White Light

When we look at the light coming from a light or the Sun, we see it as white, for the most part. But it’s more.

There are three main colors of light – red, blue and green. These three main colors combine to make all of the different colors we see. The colors are how our eyes interpret different wavelengths of light. Short wavelengths are seen as blue, medium wavelengths are green, and short wavelengths are red. The wavelengths in between are the colors inbetween - orange, yellow, and blue. When all of the colors are mixed in equal parts, we see white.

When you shine white light through a prism, you separate the wavelengths of light. Each wavelength bends at a different angle, spreading them apart. And that’s why we see a spectrum. Rainbows are formed the same way, only the light is bent by droplets of water, not a prism. Sometimes, if conditions are right, the light gets bent again and forms a secondary rainbow. In the secondary rainbow, the colors are inside out. Normally red is on the outside and violet on the inside, but on a secondary rainbow it's the violet on the outside and the red on the inside. See for yourself. The secondary rainbow is faint; you may need to click on the picture to enlarge it to see both rainbows.

(photo from Wikipedia Commons, by Eric Rolph)

Wikipedia article on color

Why does poo stink?

Thanks to Brad for this question! Poo stinks for a few reasons. Any undigested food is starting to rot, and that’s smelly. But most of the smell comes from the gases produced by bacteria. If you took the water out, most of what was left would be bacteria. Theses bacteria produce many different gases, including methane and sulfide compounds, all of which are stinky!

More than you ever wanted to know about poo

Bryozoa

You need to watch the video on this one first

What in the heck IS that thing?!? It’s a type of animal called a bryozoa. They’re colonial, which means they’re made of many tiny organisms that live together. Pretty freaky, huh?

Wikipedia article

Blue whales

Okay, sure, you know blue whales are big, but do you know how big they REALLY are?

They’re bigger than any dinosaur that ever lived. The largest blue whales are estimated at 200 tons, while the largest known dinosaur was 99 tons.

A blue whale’s lungs can hold 1300 gallons of air.

Its tongue weighs 3 tons.

Its skull is about 20 feet long.

Its heart is the size of a Volkswagen Beetle.

A baby blue whale is born the size of an adult hippo and drinks 100 GALLONS of milk a day. My four month old daughter drinks approx. 24-28 OUNCES a day.

Blue whales need 1.3 million calories a day. You probably need about 2000.

Cheetahs; one big happy family

Cheetahs are one of the most recognizable animals in Africa. They are currently listed as “Threatened” which their numbers are low. What a lot of people don’t know is that they almost died out long ago. Sometime around the last ice age their numbers dropped very low. The survivors interbred, which means that all cheetahs are descended from this small group of individuals. As a result, they are all very closely related. This was confirmed when scientists performed an experiment. They took skin grafts from several unrelated cheetahs and grafted them onto different cheetahs. In humans, any sort of transplant like this requires drugs to suppress the immune system – otherwise, your body will reject the new skin because it’s too different from you. But in the cheetahs, there was no problem at all. They are so genetically similar that their bodies accepted the skin as part of themselves!

Unfortunately, this causes problems for the cheetahs. If one of them is susceptible to a disease, then it means ALL of them are. One virus could wipe out the entire population. And that’s why scientists and conservationists are trying to help save this beautiful animal.

Wikipedia article on cheetahs, including a picture of the rare King Cheetah.

Why do people tan?

People have three pigments in their skin. This is what gives you your
color. There’s a yellow pigment, pink, and a brown pigment called
‘melanin’. Today we’ll be talking about melanin. If you have
dark skin, you have a lot of melanin, and if you’re light skinned, you
don’t. And, you guessed it, medium skinned people have a medium amount
of melanin.

When the UV radiation from the Sun hits your skin, it causes damage. So
your body reacts to prevent further damage. It produces more melanin.
Melanin absorbs the Sun’s radiation so it can’t enter your skin
cells and damage them. This increase in melanin is what causes a tan.

People with dark skin have more protection from the Sun. Their
ancestors came from places with a lot of bright sunlight, like the
tropics. But you need some sunlight to enter your skin. That’s how
your body makes Vitamin D. People with dark skin who live in bright
sunny places are fine. But if they live in colder, darker places, then
they need to make certain they get Vitamin D in their diet.

