Starts With A Bang!

The Universe is out there, waiting for you to discover it.

Discovering the Earth from Space

"You see, every astronaut aboard the International Space Station has the opportunity to experience our world from a vantage point some 300 miles (500 km) above it, taking in sights that are alien to all but a few of us. But some people have gotten incredibly creative, and captured some wonders — both natural an artificial — that far exceed anything our imaginations could have cooked up."

Sometimes, to best view the wonders of Earth, you need to leave it. Check out this incredible gallery of some amazing phenomena originating from Earth, from a perspective most of us will never experience!

The Physics of a New Generation

"What’s even better? The new Fermilab experiment, E989, should be capable of determining the magnitude of the anomaly, if it’s really a deviation from the Standard Model, to somewhere between 7 and 8σ! In other words, while all the world’s eyes have been on the Large Hadron Collider and its search for the Higgs (and potentially, new particles), the first true advance beyond the Standard Model may come from an experiment that few people pay attention to and a small group of theorists that have painstakingly calculated upwards of 12,000 corrections to the muon’s g factor."

Has particle physics taken us beyond the Standard Model at long last? For all you g-2 fans out there! 

Five Reasons We Think Dark Matter Exists

"Modifying the theory of gravity is no easy game. We have fantastically precise measurements of gravity’s influence on objects throughout our solar system which fit precisely within the current understanding of gravity from General Relativity (a fact that underpins the precision of modern GPS). If you want to change the theory of gravity, you have to preserve its behavior as we’ve already measured it in the solar system."

When you hear about dark matter, you very likely put it up there with string theory in the pantheon of “well, that’s a nice idea, now call me when you find it” style of scientific ideas. After all, direct detection of dark matter has proved elusive, despite many arduous experiments designed specifically to find it. Yet we continue to look, convinced that it exists. Why? Amanda Yoho has the top five reasons!

Messier Monday: The Butterfly Cluster, M6

"The orange one may be the brightest, but even a small amount of magnification shows the others shining brilliantly alongside it.

Messier often described stars as “small,” meaning faint, indicating that they appeared small and low-in-brightness in the optics of his own telescope. But these stars are only faint as seen from Earth; in reality, they’re huge and brilliant, even compared to our own Sun!”

What’s higher than a butterfly in the sky? The butterfly cluster, 1600 light-years “high”! Happy #MessierMonday, all!

The Dumbest Sign in History

"This is one of the most bizarre signs I have ever encountered. The sign is comical in itself: stick figure rides up the escalator and bumps his head on a hanging sign, the impact causing VIOLENT RED RAYS OF PAIN. Beware! All is well and good until, armed with a newfound caution, you look around for the offending object and realize that IT’S A SIGN ABOUT THE SIGN ITSELF."

The dumbest sign in internet history: a sign warning you against hitting your head on the sign itself.

Why didn’t the Universe collapse into a black hole?

"And yet, that very much describes the Universe we have, which didn’t collapse immediately and which didn’t expand too rapidly to form complex structures, and instead gave rise to all the wondrous diversity of nuclear, atomic, molecular, cellular, geologic, planetary, stellar, galactic and clustering phenomena we have today. We’re lucky enough to be around right now, to have learned all we have about it, and to engage in the enterprise of learning even more: science."

With some 10^90 particles in the observable Universe, even stretched across 92 billion light-years today, the Universe is precariously close to recollapsing. How, then, is it possible that back in the early stages after the Big Bang, when all this matter-and-energy was concentrated within a region of space no bigger than our current Solar System, the Universe didn’t collapse down to a black hole? Not only do we have the explanation, but we learn that even if the Universe did recollapse, we wouldn’t get a black hole at all!

The greatest supernovae that no one ever saw

"For a long time, we thought this event, estimated to have occurred in 1680, was the Milky Way’s most recent supernova. But remember the following:

-We’re some 25,000 light-years from the galactic center,

-Supernovae occur about once-per-century in galaxies,

-We haven’t seen a supernova since 1604, and

-We were able to find one only 11,000 light-years away that occurred since that 1604 event.

Are there others that occurred since 1680? Up until relatively recently, we would have said “quite possibly,” but we wouldn’t have been sure.”

Did you know the Milky Way had a supernova go off in it as recently as the 1860s?!

How the Universe grew up… and stopped.

"You might think that this means that the overdense regions will grow unabated, while the underdense regions will shrink, giving up their matter to the denser regions, which are superior at attracting it.

But this intuition greatly oversimplifies things. In reality, when the Universe is dominated by radiation, matter tries to collapse under the force of gravity, but the photon pressure very effectively pushes back outwards with an almost identical force. In reality, the growth is very slow; so long as the radiation density is greater than the matter density, it’s practically negligible. If you have a region of space that starts out 0.001% denser than average — a fairly typical density fluctuation — it won’t become 0.002% denser than average for around 10,000 years, an eternity in the young Universe!”

There was once a time when there were no stars, no galaxies, and no groups or clusters. These all formed, so at some point, the Universe was able to build these structures where there were none before. But today, everything that isn’t already gravitationally bound to itself never will be. How did we go from a perfectly uniform Universe to an almost perfectly uniform one, to one with stars, galaxies, and clusters, to one that won’t result in any new gravitationally-bound structures anymore? The physics of gravitational growth (and its end); a fascinating story.

The Smallest Possible Scale in the Universe

"It was in fact Heisenberg who first suggested that the divergences in quantum field theory might be cured by the existence of a fundamentally minimal length, and he introduced it by making position operators non-commuting among themselves. Just as the non-commutativity of momentum and position operators leads to an uncertainty principle, the non-commutativity of position operators limits how well distances can be measured."

Yes, it’s true that quantum physics from measuring a property such as length or distance to an arbitrary accuracy, but does that necessarily mean that there *is* a fundamentally “smallest” scale to the Universe? One of physics’ great open questions for millennia is still relevant, and Sabine Hossenfelder has a great exploration of it here!