February 8 – Big Smalls

Today’s factismal: Most stars aren’t visible because they are too small and too cool.

If you go out at night and look up in the sky, you will probably see lots of stars out there. Though a couple of them are bright enough to look like they have color (e.g., Betelgeuse, Aldebaran) most of them just look like little white dots in the black velvet of night. But what you may not realize is that you are just seeing part of the picture. That’s because when you look at the night sky you can only see those stars that are big enough and bright enough to be seen – and they are just a small fraction of the stars out there!

Most stars are much smaller than the Sun (a.k.a., "Sol").

Most stars are much smaller than the Sun (a.k.a., “Sol”).

How small? Well, astronomers aren’t certain but they agree that at least 70% of all stars out there are “dwarf stars” with less than half the mass of the Sun (known as “Sol” in astronomy circles); some think that it may be as much as 85%! These stars range in size from about ten to five hundred times the mass of Jupiter (to an astronomer “size” always means “mass”). Because they are so small, they burn hydrogen very slowly. Eventually, they will run out of hydrogen and turn into white dwarfs, in a mere 500 billion years or so. In the meantime, these small stars, like Epsilon Indi BB, give off very little visible light and most of their “shining” is done in the infrared (“heat”) portion of the spectrum.

The hotter something is, the "blue-er" its color is. This is true of stars as well as planets.

The hotter something is, the “blue-er” its color is. This is true of stars as well as planets.

The rare big stars, like VY Canis Majoris, have a lot of fuel but they burn through it fast becoming super-hot and glowing a bright blue that slowly changes to red as they lose mass and cool off slightly. (And I do mean “slightly”; at its start, a hypergiant like VY Canis Majoris burns about 500,000 times as brightly as the Sun but it gradually drops to a mere 200,000 times before exploding into a nova.)

Bigger stars are much more massive and much hotter; that makes them brighter and bluer than small stars

Bigger stars are much more massive and much hotter; that makes them brighter and bluer than small stars

So there are a lot of small and dim stars that aren’t visible to the naked eye; they are the candle to the rare big star’s searchlight. But the thing is that there are a lot more candles than there are searchlights. For every star you see at night, there are at least 100 more that are too small to be seen.

A look at the Milky Way using ultraviolet and infrared light (Image courtesy NASA)

A look at the Milky Way using ultraviolet and infrared light
(Image courtesy NRAO)

Big big or small, astronomers study them all. And here’s an image of what those stars look like when we peek at them using ultraviolet and infrared light. “Ordinary” stars that we can see at night glow a greenish white, where newborn and small stars heat up the surrounding dust and make it glow a bright violet for infrared and a startling purple for radio waves. If you’d like to see more pictures like this, and maybe help find hot stars in other galaxies, then point your scope to:

February 6 – The Sky’s A Rockin’!

Today’s factismal: Nearly 42,000 meteorites hit the Earth every year.

Odds are, you’ve seen the really cool dashboard video of the meteor that light up the sky in Illinois and Wisconsin last night. Right now, we don’t know much about this particular meteor other than it was big and bright. We don’t know if it landed somewhere on Earth like the 42,000 other meteorites than come to ground each year or if it headed back out into space like the The Great Daylight Fireball of 1972. We’re not even sure where it came from – was it a piece of a comet or a chunk of an asteroid?

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)

What we do know is that there will be nearly 70 different chunks of rock and ice that speed by the Earth in February alone! They’ll zoom past at distances ranging from just outside the atmosphere to 78 times the distance to the Moon. They range in size from the size of a tiny house (about 36 ft) to the size of a tiny village (about a mile across). These rocks are made up of chunks of comets and asteroids and even bits of Mars and the Moon that have been blasted into space by impacts from other chunks of rock!

A meteor streak across the Milky Way (My camera)

A meteor streak across the Milky Way
(My camera)

What is important about these chunks of rock is that they tell us how dynamic our Solar System is. Instead of being a dead old system with an orbit for everything and everything in its orbit, the Solar System is a dynamic, ever-changing system with the planets and comets and asteroids interacting to change orbits and thrown new stuff in new places. And they can provide us with samples from other planets and from the earliest formation of the system. Besides which, they are just plain pretty!

A meteorite as seen from above the atmosphere  (Image courtesy NASA/Ron Garan)

A meteorite as seen from above the atmosphere
(Image courtesy NASA/Ron Garan)

But the best thing about meteor is that you can help scientists learn more about them! If you download NASA’s Meteor Counter App (available for iPad, iPhone, and iWannaMeteor), then you’ll be able to send NASA scientists valuable information on the number of meteors that hit during the shower. They’ll then use that information to help us understand how likely it is that we’ll get hit. To learn more, go to NASA’s web site:

February 2 – Welcome To Spring!