People with light skin absorb a lot of sunlight very quickly. Their
ancestors lived in places that were cold and darker than the tropics. We
often use the term “Caucasian” to describe these people. The Caucaus
Mountains are in Russia, which is cold and darker. So the people that
live there have light skin. When you spend most of the year covered up
in heavy, warm clothes, with only your face and hands exposed to
sunlight, you need light skin to absorb enough sunlight to produce
Vitamin D.

People who live in the areas in between the extreme north and the
tropics are in the middle. The temperature and the amount of sunlight
are both sort of medium. So people who have lived in these areas for
very long periods of time (I’m talking thousands of years) have medium
skin.

Why do leaves turn colors in the Fall?

Plants have tiny little organelles in their cells called chloroplasts. Chloroplasts are where photosynthesis happens, so they contain an important pigment called chlorophyll. Chlorophyll is green. (See yesterday’s post for an explanation). But chloroplasts can only use some of the light from the Sun.

To use other colors (other wavelengths) of light, plants have other pigments that capture other colors. They also reflect different colors than chlorophyll, so they appear to be different colors. Carotenoids, for example, appear yellow to orange. These pigments are in the leaves all year long, but there isn’t very much of them. There’s a LOT more chlorophyll, so it covers up the other pigments and we see the plants as being green.

In the fall, when the leaves start to die, they lose their chlorophyll. The other pigments are now visible, with all of the splendid colors of autumn.

An article giving another explanation

Why are plants green?

Remember that plants use sunlight to power a process called photosynthesis. This means that plants need to absorb sunlight. That’s a lot of energy to absorb. If plants absorbed all of the energy from the Sun, it would be too much. So plants have to absorb most, but not all of the sunlight. The light they don’t absorb is reflected.

It’s this reflected light that hits our eyes and allows us to see the plant. Our Sun sends out a LOT of yellow and green light. So plants reflect most of it, particularly the green light, which prevents them from absorbing too much. This green light hits our eyes, and that’s why we see plants as being green.

An explanation of photosynthesis

Why is the ocean blue?

If I asked you what the color of water was, you’d probably say that it’s clear. And when you’re looking at the amount in a glass or a bath tub or even a swimming pool, it IS clear. But water is actually just a tiny bit blue. The amounts of water we generally see in our lives isn’t enough for the blue color to be visible. But when you get enough water to fill up a lake or an ocean, then the blue color is plain to see.

If little bubbles of air get trapped in ice, then it looks white. That’s why snow looks white. But when ice is solid, it’s blue tool. Most ice DOES have bubbles of air trapped in it. But sometimes large pieces of ice, like in a glacier, can melt and then refreeze. Air doesn’t have a chance to get trapped in the new refrozen ice, and it shows its true colors in spectacular stripes.

Snopes article on striped icebergs, with more pictures and good explanations

Why is the sky blue?

Light travels in waves with different wavelengths. These different wavelengths make the light different colors. Short wavelengths make red light, while long wavelengths make violet light in the order red orange yellow green blue indigo violet. School children are often taught to remember this using the name Roy. G. Biv. White light, the kind you’re most used to seeing, is actually made up of all of the different colors of light.

When light travels from one substance, such as air, into another substance, such as water, it changes speed. This causes the different waves of light to spread out from each other. You can see this if you have a prism.

Purple and blue light are spread the most. So when light enters our atmosphere and is scattered, the blue waves scatter far and cover the sky. This makes the sky look blue.

When the Sun is close to the horizon at dawn and dusk, the red light that isn’t scattered as much can be seen. This is why sunrises and sunsets are often red and orange.

Another article that explains this in more detail

Rogue waves

For as long as sailors have set out to sea, they’ve told stories of huge waves that strike unexpectedly. Not just in harbors, but out at sea. Tsunamis are well documented, but they aren’t large at sea. For many years, scientists dismissed these stories of huge waves that come out of nowhere as tall tales.

But with video and modern scientific instruments scientists have been able to confirm their existence. The first documented rogue wave occurred at the Daupner platform in the North Sea. When the average waves in the area were 39ft high, this one was 84 feet high! In 2000, a British research ship sailing west of Scotland measured the largest open ocean waves ever recorded by instruments. At least one wave reached a height of 91 ft.

