The Milky Way

The Milky Way is not just a super delicious chocolate bar, it's also the name of the galaxy that we live in. If you've ever been in a very dark place, you might have seen the dust towards the galaxy's center crossing through the night sky like the picture below.

The Milky Way is classified as a barred spiral arm galaxy. This means it has arm like structure (~5 arms), and a bar of material crossing through the center. It's about 13.2 billion years old and 100,000 light years wide. This means that if you traveled at the speed of light, it would take 100,000 years to get from one end to the other! At the center, we think there is a super massive black hole, but don't worry, we won't get sucked in anytime soon! Near the sun, the galaxy rotates at ~220 km/s, which is close to 500,000mph! Are you dizzy yet?

We aren't 100% certain about our galaxies structure because we can't take a picture of it. That would require sending a telescope way above the galaxy, which is something we are not capable of doing. But we think our galaxy looks similar to the many other spiral galaxies that exist. Below is an artists impression of the Milky Way.

Next Topic: NASA discovered an "alien"!


Image credit: Mark A. Garlick

Why Is Pluto No Longer A Planet?

As I'm sure most of you know, in 2006 the International Astronomical Union (IAU) demoted Pluto to the status of dwarf planet. That is unless you live in Illinois, where in 2009 the government decided to legally classify Pluto as a planet and make March 13 Pluto day. (And guess where the guy who discovered Pluto was from…. Illinois!)

To be a planet, the object must fit three criteria:

1. The object must orbit the Sun (Pluto does this)
2. The object must have enough gravity to pull it into a spherical shape (Pluto looks round, so that's ok)
3. The object must clear out the area immediately surrounding it (yeah… not so much)

Number 3 is the kicker. Pluto is part of what we call the Kuiper Belt; a collection of tens of thousands of small objects that orbit the outermost part of our solar system. All the other planets have nothing (except maybe some moons) near them. Pluto, on the other hand, has thousands of objects, some smaller some bigger, in its near vicinity. So this put the IAU in a tough spot. They either had to demote Pluto, or name and classify thousands of other round objects in the Kuiper belt as planets. I don’t know about you, but I'd prefer not to have to memorize a thousand planet names! But I still feel bad for Pluto.

Next Topic: A Bit About The Milky Way

Our Friend, The Sun

We take for granted that the Sun rises and sets everyday, provides us with warmth, and basically keeps us alive. But not too many people really know what the sun is, so today I present a few fun facts about our friend, the sun.

This is what the sun looks like right now (technically at 9:45 am this morning if you're on the east coast). The picture was taken by the Solar Dynamics Observatory, a solar telescope that is in orbit around the Earth. Our sun:

1. Is an average star, in astronomical terms
2. Is 150,000,000 km ( 93,205,678.8 miles) away
3. Is 1,400,000 km (869,919.6 miles) wide
4. Weighs 2,000,000,000,000,000,000,000,000,000,000 kg (4,400,000,000,000,000,000,000,000,000,000 pounds)
5. Has a surface temperature of ~5700K (9800.6 ºF)
6. Is made of 74% hydrogen, 25% Helium, 1% other elements
7. Is about the same density as water (It would float in a gigantic pool of water!)

 
Fun fact: It takes about 8min for the sun's light to reach earth. So if the sun suddenly blew up or vanished, it would be 8min before we even had a clue!

Next Topic: Why is Pluto not a planet? 

Image credit: SDO/AIA, NASA

 

Earth From Mars

In keeping with the "you are here and you're really small" theme, I thought I'd show one of my favorite pictures of all time.

This is an image take by the Mars Exploration Rover Spirit just before sunrise on the planet Mars. Spirit is a robotic instrument that has been doing science and taking pictures on Mars since January 2004. That little white spec that's enlarged in the inset image is Earth. (I swear I'm not pulling your leg, it's really Earth!) . We look just like a star in the night sky from Mars' perspective, just like Mars looks like a little red dot from Earth.