Today’s factismal: The woodchuck, or groundhog as it is often known, is the largest member of the squirrel family in North America.

Happy groundhog day, everyone! As you’ve probably heard, the world’s second-most famous rodent crept out of his burrow today and saw his shadow, indicating another six weeks of winter (boo!). As you might guess, being awakened in the middle of a six month-long nap does very little to aid Punxsutawney Phil’s prognostications; he’s only been right about 39% of the time.

A groundhog is moved after predicting six more weeks of winter (Image courtesy USFWS)

A groundhog is moved after predicting six more weeks of winter
(Image courtesy USFWS)

But why would anyone consult a groundhog about the seasons? And why on February 2nd? It all goes back to the Romans. Back in the days of the early Roman kings (about 2,700 years ago), the calendar ran from late spring to early winter and then went silent for a couple of months. The Romans held various fertility and harvest festivals to celebrate the seasons, but the actual date when those were held slipped around a bit thanks to those missing two months. Traditionally, they would consult the auguries for the end of winter about this time every year. In the old days, they would slit the animals open and examine the entrails; today, we just see how sleepy they are.

Visitors to the National Cherry Blossom Festival (My camera)

We no longer use the blooming of trees to determine the seasons – or do we? (My camera)

It wasn’t until Julius Caesar fixed the calendar that we started seeing folks who could say with any authority (a legion of armed men is authority, right?) that Spring was officially over and Summer had begun on a specific date. The interesting thing is that, while the various Roman provinces didn’t like the Romans very much (after all, what had Rome done for them other than the aqueducts, sanitation, roads, education, and the wine?), they loved the calendar because it made it easier for them to observe their religious rites and mark their seasons. And one of the most influential (at least in Europe) set of seasons was the one that modern pagans call “the Wheel of the Year”, which divided the year into four seasons (Spring, Summer, Winter, and Fall) and arranged them so that the middle of each season happened on an astronomically significant date.  Winter would show up on November 1, Spring would start on February 2, Summer would begin on May 1, and Fall would roll in on August 1 . This method of timing the seasons lasted for more than 1,900 years; you can see its influence in things such as Shakespeare’s “Midsummer’s Night’s Dream” which takes place on the Summer solstice.

But as we moved into the 20th century, we decided that those dates didn’t work well for us (mainly because there is nothing special to mark February first as the start of Spring). So we came up with a new system. Actually, we came up with two new systems. Around 1950, the meteorologists decided that the seasons would start on the first day of a specific month, so that each season was roughly the same length of time. Winter now started on December 1, Spring marched in on March 1, Summer commenced on June1,  and Fall began on September 1. (These seasons are generally referred to as “meteorological spring” etc.)

M42 (Orion Nebula) Over Virginia (My camera)

The stars don’t set our calendar either – or do they? (My camera)

At about the same time, the astronomers decided that they weren’t going to let no stinking pagans decide when the seasons started based on obsolete astrological superstitions; instead, they’d start the seasons based on the stars. So the astronomers decreed that Spring would begin on the Vernal Equinox, Summer would come in on the Summer Solstice, Fall would commence on the Autumnal Equinox, and Winter would hold sway beginning on the Winter Solstice. That this effectively shifted the seasons by half a wavelength was irrelevant; it just made more sense to the astronomers.(These seasons are generally referred to as “astronomical spring” etc.)

The three seasonal calendars in use today

The three seasonal calendars in use today

So, as a result, we now have three different dates to start each season. Of course, Mama Nature is famous for not reading calendars (as anyone who has been caught in a May snowstorm can attest); she starts her seasons when she wants and marks it by changes in the plants and animals. And it turns out that there are a lot of scientists who are more interested in reading her calendar than man’s. If you would like to help them do so by recording when the leaves change color or the butterflies leave or the buds blossom in your area, then why not write a few pages in Nature’s Notebook?

February 1 – Have A Heart!

Today’s factismal: February is American Heart Month!

Quick! If you are a woman, gather three of your female friends. Odds are that one of the four of you has heart disease. That’s because 42.9 million women in the USA, or about 28% of the female population has heart disease. And it isn’t just women who suffer from this; about one in every twelve men has heart disease. And heart disease is the number one killer in the USA, accounting for nearly a quarter of all deaths. Heart disease kills more Americans than accidents, diabetes, kidney failure, influenza, suicide, and murder combined.