Discovery Channel has a tv show called Deadliest Catch. In order to film the show, cameras are running on several crab fishing boats for weeks at a time. One of the cameras caught a rogue wave as it hit one of the crabbing boats.


Scientists aren’t certain exactly what causes these huge waves but they have several hypotheses. As time goes by and more research is done, hopefully this question will be answered.

The Wikipedia entry on rogue waves

Late Post

I want to apologize for today's post being so late. I write each week's posts over the weekends and post them in the morning each day before my baby wakes up. This morning she woke up at 4:30 am.

In honor of this, here's a song by the Arrogant Worms (yes, they're a real band) called "Baby Poo."

Swells

Swells are wind waves that have a very long wave length. They are often made by storms in the tropics, and then travel for hundreds or thousands of miles across the ocean. They are often, but not always, larger than the waves around them. If you’ve ever been on a large boat or a ship and that long, slow pitching, it was swells. Surfers often track them to catch the best waves.

Waves basically travel until they hit land. At 60 degrees south latitude, there is no land. The ocean stretches around the entire planet. Not surprisingly, this is where some of the largest swell waves are found. These seas are very tough and take experienced sailors to make it through them. A line from a sailing song goes "And as we wallop around Cape Horn you'll wish to God you'd never been born" (Cape Horn is the southernmost tip of South America).

The video below, taken in Wellington, New Zealand, is an excellent example. If you don’t like Rammstein (loud German industrial music) you may want to turn your speakers down.

Wind waves

Most ocean waves are caused by the wind. A gentle breeze blowing over a short distance will create tiny little ripples. But even a moderate wind blowing over a long distance can create large waves. Once they start, waves will travel for hundreds or even thousands of miles.

Waves move as long, low ridges out at sea, with most of the wave below the surface (remember the post about tsunamis?) It’s not until they reach the shallows near shore that they are forced up by the ocean bottom.



As the wave is forced higher and higher, the water on the bottom is slowed down as it drags across the ground. The water on top is still traveling at the same speed, so eventually it topples over. This is what causes the breakers you see at a beach.

Surprisingly, very little water is actually carried in a wave. As long as the wave hasn’t reached the line of breakers, the water really just moves in a circle. These circles are large at the surface and get smaller and smaller as you get deeper.



In some places, if the waves are large enough, you can get a spectacular show. This is Blowing Rocks Preserve on Jupiter Island near the town of Jupiter on the east coast of Florida. On a calm day it’s just a pretty place. The only unusual thing is the presence of large limestone rocks. But when the wind blows hard enough to make large waves, they break on the rocks and send spray high into the air in a show you won’t see anywhere else. It's well worth a visit.

Tsunamis

THESE are the waves that I was taught to call ‘tidal waves.’ In reality, they are seismic waves, caused by some movement of the Earth, such as earthquakes or landslides.

Out in the ocean they travel deep in the water. It’s only when they reach shallow water that they start to rise up. The Japanese word ‘tsunami’ means ‘harbor wave’ because fishermen out to sea wouldn’t notice them. It seemed like the waves just appeared in the shallow harbor.

Tsunamis aren’t necessarily large. Any water wave that is caused by a seismic event is a tsunami. So the can be a few inches to several meters high. But that doesn’t mean that all of the water will come in one giant wave. Also, a little known fact is that a tsunami may start by all of the water at the beach rusing AWAY from shore. Remember that a wave has two parts – a crest that rises above the water level and a trough that is below. If the trough arrives first, the water will rush out to sea. If you ever see this happening, run to high ground immediately. A British school girl who knew saved 100 lives.

In this video of the Boxing Day tsunami, you can see several things. It starts with a fairly large wave. Then, if you look carefully, you can see the water recede. There is a single large wave, followed by more waves as the water just keeps coming.

NOAA’s website on tsunamis.

The REAL Tidal Waves

People of my age or older (I’m 39) grew up hearing about ‘tidal waves’. This is NOT an accurate name at all. Those giant waves we heard about have nothing to do with the tides. The waves we were taught about are actually tsunamis, which I’ll talk about tomorrow. But there ARE giant waves that can be called tidal waves, although they are more accurately called tidal bores.

