The largest moon around our last planet didn’t originate with Neptune. When it comes to the moons of our Solar System, there’s only one planet that doesn’t fit in with our […]

It likely isn’t the rare occurrence we once thought it was. In our Solar System, there’s one overwhelming source of mass that all the planets orbit around: our Sun. Each planet […]

There are exposed planetary cores orbiting stars, and we may have already found them. When we take a look at the planets in our Solar System, there’s a pretty clear difference […]

For the first time in many years, there’s currently a comet visible to the naked eye in Earth’s night sky: comet NEOWISE. For the first time in many years, there’s currently […]

For northern hemisphere skywatchers, it might just be the century’s best comet so far. Every once in a while, large, icy objects pass through the inner Solar System. C/2014 Q2 (Lovejoy) […]

From the right place at the right time, it’s a sight unlike any you’ll find on Earth. In our Solar System, any planet with moons has a chance for a solar […]

This year’s June solstice coincides with a new Moon and an annular solar eclipse. Here’s how rare it truly is. As the Earth orbits the Sun, it rotates on its axis. […]

Find a clear western horizon after sunset, and this ‘triple treat’ of a dance can be yours. Every once in a while, the night sky provides a spectacular feast for our […]

There are three factors all competing to determine the fate of the Earth, and the one that’s winning now won’t win in the end. If you could measure the average distance […]

We’re not made out of the densest elements, but we’re the densest planet nonetheless. Here’s why. Of all the planets, dwarf planets, moons, asteroids and more in the Solar System, only […]

On the morning of March 31, 2020, these three worlds will be at their mutual closest in 20 years. For the past few weeks, Mars, Saturn, and Jupiter have all shone […]

It’s one of only five spacecraft that will exit the Solar System, and the only one we have a chance to aim at another star. Of all the spacecraft ever launched, […]

The NSF’s new, cutting-edge solar observatory shows us the Sun as never before. Here’s why we need to know. On December 12, 2019, the world’s most powerful solar observatory — the National Science […]

The Leonid meteor shower peaks today. Its parent comet taught us where meteor showers come from. Every year, as Earth regularly orbits the Sun, meteor showers repeatedly recur. While August’s Perseids […]

On May 9, 2016, the prior transit of Mercury occurred, and was photographed many times on a practically continuous basis by NASA’s Solar Dynamics Observatory. Transits of Mercury are rare, […]

A theoretical view of a distant world so far from our Sun that our Solar System appears barely brighter than the remaining stars in the sky. ( Caltech/R. Hurt (IPAC)) Pluto […]

Forget about alien nonsense. The Universe as it actually is doesn’t need any embellishments to be interesting. In our Solar System, the planets, moons, asteroids, comets and other masses are […]

Our Universe is 13.8 billion years old, and our Sun formed about 2/3rds of the way through. Here’s what came before it. When it comes to the great cosmic question of […]

If you think that the Moon is only good for reflecting sunlight, you’ve got another think coming. To human eyes, the Moon is the second brightest visible object, trailing only the […]

Is there life beyond Earth, even in our Solar System? This mission might be humanity’s best hope of finding it. The biggest question facing humanity might be, “Does life exists beyond […]

In 1789, William Herschel discovered this unique moon around Saturn. 230 years later, its secrets are more promising than ever. Today marks the 230th anniversary of the discovery of Enceladus, one […]

And one of our planets has the orbiting moons to prove it. Despite the dangers posed to planet Earth by a comet or asteroid strike, our Solar System is actually an […]

What makes Uranus and Neptune-like worlds so fascinating? If you only knew. What do we really know, and what mysteries are left to solve, about the outer worlds of our Solar […]

And it’s not because of leap seconds; it’s a fundamental property of most days. Human beings, in marking the passage of time, account for each day equally: with 24 hours. One […]

A case for looking beyond the planetary scientist’s (or even the astronomer’s) definition. Ever since 2006, when the International Astronomical Union (IAU) officially defined the term planet — introducing the term ‘dwarf […]

The summer solstice is the longest day of the year, but doesn’t have the earliest sunrise or the latest sunset. Here’s why. The length of a day on planet Earth might […]

It’s where Earth’s axial tilt with respect to the Sun is most extreme. Here are the consequences. Today is June 21st, 2019: the day of the solstice. Although there are […]

It’s rare but spectacular when the Moon passes in front of another planet. Here’s how to see it. From our perspective on Earth, the night sky appears virtually unchanged with the […]

Earth wasn’t the only potentially habitable planet in the early Solar System. What happened to Mars? If you could travel back in time to the early stages of the Solar System, […]

If you’re careful enough, you can learn more about the Solar System than you ever imagined. This year, on March 20th, the full Moon will illuminate the night sky. With […]