One in four women and one on twelve men suffer from heart disease

One in four women and one on twelve men suffer from heart disease

And heart disease takes many forms. There’s atrial fibrillation, where the top part of the heart beats in 8/8 time while the bottom part does a waltz. There’s coronary artery disease, where the pipes that lead to your heart get clogged up with fatty plaque. There’s heart failure, where the heart moves only a little blood even when your body wants a lot. And then there’s a heart attack, where your heart just throws in the towel and decides to take a rest on the sidelines for a bit.

Heart disease rates across the USA (Image courtesy CDC)

Heart disease rates across the USA
(Image courtesy CDC)

Fortunately, there are almost as many ways to combat heart disease as there are types of heart disease. Adding just 30 minutes of light exercise each day by walking, working in the garden, or going for a bike ride, is enough to reduce the effects of heart disease by nearly 3/4. Eating a low-fat, low salt diet cuts the risk of stroke and heart attack by more than 1/3. And keeping an upbeat attitude has also been shown to improve health (and to get you more friends to share those long walks with).

If you’d like to learn more about heart health and American Heart Health Month, then head on over to:

January 30 – ISIS Is It

Today’s Factismal: The joint USA-Canada ISIS Satellite launched January 30, 1969.

Let’s suppose that you live in Oklahoma and want to talk to a friend who lives in Canada. In the days before the internet, you had four choices: You could travel to Canada to talk to your friend, but that would take weeks and cost a lot of money. You could send your friend a letter, but that would take weeks even if it was fairly inexpensive. You could call your friend on the phone, but that was very expensive even if it was fast. Or you could radio your friend, using the ionosphere to send the signals over the horizon to Canada. And, because it was cheap, fast, and tricky, that’s what geeks would do.

Sending radio signals using the ionosphere

Sending radio signals using the ionosphere

Using the ionosphere to skip signals over the horizon and around the globe has been popular since radio was born. And it was the experience of the early radio “hams” that helped scientists predict the existence of a layer of ionized gas in the atmosphere that they called the ionosphere (“sphere of ions” in science-ese). The gas acted like a mirror, reflecting radio signals over the horizon, just as a periscope reflects light around a corner. And thanks to the ionosphere, ham radio operators and others could send their signals more than 2,000 miles across the globe, instead of being limited to the sixty miles or so that direct line of sight provides. (This is also why you can sometimes receive an AM radio signal from very far away.)

But the ionosphere is more than just a plaything for radio enthusiasts. It is also part of the Earth’s magnetosphere; the magnetic field that protects life on Earth from the deadly ionizing rays of the Sun. Without the ionosphere, solar flares would scorch the Earth and coronal mass ejections would blast the surface with radiation. But thanks in part to the ionosphere, these events get turned into harmless auroral displays; bright bands of fire, dancing in the night sky. And the Sun pushes the ionosphere closer to the Earth on the day side and pulls it further away on the night side, affecting communications and ion distribution. Because it interacts with the Sun, the ionosphere is not a fixed layer with a constant geometry. Instead, it is a constantly-moving, ever-changing layer of churning electrons, protons, and ionized plasma.

The ISIS 1 Satellite (Image courtesy CSA)

The ISIS 1 Satellite (Image courtesy CSA)

There have been a number of satellites that have investigated the ionosphere, either by recording electrical activity from above or by dipping samplers into it. One of the most successful of these was the ISIS 1 satellite. A joint project of NASA and the Canadian Space Agency, ISIS 1 measured the density of electrons in the ionosphere and the relative contributions from the Sun and from cosmic rays. The success of this program led to more joint satellites and eventually to the development of the CANADARM, a remote waldo that is installed on the International Space Station.

If you’d like to experiment with the ionosphere yourself, then join NASA’s INSPIRE (Interactive NASA Space Physics Ionosphere Radio Experiments) Project:

January 26 – All’s Whale That Ends Whale

Today’s Factismal: A whale exploded in the town of Tainan, Taiwan on January 26, 2004, shattering windows and crushing cars.

There are a few basic rules of good research. Don’t forget to turn off the Bunsen burner. Don’t drink and derive. And (most essential of all) never mess with a rotting whale.

