Ask an Astronomer

Where Is the Center of the Universe? (Ask an Astronomer)

Dr. Varoujan Gorjian explains the mind-boggling expansion of the Universe.

W-5 Star-Forming Region (What Is It?)

Visit the W-5 star-forming region with 'Ask an Astronomer'!

Why Is the Sky Blue? (Ask an Astronomer)

In this 'Ask an Astronomer' episode, Dr. Carolyn Brinkworth fills us in on what the color of the sky has to do with finding life on distant planets.

What's Between the Stars? (Ask an Astronomer)

In this 'Ask an Astronomer' episode, Dr. Michelle Thaller explains how there can be an interstellar medium in a vacuum.

Spitzer Turns Five (Ask an Astronomer Special)

This 'Ask an Astronomer' special looks at some of the biggest discoveries from NASA's Spitzer Space Telescope over the last five years.

What Will Happen to the Earth When the Sun Dies?

Our Sun won't last forever. Dr. Carolyn Brinkworth explains the ramifications for our home planet in this 'Ask an Astronomer' video.

"Can a planet have two suns?" (Ask an Astronomer)

Dr. Carolyn Brinkworth addresses a famous science fiction scenario in this 'Ask an Astronomer' video.

"Can a galaxy die?" (Ask an Astronomer)

Dr. Varoujan Gorjian gives us the answer to this 'Ask an Astronomer' question.

"Why aren't there any green stars?" (Ask an Astronomer)

Dr. Michelle Thaller answers this question for 'Ask an Astronomer.'

"How do you discover an asteroid?" (Ask an Astronomer)

Dr. Bidushi Bhattacharya helps us understand how astronomers find these tiny space rocks.

Infrared: More Than Your Eyes Can See

Dr. Michelle Thaller explains infrared light in this older video, produced by NASA's Spitzer Space Telescope (then known as the Space Infrared Telescope Facility) before

M51 and Gizmo in "Half-Baked Plan"

In this animated 'Ask an Astronomer' special, innocent alien M51 moves the Earth into a closer orbit around the sun, and learns an important lesson about life in the Univ

"What happens when galaxies collide?" (Ask an Astronomer)

Dr. Varoujan Gorjian takes us inside galactic collisions in this 'Ask an Astronomer' video.

"What is the nearest galaxy to the Milky Way?" (Ask Astron.)

Dr. Michelle Thaller explains that the answer isn't as simple as you might think!

"Why isn't Pluto a planet anymore?" (Ask an Astronomer)

Dr. Robert Hurt explains why Pluto got... well... plutoed.

"How can we see a black hole?" (Ask an Astronomer)

If no light escapes from a black hole, how can we detect them? 'Ask an Astronomer' explains.

"What is a redshift?" (Ask an Astronomer)

'Ask an Astronomer' uses an astronomer, a flying saucer, and a cow to help explain this difficult astronomical concept in simple terms.

"Do the stars really move?" (Ask an Astronomer)

The answer to this 'Ask an Astronomer' question may surprise you!

"Why do we see spiral arms in some galaxies?" (Ask an Astronomer)

'Ask an Astronomer' explains the morphology of one of the most common types of galaxy.

"Why are solar eclipses only visible in some places?" (AaA)

This 'Ask an Astronomer' episode explains eclipses of the sun and why they can't be seen everywhere.