Category: SCIENCE

Even in the very early Universe, there were heavy, supermassive black holes at the centers of galaxies. How did they get so big so fast?

Some of the most impressive objects in our Universe are supermassive black holes. Weighing in at millions, billions, or even tens of billions of solar masses, they’re the heaviest single objects contained within the known Universe. One of the great problems in modern astrophysics is the open question of how they formed and grew up, and in many ways, the dawn of the JWST era has only intensified that problem. Looking back towards the dawn of time, we find supermassive black holes existed even very early on, reaching hundreds of millions or even a billion solar masses by the time only a few hundred million years had elapsed: when the Universe was just a few percent of its current age.

Was it just plain old astrophysics that led to their creation, with nothing special happening to seed them? Or is it possible that the Universe was actually born with “seed” black holes that would rapidly grow into the supermassive behemoths we observe much later on? That’s what Predrag Branković wants to know, writing in to inquire:

“Did you see this [article]? Is it possible that those…

A longstanding mismatch between theory and experiment motivated an exquisite muon measurement. At last, a theoretical solution has arrived.

As a scientist, the most exciting moments in your professional life arise when you work hard to get a result, and — no matter how hard you try to understand it — it simply doesn’t match up with your expectations. For theorists, that moment comes when you derive a result that conflicts with what’s experimentally and observationally known to be true. For experimentalists, that moment arrives when you make a measurement that defies a theorist’s predictions. But those moments can go one of two ways: either they can be harbingers of a scientific revolution, exposing a crack in the foundations of science, or they can simply be the result of a previously undiscovered error, on either the theoretical or experimental ends.

Perhaps the greatest quest in particle physics, for perhaps half a century now, has been to find a discrepancy between theory and experiment when it comes to the Standard Model. One fascinating place to look is at the magnetic moment of the muon: a heavy, unstable relative of the electron. A Fermilab experiment known as “muon g-2″ has revealed a discrepancy between theory and…

The passage of time is something we all experience, as it takes us from one moment to the next. But could it all just be an illusion?

One of the most important aspects of physics, or of any science in general, is to always muster up the greatest challenge to the leading physical theories you can. You can challenge prior results, you can challenge the methods used to obtain them, you can concoct new tests in new regimes of potential applicability, and you can even challenge the assumptions underlying them. When it comes to our understanding of the Universe, we believe that we inhabit a four-dimensional “fabric” known as spacetime, with three spatial dimensions and one time dimension, all of which are inextricably woven together.

All of this assumes, of course, that time itself is a real thing: physically real, and fundamental in nature. But are these assumptions necessarily true? Is there any way possibly around them, and could time instead be merely an illusion, albeit a convincing one? That’s what Dave Drews wants to know, as he writes in to ask:

“We’ve all heard the philosophical question, ‘If a tree falls in a forest and no one is around to hear it, does it make a sound?’ Some people think time is an illusion, a construct of human minds and experience. If that’s true, then if there were no sentient beings…

Adams was infamously scooped when Neptune was discovered in 1846. His failure wasn’t the end, but a prelude to a world-changing discovery.

Perhaps its human nature to want to only think positive thoughts about our heroes. With the 2024 Olympics about to begin, we hope for a clean victory for our favorite beloved athletes; we don’t want our sports heroes to cheat or use performance-enhancing drugs. We want our humanitarian and political heroes to be kind, generous, and have that spirit of self-sacrifice for the greater good in all that they do; we don’t want them to be associated with any sordid scandals or criminal activity. And in science, we tend to glorify the thoughts and processes of all of our scientific heroes; we bristle at the notions that they’d ever commit the greatest of all scientific sins: the sin of having been wrong.

But science is not an endeavor one undertakes all by themselves, but rather as part of a worldwide community. And being wrong is not a death sentence, but rather is often a stepping-stone to an even greater success. The common mantra, “Once a failure, always a failure,” couldn’t be further from the truth when it comes to real life. While it’s true that even our greatest scientific heroes had their flaws, some…

As the Sun ages, it loses mass, causing Earth to spiral outwards in its orbit. Will that cool the Earth down, or will other effects win out?

One of the most important rules in all of physics is the equivalence between mass and energy, first put forth by Einstein over 100 years ago: E = mc². Perhaps most famously, this is the process at play inside all stars like the Sun: where light elements get fused into heavier ones through nuclear reactions, but where the products of the reactions are less massive than the reactants that go into them. The remaining mass gets converted into energy, where it provides light and heat to the greater Universe, including to planets like Earth. It’s these reactions, powered by nuclear fusion, that are at the heart of all Sun-like stars, with the conversion of mass into energy responsible for ultimately making the stars (and Sun) shine.

