Astronomers have discovered that the clouds of gas and dust—the interstellar medium (ISM)—found between the stars are made of the same materials as the stars themselves. In fact, hydrogen is the most common element in both stars and the ISM, followed closely by helium.
But it would be more accurate to say that stars are made of the same material as the ISM, not the other way around.
This is because all of the stars formed out of material in the ISM at some point millions to hundreds of billions of years ago. And when they die, they return that material—what’s left of it—to the ISM.
If you’ve had the opportunity to observe the night sky from a dark place, far away from the light pollution of the city, on a clear night, you might have seen this before. It’s the Milky Way—our view of our galaxy from the inside.
It’s kind of like if you lived inside a frisbee. Look up toward the flat sides, and there’s not as much material to look through. But peer out at the edges of the disk, and you have to look through a lot more stars.
Most of the stars you see in the night sky are part of the Milky Way. But this is the sight we get when we stare through to the center of the frisbee.
Thing is, though, this is far from the most spectacular sight of the night sky. Continue reading →
If you’re from a larger city and haven’t had the opportunity to venture into a place like the desert, you might not know what you’re looking at. That’s the Milky Way, our name for our galaxy.
Inside this galaxy are billions of stars, including our own. Galileo Galilei was the first to discover that it was really many tiny points of light, not just a cloud-like haze across the dark night sky.
We can’t see our galaxy from outside, but we can learn a lot about it by looking out at it from within. It’s difficult. It’s like trying to learn about a building if you can never step outside one of its rooms.
Albert Einstein’s name literally sends shivers down my spine.
This is the man who discovered physics as we know it. This is the man who filled in the gaps where even Newton’s laws of motion went wrong and expanded our understanding of the universe.
This man was a genius in every right—even if his social skills were somewhat lacking.
By the way…I can’t help but notice this is my first post with actual photographs of the scientist in question, instead of portraits. We’re moving along, people…
So. To the point. Einstein is famous for taking revolutionary and widely accepted laws of physics—those that Newton figured out—and showing where there were some holes in the math. But Einstein wasn’t just an annoying critic.
He took it all a step further…and showed us how physics really works.
In the 4th century B. C. E. (Before Common Era), scientists believed the Earth was the center of the universe. Before that, they were convinced the Earth was flat.
Now, most of us know that the Earth is not the center of the universe—nor is it flat. (Although there are definitely those who still believe we live atop a flat disk world, hurtling upwards through space.)
Not only is the Earth not the center of the universe, neither is the sun—and it’s not even the exact center of our solar system (you can read more on that here).
And if we zoomed out much farther and took a look at our galaxy from above—or below, take your pick—we’d find that the sun is not even near the center of its own galaxy.
It is, in fact, located in a small “spur” of stars just off one of the spiraling arms of the galaxy. And if our universe is in fact infinite—as the prevailing theory describes—then there can’t even be a center, so our galaxy is not the center of anything.
But what does all of this mean? Where exactly are we in the universe?