What Makes a Star Blue?

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Albireo is the distinctive double star in the head of the constellation Cygnus. You can find it yourself if you look for the Summer Triangle amid the dusty trail of the Milky Way across the night sky.

The brighter, orange star of Albireo is a K3-class bright giant. That means it’s just a few thousand Kelvins (Celsius degrees plus 273) cooler than the sun. But it’s also larger—70 times the sun’s radius—and that makes it brighter than you would expect.

The blue star, on the other hand, is a B8-class dwarf. It has only about 3.5 times the sun’s radius, although it’s hotter by about 7422 Kelvins.

Neither star in Albireo is particularly unusual. There are doubtless millions, even billions, of other stars similar to each one. But Albireo certainly offers us the most striking contrast. Bright blue and red stars don’t often appear so close together.

But what exactly gives these stars their distinctive colors? Continue reading

How Lightning Strikes

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There’s a saying that “lightning strikes whatever’s tallest.” But this is only partly true. Tall objects do attract lightning bolts, but there’s a second condition for lightning to strike: electrical conductivity.

Meaning, a lightning bolt will only strike an object that can become electrically charged.

There’s another common misconception out there, though the Google search I did reveals that knowledge of the truth is comfortingly widespread. If you were to catch sight of a lightning bolt, would you say it strikes upward or downward?

That is, does lightning start at the ground or in the clouds?

I heard from multiple reliable sources that lightning strikes from the ground up, but the video you’ll see below would seem to contradict that. I wasn’t satisfied with the results of my search, so I did some more digging.

Continue reading

What Causes the Lunar Phases?

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We see it almost every night of our lives. For thousands of years, the greatest philosophers and astronomers alike have watched its face change and wondered why.

Step outside and observe the moon every day for a month and you will notice something fascinating. Over the course of the entire month, the moon will go through an entire cycle of phases—no more, no less.

But why?

The phases of the moon are something I’ve talked about before, but I wanted to spend some time on a few common misconceptions this time around and show you the truth behind the lunar phases. Continue reading

Life vs. Rocks: What Makes Them Different?

Welcome to my third “Science Answers” post! About a month ago, I sent out a post requesting science questions from all of you; you can find it here. This post addresses the third of the questions I was asked. If you have a question, you can ask it in the comments here or on that post, or ask it in an email. Or find me on Facebook!

Q: What is the division between the physical and life sciences? For example, why do we think of rocks in a different category than we do plants and animals? (asked by Katherine)

Okay, wow. Another great question! This one is almost as fundamental as gravity, which I answered earlier.

Gravity may be pretty much the singular reason why the universe works the way it does, but the difference between the physical and life sciences is an important distinction when trying to understand the world around us.

So let’s start with what we know. When you hear “physical science,” what do you think of?

 

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You might think of any number of things—but I’ll bet you that none of those things are alive in the traditional sense.

So, how about the biological sciences? What does that make you think of?

 

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Maybe plants…or cute animals?

Whatever you think of, I’m going to guess they’re all alive.

But what makes something alive or not alive? What makes zebras leap and run, whereas rocks are forever immobile? What makes these living beings different from a vast galaxy or the Pillars of Creation? Continue reading

What is Gravity, Anyway?

Welcome to my second “Science Answers” post! About a month ago, I sent out a post requesting science questions from all of you; you can find it here. This post addresses the second of the questions I was asked. If you have a question, you can ask it in the comments here or on that post, or ask it in an email. Or find me on Facebook!

Q: What is gravity? (asked by Simon)

Wow…great question. This is a question the greatest scientific minds have asked and tried to answer for centuries. It’s a question not even Stephen Hawking, the scientific genius of the century, has fully answered.

There are a few parts to the gravity question, and they have each been addressed one by one over time:

  • How does gravity work?
  • What is gravity?
  • Why does gravity work?

Isaac Newton stood on the shoulders of the giants before him—Aristotle, Ptolemy, Copernicus, and Kepler—and figured out how gravity works. But he was at a loss to explain what exactly this mysterious force was.

Einstein built on Newton’s work and came up with a theory for what gravity is—that is, distortions in space-time.

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We have yet to understand why gravity works. Why is space-time warped? Why do objects distort it as if it were the material of a trampoline? What exactly is the nature of space?

But, lucky for me, the question above specifically asks what gravity is. And that, I can explain.

The best way to do that is to turn one of gravity’s oldest tricks, one that has perplexed scientists and philosophers for thousands of years: What makes the planets move? Continue reading

The Secrets of Magnets

Welcome to my first “Science Answers” post! About a month ago, I sent out a post requesting science questions from all of you; you can find it here. This post addresses the first of the questions I was asked. If you have a question, you can ask it in the comments here or on that post, or ask it in an email. Or find me on Facebook!

