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General Relativity
When you hear ‘quantum,’ you probably think of splitting everything into discrete, indivisible chunks. That’s not necessarily right. If you want to learn what the Universe is made out of […]
It might seem puzzling, in a Universe bound by the speed of light, that this could be true. Here’s the science behind it. If you look out into the distant Universe, […]
There are a lot of unsolved mysteries in the Universe, but dark energy is the most confusing. Here’s why. The majority of the energy in our Universe went completely undiscovered until […]
If you think about the way a gravitational wave detector works, you might encounter a paradox. Here’s the solution. One of the greatest scientific achievements in all of human history […]
100+ years ago, General Relativity came along, and Einstein gave the Universe a cosmological constant. Here’s why that was a mistake. Back in the 17th century, Isaac Newton put forth the […]
It’s been spectacularly confirmed by observation, but theoretically, it couldn’t have been any other way. If the Sun were to spontaneously cease emitting light, we wouldn’t know about it for about […]
The origin story for our Universe got a major revision nearly 40 years ago. Time to catch up. 13.8 billion years ago, all the matter and energy contained within our Universe […]
Traveling interstellar distances in human lifetimes is an amazing dream, but it won’t ever be achieved like this. For centuries, ever since we realized that every star we can see in […]
In the mid-20th century, ‘physical cosmology’ was considered an oxymoronic joke. Today, it’s Nobel-winning science. Imagine you wanted to know everything you could about the Universe. You’d want to find […]
It’s much more complex a question than dividing its mass by the volume of the event horizon. If you want to get a meaningful answer, you have to go deep. If […]
Or, quite possibly, is it more complex than either one of those scenarios? If there’s one lesson that humanity should have learned from the 20th century, it’s this: the Universe […]
A recent headline claimed they could. But if gamma-rays are just a form of light, don’t they have to travel at light-speed? There’s an ultimate speed limit in the Universe: […]
Even though it was the crowning achievement of Einstein’s career, he was only a small part of the full story. If you were a physicist in the early 20th century, there […]
As soon as you start thinking about energy and gravity, you’ll realize the need to go beyond it. When it comes to a science like physics, theoretical expectations must always be […]
Maybe, but that probably doesn’t mean what you think it does. Of all the unsolved puzzles in the Universe, perhaps the most confounding is the dark matter problem. If we look […]
You might think that we live in a three dimensional Universe based on space alone. But you cannot leave time out of it. If you were asked to describe how you […]
Black holes are regions of extreme gravity, but dark matter barely interacts at all. Do they play well together? Black holes are some of the most extreme objects in the […]
When the Universe expands, photons redshift to longer wavelengths and lower energies. So where does that energy go? Imagine the ultimate version of a toy Universe: it’s expanding, it’s full of […]
A star orbiting past our galaxy’s supermassive black hole offered a chance to test relativity as never before. The supermassive black hole at the center of the Milky Way is the […]
Particle physics is everywhere, even in the palm of your hand. When you hold out your palm and point it towards the sky, what is it that’s interacting with your hand? […]
And does it require the idea of ‘negative gravity’ in order to work? The biggest question that we’re even capable of asking, with our present knowledge and understanding of the Universe, […]
It’s very different from the colloquial meanings of “true-and-false” or “right-and-wrong.” In many ways, the human endeavor of science is the ultimate pursuit of truth. By asking the natural world […]
General Relativity has nothing to do with light or electromagnetism at all. So how to gravitational waves know to travel at the speed of light? There are two fundamental classes of […]
The quest for a quantum theory of gravity is the holy grail of physics. Here’s why it’s murkier than anyone expected. If you want to fully describe how the Universe […]
The Planck length is a lot smaller than anything we’ve ever accessed. But is it a true limit? If you wanted to understand how our Universe operates, you’d have to examine […]
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 […]
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 […]
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 […]
When we think about the birth of the Universe, was time already in place? When we look at the Universe today, we know with an extraordinary amount of scientific certainty that […]
The solar eclipse of May 29, 1919, was the nail in the coffin of a Newtonian Universe. On May 29, 1919, the world changed forever. For hundreds of years, Isaac […]