Starts With A Bang podcast

All throughout the Universe, galaxies exist in a great variety of shapes, ages, and states. Today's galaxies come in spirals, ellipticals, irregulars, and rings, all ranging in size from behemoths hundreds or even thousands of times larger than the Milky Way to dwarf galaxies with fewer than 0.1% of the stars present here in our cosmic home. But at the centers of practically all galaxies, particularly the large ones, lie superm...

Up until the early 1990s, we didn't know what sorts of planets lived around stars other than our Sun. Were they like our own Solar System, with inner, rocky planets close to our star and large, giant worlds farther away? It turned out that exoplanetary systems come in a great variety of configurations: with planets of all sizes, masses, and distances from their parent stars. But some configurations are more common than others.

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Happy new year, everyone, and with a new year comes a spectacular new podcast! We normally cover an intricate and underappreciated aspect of astrophysics on the podcast, but I had the opportunity to bring on a true expert in the field of quantum computing and just couldn't pass it up.

You've likely heard a lot of noise about quantum computers and the benefits that they're poised to bring, with buzzwords like "P=NP,...

It's hard to believe, but it was only back just a year and a half ago, in mid-2022, that we had yet to encounter the very first science images released by JWST. In the time that's passed since, we've gotten a revolutionary glimpse of our Universe, replete with tremendous new discoveries: the farthest black hole, the most distant galaxy, the farthest red supergiant star, and many other cosmic record-breakers.

What is it ...

You might not think about it very often, but when it comes to the question of "how old is a star that we're observing," there are some very simple approximations that we make: measure its mass, radius, temperature, and luminosity (and maybe metallicity, too, for an extra layer of accuracy), and we'll tell you the age of this star, including how far along it is and how long we have to go until it meets its demise.

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Out there in the Universe, there's a whole lot more than simply what we find in our own Solar System. Here at home, the largest, most massive object is the Sun: a bright, hot, luminous star, while the second most massive object is Jupiter: a mere gas giant planet, exhibiting a small amount of self-compression due to the force of gravity.

But elsewhere in the Milky Way and beyond, numerous classes of objects exist in that murk...

When we look at our nearby Universe, it's easy to recognize our own galaxy and the other large, massive ones that are nearby: Andromeda, the major galaxies in nearby groups like Bode's Galaxy, the group of galaxies in Leo, and the huge galaxies at the cores of the Virgo and Coma Clusters, among others. But these are not most of the galaxies in the Universe at all; the overwhelming majority of galaxies are small, low-mass dw...

We all knew, if Einstein's General Theory of Relativity were in fact the correct theory of gravity, that it would only be a matter of time before we detected one of its unmistakable predictions: that all throughout spacetime, a symphony (or cacophony) of gravitational waves would be rippling, creating a cosmic "hum" as all of the moving, accelerating masses generated gravitational waves. The intricate monitoring of ...

Sometimes, it's hard to believe we've come as far as we have, scientifically, in such a short period of time. We only began accumulating the first very strong evidence for supermassive black holes during the 1990s, and yet here we are, less than 30 years later, studying them, their effects, and their environments all across the Universe: from the present day to less than 1 billion years after the Big Bang.

We now believe th...

We have a pretty good idea of both what's in our Universe and how it grew up. But it's only because we have several different, completely independent lines of evidence that point to the same consensus picture that we actually believe that our Universe is 13.8 billion years old and composed of a mix of normal matter and radiation, but is dominated by dark matter and dark energy on the largest of cosmic scales.

In particula...

One of the most exciting possibilities for life beyond Earth doesn't require us going very far. While Mercury and the Moon have no atmosphere and Venus is an inferno-esque hellscape, Mars offers a tantalizing possibility for a new line of life, independent of Earth, here in our Solar System. With the same raw ingredients and more than a billion years of a watery, wet past, Mars could have had, or might even still have today, ...

Back in the 1990s, observations of type Ia supernovae were the key data set that led astronomers to conclude that the Universe's expansion was accelerating, and some new form of energy, now known as dark energy, was permeating the Universe. Over the past ~25 years, those observations have gotten so good that we now have a tension within the expanding Universe, as different methods of measuring the expansion rate yield two dif...

When stars are born, they can come with a wide variety of masses. But there are only a few ways that stars can die, and only a few types of remnants that can be left behind: white dwarfs, neutron stars, and black holes. Neutrons stars and black holes are most frequently created from core-collapse supernova events: the deaths of massive stars. Somewhere, even though we're not sure exactly where it is, there's a dividing line between...

One of the great advances of 20th and 21st century science has been, for the first time to show us two things: how the Universe began and what the Universe looks like today. The modern frontier is all about the in-between stages: how did the Universe grow up? How did it go from particles to atoms to the first stars and galaxies to the modern Milky Way, Local Group, and Universe-at-large? It's a question that, the more deeply we ans...

For life on Earth, there's no more important source of energy than the Sun; without it, it's doubtful that life would have arisen on Earth, and it certainly wouldn't have evolved to give rise to the wild diversity of biological organisms seen today. But the Sun is more than just a constant source of heat and light; it also emits particles, and there's a darker side to that activity: flares, coronal mass ejections, and the threats t...

For a cosmologist like me, "cosmic dust" is a thing that's in the way, confounding our data about the pristine Universe, and it's a thing to be understood so that it can be properly subtracted out. But the old saying, that "one astronomer's noise is another astronomer's data," proves to be more true than ever with cosmic dust, as how it's produced, where it came from, and how it comes together to form planets, molecules, and eventu...

The supermassive black holes at the centers of galaxies is a tremendously interesting area of research, advancing rapidly over the past few years. While most of these observations focus on either high-energy or radio emissions from them, there's a recent push to see what these objects are doing in other wavelengths of light, as well as how they vary in time.

Once, it was thought that supermassive black holes would become "activated...

All throughout the Universe, we see stars and galaxies everywhere we look. But as we look to greater and greater distances, we're only seeing the light that's the easiest to see: the ones from the brightest, most visible objects. But the most numerous objects of all are exactly the opposite: less luminous, smaller, and lower in mass. How can we hope to find and catalogue them all if they're the hardest ones to find?

The answer lies...

Although it seems like a long time ago, it was as recent as the early 1990s that we had no idea whether planets in the Universe were universal, common, uncommon, or even exceedingly rare. While certain data sets once seemed to indicate that practically every star in the Universe had planets around it, we now know that isn't true at all. Many stars, perhaps even most of them, have planets, but plenty of others don't. In addition, th...