Expert Voices Paul Sutter

The growing problem of space junk poses a risk to future space missions, but the solution isn't going to be easy.

A pair of astronomers have proposed two new strategies for preventing possible asteroid impacts.

If you were to place a galaxy behind the black hole and then look off to the side, you'd see a distorted image of the galaxy. Here's why.

You may have heard about the "cosmology crisis:" Different methods of measuring the age of the universe are giving different results, and cosmologists have no idea why.

The earliest and most momentous epoch in the history of the universe released a flood of gravitational waves, tiny ripples in the fabric of space-time.

A wild variety of star systems exist in the nearby regions of the Milky Way, and astronomers are eager to know where they might find an "Earth 2.0."

Astrophysicists say our universe might be shaped like a three-dimensional donut, meaning you could point a spaceship in one direction and eventually return to where you started.

Despite numerous attempts, astronomers have not yet confirmed the detection of an exomoon, a moon orbiting a planet around a distant star.

Theories that attempt to resolve the so-called black hole information paradox predict that black holes are much more complicated than general relativity suggests.

With its frigid temperatures, remoteness from the sun and general dustiness, changing Mars to be more Earth-like is more challenging than it seems (and it already seems pretty tough).

If you'd like to "bake" a universe, you need two essential ingredients and one optional ingredient.

New research shows how a hypothetical form of dark energy might be made inside the sun and could be detected here on Earth. In fact, we may have already seen it.

The supermassive black hole in the center of our galaxy may not be a black hole at all, but rather a fluffy ball of dark matter called darkinos.

Space is big — really big. And if you want to successfully navigate the interstellar depths of our galaxy, you're going to need some sort of reliable system.

Many theories of the early universe predict that the cosmos should be flooded with cracks in space-time, called cosmic strings, but no cosmic strings have been detected yet.

For decades, cosmologists have wondered if the large-scale structure of the universe is a fractal — that is, if it looks the same no matter how large the scale.

What's beyond the known limits? What lies outside the boundary of the universe? The answer is … well, it's complicated.

Physicists have long been unable to describe what happened just after the Big Bang when a teensy blip ballooned into the universe, a process called inflation. We may know why.

For years, astronomers thought that the objects responsible for short gamma-ray bursts get kicked out of their home galaxies shortly after they're born. But new observations prove otherwise.