It might be the biggest conundrum facing cosmology today. But perhaps it’s not a controversy; it might be a clue. https://soundcloud.com/ethan-siegel-172073460/starts-with-a-bang-44-the-expanding-universe/ One of the biggest conundrums in the Universe surrounds the […]

Xenon-124 isn’t stable, and the direct detection of its decay could lead us to an even greater prize. Our Universe is old: 13.8 billion years old, to be precise. Many of […]

Our outer Solar System, from Jupiter to Neptune, isn’t unique after all. In the early 1990s, scientists began detecting the first planets orbiting stars other than the Sun: exoplanets. The easiest […]

If a star spins and then collapses, what happens to its angular momentum? The most common way to form a black hole in the Universe is to have a massive […]

There was a first molecule, and we found one just like it. But there’s a big difference. The Universe’s first molecule is found at last! That’s what the headlines have […]

We’ve put so much together about the Universe. Could it all come tumbling down? We’re always on the lookout for the next big thing, and even our best guesswork is often […]

And what do we still have left to learn? The original idea of a black hole goes all the way back to 1783, when Cambridge scientist John Michell recognized that a […]

The first image of an Event Horizon is here. Here’s what it means. Variety isn’t just the spice of life, but a natural consequence of living in our Universe. Gravitation, obeying […]

We’ve never seen an image of a black hole’s event horizon before. Here’s what we’re expecting, based on what we already know. For hundreds of years, physicists have hypothesized that the […]

Beyond the oceans boiling and the death of our Sun, Earth’s ultimate fate won’t be determined until far in the distant future. It took the Universe 13.8 billion years to create […]

When the Universe gives us clues, we ignore them at our own peril. When you approach the world scientifically, you seek to gain knowledge about how it works by asking it […]

If parallel Universes or the multiverse are real, we might someday encounter a visitor who hails from another one. Here’s what to do. There are a lot of things that are […]

We assume that life is ubiquitous in the Universe. But what if it’s just us? When it comes to the question of extraterrestrial life, humans optimistically assume the Universe is prolific. […]

If you think we’ve done a great job with planet-finding so far, just wait until you learn what’s possible with microlensing! When we think about finding planets in the Universe, […]

In all the Universe, there’s only one Earth. But can we find the other worlds that are like ours? Even though the ingredients for life have been confirmed to be practically […]

There is a fundamental difference between matter and antimatter. But not enough of one to explain our Universe. Our Universe is a vast and enormous place, and if there’s one […]

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 […]

If dark energy is causing the Universe to disappear, how can we still find and see ultra-distant stars and galaxies? In the 1920s, scientists discovered that the Universe was expandingbased […]

The visible light portion of the spectrum is tiny compared to the whole thing. Here’s what we’re missing. When you look at the Milky Way in visible light, you might see […]

LIGO and Virgo have now detected a total of 11 binary merger events. But exactly 0 were in the Milky Way. Here’s why. One of the most spectacular recent advances in […]

In order to reap the greatest rewards, we have to think big and invest big. One of these four missions will deliver like never before. When it comes to exploring the […]

Even if we don’t destroy ourselves, we always have the Universe to contend with. Wiping out all life on Earth is hard, but causing mass extinctions is easy. The 1991 eruption […]

Both effects could be responsible for a redshift. But only one makes sense for our Universe. In physics, like in life, there are often multiple solutions to a problem that […]

If you accept cosmic inflation and quantum physics, there’s no way out. The Multiverse is real. Look out at the Universe all you want, with arbitrarily powerful technology, and you’ll never […]

Yes, life exists in our Universe. No, that statement doesn’t equal science. Imagine you’ve encountered a natural phenomenon you want to understand better, but don’t have the tools to do so. […]

While the web of dark matter (purple) might seem to determine cosmic structure formation on its own, the feedback from normal matter (red) can severely impact galactic scales. Both dark […]

The ‘giant impact’ that led to Earth might not have been so giant, after all. A little over 4.5 billion years ago, our Solar System began to form. Somewhere in the […]

As more time passes since the Big Bang, more of the Universe comes into view. But how much? Even though it’s been billions of years since the Big Bang, there’s a […]

Gravity gets weaker as the distance squared. But gravitational waves only get weaker as the distance. Why? One of the things we often just accept about the world is that […]

Before we formed stars, atoms, elements, or even got rid of our antimatter, the Big Bang made neutrinos. And we found them. The idea of the Big Bang has captivated the […]