A Tidal Bore happens when the tide pushes its way up a river. This might happen every day, such as in the Bay of Fundy, or only a few times a year on certain rivers. The tide comes in so suddenly and so powerfully that it forces its way upstream in one large wave, essentially forcing the river to flow backwards!

In Nova Scotia, Canada in the Bay of Fundy, you can raft on the tidal bore. In other places people have surfed them. But you need to be careful; even if they aren’t tall, these large waves are immensely powerful.

Surfing a tidal bore on the Amazon River



Showing the power of a tidal bore; people get swept downstream

Of Plants and Sex

You may ask yourself "What IS this yellow stuff that's covering everything?" And you may ask yourself "Why does it make me sneeze and cough?" And you may tell yourself "This is not my beautiful house."Sorry, got off track there. **grins**

Okay, back to the original post. That yellow stuff everywhere is pollen. Okay, yeah, great, but what is pollen? Well, the simple answer is that it's plant sperm.

Wait, what?! Plant sperm? Plants have sperm? Yes indeedy they do. Plants, most of them at any rate, use sexual reproduction to make more plants. No, that doesn't mean that they have sex. What it means is that plants have male reproductive cells (pollen) and female reproductive cells (eggs.) Some plants have genders and are either male or female, while other plants have both male and female parts. Most flowers are like that. They contain a pistil (the female parts that make eggs) and stamen (the male parts that make pollen).



(The pistil is made up of the stigma, the style and the ovary)

Pollen can be transferred by animals, such as bees or hummingbirds. This is a very efficient way to transfer pollen. Most of our food crops are pollinated by honey bees. Incidentally, honey bees all over the world are dying, and we don't know why. Stop and think about the effect of losing all of our bees. Now have some respect for the humble honey bee.


But other plants use a less direct method. They just release their pollen to be blown by the wind all over the place. A very tiny amount of the pollen actually lands on the pistil of another plant of the same species. The rest of the pollen lands on your car, or your home, or in your nose.




And speaking of your nose, let's talk about allergies. Allergies happen when your body overreacts to a harmless foreign substance, in this case pollen. The pollen enters your nose. If you're not allergic, the only thing that happens is that you get yellow snot. (Don't believe me? Go outside for a while, then blow your nose and look at the tissue. Told you so.) If you ARE allergic, your body decides that it's being invaded by Something Bad and goes into full battle mode.

Your nasal tissues swell, partially blocking your nose. This prevents more of the 'harmful' substance from getting in. Your nose makes more mucous. This catches any foreign substance and pushes it back out. You cough and sneeze more, which forces that nasty invader right back out. Your eyes may water, again to flush out any strange new stuff. So all of the symptoms of an allergic reaction are actually very reasonable and good. The problem is that your body is doing all of this for no good reason.



These symptoms are caused by chemicals in your body called "histamines." So when they are over reacting and you want to stop the symptoms of an allergic reaction, you take "anti-histamines."

Bet you'll never look at pollen the same way again.

Height

If you don’t read the web comic “xkcd” you should. The author does a fantastic job of illustrating some scientific concepts that are difficult to understand any other way.

One of these is how tall or how high up some things actually are. And if you keep going up, you get into space. How far away are those things in space? Well, xkcd has a great chart showing you. It’s on a log scale, so every two inches or so that you go up on the chart is actually DOUBLE the height of the previous two inches.

Enjoy.

Read it at the xkcd website

The Oceans Flow Through My Veins

Remember that line from a song I quoted in yesterday’s RDA? “I am made of the stuff of the stars, and the oceans flow through my veins.”

Let me explain the second part of that. Your body contains water, a lot of it. I don’t think that surprises anyone. But what not everyone knows is that it’s not pure water – it contains some salt, 0.9% by weight, as a matter of fact. And this concentration is the same for most living cells. If you’ve ever gotten a small cut on your hands and sucked on it, you may have noticed that blood is slightly salty, for instance.