Now how tiny do you really feel?

Next Topic: Our Sun (I promise this will be a more upbeat one, no more feeling itty bitty!)

Image credit: NASA Goddard Photo and Video's photostream, flickr

How Small Are We?

One common misconception people have is how small we really are when compared to other objects in the universe. When you think of the sun, you think of a really big ball of gas. But how big do you picture it? Is it twice the size of earth? 10x the size? Can you even see earth if you drew the sun and earth to scale on a piece of paper? This video (~2min long, click the picture below) helps convey how small we really are, and has some awesome dramatic background music to set the mood! It starts by showing you the planets (in size order, not order from the sun) and continually zooms out to bigger and bigger objects. Everything after the sun is a star astronomers have discovered nearby in our galaxy.

Click image for video!

So were your ideas right? Or were you thinking the earth was much bigger than it actually is? It's amazing how small we are; just little specs of stardust on a tiny planet amongst billions of stars and galaxies waiting to be discovered.

Next topic: Earth from Mars

You Are Here -->

Do you know where you live? No, I don't mean what street you live on, or what city you live in. Where in the universe do you live? With all the great technology we have today, astronomers have a pretty good idea.

We live on planet Earth, one of 8 planets in our solar system. We orbit around an average size star, which is one of about 200 billion (that's right billion) stars in our galaxy the, Milky Way. The Milky Way is a spiral galaxy, which just means it has "arms" that form a spiral shape. We don't know exactly what the Milky Way looks like, but we  have figured out that the Milky Way has 4-5 "arms" that rotate around a black hole (Oh yeah, a black hole!) at the center. The Milky Way probably looks something like the image above. We live about halfway between the center and edge of the galaxy inside one of the spiral arms. (P.S. We are so small that that little red dot on the image covers up us, plus every single star we can see when we  look outside at night!)

Now go ask a friend where they live, and when they start to give you their address, stop them and ask them what their "universe address" is! See what sort of answers you get.

Image Credit:  http://www.clarkplanetarium.com/blog/cosmic-quiz-question-the-farthest-galaxy

Next Topic: How small are we?

The Reason

Welcome to the first “lesson” of Astro Did You Know? (ADYK), the fun new website/blog I've created to teach anyone of any level about astronomy!

From my teaching experience, I've found that many people find astronomy fascinating, but feel it's too difficult to learn or keep up with. Well I'm here to tell you that astronomy isn't easy, but you sure don't have to be a Rocket Scientist to understand it! (Pun intended) The more teaching I do and the more I interact with people, the more I realize how little astronomy the world knows, and I want to change that.

I decided to start this blog in an attempt to teach you, the non-astronomer, all sorts of cool things about astronomy in a fun and interesting way. Through pretty pictures and short, simple explanations, you'll be an “astro-know-it-all” in no time!I bet you always wanted to know why Pluto isn't a planet anymore, or what a black hole really is. Well here is where you will learn all of that plus so much more!

Many postings will stem from a question I was asked, or a common misconception the public has about some topic in astronomy. I'll also try and keep you up to date with any new big astronomy events in the news (Like that “alien” NASA found a few months ago. What you didn't hear about that? Guess you'll just have to wait for the Astro Did You Know? NASA discovered an alien post!)

I hope you all enjoy this, whether your a student, friend, colleague, family member, or just someone who loves astronomy and wants to lean more. I'm sure you will learn lots of great new things, and find astronomy just as interesting as I do! (Or at least close to it!) And what did you learn from today? That anyone of any educational background can become an “Astro-know-it-all”!

From someone who has a passion for teaching, to you who has a passion for learning, I give you Astro Did You know?

Please, please, please give me your feedback! Post comments, ask questions, send me topic ideas, anything! If you hear something in the news or have always wondered about something in astronomy, let me know and I'll be sure to post it. Feedback of any sort is very welcome and can be sent to astrodidyouknow@gmail.com or posted directly on this site. Be sure to “like” and follow me on facebook as well!!