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 […]

Some galaxies might not have any dark matter. Here’s why you should care. There are two assumptions that everyone makes about the Universe for extremely good reasons, but they might not […]

A vacuum cleaner is the wrong picture. Time to bust that myth. There are no classes of object in our Universe more extreme than black holes. With so much mass present […]

At the core of the largest star-forming region of the Local Group sits the biggest star we know of. Mass is the single most important astronomical property in determining the lives […]

Two independent techniques give precise but incompatible answers. Here’s how to resolve it. If you didn’t know anything about the Universe beyond our own galaxy, there are two different pathways you […]

An entire Universe of possibilities await stars like our own, even after they run out of fuel. One of the most profound rules in all the Universe is that nothing lasts […]

Has the mystery really been solved? Doubtful. The real science goes much deeper. For perhaps the last year or so, a small galaxy located not too far away has captivated the […]

There aren’t any holes in the Universe at all. What actually exists is far more interesting. Somewhere, far away, if you believe what you read, there’s a hole in the […]

If we could see in three dimensions instead of two, we’d never have thought otherwise. Perhaps the most famous sight of a dying star is the Ring Nebula, discovered in […]

Imagine how different our understanding of the Universe would be if we saw nothing beyond the Milky Way. Our corner of the Universe was gifted with a plethora of bright, nearby […]

Even the best science imaginable has its limits. In terms of ambition, it’s hard to ask for more than to know absolutely everything there is to know about the Universe. That’s […]

A 1060-hour amateur exposure of a nearby galaxy does what even Hubble couldn’t do. The Universe is full of astronomical wonders, but it’s up to humanity to observe and analyze them. […]

Some claim that inflation isn’t science, but it sure has made some incredibly successful scientific predictions. So, you want to know how the Universe began? You’re not alone. Every other […]

Depending on how you measure it, there are two different answers that could be right. If you want to see what’s out there in the Universe, you first have to be […]

The world’s greatest observatory can go no further with its current instrument set. The Hubble Space Telescope has provided humanity with our deepest views of the Universe ever. It has […]

It’s made up of scores of telescopes at many different sites across the world. But it acts like one giant telescope. Here’s how. If you want to observe the Universe more […]

How fast is the Universe expanding? The results might be pointing to something incredible. If you want to know how something in the Universe works, all you need to do […]

Our Sun will someday run out of fuel. Here’s what it will look like when that happens. The fate of our Sun is unambiguous, determined solely by its mass. If all […]

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 […]

Now that we’ve seen our first one, we want more, and we want them better. Here’s how to get there. To resolve any astronomical object, you must achieve resolutions superior to […]

It’s the technique, from the Event Horizon Telescope, that brought us a black hole’s image. Here’s how it works. The Event Horizon Telescope has accomplished what no other telescope or telescope […]

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 […]

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 […]