Radio Astronomy: Advantages


Whoa…what’s this thing?

It’s a radio telescope, the largest in the world. It’s so huge that a normal support system can’t support its weight. So it’s basically suspended between three mountaintops. It’s 300 m across, which is 1000 feet. It’s huge.

This is the kind of construction endeavor that radio astronomers must try if they want to get much detail from radio waves. The radio wavelengths of the electromagnetic spectrum are really, really weak. You need huge telescopes to collect enough.

But, as ever, astronomers face the same basic problem: money.

Huge telescopes are expensive. It’s unfortunate for astronomers, but true—just think of the cost of labor of basically burying a whole valley under a radio dish.

So why bother? Continue reading

Galileo and the Telescope


When you hear the name “Galileo Galilei,” what immediately comes to mind?

If you thought, “inventor of the telescope,” you’re not alone. I also wouldn’t be surprised if you thought “condemned by the Inquisition for believing the Earth orbited the sun.”

But neither of these are true. If you’ve been following my more recent astronomy posts, you probably realize why—in Galileo’s time, people already knew that the Earth moved around the sun.

The idea that he invented the telescope is more understandable…but, again, it’s not true.

So what is true about Galileo, and how did he contribute to our understanding of astronomy? Continue reading

The Ecliptic


The ecliptic, as astronomers call it, is the apparent path of the sun against the background of the stars in the sky.

It’s useful because it tells us how to find the planets in the sky. They can be hard to spot if you don’t know where to look, but they will always be somewhere along one imaginary line that arcs across the sky—the ecliptic.

This pattern never changes. The planets don’t follow the ecliptic exactly, but it’s useful for getting an idea of where they should be.

But why does it work—and what exactly does it mean, when it’s obvious we can’t see the sun among the stars of the night sky? Continue reading