No matter whether it’s a bacteria or a bald eagle, a horse or a human, a blade of grass or a giraffe, we all have the same concentration of salt in our cells. Why? Well, all of the evidence that we have says that life started in the oceans. The first cells probably had the same concentration of salt inside as the ocean water did outside. And things have just stayed the same ever since.

But the oceans haven’t. The oceans have gotten increasingly salty over the many years since the first living things. So the ocean has gotten saltier, while we’ve stayed the same. But it still comes down to this; you have a certain concentration of salt in your body. It all has the same concentration as that ancient sea. You and every other living creature still hold the memory of our Mother Ocean “running through your veins.”

I am made of the stuff of the stars

Where did I come from? There are a lot of answers to that question, depending on how you interpret it. But one answer invokes wonder and awe in me, every time I think of it. A song by one of my favorite bands that contains the line “I am made of the stuff of the stars and the oceans flow through my veins.”

This is literally true. You ARE made of the stuff of the stars. Let me explain.

The universe began with the Big Bang (more on that later). But the Big Bang only made hydrogen atoms. After an extremely long time, these hydrogen atoms started to come together to form huge clouds. These clouds condensed until the pressure in the middle was so high, the nuclei of the atoms started to fuse together. This is nuclear fusion, and it’s what powers stars. Nuclear fusion is what makes all of the heat and the light from our Sun and from every other star in the universe.

In nuclear fusion, two hydrogen atoms are fused together to make helium. That’s what our Sun is doing. But our Sun is a middle aged star. When a star gets older, at some point it uses up all of the hydrogen it has. So it starts to fuse helium together to form bigger atoms. And when it runs out of helium it fuses those larger atoms together into even larger atoms. This is how all of the elements in the universe, other than hydrogen, were made.

At some point, a star can’t continue. Nuclear fusion can no longer occur. Everything collapses and the pressure builds up until the star explodes in a spectacular nova, spreading all of the atoms throughout the universe. This has already happened to all of that first generation of stars.

Eventually these heavier atoms came together to form rocky planets, like Earth. And on Earth, those atoms came together to form cells, and all of the living things on Earth, including you.

Stars were born, lived and died to create the atoms in you. You are literally a child of the stars. It took a star’s death to make you. You are an amazing, wonderful, miraculous being.

For further reading about how stars and space can create the stuff of life

xkcd comic about earthquakes and Twitter

read it at the xkcd site

Earthquakes

I had another article written for today, but I thought that with yesterday's earthquakes, understanding earthquakes would be a better idea. Oh, and if you think earthquakes NEVER happen in your area, follow the link at the bottom of the article.

Yesterday, April 4, 2010 a large earthquake occurred in Mexico and was felt in a large area, including L.A.

The Earth’s crust isn’t a solid piece of rock. It’s broken up into pieces of different sizes called tectonic plates. These plates float on magma that’s about the consistency of corn syrup. As the pieces float, they bump and jostle and slide past each other. But they don’t do it smoothly. The edges of these huge stone plates are rough and jagged, and they catch on each other. Movement grinds to a halt, and the pressure builds. Eventually the strain becomes too much, and the rock gives away. The plate jumps forward and releases all of the pressure at once. Just like a rubber band that breaks when it’s stretched too far, the rock stretches and breaks and whips around.

The energy and the motion ripple out from the center in three types of seismic waves. The Primary waves travel the fastest. They move the ground back and forth. Then the Secondary waves move things side to side. Finally the Surface waves move like water waves, both up & down and back & forth at the same time. Because they move in two directions at once, surface waves can cause the most damage.

Earthquakes happen all the time, but most of them are too small to feel. Here’s a map of all of the earthquakes on Earth in the last 7 days.
Earthquake data by country

It Came From Outer Space...or Did It?

Science Fiction Plot:

Imagine a life form that consists of thousands of individuals that come together and ‘melt’, forming one giant gelatinous blob, with the ‘brains’ of the individuals floating freely in the mass. Now imagine that the individuals were fungi, but they formed the ‘blob’ it could move to a limited degree.

It really exists – they’re called slime molds.

Good explanation

A video of slime mold

Your Relative, Yeast

Yeast - you know, that stuff that makes bread rise, or ferments beer. It's a simple, single celled organism in the Fungi Kingdom. And if you asked most people what it has in common with them, they'd probably say "nothing."

