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