This sperm's whale's death is just the beginning of a new life for thousands of other critters (Image courtesy USFWS)

This sperm’s whale’s death is just the beginning of a new life for thousands of other critters
(Image courtesy USFWS)

That last is important because of what happens when anything dies: things start to grow in it that shouldn’t. And those things generate methane, flavored with intestinal ketones and esters of pure yuck. Now, if people left the rotting things alone, then they’d do no real harm in the short run and end up giving you better soil in the long run (think of what a compost heap does for your garden). But they sure do smell, courtesy of all of those ketones and esters. And that means that people invariably want to put that smell as far away as possible.

So people try to blow up whales. And they try to bury whales. And they try to drive whales through the middle of downtown on a truck bed. And it never ends well.

At least, not on land. But scientists have done some interesting work with whale carcasses in the ocean and gotten amazing results. When whale carcasses wash ashore in California, the Monterey Bay Aquarium Research Institute pulls them out to sea and sinks them where they can be watched. Over the years, they’ve learned how whale carcasses and other big messes get cleaned up on the ocean floor.

Even when there is nothing but bones left, a whale's carcass can provide food to other critters. (My camera)

Even when there is nothing but bones left, a whale’s carcass can provide food to other critters.
(My camera)

First, the big predators like sharks, crabs, and hagfish come by and strip away the meat. Then comes a type of worm known as the “bone-eating snot flower” (Osedax mucofloris ) for its diet and shape. Osedax worms only live on whale bones; more specifically, they bore into the whale bones using acid and then suck the marrow from the bones. The marrow is rich in fat, which feeds bacteria that live in the Osodex worm. The bacteria then give off wastes that the worm is able to use as food. Within a matter of months, a colony of Osodex worms can reduce a whale skeleton to a giant pile of mush, suitable for enriching the ocean floor. There are similar detritovores that live on land, from the vulgar earthworm to the sacred dung beetle. And without them, the world would be a lot messier and less pleasant to live in.

If you’d like to try find where whales congregate and maybe tell the scientists about your close encounter with a whale (living or dead {the whale, not you}), then swim on over to the Channel Islands National Marine Sanctuary Marine
Mammal Sightings Database where you can search their database of whale sightings and add yours:

January 25 – Hot Topic, Cool Science

Factismal: IRAS was launched on January 25, 1983.

Astronomy entered a new age in 1983, with the launch of the Infrared Astronomy Satellite, or IRAS for short. IRAS wasn’t the first telescope into space, nor was it the first infrared telescope. But it was the first infrared telescope in space. And that is what matters, because it turns out that space is the place to be if you want to see something that is invisible.

The InfraRed Astronomical Satellite (IRAS) discovered the first exoplanet (Image courtesy NASA)

The InfraRed Astronomical Satellite (IRAS) discovered the first exoplanet (Image courtesy NASA)

You see, the part of the spectrum that we see is just a very, very limited part of a much wider whole. The visible spectrum, which covers the colors from blue through red, says a lot about the world. But the invisible spectrum, which covers colors that are cooler than red (the infrared) and hotter than blue (the ultraviolet), tells us a lot more about the universe. Part of that is simply because most of the universe is very, very cool. And the rest is because the parts that aren’t cool can be very hot indeed.

The hotter something is, the

The hotter something is, the “blue-er” its color is

And it turns out that the temperature is the key to the color. Back in 1900, Planck was able to show that the color of an object was intrinsically related to its color. For example, the Sun is yellow because the part of it that we see is about 5000 K (about 8540 F, or “really, really hot”). We now use that principle in a number of ways, from taking the temperature of a star to taking the temperature of a baby.

But not all colors of light make it through to the ground. To understand this, think of a brick wall. You cannot see through a brick wall because the bricks block the visible light while allowing more energetic gamma rays to pass through. Similarly, our atmosphere blocks a substantial part of the infrared light while letting the more energetic visible light through. And, just as you can see what’s on the other side of a brick wall by walking around it, telescopes can see the infrared colors blocked out by our atmosphere by going above it.

And when they did, what an amazing array of interesting things they saw. While looking at over 500,000 light sources, IRAS discovered the source of the Geminid meteor shower. IRAS discovered six new comets. IRAS saw the dust created by asteroid collisions as a giant cloud surrounding the Solar System. And IRAS saw 75,000 different galaxies with huge numbers of new stars being born. Most importantly, IRAS gave us the first picture of planets forming from a cosmic cloud of dust and gas.

And the hits from IRAS keep coming, even though the satellite quit working nearly thirty years ago. That’s because there are lots and lots of images from IRAS and other space telescopes that need people to look through them. People just like you! If you’d like to try your hand at classifying infrared images, then try the Milk Way Project: