Cosmic Perspectives from Amid the Stars:
Astronomy Blog

The Solar System—the gravitational system composed of the Sun and everything that orbits it—is like our local neighborhood in space. Nearly everything within the influence of the Sun’s gravity shares a common origin. But how did it all start? How did the Solar System form?

The universe is expanding. Not only that, but its expansion seems to be speeding up. For that to happen, there must be something adding energy to the universe’s expansion. The problem is, we don’t see anything like that. We know there must be some unknown form of energy out there, but we have yet to understand what it is. We call this mysterious force dark energy.

Gravity is the universal attraction of any two objects with mass. It is the reason we experience weight and stay firmly on the ground. But it’s also so much more than that. Nearly any interaction or process in outer space—from the tides on Earth to the formation of stars to the spirals of galaxies to the inescapable event horizon of black holes—can be traced back to gravity as a cause, whether direct or indirect. If our universe is a sculpted work of art, then gravity is the

We live in a universe that is 13.8 billion years old. But how much longer does it have left? And how will the universe meet its ultimate end? We can’t yet know for sure how the universe will end, but we can use our current understanding of the cosmos to predict what might happen.

Everything you can see and touch is made up of matter. Matter is a fundamental building block of the universe. But, somehow, 85% of it is missing. When we look at all the stars, planets, asteroids, and more in a galaxy, we can calculate its total mass. But mass is the source of gravity. And when we measure the gravitational effects of that same galaxy, we get an entirely different mass. The two methods of determining the mass of a galaxy are at odds with one another.

One of the most simultaneously perplexing and fascinating topics in astrophysics is undoubtedly the black hole. They’re holes in the very fabric of space and are famous for how they defy all conventional logic. And, most defining, once something goes in, it’s never coming out. To understand a black hole, you first have to understand gravity. We know the Earth has gravity, but actually, all objects with mass have it as well. The more massive and denser an object is, the more g