M. Baker)

The Great Daylight Fireball of 1972 (Image courtesy and copyright James M. Baker)

Now those bits of debris are more than just pretty; they also tell us a lot about how the Solar System and the Earth formed. by keeping track of where they come from and how many there are, scientists can answer questions such as “Where are the comets?” and “How many asteroids hit the Earth?” and “Did an impact really kill off the dinosaurs?” But scientists can’t spend all of their time looking up at the sky; they’ve got data to work on and papers to write and blinking to do. So what are they to do?

Why, they’ll just ask for help. And that means asking you to spend some time looking at the sky each night. If you see a meteor, then just click on the NASA Meteor Counter app; the data you create will automatically be sent to NASA to help in their work! The app is available for free on iTunes and Google Play:

October 23 – Al Aaraaf

Today’s factismal: Edgar Allen Poe wrote Al Aaraaf in honor of Tycho’s discovery of a new star.

In the 1500s, we thought that the heavens were fixed and unchangeable. And then Galileo happened. That trouble-maker developed a new instrument that was called a “far see-er” or telescope. Using the telescope, we discovered that the heavens were anything but immutable. The Moon had blotches, the planets had moons, and (worst of all) stars came and went.

Tycho's Supernova as seen by the Spitzer X-Ray telescope (Image courtesy NASA)

Tycho’s Supernova as seen by the Spitzer X-Ray telescope
(Image courtesy NASA)

The most notable of these was Tycho’s Star. In November of 1572, Tycho saw a star blossom in the night where none had ever been before; because it was new, he named it “Nova”. He didn’t realize it, but his was the first supernova seen through a telescope. The nova stayed visible to the naked eye for a few months and then faded away, which was almost as scandalous as its appearance. The discovery of the new star put the re-examination of the heavens into high gear.

And 257 years later, Tycho’s discovery would inspire Edgar Allen Poe as he wrote his first published poem, Al Aaraaf. His poem first saw the light of day in copies of the May 19, 1829, Boston Gazette, where it puzzled the heck out of a fair few readers. Thick with allusions, illusions, and confusions, it tells the story of two star-crossed lovers who spend all of eternity on the star that Tycho discovered.

If poetry isn’t your bag, then maybe looking through pictures of the Milky Way is. If so, then head over to the Milky Way project, where you can sort bubbles and clouds and help us understand how stars like Tycho’s form!