Category: science

This Is Why ‘Physical Cosmology’ Was Long Overdue For The 2019 Nobel Prize

“It is a spectacular fact of modern science that the predictions of theoretical cosmology have been verified and validated by ever-improving observations and measurements. Even more remarkably, when we examine the full suite of the cosmic data humanity has ever collected, one single picture accurately describes every observation together: a 13.8 billion year old Universe that began with the end of cosmic inflation, resulting in a Big Bang, where the Universe is comprised of 68% dark energy, 27% dark matter, 4.9% normal matter, 0.1% neutrinos, and a tiny bit of radiation with no spatial curvature at all.

Put those ingredients into your theoretical Universe with the right laws of physics and enough computational power, and you’ll obtain the vast, rich, expanding and evolving Universe we have today. What was initially an endeavor of just a handful of people has now become the modern precision science of cosmology. In the middle of the 20th century, legendary physics curmudgeon Lev Landau famously said, “Cosmologists are often in error but seldom in doubt.” With the 2019 Nobel Prize in Physics going to Jim Peebles, perhaps the world will recognize it’s long past time to retire Landau’s quote. We may live in a dark Universe, but the science of physical cosmology has shed a light on it like nothing else.”

I see you out there. You, the person who’s skeptical of dark matter. You, the one who thinks dark energy must be an enormous cosmological mistake. You, who thinks the Big Bang is a hoax and that inflation is a band-aid for a failing theory. And you, especially you, the one who derides cosmology as a pseudoscience, quoting Landau like his more-than-60-year-old quote is still relevant.

Physical cosmology is a real, robust science. It’s not only my field, but my grand-advisor, Jim Peebles, won the 2019 Nobel Prize for his work pioneering it. Come learn what all the fuss is really about.

Did Our Universe’s Structure Grow From The Top-Down Or From The Bottom-Up?

“A century ago, we didn’t even know what our Universe looked like. We didn’t know where it came from, whether or when it began, how old it was, what it was made out of, whether it was expanding, what was present within it. Today, we have scientific answers to all of these questions to within about 1% accuracy, plus a whole lot more.

The Universe was born almost perfectly uniform, with 1-part-in-30,000 imperfections present on practically all scales. The largest cosmic scales have slightly larger imperfections than the smaller ones, but the smaller ones are also substantial and collapse first. We likely formed the first stars just 50-to-200 million years after the Big Bang; the first galaxies arose 200-to-550 million years after the Big Bang; the largest galaxy clusters took billions of years to get there.

The Universe is neither top-down nor bottom-up, but a combination of both that implies it was born with an almost scale-invariant spectrum. With future survey telescopes such as LSST, WFIRST, and the next-generation of 30-meter-class ground-based telescopes, we’re poised to measure galaxy clustering as never before. After a lifetime of uncertainty, we can finally give a scientific answer to understanding how our Universe’s large-scale structure came to be.”

In a top-down scenario, the Universe would form structures on large scales first, then fragment to form individual galaxies. In a bottom-up scenario, the Universe forms tiny structures first, which then collect and clump under their own gravity to bring about a Universe rich in large-scale structure. So, which one is the Universe we have? 

As is often the case, the answer is much more complex than just one of these two possibilities. Come get the full story today.

Advances Vs. Consequences: What Does The 21st Century Have In Store For Humanity?

“We now live in a time where the actions of a small group of people ⁠— whether through malicious or benign intentions ⁠— are capable of leading to global catastrophe. It’s not just climate change or the threat of nuclear war that hangs over us; it’s a slew of facts.

It matters that a mass extinction is occurring right now: we’re destroying this planet’s proverbial “book of life” before we’ve even read it.

It matters that computers are permeating ever-increasing facets of our life, as humanity’s recently rising electricity use (after a plateau earlier this decade) is almost entirely due to new computational uses, like cryptocurrencies and blockchain.

It matters that the population is greater than ever before, as managing and distributing the edible food and drinkable water we produce is a greater challenge than ever before.”

Do you like big, sweeping conversations that tackle the biggest existential questions facing our species today? Looking to the larger picture, of humanity’s future on Earth, scientist Martin Rees has written a book detailing the challenges facing our civilization in the 21st century, and is about to deliver a public lecture on the topic of navigating the course that could lead us into a true golden age… or to ruin.

I’ll be live-blogging the lecture with many thoughts to add, and I hope you’ll join me in enjoying it!

Was Dark Matter Really Created Before The Big Bang?

“So if that’s what the observational data points towards, what can we say about where dark matter comes from? A recent headline that made quite a splash claimed that dark matter may have originated before the Big Bang, and many people were confused by this assertion.

It might seem counterintuitive, because the way most people conceive of the Big Bang is as a singular point of infinite density. If you say the Universe is expanding and cooling today, then you can extrapolate it back to a state where all the matter and energy was compressed into a single point in space: a singularity. This corresponds to an initial start time for our Universe — the beginning of our Universe — and that’s the Big Bang.

So how could something that exists in our Universe, like dark matter, have originated before the Big Bang? Because the Big Bang wasn’t actually the beginning of space and time.”

Last month, a paper came out claiming that dark matter may have been created before the Big Bang. Although it might sound implausible, it’s absolutely a possibility that we cannot rule out, although it might be an idea that’s extraordinarily difficult to test when we compare it up against the other options. We have to keep every scenario that hasn’t been ruled out in mind, and understand that despite all we don’t know about dark matter, there’s a ton of indirect evidence brought to us by the full suite of observations at our disposal.

Could dark matter have been created before the Big Bang? Yes, but three other possibilities are maybe even more viable. Come find out why today.

This One Experiment Reveals More About Reality Than Any Quantum Interpretation Ever Will

“So you fire a beam of electrons at a barrier with two slits in it, and look at where the electrons arrive on the screen behind it. Although you might have expected the same result you got for the pebble-experiment earlier, you don’t get it. Instead, the electrons distinctly and unambiguously leave an interference pattern on the screen. Somehow, the electrons are acting like waves.

What’s going on? Are these electrons interfering with each other? To find out, we can change the experiment again; instead of firing a beam of electrons, we can send one electron through at a time. And then another. And then another. And then another, until we’ve sent thousands or even millions of electrons through. When we finally look at the screen, what do we see? The same interference pattern. Not only are the electrons acting like waves, but each individual electron behaves as a wave, and somehow manages to create an interference pattern only by interacting with itself.”

It’s been around for more than 200 years, but the double-slit experiment remains one of the best concrete ways to probe the quantum nature of reality. By tinkering with the apparatus and how it’s set up, you can determine how nature behaves under a wide variety of conditions, and wow, is it ever surprising and unintuitive. Instead of arguing over unanswerables like which philosophical interpretation is most pleasing, why not look at something real? 

These are the questions we’re actually answering, and you won’t find anything more profound than the answers that nature provides us with.

Every single softeng lab in Greece be like

Photo

nemfrogfilms:

Interference of photons. 1959. Physical Science Study Committee.

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