The truth is, you both have a lot in common.
1. You're both made of cells.
2. Your cells contain smaller units called organelles that perform special jobs, just like the organs in your body do.
3. You both perform complex chemical reactions, like fermentation in yeast and cellular respiration in you.
4. You both grow.
5. You are both capable of reproduction.
6. You both respond to changes in your environment.
7. You both use DNA as an instruction manual to tell your cells how to do their jobs.

But wait, there's more. 30% of your genes are similar to the genes of yeast. And not just similar, VERY similar!

What the...?!? How? Why? Well, it seems that, no matter how complicated or how simple an organism is, at the heart of matters, we're all made of cells. And cells work in fundamentally the same way. There are certain things that all cells need to do, in order to stay alive. Once cells "figured out" how to do these things, they just kept the instructions the same. So the genes that tell cells how to do all of these things are the same, whether they're in our cells or those of yeast.

So the next time you're eating bread, or drinking beer (if you're old enough) take some time to thank your relative, the humble yeast.

Fairy Rings

Old myths say that if you ever find mushrooms growing in a ring, beware of treading in it lest the fairies that made them grow that way cart you off!

I can’t prove the existence of fairies, but the scientific explanation is almost as neat. The mushrooms that you see aren’t separate organisms; instead, they’re all connected. Starting from a single spore, an underground part of the fungus called the mycelium grows larger and larger in all directions, making a circle. The mushrooms sprout from the edges of the mycelium.

There are two types of fairy rings. One type grows in lawns and meadows. As the mycelium grows outward, it secretes chemicals that break down organic matter and release the nutrients into the soil. For a short time, the grass in the area benefits from this, but as the mycelium grows to reach the area, it takes up all of the nutrients and the grass dies. The central mycelium eventually uses up all of the nutrients and dies itself, but the outer edges keep growing.
The second type is called a tethered ring. These grow in forests, and the mushrooms grow in symbiosis with the roots of trees. Indeed, they grow ‘tethers’ that keep them connected to the tree roots, thus their name. Both the mushroom and the trees benefit from this relationship.

Fairy rings can grow to be HUGE – several hundred meters across, and can live to be hundreds of years old. One that was discovered in France is almost half a mile across and may be 700 years old!

Fairy Ring Facts

Is there life somewhere else in the universe?

I can’t answer this for certain, but more and more the answer seems to be “probably.” We keep looking in places here on Earth where nothing could live, and we keep finding living things there!

We thought no ecosystem could survive without light to power photosynthesis. But then Robert Ballard discovered organisms living around deep ocean geothermal vents. Whole ecosystems that depend on chemosynthesis flourish in the depths.

Surely nothing can live in boiling, or almost boiling water. I mean, that’s how you sterilize things, right? But in the Grand Prismatic Spring at Yellowstone, we are proven wrong again, spectacularly. Water bubbles into the spring at 160 degrees. For comparison, hot tubs are at or below 104. Your home's water heater should be at 120, so that you don't get scalded. As the water in the spring moves towards the shore, it cools slightly. Different species of bacteria live in the different temperatures, giving the spring its colors. By the way, that brown line on the left of the photo is a boardwalk. If you look closely, you can see people on it.

Okay, what about cold temperatures? Well gallfly larvae and even some turtles can freeze solid! Some fish produce antifreeze. And recently, after scientists drilled a hole through 600 feet of ice, they found living things.

So every time we think we find an environment that can’t support life, we’re proven wrong. So while I can’t guarantee that there is life on other planets, I’d say it’s probable. Life finds a way.

Sliding Scale

Much like I talked about in my Powers of Ten post, it’s very difficult to really understand how small some things are. This website does the best job of any that I have found to truly show you the sizes. If you scroll down to the bottom of the picture, you’ll see a slider. Slide it to the right to go down in size.