But the Earth also relies on the Sun’s gravitational influence to keep it in orbit, and as the Sun loses mass, that’s going to cause Earth’s orbit to change. When our orbit changes, will the climate change as well? And if so, how? That’s the question of Corina Gherasimescu, who inquires:

“I came across an old article… about the Sun…

Just 13.8 billion years after the hot Big Bang, we can see objects up to 46.1 billion light-years away. No, this doesn’t violate relativity.

If there’s one rule that most people know about the Universe, it’s that there’s an ultimate speed limit that nothing can exceed: the speed of light in a vacuum. If you’re a massive particle, not only can’t you exceed that speed, but you’ll never reach it; you can only approach the speed of light. If you’re massless, you have no choice; you can only move at one speed through spacetime: the speed of light if you’re in a vacuum, or some slower speed if you’re in a medium. The faster your motion through space, the slower your motion through time, and vice versa as well. There’s no way around these facts, as they’re the fundamental principle on which relativity is based.

And yet, when we look out at distant objects in the Universe, they seem to defy our common-sense approach to logic. Through a series of precise observations, we’re confident that the Universe is precisely 13.8 billion years old. The most distant galaxy we’ve seen so far is presently 32 billion light-years away, the most distant light we see corresponds to a point presently 46.1 billion light-years away, and galaxies beyond…

On a cosmic scale, our existence seems insignificant and inconsequential. But from another perspective, humans are completely remarkable.

On the scale of the Universe, humanity isn’t even a speck.

We’re each just a tiny, minuscule fraction of our own planet: Earth.

It would take nearly an Avogadro’s number of humans to equal Earth’s mass.

Earth is just one modest planet orbiting our Sun: one of ~400 billion stars within the Milky Way.

On the largest of cosmic scales, the Universe is expanding. But it isn’t all-or-nothing everywhere, as “collapse” is also part of the story.

One of the most remarkable revelations in our understanding of the cosmos is the fact that the Universe is expanding. Distant galaxies, on average, all appear to recede from us, with faster and faster recession speeds for galaxies that exist at greater distances. While individual objects and systems may be gravitationally bound together — stars and planets, galaxies, plus galaxy groups and clusters — the space between these structures is not only expanding today, but has been expanding for all 13.8 billion years of cosmic history, and will continue to expand indefinitely far into the future as well.

But is the expanding Universe truly an all-or-nothing proposition? Are there exceptions to the expanding Universe, and is “collapse” a scenario that’s been ruled out entirely? That’s the question plaguing the mind of Patreon supporter Brent Minder, who wants to know:

“Does the universe’s current state have to be all or nothing in terms of expanding or collapsing? Is there a theory that the universe is in a mid-state of collapse and expanse? That is: what if the…

There are many things that separate science from ideology, politics, philosophy, or religion. Follow these 10 commandments to get it right.

From the 10 biblical commandments to the first 10 amendments of the US constitution which comprise the Bill of Rights, there are many lists of governing rules that apply to our individual lives as members of civilized society. Yet for scientists, there are many other “best practices” we need to constantly keep in mind as we investigate the natural phenomena around us, from the subatomic world to the cosmic realm and everything in between. Although we often talk about following the scientific method, we rarely lay out anything more than a rough procedure to follow when it comes to conducting science itself.

Sure, it’s important to have ideas, formulate hypotheses, and then devise methods to test those hypotheses, gather results, and draw conclusions that either support and validate or contradict and refute those hypotheses: the rough outline of how science is performed. But there’s so much more that goes into being a scientist that gets to the very core of what it means to investigate the origin, nature, and root cause of any phenomena that we dare to observe, design experiments around, and measure. Here, without further ado, are the 10…

Sure, there’s less daylight during Winter than Summer, as your hemisphere is tilted away from the Sun. But darkness goes deeper than that.

If you take a look outside these days, if you live where most of Earth’s humans do — in the northern hemisphere — you’re likely to see something completely expected: how bright it is compared to six months ago, in the dead of winter. It’s not just that the days are longer and the nights are shorter, which is what’s seasonally true in the Summer as opposed to Winter, but there are many other ways that the Summer is brighter than the Winter. These include:

• the darkest part of the sky, as seen during the day, is less dark in the Summer than in the Winter,
• the sky, just after sunset, gets darker more quickly in the Winter than in Summer,
• and that the darkest part of the night, in Winter, is both darker and lasts for much longer as compared to Summer.

Sure, the Earth rotates on its axis, and whether your hemisphere (north or south) is tipped towards or away from the Sun determines whether it’s Summer or Winter. While that accounts for the extended daylight hours of Summer and the shortened daylight hours of Winter, that doesn’t…