And by the way…I do apologize for getting this post out so late. But here you are.

Q: What is magnetism? And what’s the difference between electromagnetism and the “magnetism” found in minerals? (asked by Simon)

So…let’s start with something most of us are familiar with.

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Can I just say, I’ve never seen a fridge with so many magnets?

Usually, the magnets in our lives serve practical purposes. In your typical household, these fridge magnets would be used to hold up notes, photos, recipes, etc. that you’d want to display in your kitchen.

(Of course, magnet collecting is a perfectly reasonable hobby, if the sheer variety on this fridge is any indication.)

Magnets are something we take for granted. But they are even more a part of our lives than we realize. Continue reading

Science Questions, Anybody? (#1)

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I want to try out something new. Up until now, for every post on this blog, I have chosen a topic and written about it in the hopes that you’re curious about it.

This time, I want to know what you are curious about.

You’re welcome to ask any question about science. No matter what it is, I will do my best to answer it. If I don’t immediately know the answer, I’ll research it. And remember—there are no stupid questions, only stupid answers.

Just leave your question in the comments below. If you’re not a WordPress user, you’ll need to enter your name and email address, but I’m the only person who will ever see your email.

I will answer every question that’s asked. Depending on how many there are, I’ll either answer them all in a post coming up soon, or I’ll answer one in each of a series of posts to be published over the next few days.

If you think you know the answer to your question but aren’t quite sure, you’re still welcome to ask it—and even let me know what you think the answer is! I’ll make sure to point out what you’re right about when I answer your question.

I’ll also reproduce the question and credit you (the name you use in the comment form) for asking it. Then I’ll answer your question in detail. If anything’s still not clear afterwards, you are welcome to comment again or email me.

All answers will be archived on my “Myth & Science” page, underneath the “Science Answers” drop-down menu.

I’ll keep comments open for a few weeks. But if you miss out on this first “Science Questions, Anybody?”, don’t worry about it. I’ll do this again sometime soon.

Questions, anyone?

Update 5/11/18: You can now submit questions through the form on my “Got Questions?” page up in the menu. The guidelines are the same: anything you’re curious about, I’ll answer. There are no stupid questions, only stupid answers. I look forward to hearing from you!

Evidence vs. Belief

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I remember something my ninth grade advanced biology teacher told our class. It was essentially a story about an invisible dragon.

Now why, you ask, would a biology teacher teach us about an invisible dragon?

Her message had nothing to do with the dragon, and everything to do with the lengths one of the story’s characters went to in order to disprove the dragon’s existence. Her intention was to help her students distinguish between evidence and belief.

On a broader level, her intention was to show us the difference between science and religion. See, back when I was in eighth and ninth grade, there seemed to be a lot of controversy in schools surrounding science and religion.

Teachers of students that age felt the need to preempt their entire class with a disclaimer—that students were still free to believe whatever they believed, no matter what science the class taught.

Most teachers just made a general announcement on the first day. But my biology teacher told us this story about a dragon—and it continues to impact me to this day.

It goes like this: Continue reading

The Reason for the Seasons

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As a born Californian, I never saw seasons this dramatically until I went to college in Flagstaff, Arizona.

I remember, in my first year here, when I was taking a walk around campus with a few friends. We passed over a riverbed where water was gently trickling along. Green grass and brush lined the banks. The sight absolutely captivated me. I had never seen anything like it, even in the springtime.

Then winter hit in all its blizzarding glory. At night, the temperature dropped below freezing. Snow fell in flurries that contrasted beautifully with the night. By morning, snow banks over a foot high lined the footpaths. To say nothing of the state of my winter jacket!

Summer in Flagstaff is hot. And I mean hot. It’s sweltering. Everyone crowds under the nearest tree. I experienced two days of it during orientation, and I never want to be here in the summer again.

Flagstaff’s autumn isn’t quite like the red and golden season depicted above. It pours. The rain sweeps down from the skies in torrents, soaking you through to the bone within minutes of being outside. Don’t think you’re safe under an umbrella. Better get some waterproof slacks to cover up those jeans, or you’ll be freezing in your classes all day.

I remember learning that my good blogging friend, the Momma, experiences the opposite seasons. When it’s pouring over here, it’s all green and sunny in Australia. When it snows here, she’s getting summer—I only hope it’s not as sweltering as it is in Flagstaff!

But why? Why should Australia have seasons that are opposite those in America? Continue reading