Sliding scale cell size

How many

How many...

times will your heart beat in your lifetime? About 2.5 billion

pounds of food will you eat? About 60,000 - 100,000.

calories does it take to run a marathon? About 2,000, which is the same amount it takes just to keep you alive for one day.

times will you breath? About 473 million times

miles will you walk in your lifetime? About 100,000. That's 4 times around the Earth.

times will you be in a traffic accident? The average is once.

times a day should you go to the bathroom? Once for #2. For #1, it depends on how much you drink.

times do you blink a year? About 10 million

people are in the world? As of 10am on March 24, 2010 it was approx 6 billion, 996 million, 70 thousand

people have your name? Well there are 11 people with my name.

Quick Comment

I'm very amused that the ads on this site are currently for Virgin Galactic "an accredited space agency". Yay future!

How big is the Sun?

BIG. No, bigger than that. Seriously, it’s almost unimaginably big.

It’s made of hydrogen and helium, the two smallest and lightest elements. And yet the Sun is 99% of the mass of the Solar System. All the rock of the Earth, Mercury, Venus, Mars, and the asteroids, PLUS all of the gas of Jupiter, Saturn, Uranus and Neptune, PLUS the ice of all of the comets and Kuyper Belt objects, including Pluto and Eris, is only a measly 1%.

You could fit 1.3 million Earths inside it.

It’s 4.4 million km in circumference. The average human walks at about 4.4 km per hour, so it would take you 1 million hours to walk around it. That’s 41,667 days. That’s 114 years, nonstop 24/7 walking.
The Sun sometimes sends out huge bursts of material, called solar prominences. Here’s a nice one.

But how big is this compared to the Earth?

Great website with pictures of the Sun.

Got Questions?

Do you have any questions that you'd like answered? Something that you've always wanted an answer to? Feel free to post in the comment section and I'll do my best to answer it for you!

I Wanna Go To Space!

We are one step closer to real space tourism. On Monday March 22, 2010 the Virgin Galactic spaceship Enterprise (geek love for that name). successfully completed its first captive carry flight. with its launch vehicle/mothership Eve.

This all started with the X Prize - $10 million to the first privately built craft to safely carry a human pilot into space twice. Virgin, the parent company of Virgin Airline, sponsored Burt Rutan. If you don't know Rutan, I'll just say that if you a new and innovative design to do things no other plane has done before, you go to Rutan.

No surprise, his design which featured a launch vehicle (WhiteKnightOne) that flew up to about 50,000 feet, then released the spacecraft, SpaceShipOne, was the winner.

Rutan redesigned things for commercial flight, making the new spacecraft design (called SpaceShipTwo) able to hold 6 passengers. Tickets are available for $200k, with deposits as low as $20k currently being accepted.

Anyone feel like loaning me some money?

Virgin Galactic's website.

Which came first, the chicken or the egg?

All the evidence we have indicates that birds are descended from dinosaurs. In the 1800’s Thomas Huxley noted that birds have skeletons that are almost identical to some dinosaurs, other than the beak, of course. There are some striking anatomical similarities.
But if I asked you to tell me what makes birds different from all other animals, I’m guessing you’d tell me feathers. So how can we say that birds are descended from dinosaurs? Where did the feathers come from?
Well, it turns out that there were feathered dinosaurs! How do we know? Because we’ve found fossils with feathers.
So we have critters that aren’t birds, but that have skeletons very similar to birds. With feathers. And of course reptiles lay eggs. As time goes on, they get less and less like reptiles and more and more like a bird, until we end up with something almost, but not quite, a bird. It laid an egg in which the final mutation had occurred, and from which the first bird hatched. So our answer is – the egg!
Or you could go to a restaurant and order two sandwiches, egg salad and chicken salad, and see which comes first. :P

Momentum

Momentum is the tendency of a moving object to keep moving. You can find the momentum of an object by multiplying its mass times its velocity. In other words, heavy things, and things going fast, have a lot of momentum. A heavy thing that is also going fast have LOTS of momentum. Things with a lot of momentum have a hard time slowing down.

Why should you care? Because trains and large trucks have a LOT more momentum than your car.

Respect the momentum of a truck.
The average freight train takes over a mile to stop.

Equinox

Tomorrow is the Equinox, when the amount of daylight and the amount of darkness will be equal. It's the first day of Spring.

