After more than two decades of precision measurements, we've now reached the "gold standard" for how the pieces don't fit.

After decades of development, whether NASA's Webb succeeds or fails all comes down to five critical milestones that are only days away.

Every December, the Geminid meteor shower reaches its peak. Its 2021 show will be spectacular, but only if you do it right.

Our Solar System's outer reaches, and what's in them, was predicted long before the first Oort Cloud object was ever discovered.

Previously, only the brightest and most active galaxies could pierce the obscuring wall of cosmic dust. At last, normal galaxies break through.

We should all pause to appreciate the awe-inspiring beauty of the Universe.

The stars, planets, and many moons are extremely round. Why don't they take other shapes?

From hellishly hot planets to water worlds, some distant planets are like nothing in our Solar System.

Finding out we're not alone in the Universe would fundamentally change everything. Here's how we could do it.

The most unique interloper into our Solar System has a natural explanation that fits perfectly — no aliens required.

We haven't seen a partial eclipse lasting this long since 1440, and won't again until 2669. North America is perfectly positioned for 2021's.

Based on the atoms that they're made out of, the innermost planet should always be the densest. Here's why Earth beats Mercury, hands down.

There are over 100 known elements in the periodic table. These 8 ways of making them account for every one.

But the upcoming James Webb Space Telescope compels us to add, “so far.” Beginning with its 1990 launch, NASA’s Hubble Space Telescope revolutionized our conception of the Universe. This photo of […]

How the search for alien life is taking place right here in our own Solar System. If you want to understand the origin of life in the Universe, you have three […]

The highest-energy particles of all come from space, not human-made colliders. When it comes to the most energetic particle collisions of all, you might think that the Large Hadron Collider […]

Without these two elements, we’re doomed to fail. In this day and age, it’s virtually impossible to have sufficient expertise to figure out what the complete, comprehensive, scientifically validated truth surrounding […]

Whatever’s lurking out there, it isn’t all, or even mostly, normal matter. When it comes to the Universe, it’s only natural to wonder what, exactly, it is that makes everything up. […]

“Hubble’s Law” is only an approximation, and breaks down when we need it most. From anywhere in the Universe, you can choose to look out at any other galaxy that’s present. […]

It happened more than once, and needed to. Here’s why. If there’s one thing you can be certain about when it comes to outer space, it’s that it’s transparent, not opaque, […]

Both made monumental contributions that were far ahead of their time. It’s hard to believe, but the idea that the Universe was dominated not by normal matter but rather by dark […]

Hubble, our greatest space-based observatory today, is just the beginning. The Hubble Space Telescope has been astronomy’s most revolutionary observatory in history. The stars and galaxies we see today didn’t […]

Galaxies can have regions both hotter and colder than the background radiation of the Universe. When we talk about the depths of space, we get this picture in our heads […]

Theoretically, we know what happened on the red planet. Here’s how we’ll find out whether we’re right. When it comes to the worlds beyond Earth in our Solar System, it’s only […]

We’ve already observed three cases where it’s happened. When you look at an object in space, it’s pretty easy to tell if it’s a star or a planet. Stars are […]

It could evolve, strengthen, decay, or not be alone. Our known Universe contains matter, radiation, and dark energy. While matter (both normal and dark) and radiation become less dense as […]

And the one step we can take to show extraterrestrials we’re figuring it out. Every year, Earth’s meteor showers accomplish two important tasks. This composite photograph shows a large number of […]

The ‘final parsec problem’ is still a mystery for astronomers. When it comes to black holes in the Universe, we know there are at least two major types. There are […]

It peaks the nights of August 11–13, but it’s no longer the year’s most reliable meteor shower. Every year, beginning in mid-July, planet Earth commences passing through an enormous debris […]

At 35 light-years away, it’s also the 2nd coolest, 2nd widest planet ever found. Despite discovering more than 4000 exoplanets, most remain obscure. Although more than 4,000 confirmed exoplanets are known, […]