Astronomy

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What is the Milky Way?

Sunday, May 25th, 2008

 
If you ever find yourself far removed from the light pollution that saturates the city and suburban skies, take a look at the night sky and prepare to be impressed. Those of us who spend most of our lives in and around cities are often awestruck by how many stars there are out there once […]

What is a galaxy?

Wednesday, May 21st, 2008

A galaxy is a massive collection of stars gravitationally bound around a common central core. It is believed that most, if not all galaxies have at their core a super massive black hole - a black hole coming in at hundreds of thousands or billions times more massive than our own Sun.
Speaking of our own […]

What is a Black Hole?

Monday, May 19th, 2008

From some of my previous posts you know that objects don’t just have size, they have mass. A three-foot diameter ball of loosely packed feathers, for example, has far less mass than a three-foot diameter ball of lead. But if you keep compressing feathers into that three-foot sphere, keep squeezing and squeezing them in, you’ll […]

What is the closest star to the Earth

Wednesday, May 14th, 2008

We’ve already answered in a previous post that the Sun is the closest star to the Earth, but when most people ask this they’re really asking, what is the closest star to the Sun. The closest star to the Sun is Proxima Centauri at 4.2 light-years away.
Interestingly, most folks often think of Alpha Centauri as […]

How long is a light-year?

Monday, May 12th, 2008

You might be surprised to know that a light-year is just one normal Earth year long (a Julian year of 365.25 days)! Confused? Think of it this way, a light-year isn’t a measure of time, but a measure distance within a certain amount of time (a year).
If you’ve kept up with all my other posts on space, you’ll know […]

What is the speed of light?

Saturday, May 10th, 2008

After years of “close” estimates, the speed of light was nailed down to 299,792.458 kilometers per second or 186,282.397 miles per second in 1983. Previous estimates came surprisingly close to the mark given how difficult it must be to put a limit on something as fast as light. We also know that the speed of […]

How big is our solar system?

Wednesday, May 7th, 2008

Measuring the dimensions of our solar system brings up a question of preference. Are you interested in the diameter from the Sun to the outermost planet? To the innermost edge of the Kuiper Belt? To the outermost edge of the belt? To the Oort Cloud? Would you fully grasp the true scale even were I […]

What is an Astronomical Unit? How big is an Astronomical Unit?

Wednesday, May 7th, 2008

When dealing with measurements on an orbital scale, you have to think big. As my previous astronomy posts have shown, the distances are vast. Though humans see and use numbers like million, billion and trillion all the time, our brains have a tough time conceptualizing what those numbers really translate to. How often, for example, […]

Are black diamonds rare? Are they expensive?

Friday, May 2nd, 2008

What is this question doing in the middle of my Week of Astronomy? Well, stay with me and you’ll find out! Kathleen of Virginia asked this one, maybe as a hint to her husband?
Kathleen – Black diamonds, also known as Carbonado, are indeed rare in the same sense that any gem is relatively rare compared […]

What is a solar system?

Friday, May 2nd, 2008

With all this talk about stars, planets and moons in previous posts, it’s about high time I mentioned a solar system. A solar system is exactly what the name implies - the system associated with a sun (star). Our own solar system contains 8 planets. We once had nine but the planet Pluto was downgraded […]

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