The seasons are NOT caused by the Earth getting closer or further away from the Sun. There ARE times when we are a little bit farther away from the Sun; that happens during the summer in the Northern Hemisphere, so that can't be the cause of winter. Also, the seasons are the opposite in the Southern Hemisphere - right now in Australia they're getting ready for fall. And at the Equator, there aren't really any seasons at all. It's warm all of the time. If we had seasons because we got further away or closer to the Sun, then the whole Earth would have the same seasons.

The reason we have seasons is because the Earth is tilted. This means that during some parts of the year, your hemisphere is pointed towards the Sun, and at other parts, it's pointed away. When your hemisphere is pointed towards the Sun, more sunlight falls on each square meter. This makes it warmer and brighter. You've probably noticed that summertime is not only warmer, but brighter too. Now you know why!

When your hemisphere is pointed away from the Sun, less sunlight falls on each square meter. So it's colder and not as bright. That's why even a sunny winter day isn't as bright as a summer's day.

In addition, because of the tilt, during the winter time your hemisphere spends more time in the dark shadow of the Earth on the side opposite from the Sun. That means that the night time is longer. But it's the opposite in the Summer. So right now, every night is a little bit shorter and each day is a little bit longer, about 2 minutes on average. Nights keep getting shorter and days keep getting longer until one day, night is equal to day. "Equi" means "equal" and "nox" means "night". So the equinox is when the day and night are equal in length. After tomorrow, days will be longer than night. They will keep getting longer until the Solstice, which I'll talk about in June.

Bill Nye song about the seasons

Powers of Ten

I was listening to my Schoolhouse Rocks CDs yesterday, and heard "My Hero, Zero" again for the first time in a long time. Most of us learned in school that if you put a zero after a number, you've multiplied it by 10. And if you take a zero away, then you've divided the number by 10.

This is what leads us to scientific notation. 10⁴ means 10 times itself 4 times, or 10 x 10 x 10 x 10. Well the easy way to do that is just to write a 1 followed by 4 zeros, 10000.
10¹ = 10
10² = 100
10³ = 1,000
10⁴ = 10,000
10⁵ = 100,000

So 2 x 10⁴ means that you take 10 ⁴ and then multiply it by 2, or 2 followed by 4 zeros (20,000).
7 x 10⁴ = 70,000
4 x 10⁴ = 40,000
6 x 10³ = 6,000
3 x 10² = 300
8 x 10⁵ = 800,000

And if that superscript number is negative, you're talking about fractions. 2 x 10^-4 is 1/20000.

Okay, so you can do scientific notation, but what does it all MEAN? I can tell you that a human blood cell is 8 x 10 ^-6 meters small, but you probably don't really understand how small that is. Or I can say that the Sun is 1.5 x 10¹¹ meters away, but you probably don't get how big that is. So here is a great video that shows you exactly what all of those numbers mean.

Powers of Ten video
Powers of Ten website

A St. Patrick's Day Parable

Why are there no snakes in Ireland? Well, actually many islands have no snakes. It all depends on whether the island is volcanic (was formed by a volcano on the sea floor that grew until it broke the surface) or continental (broke off from a continent).

Volcanic islands, like Hawaii, rise up out of the sea as bare rock. Only plants and animals that can be blown there (small seeds, flying animals) or cross the sea on floating natural rafts of vegetation (coconuts, small reptiles) will colonize the new island. So volcanic islands rarely have snakes, unless they formed very close to another land mass, close enough for snakes to survive on rafts.

Continental islands are another story. When they break off, they carry with them all of the plants and animals that are on them at the time. Continental islands often give us a snapshot of evolution in progress. Madagascar broke off from Africa before monkeys evolved, so there are no monkeys on Madagascar. This allowed the lemurs to survive on the island, whereas on the mainland they were outcompeted by the monkeys and died out. In the same way, Australia broke off from a supercontinent after marsupial mammals had evolved but before placental mammals.

Once the island breaks off, it has its own story. In Ireland, the Ice Age came along and killed off anything that couldn't survive the cold, such as many reptiles. The same thing happened on the continent. However, on the continent, once things warmed up, snakes could migrate back from the warm places further south where they had survived. But they couldn't cross the cold sea to recolonize Ireland.

A better written, longer version of this, and the article that gave me the title of today's post.